Aurora 4x
VB6 Aurora => Newtonian Aurora => Topic started by: Steve Walmsley on August 29, 2011, 09:00:45 AM
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I know I have been absent for a couple of weeks. Partially work-related but partially because I have been playing around with a variant of Aurora, which I will probably call Aurora FTL. This isn't a change to the main game, but an optional alternative that should be available in a few months, spare time permitting. The two major differences will be a Newtonian flight model and FTL instead of jump points. The latter is partially forced by the former because speeding up and slowing down at each jump point on long journeys would use so much fuel it would render it unplayable. I am working on the Newtonian element at the moment, which is a huge change to many parts of Aurora, and then I will move on to the new universe model. This is really an experiment because I am still not convinced that a newtonian game is playable but it's something I thought about many times and it has been suggested on here a lot. I decided that I may as well give it a go because if I don't I will always wonder if it was possible :). As a taster of the final game, here is a summary of the current changes to engine design and ship design in Aurora FTL.
Engines
The concept of Military Engine, Commercial Engine, Fighter Engine, etc has been removed and Hyper Drives have been removed. The five elements of engine design are now:
Engine Technology: As before, except the base values are different and those values are expressed in Meganewtons of thrust per HS of engine. One Meganewton (MN) is equal to the amount of net force required to accelerate a mass of one ton at a rate of one kilometre per second squared. For example, the Internal Confinement Fusion Drive has a rating of 2 MN per HS, so an unmodified size 5 engine would produce 10 MN of thrust.
Base Fuel Efficiency: This is similar to the old Fuel Efficiency, although it is now modified by other factors in engine design. The Base Fuel Efficiency is critical though and will be more important than in the past. It starts at 20 and additional technology levels will lower that figure. An Engine is rated in the number of litres of fuel per hour it consumes. This amount is derived from Engine Power x Fuel Efficiency. So an Engine with 10 power and a fuel efficiency of 12 would consume 120 litres of fuel per hour at full burn.
Engine Size: You can now select the size of engine from 1 HS to 50 HS. Larger engines are more fuel efficient so Fuel Efficiency is modified by 1 - (EngineHS / 100). In simpler terms, each HS of engine reduces fuel efficiency by 1%, so a size 10 engine reduces Base Fuel Efficiency by 10% and a size 25 engine reduces it by 25%.
Thermal Reduction: As before, this reduces the thermal signature of engines, which is equivalent to 10x thrust in MN.
Engine Power / Fuel Efficiency Modifiers: There are two new tech lines to research, called Max Engine Power Modifier and Min Engine Power Modifier. These establish the range within which you can change engine thrust from that provided by the base engine technology. Increasing thrust has a significant effect on fuel efficiency and decreasing thrust can provide huge savings in fuel efficiency. Power can be increased by up to 300% of normal and decreased to 10% of normal if you have the prerequsite techs. The dropdown on the design window will have options from the minimum possible to the maximum possible in 5% increments. So 40%, 45%, 50%, 55% ...... 180%, 185%, etc. Each engine power modifier percentage is accompanied by a fuel efficiency modifier, based on the formula Fuel Efficiency Modifier = (10 ^ Engine Power Modifier) / 10.
For example if you choose to increase Engine Power to 125% of normal. The Fuel Modifier would be (10 ^ 1.25)/10 = 1.7783, so for a power increase of 25% fuel use would increase by 78%. This is shown on the dropdown as "Engine Power Modifier 1.25. Fuel Modifier 1.78". For an engine with 200% of normal thrust, the fuel modifier is 10x. This is the equivalent of a FAC engine in Aurora, except now you can have different size engines and you can have more than 1 per ship.
Here is the design summary for an engine of 5HS, using Internal Confinement Fusion technology, with a 25% increase in thrust, base fuel efficiency of 8 and no thermal reduction.
Internal Confinement Fusion Drive
Power Output: 12.5 MN Exp Chance: 12 Fuel Efficiency: 13.5151 Thermal Signature: 125
Base Acceleration: 50 mp/s (5.1G)
Fuel Use at Full Burn: 168.9388 litres per hour
Engine Size: 5 HS Engine HTK: 2
Cost: 62 Crew: 8
Materials Required: 15.5x Duranium 46.5x Gallicite
Development Cost for Project: 620RP
The Fuel Efficiency is calculated as base 8, x0.95 for engine size, x1.7783 for engine power modifier, which equals 13.5151. Fuel use in litres per hour is therefore 12.5 MN x 13.5151 = 168.9388. As that single engine alone would use up a 1 HS fuel tank in a little over 12 days, you can already see that fuel tanks are going to be a lot bigger in Aurora FTL. Based on testing so far, fuel is going to be 10-20% of hull mass for warships. A lot less for freighters as you can build some very fuel efficient engines as well.
The base acceleration is for the engine accelerating itself with no accounting for where the fuel is coming from. While this is obviously never achievable in practice, it provides a way to rate engines against each other. 50 mp/s is an acceleration of fifty meters per second squared. The 5.1G is the force a passenger on the engine would feel. This subject is covered more realistically in the ship design below. Exp Chance is based on 10% of the engine power modifier, rounded down.
Now lets look at an engine designed around fuel efficiency rather than thrust. This is an engine of 25HS, using Internal Confinement Fusion technology, with a 70% decrease in thrust, base fuel efficiency of 8 and no thermal reduction.
Commercial Internal Confinement Fusion Drive
Power Output: 15 MN Exp Chance: 3 Fuel Efficiency: 1.197 Thermal Signature: 150
Base Acceleration: 12 mp/s (1.22G)
Fuel Use at Full Burn: 17.955 litres per hour
Engine Size: 25 HS Engine HTK: 12
Cost: 75 Crew: 2
Materials Required: 18.75x Duranium 56.25x Gallicite
Development Cost for Project: 750RP
The Fuel Efficiency is calculated as base 8, x0.75 for engine size, x0.1995 for engine power modifier, which equals 1.197. Fuel use in litres per hour is therefore 15 MN x 13.5151 = 17.955. So this engine produces more thrust than the above one and only uses a tenth of the fuel. However, it is 5x larger so the base acceleration is much lower. Even so, you will actually get more Delta-V for the same fuel from this engine than the one above - it will just take longer to do it. More on Delta-V in the ship design section.
Note that there is no accounting for exhaust velocity in the engine design. This is a key element in the design of real rocket engines. It has a huge effect on fuel efficiency and will affect the acceleration provided by the engine once the speed of the rocket approaches that of the engine's exhaust velocity. However, I have to draw a line somewhere between realism and fun and in the case of exhaust velocity I decided that having a simpler fuel efficiency rating for the engine that could easily be understood by players would be preferable to players having to understand Tsiolkovsky's rocket equation and associated material. I think the current mechanics of engine design allow for a lot of freedom, and provide the players with the feel of a Newtonian game without having to get into serious math.
(http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation)
Ship design
The ship below is a Daring class area defence cruiser from my NATO vs Soviet Union campaign, converted to use the new engine mechanics.
Daring class Area Defence Cruiser 6,873 tons standard 10,700 tons full load 682 Crew 1643.6 BP
Armour 5-43 Shields 0-0 Sensors 1/1/0/0 Damage Control Rating 6 PPV 15
Maint Life 4.98 Years MSP 576 AFR 152% IFR 2.1% 1YR 39 5YR 580 Max Repair 252 MSP
Active Signature 214 Thermal Signature 1500 EM Signature 1680/0
Magazine 831
Newtonian Magnetic Confinement Fusion Drive (12) Total Power 150 MN Fuel Use 1200 litres per hour Exp 5%
Full Load Acceleration 14.02 mp/s (1.43G) Hourly Acceleration 50.47 km/s Daily Acceleration 1211.22 km/s
Standard Acceleration 21.83 mp/s (2.23G) Hourly Acceleration 78.57 km/s Daily Acceleration 1885.77 km/s
Fuel Capacity 1,750,000 Litres Full Burn Duration 60.8 days Delta-V Budget (Full Load) 80,366 km/s
Mk5 Guided Missile Launching System (15) Missile Size 1 Rate of Fire 10
SN/SPG-31 Anti-Missile Fire Control (3) Range 35.3m km Resolution 1
SN/SPN-27 Navigation Sensor (1) GPS 1680 Range 30.4m km Resolution 60
SN/SPS-30 Missile Detection Sensor (1) GPS 252 Range 35.3m km Resolution 1
The key changes are as follows:
Standard vs Full Load: The standard mass of the ship is without any fuel, cargo, ordnance, colonists or parasites. Full load obviously assumes everything that could be loaded is loaded. In Aurora FTL, the current mass of the ship is tracked very carefully, so as you use fuel or fire missiles, the mass of the ship will be slightly reduced and your maximum acceleration rate will increase. The full load is also the volume of the ship, which will be used for FTL purposes. Volume is not affected by current mass and will always be equal to the full load mass.
No Maximum Speed: Maximum speed has been removed from the summary. Ships no longer have a maximum speed as it is based on acceleration rates and available fuel. In Aurora a ship had to continue using fuel to maintain velocity. In Aurora FTL, once you have velocity you can turn off the engines and you will continue at the same speed. However, you will need to use the engines to slow down again.
Active, Thermal, EM Signatures: These now have their own line on the summary. Many players didn't know what the old abbreviations meant and space on the top line was an issue with the additional of the standard load tonnage.
Engine Line: The engine line now shows the total thrust of the engines, compared to the old individual power rating from Aurora. Fuel use is the combined fuel use for all engines, in this case 1200 litres per hour. Bear in mind that most ships will likely spend a considerable amount of movement time with engines off. They can accelerate to a desired velocity, disengage engines and then engage the engines again to decelerate when required.
Full Load Acceleration: The 14.02 mp/s (1.43G) section indicates that at full load, this ship has an acceleration rate of just over fourteen meters per second, which is equivalent to 1.43G for the crew. In an hour the ship can accelerate to a fifty kilometers per second and in a day to 1200 km/s. Bear in mind it will take just as long to decelerate. This utterly changes the tactical situation from Aurora. For example, if you charge into an unknown system you cannot simply reverse course if you detect an alien ship. You will have to either decelerate first and then reverse course, maybe increase speed and try to charge past, or attempt to change course, which is going to be extremely difficult unless you are going relatively slowly in comparison to your acceleration rate. I haven't done the final course change calculations yet but I can already see that you are probably going to have a pick a destination very carefully.
I haven't decided yet what to do with regard to gravity but I am leaning toward technobabble which states the existing trans-newtonian materials from Aurora are anti-grav materials in Aurora FTL, allowing you to build ships with an anti-gravity field. This solves the gravity issue not just in playability terms, as otherwise a lot of early ships wouldn't be able to leave Earth :), but also in performance terms as otherwise I would have to be checking the gravitational effect on every ship for every significant body in the system on every sub-pulse. Yuck! The disadvantage of ignoring gravity is that you can't do maneuvers to pick up speed from planets, although I can probably build something into the technobabble along those lines (switching off the anti-grav, etc). I will also probably add aerobraking maneuvers as well. Still a lot of work, which is why it will be months before anyone see this.
Standard Acceleration: This provides the same as above, with the assumption the ship is not carrying anything and is using its last dregs of fuel. This line and the one above provide a range of acceleration rates between which the ship will be operating. On the Ship window, the Ship summary substitutes this line with Current Acceleration, with the values based on the current ship mass.
Fuel Capacity: The first section is as before, with the total fuel capacity. This will likely be far greater in Aurora FTL than in Aurora. Next is the Full Burn Duration, which is the total time the ship could run its engines at full power using the total fuel capacity. Finally, the Delta-V Budget. There is no such thing as range based on fuel in Aurora FTL because you have effectively unlimited range. Instead you have a Delta-V budget, which is the total amount of velocity change you can achieve with your current fuel. The Daring has a Delta-V Budget of approximately 80,000 km/s, which means it could accelerate to 40,000 km/s and then decelerate down to zero, or it could accelerate to 4000 km/s and back to zero ten times, or carry out any combination of acceleration and deceleration that adds up to 80,000 km/s. This budget is calculated using a minute by minute calculation of the full burn duration, taking into account the slowly decreasing mass of fuel over the 60.8 day period.
Delta-V is the key value when looking at the ship design and the use to which you intend to put it. A system defence ship which is intended to fly toward an intruder, engage it and return home to its fuel source will only need enough fuel to accelerate to a desired speed, decelerate to zero and then carry out the reverse in order to return home. The outward leg will presumably require a longer period of acceleration as velocity is more important. A Delta-V budget of 15,000 km/s would allow an acceleration to 5000 km/s, the same deceleration to zero and then a return home leg with an acceleration to 2500 km/s. A long range geological survey ship would probably accelerate and decelerate many times. It will need a very fuel efficient engine and a very large delta-V budget.
As a further example, here is an early game freighter. This ship is designed with much more fuel efficient engines. The Delta-V budget is 30,000 km/s as that is deemed sufficient to carry out four accelerations and decelerations with an final intended speed of around 3000 km/s, while still allowing some reserve. This is because the FTL system in Aurora FTL, which I will go into in a future post, will often result in you entering your destination system with the wrong heading. It may be possible to correct course if the deviation is minor, or it may be necessary to decelerate to rest and accelerate again.
Atlas class Freighter 8,350 tons standard 34,100 tons full load 26 Crew 528.6 BP
Armour 1-93 Shields 0-0 Sensors 1/1/0/0 Damage Control Rating 1 PPV 0
MSP 10 Max Repair 50 MSP
Active Signature 682 Thermal Signature 400 EM Signature 0/0
Cargo 25000
Commercial Ion Engine (4) Total Power 40 MN Fuel Use 105.5 litres per hour Exp 4%
Full Load Acceleration 1.17 mp/s (0.12G) Hourly Acceleration 4.22 km/s Daily Acceleration 101.35 km/s
Standard Acceleration 4.79 mp/s (0.49G) Hourly Acceleration 17.25 km/s Daily Acceleration 413.89 km/s
Fuel Capacity 750,000 Litres Full Burn Duration 296.2 days Delta-V Budget (Full Load) 30,362 km/s
I realise this alternative Aurora will not be for everyone and it will be a niche area of a niche game :). Tactical planning is going to be critical, combat will be totally different, expansion will be slow and there will be a little more micromanagment than Aurora, although I will try and reduce that as much as possible. For example, in the fleet orders window you can include a maximum speed in an order so a fleet will accelerate to that speed, then switch off engines. Engines will be re-engaged when the fleet decides it needs to start slowing down. I'll post updates as I add new features and probably some mini-AARs from testing. I am not promising a release date :) as it depends on outside factors but hopefully there will be something before Xmas.
Steve
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Tactical planning is going to be critical, combat will be totally different, expansion will be slow and there will be a little more micromanagment than Aurora, although I will try and reduce that as much as possible. For example, in the fleet orders window you can include a maximum speed in an order so a fleet will accelerate to that speed, then switch off engines. Engines will be re-engaged when the fleet decides it needs to start slowing down.
Sounds pretty neat.
I hope that the AI will give you the option of a direct-most route, a fuel conservation route, and so forth. Additionally I hope that the computer will know when to start decelerating, because if I do it I will invariably overshoot or undershoot.
Will gravity slingshots be available?
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Sounds awesome!
I assume missiles will be totally overhauled too? As they have virtually unlimited range now too.
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Does this mean that transnewtonian elements will be removed and replaced by something more scientific like umm... Helium2 as fuel source, not Sorium?
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Sounds awesome!
I assume missiles will be totally overhauled too? As they have virtually unlimited range now too.
Yes, missiles will be changed to use the new rules too. Interception of ships will be a lot harder though because missiles won't have as much maneuverability. I think two stage missiles with a high-G second stage might be useful. I may also have to look at laser heads for missiles, or proximity detonations. Missile targeting will have to use the probable location of the enemy ship at the time the missile is due to arrive, rather than the enemy ship's location at the time of firing.
Steve
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Does this mean that transnewtonian elements will be removed and replaced by something more scientific like umm... Helium2 as fuel source, not Sorium?
Probably not, at least in the short term. I am going to leave as much of normal Aurora in place as I possibly can, given the amount of work the changes already planned will require. They won't be called transnewtonian elements though - more likely anti-gravity elements :)
Steve
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Will gravity slingshots be available?
Some form of gravity slingshot will be available, allowing spacecraft to increase/decrease speed and change direction by passing very close to planets/moon, etc. I need to take a detailed look at the math before coming up with a simplified Aurora FTL version. I think in reality this will also work with lagrange points, so that could be used in the game too (http://en.wikipedia.org/wiki/Interplanetary_Transport_Network)
Steve
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This looks as if it'll be a great idea. Thank you very much.
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What if you made jump points at gravity wells (Say, near a planet)? Then ships could slow down enough to transit without sucking away fuel.
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why stop to get through a jump point? If jumping preserved momentum, thats an interesting approach for combat.
Makes invasions somewhat interesting, an alien species could come roaring through the jumppoint at high speed but have their engines off--no thermal sig-- then just coast all the way to the inner planets and when suddenly they flip on the shields and actives and engines and fling missiles in every direction.
Also, ships already moving at 10km/s make defending jump points trickier-- the enemy ships will emerge and start moving fast, so beam ships won't be able to sit there and pave blinded ships as effectively.
(of course i guess we get FTL rather than Jump Points)
Side note: while I'm always interested in new expansions to aurora, this is one that at first glance I do not feel likely to use, being that i'm more interested in economics and combat than newtonian physics.
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good idea look forward to it
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Could have a lot of fun with box launcher armed ships in this, or really an situation where you can shoot your magazines dry quickly and then use your now much lighter ships higher accel to escape defenders that are fully loaded.
Missile fighters should see some good advantages.
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for the engines part which directly influence also missiles...it's like that mass effect quotation, were there are two soldiers outside of the capital and their sergeant is speaking to them:
"you know, in space there is no gravity. So something which moves will move on forever"
"yessir!"
"so, you do not shoot by the eye, because otherwise, somewhere, sometime, someone is going to receive a nasty fifty ton surprise of a hit"
"yessir!"
"AND THIS IS WHY YOU WAIT FOR THE SENSORS TO GIVE YOU THE ALL CLEAR!"
"yessir"
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for the engines part which directly influence also missiles...it's like that mass effect quotation, were there are two soldiers outside of the capital and their sergeant is speaking to them:
"you know, in space there is no gravity. So something which moves will move on forever"
"yessir!"
"so, you do not shoot by the eye, because otherwise, somewhere, sometime, someone is going to receive a nasty fifty ton surprise of a hit"
"yessir!"
"AND THIS IS WHY YOU WAIT FOR THE SENSORS TO GIVE YOU THE ALL CLEAR!"
"yessir"
^_^
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...Aaaand..
O.M.G..Steve.
Awesome idea..
Damn..,i send u : Good Work mate!!!!
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for the engines part which directly influence also missiles...it's like that mass effect quotation, were there are two soldiers outside of the capital and their sergeant is speaking to them:
"you know, in space there is no gravity. So something which moves will move on forever"
"yessir!"
"so, you do not shoot by the eye, because otherwise, somewhere, sometime, someone is going to receive a nasty fifty ton surprise of a hit"
"yessir!"
"AND THIS IS WHY YOU WAIT FOR THE SENSORS TO GIVE YOU THE ALL CLEAR!"
"yessir"
So will there be such things? Shoot something while moving reallllly fast and BOOM? Kinetic energy more powerful then nuclear bombs?
Also bombing planets from enormous distances? So fast that intercepting is impossible? (like bombing planets in Lost Fleet?)
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Sounds like a fantastic project, can't wait to see some more details.
From the designs you have posted it looks like fuel logistics will become a very significant part of the game and also part of ship and engine design. I guess once play tested a bit you can tweak fuel consumption / efficiency to see balance proportion of ships that will be taken up with fuel stores and also mining and fuel production rates.
I guess boarding actions are going to pretty much going to become a thing of the past.
I agree that combat is going to need a re-work. Perhaps ships will need a manoeuvre rating as well as acceleration rating to indicate how well they can adjust course quickly to avoid fire - this could be adjusted on ships by the use of thrusters as an additional component to engines. Chance to hit then become related to this factor as much as base speed.
For weapon systems I can see energy weapons needing quite a change as well. Perhaps you have two weapon ratings - one to deal with engagement speed ie the actual speed of the hostile and another to deal with the manoeuvrability of the hostile as above. Otherwise people will need to have very significant turret tracking to deal with heavy burn ships.
Of course Steve if you need any help play testing any of your changes happy to help!....
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Probably not, at least in the short term. I am going to leave as much of normal Aurora in place as I possibly can, given the amount of work the changes already planned will require. They won't be called transnewtonian elements though - more likely anti-gravity elements :)
Steve
This sounds incredibly cool, but why not call them Transuranic? There is that supposed Island of Stability that we haven't managed to get to yet.
hxxp: en. wikipedia. org/wiki/Island_of_stability
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for the engines part which directly influence also missiles...it's like that mass effect quotation, were there are two soldiers outside of the capital and their sergeant is speaking to them:
"you know, in space there is no gravity. So something which moves will move on forever"
"yessir!"
"so, you do not shoot by the eye, because otherwise, somewhere, sometime, someone is going to receive a nasty fifty ton surprise of a hit"
"yessir!"
"AND THIS IS WHY YOU WAIT FOR THE SENSORS TO GIVE YOU THE ALL CLEAR!"
"yessir"
feature=channel_video_title
And THAT is why Sir Issac Newton is the DEADLIEST son of a bitch in space!
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Sounds like a fantastic project, can't wait to see some more details.
From the designs you have posted it looks like fuel logistics will become a very significant part of the game and also part of ship and engine design. I guess once play tested a bit you can tweak fuel consumption / efficiency to see balance proportion of ships that will be taken up with fuel stores and also mining and fuel production rates.
I guess boarding actions are going to pretty much going to become a thing of the past.
I agree that combat is going to need a re-work. Perhaps ships will need a manoeuvre rating as well as acceleration rating to indicate how well they can adjust course quickly to avoid fire - this could be adjusted on ships by the use of thrusters as an additional component to engines. Chance to hit then become related to this factor as much as base speed.
For weapon systems I can see energy weapons needing quite a change as well. Perhaps you have two weapon ratings - one to deal with engagement speed ie the actual speed of the hostile and another to deal with the manoeuvrability of the hostile as above. Otherwise people will need to have very significant turret tracking to deal with heavy burn ships.
Of course Steve if you need any help play testing any of your changes happy to help!....
Fuel logistics will definitely be a huge part of the game. A lot more fuel will be consumed so I think I might radically improve the extraction rate of Sorium from gas giants.
I have been loooking at course changes. The ideal course change mechanic is going to one that is simple to understand yet gives the right feel for the physics involved. For the moment I am working with a one degree course change requiring delta-V equal to 1/90th of your speed. This is very simplistically based on the fact that reversing course and achieveing the same speed requires a delta-V equal to double your speed, so if 180 degrees = 2x speed then 1 degree = 1/90th your speed. So if you are moving at 2000 km/s, a five degree course change will require 5/90 x 2000 km/s = 111.11 km/s of delta-V. If your spacecraft has an acceleration rate of 15 mp/s then the course change would require an engine burn of 123 minutes. I may make this more simple and use 1% of velocity per degree rather than 1/90th. It is slightly more generous but far easier to visualize for players. In this case, the above would require an engine burn of 111 minutes.
Given the relative difficulty of altering course and the fuel requirements to reach high speeds, I think average speeds may actually be a little lower in Aurora FTL. Therefore it may turn out the existing tracking ratings are actually too high :). I'll see how playtesting goes. Boarding actions may actually become easier too. I will be basing it on speed and course differential so if you can match course and speed, you will be able to board ships that would be moving too fast in normal Aurora.
Steve
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Steve,
I apologize if you mentioned this in your post about the new engine design, but will you continue to have the limit of one engine type per ship? It seems to me that one route a player may be interested in trying is a ship that has high-efficiency low-thrust engines for long-distance travel, while using low-efficiency high-thrust engines in a combat situation.
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I have been loooking at course changes. The ideal course change mechanic is going to one that is simple to understand yet gives the right feel for the physics involved. For the moment I am working with a one degree course change requiring delta-V equal to 1/90th of your speed. This is very simplistically based on the fact that reversing course and achieveing the same speed requires a delta-V equal to double your speed, so if 180 degrees = 2x speed then 1 degree = 1/90th your speed. So if you are moving at 2000 km/s, a five degree course change will require 5/90 x 2000 km/s = 111.11 km/s of delta-V. If your spacecraft has an acceleration rate of 15 mp/s then the course change would require an engine burn of 123 minutes. I may make this more simple and use 1% of velocity per degree rather than 1/90th. It is slightly more generous but far easier to visualize for players. In this case, the above would require an engine burn of 111 minutes.
I own Attack Vector: Tactical. I can totally bust out the math if you want :P
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Honor Harrington.
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Honor Harrington.
Well ships will be accelerating at 1-2G rather than 500G+ but there should be some similarities in the way that battles develop. Also, the current model gives a lot of room for expansion into higher tech levels with inertial compensators and much higher acceleration rates. I want to keep it relatively straightforward to begin with though.
Steve
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Steve,
I apologize if you mentioned this in your post about the new engine design, but will you continue to have the limit of one engine type per ship? It seems to me that one route a player may be interested in trying is a ship that has high-efficiency low-thrust engines for long-distance travel, while using low-efficiency high-thrust engines in a combat situation.
Initially I will have the one engine type per ship rule. It solves a lot of potential issues. Besides, if have two sets of engines, each set of engines will be handicapped by the mass of the other so it may not be efficient overall.
Steve
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<snip> Boarding actions may actually become easier too. I will be basing it on speed and course differential so if you can match course and speed, you will be able to board ships that would be moving too fast in normal Aurora.
Steve
If I may suggest... require some form of ship to ship linking. First the assaulting ship/shuttle/etc must successfully grapple/tractor/whatever and then successfully breach, if opposed, before boarders cross.
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I own Attack Vector: Tactical. I can totally bust out the math if you want :P
I wouldn't mind knowing how Attack Vector: Tactical handles it. My research online hasn't been very productive on this particular question yet. My intention though is to go with something that reflects the difficulty in changing course at high speed, is easy for players to understand and generally follows the applicable physical laws, without the requirement to follow those laws exactly
Steve
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Congratulations for getting me well and truly distracted from work today by the way!
Was just thinking a little more about tactical implications. Looking at your example cruiser, using rounded numbers and some noddy maths - if the ship is doing 4000 km/s its going to take it about 576m k to slow down to zero. That's about the range of my best size sensor so if something is coming the other way at the same speed on an intercept I can expect to be getting up close and personal with them whilst still at significant speed. It also means it's going to take a couple of days for the fleet to come round and make a second approach. That feels like maybe too little reaction time and too long on any re-engagement time.
Weapons wise it also looks to be leaning very heavily towards the massive volley strikes with missiles once in range and also maybe lots of energy weapons with reduced size and recharge rate.
Maybe some option for limited higher g manoeuvres would be a good way to help with this.
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I wouldn't mind knowing how Attack Vector: Tactical handles it. My research online hasn't been very productive on this particular question yet. My intention though is to go with something that reflects the difficulty in changing course at high speed, is easy for players to understand and generally follows the applicable physical laws, without the requirement to follow those laws exactly
Steve
I'd be happy to write up a quick summary of it once I get out of work.
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Firstly, a big thanks to Steve for another incredible development for Aurora. Very much looking forward to this.
Congratulations for getting me well and truly distracted from work today by the way!
Was just thinking a little more about tactical implications. Looking at your example cruiser, using rounded numbers and some noddy maths - if the ship is doing 4000 km/s its going to take it about 576m k to slow down to zero. That's about the range of my best size sensor so if something is coming the other way at the same speed on an intercept I can expect to be getting up close and personal with them whilst still at significant speed. It also means it's going to take a couple of days for the fleet to come round and make a second approach. That feels like maybe too little reaction time and too long on any re-engagement time.
Weapons wise it also looks to be leaning very heavily towards the massive volley strikes with missiles once in range and also maybe lots of energy weapons with reduced size and recharge rate.
Maybe some option for limited higher g manoeuvres would be a good way to help with this.
Maybe reintroduce the Hyperdrive as a kind of 'overload' function for engines? Maybe missiles too for final attack runs?
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I wouldn't mind knowing how Attack Vector: Tactical handles it. My research online hasn't been very productive on this particular question yet. My intention though is to go with something that reflects the difficulty in changing course at high speed, is easy for players to understand and generally follows the applicable physical laws, without the requirement to follow those laws exactly
Steve
AT:V simplifies, in the first place, by using a hex grid. Ship vectors have three components... one on the z axis, and two on the xy axes, that can be 60-degrees apart. This allows it to deal with vector math relatively simply: opposing vectors (180) cancel out. Vectors 120 apart "meet in the middle": add the 120-degree off vector to the 60-degree off vector, then subtract it from the 0-degree vector.
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For reference this is extracted from GZG's Full Thrust/Fleet Book One where vector movement is introduced to that minitures system.
COURSE AND FACING
Under the standard Cinematic FT movement, a ship will always be facing in the same
direction that it is moving; under the VECTOR system the ship may be moving one way
and facing another. The direction in which the ship is actually MOVING is termed its
COURSE, while the direction in which the ship model is actually pointing is called its
FACING. The current COURSE is indicated by a small arrow marker placed next to the
ship’s stand, and this marker is also used as a reference point during the process of
moving the model. It should be noted that the FACING of a model should always be one
of the 12 “clockface” points, though the mechanics of the vector movement mean that
the COURSE will usually NOT correspond exactly to a clockface direction.
MAIN DRIVE THRUST
The THRUST RATING of any ship is the amount of thrust that can be produced by its
MAIN DRIVE - the “big engine” at the back. Each point of thrust applied in a turn will
accelerate the ship by 1 inch (or other movement unit) ALONG THE AXIS OF THE SHIP,
so if a ship that is facing in its direction of travel (i.e. its “course” and “facing” are the
same) and currently moving 6" per turn applies 4 points of thrust from its main drive,
it will end up moving at 10" per turn. If the ship’s facing and course are NOT the same
(i.e.: the model is pointing one way and moving another) then the application of thrust
from the main drive will alter the ship’s course AND velocity. To DECELERATE using the
main drive (as opposed to using the forward “retro” thrusters), the ship must be turned
so that it is pointing “backwards” relative to its current course. When writing orders for
your ship, Main Drive thrust is written as MD followed by the number of thrust points
being applied - so MD4 will move the ship 4" in the direction of its present facing.
If using existing ship designs (whether from this book, from FT2 or elsewhere) then the
thrust level shown in the ship’s drive icon is the rating used for the main drive.
MANOEUVRING THRUSTERS
In addition to the main drive, all ships have THRUSTERS - small drives positioned in
clusters around the ship, pointing forward, port, starboard etc. (in reality ships would
also of course have “up” and “down” orientated thrusters, but as we are not concerned
with 3D movement in FT we can ignore these except for their use in rolling the ship).
The thrusters may be used to “push” the ship to alter its course, or to rotate the ship
onto a new facing. The power available to the ship’s thrusters is equal to half the
thrust rating of the main drive - so a ship with a main drive TR of 6 would have 3
manoeuvre points available from its thrusters; unlike the Cinematic movement rules,
thruster use is allowed in addition to applying full available thrust with the main drive
- so that a ship with a Thrust Rating of 4 could apply 2 points of thruster use and still
use all 4 thrust points from its main drive.
We have not depicted the Thruster systems as separate icons on the ship diagrams, in
order that any design may be used with either movement system without alteration.
For the purposes of damage, assume that the thrusters are driven by the same power
systems as the main drives - when the main drive takes damage, thruster power is
halved or lost accordingly.
ROTATION
Rotation of a ship around its axis requires much less power than actually changing its
vector. When the thrusters are used to rotate a ship onto a new heading, ONE
manoeuvre point from the thrusters allows the ship to be rotated by any desired
number of facing points. Thus, for the expenditure of one point of thruster power a
ship can be rotated to face in any of the 12 possible facing directions, regardless of
the thrust rating of its drives (the only difference between rotating 30 degrees and
rotating 180 degrees is simply that, once the thrusters have started the ship spinning,
the ship is allowed to rotate for longer before the thrusters burn again to cancel the
spin). Note that a ROTATION changes the ship’s FACING only, and never its COURSE.
Note: when thrusters are used to rotate the ship onto a new facing, it is assumed that
several of the ship’s thrusters are fired in unison to achieve the desired effect - for
example, to rotate the ship to starboard it would fire the PORT FORWARD thrusters and
the STARBOARD REAR ones simultaneously to spin the ship around its centre of mass. It
is assumed that, in the same turn, a compensating burst is applied as the desired new
facing is reached in order to stop the ship’s rotation - the combined effect of these
operations constitutes one “rotation” action.
ROTATION orders should be written down as TP (Turn Port) or TS (Turn Starboard),
followed by the number of points of heading change - thus TP2 indicates a rotation to
port of 2 clockface points (ie: 60 degrees).
THRUSTER PUSHES
A thruster “push” is firing a combination of manoeuvre thrusters to alter the course
and/or velocity of the ship, WITHOUT affecting its actual facing (i.e.: the ship ends the
turn with its model pointing the same way it started, although its course may have
changed). Pushes may be made to PORT, STARBOARD or REVERSE (using the forward
“retro” thrusters to slow the ship down without having to spin it round and use the
main drive). It requires ONE manoeuvre point of thrust applied to displace the ship by
one movement unit; a push of 3 with the port-side thrusters will shift the ship 3" to
starboard (for simplicity of play, this is referred to as a STARBOARD PUSH - to avoid
confusing of orders we always use the direction of the EFFECT rather than the location
of the thrusters being used). Note that a PUSH changes the ship’s COURSE (and/or
VELOCITY) only, and never its FACING.
PUSH orders should be written as PP (Push to Port), PS (Push to Starboard) or PR (Push
in Reverse), again followed by the number of thrust points applied - so PR3 would be
using 3 manoeuvre points from the retros to push the ship 3 units “backwards” relative
to its current heading. Pushes may only be applied directly to port, starboard or
rearward relative to the ship’s facing at that moment.
COMBINING MANOEUVRES
If desired, a ship may combine both ROTATION and PUSH uses of its manoeuvring
thrusters in a single game turn, but no more than ONE of each, provided the TOTAL of
manoeuvre points expended does not exceed the total available. It is quite acceptable
for a ship with (say) 3 manoeuvre points of thruster power available to make a rotation
(using up 1 thruster point), then apply a main drive burn, then use the remaining 2
manoeuvre points for a 2" thruster push to port, starboard or aft as desired. The final
position, course and velocity would be measured after ALL manoeuvres are completed.
ORDER SEQUENCE
The actual sequence in which thruster and main drive burns are applied in a single turn
will make a difference to the final course and velocity of the ship, so it is necessary to
rule on what order things are done in. Each effect is applied to the ship strictly IN THE
ORDER THEY ARE WRITTEN DOWN BY THE PLAYER. If the player writes TP2, MD6 then
the ship will first be moved according to its starting vector (as always), then turned 2
points to port (TP2) and then moved 6" along its new facing (MD6). If, on the other
hand, the order is written MD6, TP2 (thus applying the main drive burn BEFORE
rotating the ship to its new facing) then the result will be VERY different in terms of
the ship’s final vector and position - plot each one out and you’ll see what we mean!
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Congratulations for getting me well and truly distracted from work today by the way!
Was just thinking a little more about tactical implications. Looking at your example cruiser, using rounded numbers and some noddy maths - if the ship is doing 4000 km/s its going to take it about 576m k to slow down to zero. That's about the range of my best size sensor so if something is coming the other way at the same speed on an intercept I can expect to be getting up close and personal with them whilst still at significant speed. It also means it's going to take a couple of days for the fleet to come round and make a second approach. That feels like maybe too little reaction time and too long on any re-engagement time.
It occurs to me that all the current games with some element of Newtonian mechanics are all tactical. So the timespan for acceleration is very limited and thus course changes are also possible in fairly short timespans. In Aurora FTL, ships may have been accelerating for days or weeks so it is only reasonable that they would require a long time to change course. I think intelligence gathering and scouting will be even more important. Probes will become much more common as you could send one coasting into an inner system after it bulds velocity a long way out.
Given accelerations of 1-2G, I think the 'commit yourself to a course' situation is how combat would turn out in reality.
Weapons wise it also looks to be leaning very heavily towards the massive volley strikes with missiles once in range and also maybe lots of energy weapons with reduced size and recharge rate.
Maybe some option for limited higher g manoeuvres would be a good way to help with this.
As with Aurora, I want to stay within the physics model for the game. The only way I can think of adding higher G maneuvers is to have some strap-on boosters with high-G and incredibly low fuel efficiency. Missiles will follow the fuel efficiency model as ships but I may extend it up to 500% boost and 10,000x fuel (which is the same as Aurora), so the strap-on booster could be modelled as a huge missile. A ship would have hardpoints for boosters or disposable fuel tanks. That type of things is some way in the future though after I have the basic movement model working.
Steve
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AT:V simplifies, in the first place, by using a hex grid. Ship vectors have three components... one on the z axis, and two on the xy axes, that can be 60-degrees apart. This allows it to deal with vector math relatively simply: opposing vectors (180) cancel out. Vectors 120 apart "meet in the middle": add the 120-degree off vector to the 60-degree off vector, then subtract it from the 0-degree vector.
The model I am planning to use is just a more detailed version of that, except in 2D not 3D. Aurora FTL will track headings to 1/10,000th of a degree so I should be able to get the right feel for maneuvers. I think I am going to go with 1% of velocity as the required delta-V for 1 degree of course change. That is about 10% better than reality but it is very easy for players to visualise and make calculations in their head. The fleet window will show the delta-V budget for each fleet/ship, along with estimated time and distance to decelerate to rest and other useful stats as I think of them.
Steve
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Side question: are you finished with the latest campaign since you are devoting more time to FTL? I was kinda rooting for the Chinese to come back with gusto!
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Side question: are you finished with the latest campaign since you are devoting more time to FTL? I was kinda rooting for the Chinese to come back with gusto!
No, I have already done a little more with that campaign since the last AAR and I do intend to come back to it at some point. I just haven't had time due to my latest distraction :)
Steve
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All this talk of Newtonian movement and delta v is really giving me a Larry Niven Protector vibe, I might read that again, its well worth another bash.
If your current plans make combat less black and white then I'm all for it, currently we are facing the same problem as the admirals who squared off at Jutland - its safer not risking everything on a single combat which invariably is devastating for one side.
Ohh and +1 on a Chinese comeback.
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As with Aurora, I want to stay within the physics model for the game. The only way I can think of adding higher G maneuvers is to have some strap-on boosters with high-G and incredibly low fuel efficiency. Missiles will follow the fuel efficiency model as ships but I may extend it up to 500% boost and 10,000x fuel (which is the same as Aurora), so the strap-on booster could be modelled as a huge missile. A ship would have hardpoints for boosters or disposable fuel tanks. That type of things is some way in the future though after I have the basic movement model working.
Steve
Would you be able to do this through an extension of the fuel efficiency of engines when in use on top of fuel efficiency for size? I.e. make the current fuel consumption and thrust levels set for 50% max power which becomes the most efficient means of acceleration and deceleration. Then make decreasing returns on increasing thrust and increasing fuel cost up to 100% engine power. This allows ships to make relatively brief heavier accelerating or breaking manoeuvres at the cost of more rapid use of available Delta V?
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AT:V simplifies, in the first place, by using a hex grid. Ship vectors have three components... one on the z axis, and two on the xy axes, that can be 60-degrees apart. This allows it to deal with vector math relatively simply: opposing vectors (180) cancel out. Vectors 120 apart "meet in the middle": add the 120-degree off vector to the 60-degree off vector, then subtract it from the 0-degree vector.
Very similar to how I do it in Astra Imperia, except I stick with 2 dimensions. A third would be hard without some form of aid.
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For the moment I am working with a one degree course change requiring delta-V equal to 1/90th of your speed. This is very simplistically based on the fact that reversing course and achieveing the same speed requires a delta-V equal to double your speed, so if 180 degrees = 2x speed then 1 degree = 1/90th your speed. So if you are moving at 2000 km/s, a five degree course change will require 5/90 x 2000 km/s = 111.11 km/s of delta-V.
Umm actually the trigonometric answer would be (2*sin(theta/2)*V), where theta is the angle turned. This is gotten by drawing a circle of radius V, drawing radii in the direction of the old course and the new course, then drawing a line between the two endpoints (giving you an isoscelese triangle). If you split the triangle down the middle, you get two right triangles, with angle at the center of theta/2. The length of the split side is 2*(V*sin(theta/2)). Note that for theta = 180 degrees, this gives the 2*V answer you have. For small theta, you can use sin(angleInRadians) ~ angleInRadians, to get dV = V*thetaInRadians = V*(thetaInDegrees)*(pi Radians/180 degrees) ~ (V/60)*theta. Note that the speed drops during the burn. If you want to keep constant speed during the burn, then you basically want to keep the small angle formula for the full angle change, so the constant-speed equation is just V*(pi/180)*thetaInDegrees. This makes sense, since to do the constant speed course reversal the velocity arrow would need to travel 1/2 circumference of the circle, while to do the "turn over and start blasting" reversal the velocity arrow travels the length of the diagonal. By definition the ratio of these two distances is pi/2, which is the ratio of the two answers.
To put it a different way, your formula is about 50% (pi/2) too generous for small-angle course changes.
John
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All this talk of Newtonian movement and delta v is really giving me a Larry Niven Protector vibe, I might read that again, its well worth another bash.
I'm getting a CJ Cherryh (Earth Company/Union/Merchanter's Alliance) vibe myself. Although the Merchanter universe has jump not warp, they have to worry about velocity and so forth.
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The model I am planning to use is just a more detailed version of that, except in 2D not 3D. Aurora FTL will track headings to 1/10,000th of a degree so I should be able to get the right feel for maneuvers. I think I am going to go with 1% of velocity as the required delta-V for 1 degree of course change. That is about 10% better than reality but it is very easy for players to visualise and make calculations in their head. The fleet window will show the delta-V budget for each fleet/ship, along with estimated time and distance to decelerate to rest and other useful stats as I think of them.
Steve
Steve, I don't think your math is as good as within 10%. Here's a quick example: the delta-v necessary for a 90-degree course change. In your system, that'd be a delta-v equal to 90% of the velocity, right? What would be necessary in reality is a delta-v of 141% (square root of two, basically).
At 180 degrees, of course, the math is simple... you're costing 180% v rather than 200% v, so you're only off by about 11% there. The smaller the angle, the worse the margin of error gets; at 1%, you charge 1% rather than the real 1.74%.
I take it your current coordinate system is based on speed and angle, rather than x and y vectors?
EDIT: sloanjh got here before me, I just figured I'd crunch the numbers and toss them into a spreadsheet to make sure I wasn't miscalculating.
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Err..am only need one simple thimg: "Where r the Red Engine Button,Sir?"..here..ok..pusch to engine on.
Am a "simple" man,dude..
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If this direction actually works out, I may just have to learn how to play this game.
The thought of Newtonian elements makes this game much more attractive for me at least.
There are a number of games out there with 'reactionless' and 'jump points'.
Doing it the hard way, and not just a tactical game, would be incredible.... :)
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Umm actually the trigonometric answer would be (2*sin(theta/2)*V), where theta is the angle turned. This is gotten by drawing a circle of radius V, drawing radii in the direction of the old course and the new course, then drawing a line between the two endpoints (giving you an isoscelese triangle). If you split the triangle down the middle, you get two right triangles, with angle at the center of theta/2. The length of the split side is 2*(V*sin(theta/2)). Note that for theta = 180 degrees, this gives the 2*V answer you have. For small theta, you can use sin(angleInRadians) ~ angleInRadians, to get dV = V*thetaInRadians = V*(thetaInDegrees)*(pi Radians/180 degrees) ~ (V/60)*theta. Note that the speed drops during the burn. If you want to keep constant speed during the burn, then you basically want to keep the small angle formula for the full angle change, so the constant-speed equation is just V*(pi/180)*thetaInDegrees. This makes sense, since to do the constant speed course reversal the velocity arrow would need to travel 1/2 circumference of the circle, while to do the "turn over and start blasting" reversal the velocity arrow travels the length of the diagonal. By definition the ratio of these two distances is pi/2, which is the ratio of the two answers.
To put it a different way, your formula is about 50% (pi/2) too generous for small-angle course changes.
John
I couldn't find the formulas I needed online so I went for a total guess that happened to work well for game mechanics and ease of player understanding :). Even though I now know the correct formulas I am still tempted to go for 1% per degree, although I suppose 1.5% per degree isn't really any harder to visualise.
Steve
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Steve, I don't think your math is as good as within 10%. Here's a quick example: the delta-v necessary for a 90-degree course change. In your system, that'd be a delta-v equal to 90% of the velocity, right? What would be necessary in reality is a delta-v of 141% (square root of two, basically).
At 180 degrees, of course, the math is simple... you're costing 180% v rather than 200% v, so you're only off by about 11% there. The smaller the angle, the worse the margin of error gets; at 1%, you charge 1% rather than the real 1.74%.
I take it your current coordinate system is based on speed and angle, rather than x and y vectors?
EDIT: sloanjh got here before me, I just figured I'd crunch the numbers and toss them into a spreadsheet to make sure I wasn't miscalculating.
Thanks for running the numbers. Based on your math and John's, I guess a flat 1.5% per degree would be a reasonable compromise between reality, playability and ease of player understanding.
Yes, fleets now have a heading and velocity and movement is based on that. They don't have a facing in the combat sense however. I don't want to get that tactical.
Steve
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Will missiles start off at the same velocity as the ship that launches them? So you could do things like whip a missile up to . 1 c or something by charging in to a system, aiming it at the enemy, and letting it use its fuel mostly for maneuvering?
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Thanks for running the numbers. Based on your math and John's, I guess a flat 1.5% per degree would be a reasonable compromise between reality, playability and ease of player understanding.
Given that this is a computer game, I'm curious why you think a flat rate would be more playable than just having the computer calculate the cost. (Don't take this as a disagreement - I'm just wondering.) It seems to me like most of the movement orders should be set up such that the player tells the computer where the fleet should be and when, and then the computer manages the course calculation. And by "where and when" I really mean a whole host of conditions, such as "least time intercept", "least time zero-zero intercept", "lowest fuel zero-zero intercept within time deltaT", .... The computer would then just use the appropriate formula.
One thing that will vastly change the interface/complexity: will the ships have enough fuel to do continuous max-burns for an interplanetary trip, or will they only be able to do a short burn then coast most of the way. The second one is a lot more in line with the deltaV thing above - the first one means solving quadratic equations....
John
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Could I humbly ask that fuel and reaction mass be divided?
Reaction mass could simply be virtually anything your engine throws out the back. Obviously, engine designs will vary depending on the reaction mass used, so each engine design could have another line:
eg.
Reaction mass - H2O
Reaction mass - Inert Gas
This would reduce the massive amounts of fuel needed to the amount of power needed by your engines. Sorium could simply be something that makes fusion power easily feasible, and that drives the engine.
Would make ice asteroids and gas giants sources of reaction mass at which ships could easily fill up again, say with a maintenance module/facility. Some extra mass dedicated to sorium storage would then allow ships to hop from one reaction-mass point to another so as not to need massive fuel tanks to go all the way.
Also have to second sloanjh's suggestion that the computer work out paths.
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Could I humbly ask that fuel and reaction mass be divided?
Reaction mass could simply be virtually anything your engine throws out the back. Obviously, engine designs will vary depending on the reaction mass used, so each engine design could have another line:
eg.
Reaction mass - H2O
Reaction mass - Inert Gas
This is a really good idea if you want to be realistic. Not so much because of the "different fuels" issue, but because of the interplay between engine mass, fuel mass, and reactor mass.
The way a reaction engine works is that you "burn" fuel in an engine to provide energy to throw "reaction mass" out the back end at some exhaust velocity to generate delta-momentum = mass thrown*velocity thrown. This is what's behind the fundamental difference between airplanes and rockets - the airplane doesn't have to carry its reaction mass - it uses its wings to thrown air downwards, and in the engine it uses the core to drive high-bypass fans to throw more air backwards more slowly than if the fans weren't there. If you go through the equations, this means that airplanes want LOW exhaust velocity, because that gets the most delta-momentum per delta-energy (fuel) (because kinetic energy = momentum^2/(2*mass)). Rockets, on the other hand, need to carry their reaction mass along with them, and pay for accelerating it before it's used. This causes reaction mass consumption to be exponential in the final velocity, btw, in the case where most of your ship is reaction mass. Since you're carrying the reaction mass along, you want to squeeze as much delta-momentum as possible out of each unit of it, so you want HIGH exhaust velocity. Rockets like a titan use combustion products as the reaction mass, while ion engines use a reactor or solar cells for the energy source and heavy ions as reaction mass. So there's a whole host of tech line possibilities:
* exhaust velocity
* fuel efficiency (how much energy is in one mass-unit of fuel)
* engine efficiency (how many mass units of engine it takes to process one mass-unit of fuel)
* fuel type (does the fuel get thrown overboard like rockets or kept on as deadweight e.g. reactor-mass, or is it solar powered)
One more thing to emphasize: if most of the mass of your ship is going to be fuel, you need to use the rocket equation, which says IIRC that the cost in reaction mass will be exponential, i.e. deltaV is something like log(TotalMassInitial/TotalMassFinal).
John
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^I was mainly trying to allow Titan to be a refueling source. You can scoop some helium from Saturn and deposit on Titan or you can Titan's ice.
Also lends some tactical depth as ice asteroids or planets as well as gas giants become refueling sources for reaction mass that limit the delta-v of your ship.
While reactor fuel is what limits the life of your ship, and that needs a population and refineries.
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The need tp seperate engine fuel and reaction mass will only be needed if Steve goes with a thrust/reaction drive. It is entirely possible he plans to use a field manitulation model (ala Weber's "wedge" in the Honor-verse) that does not use reaction thrust.
Grub for pondering
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The equations about burning fuel and delta-v heavily imply a reaction drive.
Field manipulation and reactionless drives have whatever physics you want to give them. Weber's wedge in particular applies an acceleration and according to many instances in the series, bringing things into the wedge does not slow down the ship at all.
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So far the only thing I see is that inertia, and a host of important baggage, is replacing the current inertialess movement system. Whether "conventional" reaction thrust or some yet to be determined thust model based on handwavium and unobtainium that generates a field to influence acceleration and course change is as yet unknown.
My only point is that reaction thrust should not be assumed at this stage.
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Fair enough. I only proposed it as a possible solution to the "ships need too much fuel" problem.
The key points are:
Reaction mass, that makes your ship go, can be easily gotten. IE. full refueling where you have a minor base, no refineries needed.
Reactor fuel, that makes your lights stay on, need to be provided by industry.
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So far the only thing I see is that inertia, and a host of important baggage, is replacing the current inertialess movement system. Whether "conventional" reaction thrust or some yet to be determined thust model based on handwavium and unobtainium that generates a field to influence acceleration and course change is as yet unknown.
My only point is that reaction thrust should not be assumed at this stage.
I just went and actually read closely Steve's initial post, and the rocket equation still applies even if it's a reactionless drive, if you define a equivalent exhaust velocity that I suspect is thrust/fuelBurnRateInMassPerTime. So dV should be Veff*ln(M0/M1). The fuel source, exhaust velocity, engine mass etc. can be abstracted into the engine mass fuel efficiency that Steve already has, if you define "fuel" as "power source + reaction mass, as appropriate". One thing this brings up is that I'm assuming that the mass == volume simplification would be thrown out: mass should == volume - volumeOfFuelAlreadyBurned at the very least (unless the new inertia is volume-based rather than mass based due to some foible of a handwavonium reactionless engine).
John
PS - Just to be clear, I'm not at all invested in which direction Steve decides these things, I'm just trying to point out the Newtonian physics where applicable.
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Will Aurora II use these physics?
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Will Aurora II use these physics?
It will be more of a spinoff of the original for the people who want more realism.
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If Steve wanted to simplify things then the argument could be made (handwaving time) that Aurora drives are variants of matter-anti-matter drives. In this case the actual mass of the fuel is trivial compared to the mass of a ship. The volume could be thought of as the size of the magnetic confinement magic required to contain anti-matter. But then again I'm lazy.
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Will missiles start off at the same velocity as the ship that launches them? So you could do things like whip a missile up to . 1 c or something by charging in to a system, aiming it at the enemy, and letting it use its fuel mostly for maneuvering?
Yes, missiles will start with the velocity of the ship that launched them, so you could use the above tactic. I will be looking at a lot closer at kinetic weapons because with the potential speeds involved kinetic weapons could be deadly. In fact, I will probably be redesigning a significant part of beam weapons mechanics to allow much longer range. In the past, anything above 5 light seconds was impossible on the basis that ships ignoring the effects of inertia could instantly change course. With ships generally following far more predictable courses, beam weapons and kinetic weapons could be fired at great distances and tracked on the map over time like missiles. Ships will be able to make themselves more difficult targets by expending an amount of fuel to make minor course changes or minor changes in velocity but these would use a lot of fuel if they were used as a matter of course (and would make the ship detectable to thermal sensors) so different levels of evasion would likely be employed based on the potential threat. As a counter-counter, kinetic weapons might fire a slowly spreading cloud of small but high speed projectiles. I will also look at point defence being able to intercept kinetic projectiles. All the above is thinking out loud at the moment so it may change when I get down to the coding.
Steve
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Given that this is a computer game, I'm curious why you think a flat rate would be more playable than just having the computer calculate the cost. (Don't take this as a disagreement - I'm just wondering.) It seems to me like most of the movement orders should be set up such that the player tells the computer where the fleet should be and when, and then the computer manages the course calculation. And by "where and when" I really mean a whole host of conditions, such as "least time intercept", "least time zero-zero intercept", "lowest fuel zero-zero intercept within time deltaT", .... The computer would then just use the appropriate formula.
One thing that will vastly change the interface/complexity: will the ships have enough fuel to do continuous max-burns for an interplanetary trip, or will they only be able to do a short burn then coast most of the way. The second one is a lot more in line with the deltaV thing above - the first one means solving quadratic equations....
John
The simplification is really so that players can visualise how much time/effort is involved in a given course change without relying on difficult calculations. I do plan to have information available to the player for least time intercept, zero-zero intercept, etc. and the movement/intercept orders will be using estimated future positions for their destinations rather than current. I am just happier with a simple formula rather than one than can only be calculated by a computer. I could be possibly persuaded otherwise, based on whether the increased realism added more to the player experience, or if players would prefer to be able to quickly calculate course changes in their head.
I seriously doubt spacecraft will have enough fuel for continual max burns. I would guess the majority of time would be spent with engines off.
Steve
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I just went and actually read closely Steve's initial post, and the rocket equation still applies even if it's a reactionless drive, if you define a equivalent exhaust velocity that I suspect is thrust/fuelBurnRateInMassPerTime. So dV should be Veff*ln(M0/M1). The fuel source, exhaust velocity, engine mass etc. can be abstracted into the engine mass fuel efficiency that Steve already has, if you define "fuel" as "power source + reaction mass, as appropriate". One thing this brings up is that I'm assuming that the mass == volume simplification would be thrown out: mass should == volume - volumeOfFuelAlreadyBurned at the very least (unless the new inertia is volume-based rather than mass based due to some foible of a handwavonium reactionless engine).
When you design a ship it will have full load tonnage and standard tonnage. Standard is with nothing loaded and is equal to the full load tonnage minus cargo, colonists, fuel, ordnance and parasites. The mass of a ship for movement purposes is always based on the standard tonnage plus the mass of anything being carried, so as a ship uses fuel, launches missiles or fighters, etc. its mass will decrease and its acceleration rate will increase. Volume, which will be used for FTL drives, is equal to the full load tonnage and never changes.
Steve
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Will Aurora II use these physics?
At the moment Aurora II will be based on normal Aurora, although I haven't touched it in months so it is a long way off; years rather than months. Newtonian Aurora is more of an experiment. The whole concept may not even work once I try it, but I am going to try anyway :)
Steve
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Any comment on the reaction mass / reactor fuel split?
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Oops. I brought up AV:T and didn't even talk about it!
Anyway, the ships in the game have a particular DeltaV (Based on the mass of the ship and power of the engines, much like in Aurora) which can give them a certain amount of velocity change per game segment. A thrust of 1 (About 0.25G of velocity change) imparts enough momentum to accelerate the ship to a movement of one hex a turn, which is 20 kilometers over 128 seconds. Of course, being space, once that momentum is set, you don't need to keep the engines on until you want to change direction :P Rail gun shells and missiles scale off of this mechanic as well, doing more damage as the crossing vector to the target increases. Fast ships can punch a nice sized hole in the enemy, but of course, this consumes more fuel, as turning around for another pass will take a lot of momentum change to move you back. All of the fine math is based on the technology specific to the game, and of course, Aurora has it's own tech (The ships in AV:T use Fusion Torches, and the reactors output 63.5 MW, so it's fairly low in the tech tree compared to Aurora).
And of course, all the other fun stuff like heat that isn't in Aurora :)
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Any comment on the reaction mass / reactor fuel split?
It is unlikely I would go for that. I will just have an engine and fuel. I am trying to simplify where I can while retaining the type of decisions with which you would be faced in a Newtonian environment. It always comes down to complexity vs fun gameplay and trying to find the right balance. For each potential increase in complexity the question is how much would adding this complexity increase the fun. Having reaction mass and reactor fuel would add complexity but I don't think it would add a lot in terms of gameplay and decision making. That doesn't mean the idea of getting fuel from other sources couldn't be used however. Fuel sources are going to be a lot more important in this game and I will definitely be increasing the rate at which you can extract fuel from gas giants. Maybe there are other places you can get fuel fuel too.
Steve
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Make all gas giants have fuel in them. This will help a lot for finding fuel where you need it. Currently I seem to get about 10% of gas giants with fuel. At that percentage it would be easy to have an area with no fuel available.
Brian
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Maybe there are other places you can get fuel fuel too.
Steve
Gas scoops when flying through nebulae perhaps?
Also: such scoops mounted on troop transports when flying through certain nebulae (http://www.fermentarium.com/random-news/giant-cosmic-space-clouds-of-beer/) should increase morale by, well, a lot.
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It is unlikely I would go for that. I will just have an engine and fuel. I am trying to simplify where I can while retaining the type of decisions with which you would be faced in a Newtonian environment. It always comes down to complexity vs fun gameplay and trying to find the right balance. For each potential increase in complexity the question is how much would adding this complexity increase the fun. Having reaction mass and reactor fuel would add complexity but I don't think it would add a lot in terms of gameplay and decision making. That doesn't mean the idea of getting fuel from other sources couldn't be used however. Fuel sources are going to be a lot more important in this game and I will definitely be increasing the rate at which you can extract fuel from gas giants. Maybe there are other places you can get fuel fuel too.
Steve
in Traveller and Megatraveller,the fuel Giant's operation in fuel scoop..for a Fleet become.."crucial" in Time of war..
Do u remember sure..
Gas Giant are carefully planned in a Fleet Jump route task
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I steadily grew a bigger smile while reading this, which survived through meetings and lunchbreak whenever I came back.
I commend your effort!
Even if it doesn't play out well, it's an interesting experiment.
I just love to ponder the possibilities.
How will the FTL work out?
I suppose if you get something for that, which is not entirely newtonian, the question is why is that not possible to be used in systems as well, a lot weaker?^^
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I for one would like to see more use for "real" materials. Superdense Unobtanium that allows for electrical control of gravity is great, but it's hard to imagine a superdense material that would be stronger by weight than. . . well, damp cardboard really. The island of stability is really high up there, and some hidden island would be even worse. Titanium and steel (or rather, alloys of those) will probably be used for the next few thousand years at least.
A fusion-moderating superdense element could be reasonable. Perhaps it's some kind of fusion catalyst, which briefly fuses to two hydrogen atoms, then rapidly degrades to itself and a helium, spitting out heat and collectable particles.
Hey wait that actually sounds like it would work. I'm going to go see if I can get a grant for this.
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Few comments.
First of all, if the effects of gravity is being ignored, isn't it possible for the effects of acceleration to be ignored or at least reduced? I am thinking of an inertial drive, something that is in fact simpler than artificial gravity. It is simply the ability for all objects in the ship to accelerate at the same time, as opposed to the hull accelerating and pushing on your body, which in turn accelerates it, but can kill it if it is too much. A super-efficient chair strap. You still need to be able to survive the gravity, but it'll be constant over your whole body and not crushing which helps lots, though this relies on artificial gravity.
This could possibly be a tech tree on its own, where without it you can only have a max delta-v of 5x-10x of your race's gravity tolerance, but with higher tech can be more. (Or bred crew with higher g tolerance, different from usual engineering of population with lower g tolerance who colonise moons. )
Second thing I'd like to add is the concept of escape velocity and orbits. Essentially to orbit (at ground level) earth, you are travelling at 11. 2 km/s. If you leave earth all you have to do is be nudged out of orbit and you have already attained that speed, no need to accelerate from 1km/s. Well, that's at ground level. Wikipedia says the actual low earth orbit speed is at maximum 8. 2 km/s, but that can be calculated I am sure.
My suggestion is that when entering and leaving an orbit you only have to speed up from the source's orbit velocity and only brake to the destination's escape velocity. This isn't that much difference for earth, but with Jupiter having an escape velocity of 59. 5 km/s it could add up, if ever so slightly, especially since this also invokes free course changes at this (low) speed.
Now what I am REALLY thinking is that the Sun's escape velocity is 619 km/s. Starting at that speed on spotting an enemy could be a SIGNIFICANT advantage. Course, you need to be far away enough from the Sun to not be toasted so that figure would be significantly slashed, but I can imagine a starting speed of 300 km/s already being a possible consideration for advanced races, esp for black hole systems which have even LARGER time dilated orbit speeds.
On time dialation, I'd like to see military ships travelling at relativistic speeds (or very near INTENSE gravity) having their maintainance clock slowed. It is unlikely to often happen so would be a small check with usually a small effect, but it is just that extra touch of detail without adding extra micro-management that Aurora is famous for. Might happen more often and be more relevant to inter-system travel which by necessity is FTL, if jump points aren't used.
On to accelerators. You have mass drivers, why not a mass driver for a ship? Imagine a launching platform with intense engines that can throw out fighters or even larger ships at 2000 km/s or more. This could even be miles and miles long to allow less of a gravity delta, but would likely rely on inertial and gravity technology for anything manned. Once you have accelerators though there is no reason you can't have them 'catch' too, reducing the delta-v needed for ships to leave and enter orbit(possibly at a fuel cost). If this is something that like shipyards need to be built or tugged this will mean an advantage for any race acting in its 'home' system, though a critical piece of infrastructure to reduce the costs of running an empire. I can even imagine engineless ships being flung intra-system, accelerated and decellarated only at the endpoints by these accelerators.
Now extending accelerators to missiles. There's no reason for missiles to start at the same velocity as the ship, when the ship can offer a boosting thrust. Since missiles are unmanned these accelerators can be shorter and more powerful than for ships. This will directly affect the fuel needed for missiles and through that their range. This will also mean that missile launchers on ships will have more tech variables than just reload speed and size and be something that actually needs to be updated with advancing technology. Such missiles can potentially operate with no fuel at all, having only enough to maneuver and course correct as it approaches its target. Also that the same missile launched with two different launchers can act VERY differently, either a powerful launcher with more range and less agility(harder to course correct a faster object) or a less powerful launcher with the reverse. I am unsure whether this extra complications of an already complex missile design system is needed, but it follows naturally from the accelerators idea above.
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The simplification is really so that players can visualise how much time/effort is involved in a given course change without relying on difficult calculations. I do plan to have information available to the player for least time intercept, zero-zero intercept, etc. and the movement/intercept orders will be using estimated future positions for their destinations rather than current. I am just happier with a simple formula rather than one than can only be calculated by a computer. I could be possibly persuaded otherwise, based on whether the increased realism added more to the player experience, or if players would prefer to be able to quickly calculate course changes in their head.
I seriously doubt spacecraft will have enough fuel for continual max burns. I would guess the majority of time would be spent with engines off.
Steve
I think the simple formula would be best. I really have doubts that this endeavor, while notable for seeing if it will actually work, will end up actually be more of a simulation than a game. I could be wrong and it may actually be fun. But I for one am not going to sit and calculate out intercepts for one Task Group let alone multiple ones as the empire grows. It's too easy to make a mistake and miss an intercept and it becomes trial and error. And frustrating.
Also what would happen when a Task Group runs out of fuel? Does it keep on going forever?
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I think the simple formula would be best. I really have doubts that this endeavor, while notable for seeing if it will actually work, will end up actually be more of a simulation than a game. I could be wrong and it may actually be fun. But I for one am not going to sit and calculate out intercepts for one Task Group let alone multiple ones as the empire grows. It's too easy to make a mistake and miss an intercept and it becomes trial and error. And frustrating.
I would imagine that we would be able to 'lay courses' which would do our calculations for us, point at a destination and it'll tell us the fuel and time it will take to complete same as now. Maybe even the ability to plot unbuilt designs with varying loads and burns? This will allow us to be warned whether or not our new freighter design will actually be able to make it to the colony next system over or not. This would of course need new UI elements that are not in the game just yet.
Also what would happen when a Task Group runs out of fuel? Does it keep on going forever?
Pretty much. Rescue is still possible, but will require a pretty fast and maneuverable ship with high fuel capacity.
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I would imagine that we would be able to 'lay courses' which would do our calculations for us, point at a destination and it'll tell us the fuel and time it will take to complete same as now. Maybe even the ability to plot unbuilt designs with varying loads and burns? This will allow us to be warned whether or not our new freighter design will actually be able to make it to the colony next system over or not. This would of course need new UI elements that are not in the game just yet.
Pretty much. Rescue is still possible, but will require a pretty fast and maneuverable ship with high fuel capacity.
And so.."Run Out of Fuel" situation become VERY bad situation:)
Age's Fleet disapears into void space..:)
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Bad planning makes you a very dead man. I like.
As for fuel, now that we have our super handwavium materials, couldn't we use them in addition to a few base materials available on every planet, abstractes as metal, fossil fuels, and 'other stuff'?
You could just require two types of fuel, a bit of sorium fuel for everything and regular fuel you'd get from any atmosphere or gas giant for most movement.
Then players could temporarily boost their ships by directly burning Sorium, which would be very expensive but might get you to the next gas giant.
I'm intrigued how the general system will influence ground combat, I'd expect planetary invasions to become a bit more common if space combat is sufficiently complicated.
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Traveller@ and Megatraveller@ use two fuel:
Refined and Raw
Refined from fuel scoop and ok for Jump Engines.
Raw for power plants and for Emergency Jump operation but can lead into a mistake jump or engine blow up..:)
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Gas scoops when flying through nebulae perhaps?
Also: such scoops mounted on troop transports when flying through certain nebulae (http://www.fermentarium.com/random-news/giant-cosmic-space-clouds-of-beer/) should increase morale by, well, a lot.
The Space Empires series has atmospheric scoops :)
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Another update - this time on FTL Drive design. FTL Drives replace Jump Drives in Newtonian Aurora. In the create research project window, they have five design parameters:
FTL Drive Efficiency: This serves the same function as jump drive efficiency, except it starts at efficiency 4 rather than 3 and each level is half the cost in research terms. For example, efficiency 6 is 8000 RP instead of 15,000 RP. In Newtonian Aurora you won't be able to use a gate to get between systems so non-FTL-capable ships can only be moved between systems via squadron jump or in hangar bays. Therefore FTL drives will be a lot more common than jump drives.
Max FTL Squadron Size: The same as standard Aurora, except that squadrons will travel through hyperspace together rather than through jump point. There will only be squadron jumps as there are no jump points to hold open. Creating drives that can jump multiple ships is easier though as the base drive can handle four ships and the research costs are half as much as before.
Hyperspace Dimension: The hyperspace dimension through which the ship or squadron will travel. Higher dimensions bring real space locations closer together and increase effective speed. Each dimension is rated for the speed multiplier it provides. The Alpha Dimension is 500x speed, the Beta Dimension is 1000x, Gamma is 1500x, etc.
Base Size: The base size of the FTL drive. This is comparable to the size of a military jump drive in standard Aurora, although there is no distinction between military and commercial drives in Newtonian Aurora.
FTL Size vs Stealth: It is possible to increase the base size of the drive without affecting cost or crew requirements, in order to create drives for much larger ships such as freighters. This has a penalty though. Each of the size modifiers has an effect in sensor blindness and drive flare. The x1 size modifier is the normal drive, causing no blindness and resulting in no drive flare. The 1.5x size modifier causes 15 minutes of sensor blindness and causes a drive flare equal to the arrival speed. Drive flares can be detected by EM sensors. The 2x size modifier causes 30 minutes of sensor blindness and causes a drive flare equal to double the arrival speed, et cetera. The size modifiers go up to size x10, which has 32 hours of sensor blindness and a drive flare equal to 10x speed, which is obviously not a good idea if you want to arrive unseen or detect anything else. However, it is probably fine for a freighter or colony ship travelling in known space.
Example: Here is a military-style drive intended for a ship of 6000 tons. This uses the efficiency 8 (15k RP), the Delta hyperspace dimension (8000 RP) level and the base squadron size (2000 RP)
Combat FTL Drive
Max Ship Size: 120 (6000 tons) Max Squadron Size: 4 Speed Multiplier: 2000
Jump Engine Size: 15 HS Efficiency: 8 Jump Engine HTK: 3
Sensor Blindness: None Drive Flare: None
Cost: 56 Crew: 75
Materials Required: 11.2x Duranium 44.8x Sorium
Development Cost for Project: 560RP
Here is exactly the same drive but with the max size modifier
Commercial-style FTL Drive
Max Ship Size: 1200 (60000 tons) Max Squadron Size: 4 Speed Multiplier: 2000
Jump Engine Size: 150 HS Efficiency: 8 Jump Engine HTK: 3
Sensor Blindness: 32 hours Drive Flare: 10 x Arrival Speed
Cost: 56 Crew: 75
Materials Required: 11.2x Duranium 44.8x Sorium
Development Cost for Project: 560RP
FTL Travel
Travel between different star systems is only possible using an FTL drive (although you never know - sub-light generation ships might make an appearance at some point). Stars have a hyper limit, inside which it is not possible to activate an FTL drive. This limit is equal to primary star mass squared, multiplied by three billion kilometers. For Sol, this is about the orbit of Uranus. In order to reach another star system, the FTL-capable ship or fleet has to align ltself with the destination system. This can be done using the new "FTL Align and Jump" order. Until the ship is on an exact course for the destination it will be unable to jump. Aurora will automatically make course corrections (using any available DeltaV) in order to align while this order is in effect. You will also be able to optionally specify a minimum jump speed so the ship will not enter FTL until it reaches the desired speed.
At this point, you wil lose contact with the ship and be unable to communicate until it reaches its destination system, which may be a period of weeks or months. If a full gravitational survey of the destination has been carried out, the ship will arrive with approximately the same speed at which it entered hyperspace, on a bearing from the primary within six degrees of the direct course from the start system and at a range from the primary between 100% and 110% of the hyper limit radius. If the destination system has not been surveyed at all, the location of arrival could be anywhere in a toroid, between 100% and 170% of the hyper limit distance, on any bearing from the star. The heading of the ship will still be directly away from the start system so you could end up on a course perpendicular to your destination, or even beyond it and heading away. A partial survey of the destination will result in a scenario somewhere between the two extremes. A lack of survey information could also result in the ship arriving slower or faster than expected, although within 30% of departure speed, and correspondingly earlier or later than expected. Because the ship is out of contact, you will be unable to determine the likely arrival point ahead of its arrival.
This uncertainty will make assaults on unsurveyed systems 'interesting' to manage. As well as the obvious issue of coordinating multiple squadrons, it will be a lot harder to pull out of an assault if things are not going well. To return to their starting system, ships will have to slow to zero and then begin accelerating along a reciprocal course. Another option may be to escape to another system that is on an easier escape course, fuel permitting. One other result of the above is that there will be far more 'spreading out' of civilian traffic rather than the current situation where ships tend to travel in large groups.
The speed at which interstellar travel takes places is equal to the speed at which you enter hyperspace multiplied by the speed multiplier of the FTL Drive. For example, if a ship using the drive shown above entered hyper at 8000 km/s, its effective speed would be 8000x2000 km/s, which is about 53x light speed. A journey to Alpha Centauri would therefore take about a month and a journey of ten light years would require about 10 weeks. Ships cannot accelerate or decelerate within hyperspace so the decision is whether to expend fuel and time to reach a high speed before entering hyperspace, or to enter at lower speed, saving fuel but extending journey time.
Steve
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That's a truly impressive number of moving parts.
I look forward to encountering and solving those problems. =)
Add that to the delta-V budget of ships, and I think Aurora FTL could easily qualify as one of the most complicated games to play. Ever.
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I like it, a lot.
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with the random appearing in the system, wouldn't it be realistic to add the "oh hell"-unluck factor of ending up on a crash course against an asteroid? or a planet? or a moon.
"commander we have reach...CHANGE COURSE CHANGE crhshhhhhhhH"
"what do you mean we lost signal with the ships!?"
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That looks awesome.
Will it be possible to hyperjump between planets in large Multi-star systems, like todays Hyperspeed engines in normal Aurora?
And will planets have jump limits as well?
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This looks great, yet more significant decisions to make that can come back to haunt you months after you have made them. Couple of things:
- Do you plan on having a representation on the galactic map of estimated progress of fleets in hyperspace? I can see it getting very easy to loose track of ships if not.
- One thing that I don't see on that list of attributes is hyperspace jump range, I was kinda hoping that there would be limits on this that create choke points and central systems.
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Just to add in yet another equation:
The velocity triangle involved in a course change can be easily calculated using the law of cosines, which allows calculation for more than just simple heading changes at fixed speed.
dv^2 = vi^2 + vf^2 - 2*vi*vf*cos(theta)
Here dv is the delta-v required to perform the course change, vi is the initial speed, vf is the final speed, and theta is the smallest angle between the two headings. (Generally, you wouldn't perform more than a 180 degree course change. If you wanted to change course by 270 degrees, you'd just turn 90 degrees the other way, since we're not taking combat-level facings into account).
In the case where you're ONLY making a heading change, and you want your initial and final speeds to be the same, the equation reduces to:
dv^2 = 2*vi^2*(1 - cos(theta))
Also, I love that FTL system, and I'd kind of like to see it replace jump gates even if the rest of the Newtonian system turns out to be unplayable.
This correctly reduces to dv = 2 * vi for the case of 180 degrees. (cos(180 degrees) = -1).
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Steve, you can´t do this!
You are going to kill what little is left of my social life!
;D ;D ;D
Seriously, this sounds absolutely awesome!
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Steve, you can´t do this!
You are going to kill what little is left of my social life!
;D ;D ;D
Seriously, this sounds absolutely awesome!
Yeah...
Also, slightly off topic, but will we get solar sails with Newtonian physics?
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So, send in stealth grav survey ships, then assemble a fleet of large ships with a large-squadron jump ship, all equipped with box launchers.
Then jump to the target system at high speed and do a drive-by nuclear holocaust to anything that'll stand in the way of the ground troops.
I like it.
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Ladies and gentlemen, we have what is probably the first time in history the term "drive by nuclear holocaust" has ever been used.
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I feel proud to be witness to such a historic moment. ;D
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I feel proud to be witness to such a historic moment. ;D
+1
Second,
i like it,VERY much.
"FTL drive.." "between star system.." "lost commo with Fleet on FTL warp.."..
Slurp..
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I have been doing some work on the galactic map as the old one is not much use for the new FTL model. Based on feedback in the other thread I have decided to start with a random map for the purposes of trying out the newtonian model and later I will add some form of 2D real stars map that is a squashed flat version of the real thing. Attached are a couple of screenshots. Still work to do but this will be enough to give a general idea. The purple area are nebulae.
Steve
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Looks good: what impact will nebulae have on this version of Aurora?
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Need a pre-pre-pre-Alpha tester? :)
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looks great!
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My dreams coming true! Thanks Steve!
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Looks good: what impact will nebulae have on this version of Aurora?
They will impose on upper limit on FTL speeds, although I haven't decided the formula yet, and a similar limit to the current one for in-system speeds. Accelerating beyond that limit will probably be possible but dangerous.
Steve
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Steve,
Re your example Galactic maps - would all stars be visible on the map from commencement of game or would one need to locate them as per the "standard" version.
Also do you envisage having the same average number of stars / galaxies as per the standard - i.e 1,000.
DavidR
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Steve,
Re your example Galactic maps - would all stars be visible on the map from commencement of game or would one need to locate them as per the "standard" version.
Also do you envisage having the same average number of stars / galaxies as per the standard - i.e 1,000.
DavidR
All systems will be visible at the start and you will know what stars are in each system. However, the planets, moons, asteroids, etc for each system will only be generated when the first ship makes an FTL jump to that system. I am using 250 systems for my test game. The total number of systems can be lower than standard Aurora as one of the reasons for the high number is avoiding a lot of jump point loops, rather than the intention to visit every system.
I currently have two gravitional survey ships and one geological survey ship at work in Sol, using default orders. Everything is working OK so far and the ships are accelerating and decelerating by themselves as required. It is taking significantly longer to carry out surveys than before. One other difference from standard Aurora is that orbital movement now takes place during the regular movement phase rather than during the 5-day increment. This is a slight overhead but it will be offset by the fact that no jump chain calculations will be required when I get around to pathfinding for NPRs and Civs.
One other note is that hyper drive and lagrange points won't be in Aurora FTL. You will now be able to reach much higher speeds given sufficient time so travel between different stars in the same system will be far more practical.
Steve
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Can you make the test version available to download to help find bugs? ;D
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Can you make the test version available to download to help find bugs? ;D
At the moment it is nothing but bugs :) and only a small proportion of the functionality works. I am working my way through the program, updating and fixing as I go. Once I get to the point where you have to look for bugs instead of being mobbed by them I will release a test version.
Steve
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Steve if i would have some sort of crazy overengineered ion-drive (like we usein present day probes) with enough fuel to reach relativistic speeds, would it be possible to snail my way into another system?
There is a small number of stars that are "reachable" from earth in reasonable time for exmple proxima and alpha Centauri which are 4.22 Ly and 4.36 Ly away respectivly.
How will massdrivers work or will they be removed?
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Steve if i would have some sort of crazy overengineered ion-drive (like we usein present day probes) with enough fuel to reach relativistic speeds, would it be possible to snail my way into another system?
There is a small number of stars that are "reachable" from earth in reasonable time for exmple proxima and alpha Centauri which are 4. 22 Ly and 4. 36 Ly away respectivly.
How will massdrivers work or will they be removed?
I was thinking much the same thing myself- sleeper ships would be fun to have.
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Slightly off topic but could be of interest. Just finished reading "through struggle, the stars" by John Lumpkin. Aside from being a pretty good read I thought it had an excellent take on combat in a Newtonian environment and has some very good points:
- Basically no one does head on attacks because the closing speeds given so much kinetic energy to any slugs that it's pretty much suicide for both sides.
- Missiles tend to get shot down a lot but when they do get through they are pretty devastating. These are also basically MIRVS with lots of flechettes.
- Rail guns etc are used to help command the combat space rather than trying to hit things in most cases ie fill a section of space with a lot of lead to stop your enemy moving there and limiting their ability to undertake evasive mans.
- Lasers are the main close in armament. There is also an interesting concept of an overall laser wattage that can be directed between the offensive lenses and the defensive ones which gives captains some interesting decisions as to how aggressive they want to be.
Anyway perhaps some food for thought!
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- Rail guns etc are used to help command the combat space rather than trying to hit things in most cases ie fill a section of space with a lot of lead to stop your enemy moving there and limiting their ability to undertake evasive mans.
Thats horrifying. Talk about space junk for eternity.
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Thats horrifying. Talk about space junk for eternity.
And a million years later , a young race, only years after its first successful launch of a satelite, will have a very bad day
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As long as you don't attach a return address, I'd say thats fine. :-X
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Steve if i would have some sort of crazy overengineered ion-drive (like we usein present day probes) with enough fuel to reach relativistic speeds, would it be possible to snail my way into another system?
There is a small number of stars that are "reachable" from earth in reasonable time for exmple proxima and alpha Centauri which are 4.22 Ly and 4.36 Ly away respectivly.
That won't be within the scope of the game. Systems are still separate entities even though the method of travel between them has changed. I guess it could by simulated though by using slower than light FTL :)
How will massdrivers work or will they be removed?
They will work as before. They are inert chunks of rock propelled by planet-based mass drivers so they aren't affected by the changes in propulsion.
Steve
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Slightly off topic but could be of interest. Just finished reading "through struggle, the stars" by John Lumpkin. Aside from being a pretty good read I thought it had an excellent take on combat in a Newtonian environment and has some very good points:
- Basically no one does head on attacks because the closing speeds given so much kinetic energy to any slugs that it's pretty much suicide for both sides.
- Missiles tend to get shot down a lot but when they do get through they are pretty devastating. These are also basically MIRVS with lots of flechettes.
- Rail guns etc are used to help command the combat space rather than trying to hit things in most cases ie fill a section of space with a lot of lead to stop your enemy moving there and limiting their ability to undertake evasive mans.
- Lasers are the main close in armament. There is also an interesting concept of an overall laser wattage that can be directed between the offensive lenses and the defensive ones which gives captains some interesting decisions as to how aggressive they want to be.
Anyway perhaps some food for thought!
I have also read the book recently and I think some of the above will be relevant in Aurora FTL. Missile combat is certainly going to be almost unrecognizable from standard Aurora (I'll explain why in a separate post) and kinetic weapons could become more effective. I am currently looking at whether you could use a large railgun to launch a missile in order to provide a greater initial velocity.
Steve
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Missile Design - Part 1
Missile design is going to change significantly for Aurora FTL. The major changes are as follows:
1) Agility will no longer exist as actual interceptions will be calculated. If the missile manages to intercept the ship it will hit 100% of the time. However, you will be able to try to physically avoid it by changing course. If the missile cannot generate the necessary Delta-V to intercept it is going to miss. However, unlike Aurora, the missile is going to keep trying to hit until you destroy it or it loses its ability to maneuver by running out of fuel. Therefore the missile agility tech progression has been removed.
2) Missile engines are now designed in the same way as shipboard engines and you can have multiple engines per missile. The missile engine tech progression has been removed as you can use the normal engine tech progression for missiles. More on this later
3) The concept of MSP (missile space points) has been removed. In terms of size, Missiles are now simply rated in tons and launcher sizes will be adjusted accordingly. When allocating size to a missile, one ton will provide the same effect for warheads as 1 MSP used to do, which means warhead strengths per ton have been increased by 2.5x. However, they are going to need a lot more fuel than before so missiles will generally have smaller warheads as a percentage of total missile size.
4) There are no longer missiles, drones and buoys. There are simply missiles. The flexibility in the new design process will allow you to cover the abilities of all three previous missile categories. The drone engine tech progression has been removed.
5) Missiles have to accelerate, just like ships, so they are going to be less effective overall and far less effective at close range. Anti-missiles are going to be less effective too but, due to lower expected missile speeds in many cases, energy-based point defence is likely to become more effective.
Missile Engines
The four elements of missile engine design are described. It is probably worth reviewing the detail on ship engines contained in the original post in this thread before reading the details of missile engines.
Engine Technology: Exactly as ship-based engines. However, the base value of power is doubled on the basis that missile engines have no radiation shielding or maintenance access requirements. Power output is rated in meganewtons. For example, the Internal Confinement Fusion Drive has a rating of 2 MN per HS, so a missile engine of 1 ton would provide (2MN/50) x 2 (missile power modifier) or 0.08 MN.
Engine Size: Missile engines can be from 0.1 tons to 5 tons in 0.1 ton increments.
Base Fuel Efficiency: As with ship engines, a Sorium-based missile engine is rated in the number of litres of fuel per hour it consumes. This amount is derived from Engine Power x Fuel Efficiency. So an Engine with 0.08 power and a fuel efficiency of 12 would consume 0.96 litres of fuel per hour at full burn.
Engine Power / Fuel Efficiency Modifiers: Sorium-based missile engines use the same principle as ship engines and use the same tech lines (Max Engine Power Modifier and Min Engine Power Modifier). However, the upper end of the range is doubled for missile engines. So if the Max Engine Power tech is 175%, missile engines can use up to 350%, again with the rationale that these are designed for single use, unmanned craft and therefore have significantly different engineering requirements. As with ship-based engines, increasing thrust has a significant effect on fuel efficiency and decreasing thrust can provide huge savings in fuel efficiency. As the missile modifer is double that of ships, power can be increased by up to 600% of normal and decreased to 10% of normal if you have the prerequsite techs. The dropdown on the design window has options from the minimum possible to the maximum possible in 5% increments. So 40%, 45%, 50%, 55% ...... 180%, 185%, etc. Each engine power modifier percentage is accompanied by a fuel efficiency modifier, based on the formula Fuel Efficiency Modifier = (10 ^ Engine Power Modifier) / 10. So a missile with a 500% engine power modifier would have a 10,000x fuel modifier.
Unlike ship engines, you have the option to use chemical-based rocket engine technology. In this case, the chemical-based technology has its own fuel efficiency which is not modified by the Racial Base Fuel Efficiency or the Engine Power / Fuel Efficiency modifier. The engine power of chemical technology can not be modified either. Available as starting technologies are the LOX/LH2 Rocket Engine, which has a fuel efficiency of 800,000 and a base engine power of 35, and the LOX/RP-1 Rocket Engine which has a fuel efficiency of 1,100,000 and a base engine power of 45 (including the x2 power modifier for missiles). There is also an Advanced LPX/RP-1 Engine with an engine power of 70 which can be developed. Actually this was developed by the Soviet Union as the NK-33 but the US didn't develop equivalent tech. In a multi-nation start this could be SM-assigned to Russia. As you can imagine, Chemical engines need a LOT of fuel. Those figures are based on converting modern day rocket engines to Aurora fuel efficiencies and demonstrate how incredibly fuel efficient Sorium-based engines are.
As I have figured out how to convert modern-day rockets in Aurora numbers, there is an option to enter modern-day rocket engines into Aurora and use them as part of missile design. You have to enter name, thrust in meganewtons, mass of the engine and specific impulse (Isp). Aurora uses the specific impulse to derive the fuel efficiency, which is 367,099,200 / Isp. That number is derived from the formula to convert Isp into thrust-specific fuel consumption (TSFC), which is 101972/Isp. TFSC is used today to calculate fuel consumption per unit of power. This is nominally grams per Kilonewton second, but is equally correct for kilograms per meganewton second or litres per meganewton second. As Newtonian Aurora hourly fuel consumption is based on engine power (in meganewtons) x fuel efficiency, then TFSC multiplied by 3600 is equal to Aurora fuel consumption. Converting in the opposite direction means that (101972 x 3600)/ISP = Aurora fuel efficiency.
For example, if you enter the Space Shuttle Main Engine (SSME), which has thrust of 2.18 MN, mass of 3.177 tons and Isp of 453 in vacuum, Aurora uses the name, mass and thrust directly and converts the Isp into a fuel efficiency of 810,373.7. Using that SSME in a missile design shows a fuel consumption rate of 490.73 litres per second. The TFSC of the real SSME is 225, which multipled by the 2.18 MN thrust equal a consumption of 490.73 litres per second. So you can use real rocket engines with real rates of fuel consumption. Of course this is still massively simplified from real world considerations but it will provide the right flavour for the game. It also will be hard to achieve anything major with modern day engine technology but you can try :). As the fuel for chemical rockets will be far more accessible than Sorium, it will be considered to be easily made by ordnance factories and not tracked in terms of cost or storage. Obviously once it is in the missile, the chemical fuel will be tracked.
Anyway back to sorium-based engines. Here are four two ton missile engine designs using Ion engine technology and a base fuel efficiency of 14. The first uses Engine Power Modifier x1, Fuel Modifier x1.
Fuel Efficient 80 KN Missile Engine
Power Output: 0.08 MN Fuel Efficiency: 14 Thermal Signature: 0.8
Base Acceleration: 40 mp/s (4.08G) Per Min: 2.4 km/s Per Hour: 144 km/s
Fuel Use at Full Burn: 1.12 litres per hour
Engine Mass: 2 tons Cost: 0.4 Crew: 0
Materials Required: 0.1x Tritanium 0.3x Gallicite
Development Cost for Project: 40RP
Note that while this is more powerful in terms of thrust-weight ratio than a ship-based engine and doesn't use much fuel in missile terms. It would take an hour to accelerate itself to 144 km/s and that assumes no fuel mass. Shown below are three designs using engine power modifiers of x2, x3 and x3.5 respectively. (3.5x requires the max engine boost 175% tech, which is 8000 RP). Note the acceleration rate increases but the fuel consumption goes up very quickly indeed.
160 KN Missile Engine
Power Output: 0.16 MN Fuel Efficiency: 140 Thermal Signature: 1.6
Base Acceleration: 80 mp/s (8.16G) Per Min: 4.8 km/s Per Hour: 288 km/s
Fuel Use at Full Burn: 22.4 litres per hour
Engine Mass: 2 tons Cost: 0.8 Crew: 0
Materials Required: 0.2x Tritanium 0.6x Gallicite
Development Cost for Project: 80RP
240 KN Missile Engine
Power Output: 0.24 MN Fuel Efficiency: 1400 Thermal Signature: 2.4
Base Acceleration: 120 mp/s (12.24G) Per Min: 7.2 km/s Per Hour: 432 km/s
Fuel Use at Full Burn: 336 litres per hour
Engine Mass: 2 tons Cost: 1.2 Crew: 0
Materials Required: 0.3x Tritanium 0.9x Gallicite
Development Cost for Project: 120RP
280 KN Missile Engine
Power Output: 0.28 MN Fuel Efficiency: 4427.1892 Thermal Signature: 2.8
Base Acceleration: 140 mp/s (14.28G) Per Min: 8.4 km/s Per Hour: 504 km/s
Fuel Use at Full Burn: 1239.613 litres per hour
Engine Mass: 2 tons Cost: 1.4 Crew: 0
Materials Required: 0.35x Tritanium 1.05x Gallicite
Development Cost for Project: 140RP
Finally, here is a 2 ton LOX/LH2 rocket engine, similar in technology to the space shuttle main engine - note the fuel use is shown per minute, not per hour. Also bear in mind all the acceleration figures are for the engine alone with no fuel mass and no payload.
1400 KN Missile Engine
Power Output: 1.4 MN Fuel Efficiency: 800000 Thermal Signature: 14
Base Acceleration: 700 mp/s (71.38G) Per Min: 42 km/s Per Hour: 2520 km/s
Fuel Use at Full Burn: 18,667 litres per minute
Engine Mass: 2 tons Cost: 7 Crew: 0
Materials Required: 1.75x Tritanium 5.25x Gallicite
Development Cost for Project: 700RP
As you can see from the above designs, once you add fuel and payload, getting a missile up to an appreciable speed is going to take some time and there would be little point firing missiles at a fast moving ship if the missiles can't even match its speed for several hours. On the other hand, missiles fired from three or four billion kilometers away will be going pretty fast when they reach their target. Also bear in mind that missiles will be able to switch off the engines mid-flight once they reach a pre-designated speed and use any remaining fuel for course corrections so they have an effectively unlimited range - just as they would in reality. Finally, the missile is going to have an initial speed and heading equal to that of the launching ship so firing at pursuers is going to be tricky. Missile combat is going to require a lot of planning and will depend a lot more on targeting and course correction than missile range. I'll cover the specifics of missile design in the next post.
Steve
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This sounds like Laser warheads will be a lot more useful since they wouldn't require a direct hit against a target that might be accelerating wildly. Will there be any additions to this technology?
Also, if a missile reaches it's chosen terminal velocity and shuts down its engines, will that lower its thermal reading? Seems like keeping active sensors going might be more important if a wave of powered down missiles might smash into your fleet without warning.
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So will we get missile launchers that base on Railgun or Massdriver technology? I would favor a massdriver for missiles. Willit be possible to have purely kinetic missiles?
That won't be within the scope of the game. Systems are still separate entities even though the method of travel between them has changed. I guess it could by simulated though by using slower than light FTL Smiley
I hope that works for drones too. It would be neat to send a sensor drone into an unexplored system ;) .
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I'm drooling onto my keyboard a bit, here.
It would be neat to send a sensor drone into an unexplored system ;) .
Or relativistic nukes into an inhabited.^^
Isn't it pretty pointless for a missile to turn and try again?
It'll take days before it reaches the required speed if the target just runs past it.
And how will active ECM impact a missiles accuracy?
Will it just give out false targets?
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Isn't it pretty pointless for a missile to turn and try again?
It'll take days before it reaches the required speed if the target just runs past it.
But it will take days to get to the required speed the first time too, so what's the difference? And if the enemy isn't expecting it because the missiles all missed and weren't detected, they can still do a lot of damage.
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The other consideration is the relative vectors of the missiles and the target. If they are close enough then the missile doesn't need to make a big correction. If however they were on oposite courses then the missile doesn't have a chance to turn around, and catch up anytime quickly.
brian
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If a missile misses, what about retargetting? Turning around may or may not be practical, but what if when it misses it will consider other targets, if it has a sensor on it.
Also, what about evasive maneuvers? No need to run away from missiles if you just add a little random walk into your motion, but keep heading same way, use up fuel to create random delta-v's to mess up and make less predictable any predictive targeting on both non-light speed kinetics and missiles. Maybe lasers too if their range is increased to well past 300k, aka a light-second. The effectiveness of evasive manuevers will of course depend on both the max delta-v of the engines and fuel being used, as well as distance from the sensor and the weapon.
Hmm, I might need to calculate that... how much delta-v do you need so that after 1 second you have displaced your entire cross-section from where it would have been had you not thrusted?
Additionally... limited ranges on lasers kinda make more sense now I think of it in these terms, even if not how its wavelength affects it. Lasers can work from the other side of the system, but... its practicality at those distances is suspect indeed, since even at a measely 50 million km you need to know where your target will be in 166.7 light-second in order to actually hit your target. And PDCs often have atmosphere that protects it from being hit at those ranges, even if prediction is much easier then.
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So will we get missile launchers that base on Railgun or Massdriver technology? I would favor a massdriver for missiles. Willit be possible to have purely kinetic missiles?
I hope that works for drones too. It would be neat to send a sensor drone into an unexplored system ;) .
OOoooo... I like the concept. One more unification, and it makes sense- it's a continuum between fast-moving, simple, preaccellerated projectiles, and slow, expensive, self-propelled warhead devices.
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OOoooo... I like the concept. One more unification, and it makes sense- it's a continuum between fast-moving, simple, preaccellerated projectiles, and slow, expensive, self-propelled warhead devices.
guided projectiles, projectiles with warhead, kinetic missles
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Actually, instead of just flatly combining all of them, Steve could change Railguns, Gauss cannons, and Missile launchers to all have a shared "Magnetic Accelerator Launch Velocity" tech. Missile Launchers would then have some alternate launch methods, maybe lower tech than magnetic accelerator. In David Drake's RCN series, they launch their missiles just using steam which I thought was deceptively simple and elegant for a civilization that's literally hopping in and out of the universe regularly and uses antimatter/matter annihilation drives for missile engines.
Additional alternate methods could be like... A modified Carrier launch catapult, for box launchers just letting it shoot off inside of the VLS... I know there's a couple of other potential ideas, but my sleep-deprived mind cannot fathom them at the moment.
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I have been doing some work on the galactic map as the old one is not much use for the new FTL model. Based on feedback in the other thread I have decided to start with a random map for the purposes of trying out the newtonian model and later I will add some form of 2D real stars map that is a squashed flat version of the real thing. Attached are a couple of screenshots. Still work to do but this will be enough to give a general idea. The purple area are nebulae.
Steve
AWESOME!! damn..
Looks good,Steve!!! going on:))
Ahhh a "Aurora New Era" (@)
eheheh same as "traveller New Era"..:)..ur map seem like as "2300 AD"..:)
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@Steve : any idea when ur Newtonian can come into playable situation? (zzz..my english...)
December? January 2012?..more later?
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Isn't it pretty pointless for a missile to turn and try again?
It'll take days before it reaches the required speed if the target just runs past it.
Depends on the relative speeds of ship and missile. Bear in mind the ship may not be going that fast either. I think speeds in Aurora FTL are likely to be lower overall.
And how will active ECM impact a missiles accuracy?
Will it just give out false targets?
ECM is probably going to become a lot more important. I may revisit the mechanics for Aurora FTL
Steve
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This sounds like Laser warheads will be a lot more useful since they wouldn't require a direct hit against a target that might be accelerating wildly. Will there be any additions to this technology?
Also, if a missile reaches it's chosen terminal velocity and shuts down its engines, will that lower its thermal reading? Seems like keeping active sensors going might be more important if a wave of powered down missiles might smash into your fleet without warning.
I will be working on laser warheads before release as they will be very useful. I will probably allow them at lower tech as well. I also may have some form of shrapnel warhead for use against other missiles.
If a missile has its engines off it will have a minimal thermal reading.
Steve
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So will we get missile launchers that base on Railgun or Massdriver technology? I would favor a massdriver for missiles. Willit be possible to have purely kinetic missiles?
Over the last few days I have been reading online regarding railguns and their potential for launching missiles. There 'kinetic missiles' will be railgun shots, although the lines between some of the weapons may blur. I may revisit weapon designs to make kinetic weapons more reality-based.
Steve
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@Steve : any idea when ur Newtonian can come into playable situation? (zzz..my english...)
December? January 2012?..more later?
Difficult to judge at this stage. This is so much to do :). I am particularly not looking forward to working my way through the AI code.
Steve
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Over the last few days I have been reading online regarding railguns and their potential for launching missiles. There 'kinetic missiles' will be railgun shots, although the lines between some of the weapons may blur. I may revisit weapon designs to make kinetic weapons more reality-based.
Steve
NewA (Newtonian Aurora) seem a very nice project..a thoughest one.
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I'm looking forward to launching long range missiles from stealth ships and not activating their engines until it's too late.
Nice to see you found new borders to fuel your coding creativity. And yeah, AI's gonna be a bitch.
While at it, will we see tech lines like "Light weight Armor" that increases the TCS, but reduces mass?
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Project Rho (http://www.projectrho.com/rocket/) has some very interesting things that could be relevant to Newtonian Aurora (for menu see top right).
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Over the last few days I have been reading online regarding railguns and their potential for launching missiles. There 'kinetic missiles' will be railgun shots, although the lines between some of the weapons may blur. I may revisit weapon designs to make kinetic weapons more reality-based.
Steve
The Missiles in Attack Vector are actually rocket propelled rail gun shells. It's basically just a missile that rather than having an explosive, deploys several shells at a certain distance from the enemy ship, so you get the benefit of the increased crossing vector and momentum that a separate thruster can provide, over simply moving the ship fast enough and hoping it works out as well.
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This puts up another interesting point. Kinetic Impact missiles could be devastating at these speeds.
Will be be able to choose between Nuclear warheads (higher "cross section(hit chance)" and damage independent of impact velocity) and Kinetic Impact (high damage and armor penetration dependent on speed)?
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This is totally and utterly groundshakingly worldscollidingly awsome! NewA looks like the game I always wanted to play. DeltaV, omfg! Rocket equations! More logistics! FTL Drives! Real kinetic weapons! The integration of the design system is also a great step into the right direction. This is not niche, it's the only way!
Just include the option of a sublight universe where no FTL exists (FTL factor 1) ... and with relativistic effects: Engine thrust decreases with speed!
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Engine thrust decreases with speed!
You mean mass increases with speed but thrust stays the same. =P
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You mean mass increases with speed but thrust stays the same. =P
Actually no because that way you could create relativistic weapons, and I guess we want to avoid that. If not we should also decrease the sensor signature of relatistic objects since they are close behind their signal front. Planet busters without warning.
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Well, non-FTL sensors will be problematic to code.
In any case, if this is going to remain newtonian, I forsee a particular kind of megaproject:
Build a ship and speed it up to lightspeed.
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I also may have some form of shrapnel warhead for use against other missiles.
If shrapnel warheads mean larger, slower anti-missile missiles become viable, does that mean we're going to want anti anti missile missile missiles to escort our salvos of regular missiles?
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Since missiles can now be fired from any range in system does this mean Missile Fire Controls have no limits apart from a active sensor contact? Will this mean beam fire controls have the same unlimited range?
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anti anti missile missile missiles
Creation of the day. ;D
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Well, non-FTL sensors will be problematic to code.
In any case, if this is going to remain newtonian, I forsee a particular kind of megaproject:
Build a ship and speed it up to lightspeed.
Non-ftl sensors can still be somewhat usefull if the turn and accelaration respecktive deceleration speeds are limited. You (or the game) could precalculate a certain "area" where your target object passes through with a certain "chance" (calculated via the intel on the object?). Well you may have a problem if the object is on direct course to you but for that you could do a triangulation with a second sensorship.
Laser-, Carronade-, Particlebeam -shots as well as Rail and coilgunslugs would maybe have to be handled like objects for that.
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Couple if thoughts:
With ships being able to fly directly to any target system (FTL doesn't consume fuel), there is no need to fly into one of the systems inbetween, not even for refuel and resupply. Uninteresting systems with few bodies will never be visited at all and fall completely to the wayside. That also means that there are no frontlines and few chokepoints. Every point needs its own defenses, and these defenses must be considerable as an enemy battlefleet can pop out of nowhere anytime. Friendly assets cannot spot the enemy a few systems out or ride to the rescue. The frontline is everwhere, no safe back-areas, shipping is always under threat. You need eyes everywhere. You have to spot any fleet or even any ship that accelerates into the direction of one of your systems.
Then there are FTL missiles:
- Build ships with an FTL drive and magazines.
- Build tugs which are all-engine and fuel.
- Using the tugs, accelerate the FTL ships to 100 000 km/s into the direction of the enemy home star.
- You can do this at your leisure in a system under your control. The high entry speed will
propel your ship to the enemy in a couple of weeks maximum.
- Once in the enemy home system, jettison the missiles. Using Sol as an example,
the missiles need about 8.3 hours to reach Earth, with a maximum needed course correction delta-V of 5000 km/s
(1AU/3 billion km*100 000 = 5000).
5000km/s in 8 hours should be doable with antimatter drives, judging the ion engine missile examples and estimating
fuel and payload. Also 5000 is the maximum. You could time the attack in a way that you do not need much course correction at all.
- The FTL ships drive into the sun or are lost in space.
- The defenders now have a time window of 8 hours before the drive-by nuclear holocaust. That means only defensive assets on and around the target planet are able to intervene.
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It's entirely realistic. The problem is that Aurora's diplomacy engine is not currently configured to deal with such things. After all, if you kill someone that way, the rest of the galaxy might not look too favourably on your actions. There is a good treatment of the problem here (http://www.projectrho.com/rocket/aliens.php#id--The_Fermi_Paradox--The_Killing_Star).
Also, some sort of gravitational-wave/handwavium based means of detecting approaching FTL ships/missiles, ought to be possible.
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Well, I think that FTL drives should indeed have fuel requirements or a maximum range.
An object should only have unlimited range by standard means of movement, which means it'll be traveling for many years.
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Fuel requirement is maybe necessary, but then it must be hefty. Like Traveller - each parsec of range takes 10% of ship volume. So in case of the Daring class with Jump-3 (parsecs) capability it has about 45% of its volume devoted to tanks. Extremely prohibitive. With even more fuel consumption, fuel sources need to be everywhere (like Traveller). And if they are everywhere, fuel logistics might become only a repetitive task, not a strategic problem (in addition to a repetitive task). If fuel can't be found almost everywhere, most of your shipbuilding is bound to be supertankers.
With a maximum range, it could become much like the stargate system where most ships hop from one system to the adjacent one. Something I would want to avoid.
Two possible solutions:
1. FTL drives do not need engine fuel but a different FTL drive fuel. Maintenance parts come to mind. These can be build everywhere and hopefully tansported in normal cargo holds. Maintenance space is felt sharply by ship designers. Should these parts be special FTL parts or just regular parts?
2. Ships in hyperspace can be detected by hyper-surveillance stations in real space and become visible on the galaxy map. Hypersensors can be active or passive. STL ships can be there too, albeit not detectable by hypersensors and only known to the owner. Total surprise can only be achieved by STL ships.
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I like the 2300 or Renegade Legion answers to limiting FTL range, after a certain distance (7.7LY for 2300) or time (30 Days for RL) you need to spend time in a gravity well to dissipate the unwholesome icky hyperspace luugies (or possibly radiation) before entering hyperspace again
Matt
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Another idea against Nuclear Holocaust bypass could be planetary shields like in David Weber's Mutineer's Moon series. Where they protect earth from alien asteroid bombardment with such thing.
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mmm one new type of weapon could be a ship with tractor beam+inertia+ASTEROID.
that could be funny.
you set the course for the planet with a tractor beam ship with an asteroid attached.
you then remove the ship from orbit and from the asteroid. Voilà...an incoming weapon of mass destruction
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As is required at these times..
Rocks are NOT ‘free’, citizen.
Firstly, you must manoeuvre the Emperor’s naval vessel within the asteroid belt, almost assuredly sustaining damage to the Emperor’s ship’s paint from micrometeoroids, while expending the Emperor’s fuel.
Then the Tech Priests must inspect the rock in question to ascertain its worthiness to do the Emperor’s bidding. Should it pass muster, the Emperor’s Servitors must use the Emperor’s auto-scrapers and melta-cutters to prepare the potential ordinance for movement. Finally, the Tech Priests finished, the Emperor’s officers may begin manoeuvring the Emperor’s warship to abut the asteroid at the prepared face (expending yet more of the Emperor’s fuel), and then begin boosting the stone towards the offensive planet.
After a few days of expending a prodigious amount of the Emperor’s fuel to accelerate the asteroid into an orbit more fitting to the Emperor’s desires, the Emperor’s ship may then return to the planet via superluminous warp travel and await the arrival of the stone, still many weeks (or months) away.
After twiddling away the Emperor’s time and eating the Emperor’s food in the wasteful pursuit of making sure that the Emperor’s enemies do not launch a deflection mission, they may finally watch the ordinance impact the planet (assuming that the Emperor’s ship does not need to attempt any last-minute course correction upon the rock, using yet more of the Emperor’s fuel).
Given a typical (class Bravo-CVII) system, we have the following:
Two months, O&M, Titan class warship: 4.2 Million Imperials
Two months, rations, crew of same: 0.2 MI
Two months, Tech Priest pastor: 1.7 MI
Two months, Servitor parish: 0.3 MI
Paint, Titan class warship: 2.5 MI
Dihydrogen peroxide fuel: 0.9 MI
Total: 9.8 MI
Contrasted with the following:
5 warheads, magna-melta: 2.5 MI
One day, O&M, Titan class warship: 0.3 MI
One day, rations, crew of same: 0.0 MI
Dihydrogen peroxide fuel: 0.1 MI
Total: 2.9 MI
Given the same result with under one third of the cost, the Emperor will have saved a massive amount of His most sacred money and almost a full month of time, during which His warship may be bombarding an entirely different planet.
The Emperor, through this – His Office of Imperial Outlays – hereby orders you to attend one (1) week of therapeutic accountancy training/penance. Please report to Areicon IV, Imperial City, Administratum Building CXXI, Room 1456, where you are to sit in the BLUE chair.
For the Emperor,
Bursarius Tenathis,
Purser Level XI,
Imperial Office of Outlays.
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where did you find that? O_O
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Change to Fuel Modifier for Engines:
Until now I have been working on a thrust boost vs fuel use modifier of (10 ^ Engine Power Modifier) / 10. So if you double engine power you use 10 times more fuel and if you triple engine power you use 100 times more fuel. This is similar to the fuel use multiplier in standard Aurora. However, I have now changed it to (4^ Engine Power Modifier) / 4, which means if you double engine power the fuel use is x4 and if you triple engine power the fuel use is x16, etc.. This is because the old formula resulted in low thrust missiles being superior to high thrust, because the amount of fuel required actually gave low thrust engines a better overall power to weight ratio once you included the fuel :)
I have also upped the rate at which engine power increases between at different technology levels. Engine power for TL3 (Ion engines) is now 50% higher than before and engine power for TL12 (Photonic Drive) is about 300% higher. Each new engine tech will increase power from the previous one somewhere at a rate between 30% and 50%. This is because with absolute top speeds, a small increase made a significant difference. Now the difference is in acceleration rates so a larger increase is possible without it being tactically overwhelming.
This means the previously displayed engine designs are out of date. Here are the four two-ton missile engine designs using Ion engine technology and a base fuel efficiency of 14 that I described in the post on missile engines. Below each one is the updated version using the same parameters but with the new numbers. The four designs use engine power modifiers of x1, x2, x3 and x3.5 respectively.
Msl #1 80 KN Missile Engine - old numbers
Power Output: 0.08 MN Fuel Efficiency: 14 Thermal Signature: 0.8
Base Acceleration: 40 mp/s (4.08G) Per Min: 2.4 km/s Per Hour: 144 km/s
Fuel Use at Full Burn: 1.12 litres per hour
Engine Mass: 2 tons Cost: 0.4 Crew: 0
Materials Required: 0.1x Tritanium 0.3x Gallicite
Development Cost for Project: 40RP
Msl #1 120 KN Missile Engine - new numbers
Power Output: 0.12 MN Fuel Efficiency: 14 Thermal Signature: 1.2
Base Acceleration: 60 mp/s (6.12G) Per Min: 3.6 km/s Per Hour: 216 km/s
Fuel Use at Full Burn: 1.68 litres per hour
Engine Mass: 2 tons Cost: 0.6 Crew: 0
Materials Required: 0.15x Tritanium 0.45x Gallicite
Development Cost for Project: 60RP
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Msl #2 160 KN Missile Engine - old numbers
Power Output: 0.16 MN Fuel Efficiency: 140 Thermal Signature: 1.6
Base Acceleration: 80 mp/s (8.16G) Per Min: 4.8 km/s Per Hour: 288 km/s
Fuel Use at Full Burn: 22.4 litres per hour
Engine Mass: 2 tons Cost: 0.8 Crew: 0
Materials Required: 0.2x Tritanium 0.6x Gallicite
Development Cost for Project: 80RP
Msl #2 240 KN Missile Engine - new numbers
Power Output: 0.24 MN Fuel Efficiency: 56 Thermal Signature: 2.4
Base Acceleration: 120 mp/s (12.24G) Per Min: 7.2 km/s Per Hour: 432 km/s
Fuel Use at Full Burn: 13.44 litres per hour
Engine Mass: 2 tons Cost: 1.2 Crew: 0
Materials Required: 0.3x Tritanium 0.9x Gallicite
Development Cost for Project: 120RP
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Msl #3 240 KN Missile Engine - old numbers
Power Output: 0.24 MN Fuel Efficiency: 1400 Thermal Signature: 2.4
Base Acceleration: 120 mp/s (12.24G) Per Min: 7.2 km/s Per Hour: 432 km/s
Fuel Use at Full Burn: 336 litres per hour
Engine Mass: 2 tons Cost: 1.2 Crew: 0
Materials Required: 0.3x Tritanium 0.9x Gallicite
Development Cost for Project: 120RP
Msl #3 360 KN Missile Engine - new numbers
Power Output: 0.36 MN Fuel Efficiency: 224 Thermal Signature: 3.6
Base Acceleration: 180 mp/s (18.35G) Per Min: 10.8 km/s Per Hour: 648 km/s
Fuel Use at Full Burn: 80.64 litres per hour
Engine Mass: 2 tons Cost: 1.8 Crew: 0
Materials Required: 0.45x Tritanium 1.35x Gallicite
Development Cost for Project: 180RP
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Msl #4 280 KN Missile Engine - old numbers
Power Output: 0.28 MN Fuel Efficiency: 4427.1892 Thermal Signature: 2.8
Base Acceleration: 140 mp/s (14.28G) Per Min: 8.4 km/s Per Hour: 504 km/s
Fuel Use at Full Burn: 1239.613 litres per hour
Engine Mass: 2 tons Cost: 1.4 Crew: 0
Materials Required: 0.35x Tritanium 1.05x Gallicite
Development Cost for Project: 140RP
Msl #4 420 KN Missile Engine - new numbers
Power Output: 0.42 MN Fuel Efficiency: 448 Thermal Signature: 4.2
Base Acceleration: 210 mp/s (21.41G) Per Min: 12.6 km/s Per Hour: 756 km/s
Fuel Use at Full Burn: 188.16 litres per hour
Engine Mass: 2 tons Cost: 2.1 Crew: 0
Materials Required: 0.525x Tritanium 1.575x Gallicite
Development Cost for Project: 210RP
Steve
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I'll post the section on missile design soon but I have been diverted a little into looking at railguns. I think based on my research so far you can safely forget everything about standard Aurora's energy weapons because the Newtonian Aurora weapons are likely to be completely different :)
Railguns (in the real world) are rated for their muzzle energy in megajoules (MJ). This is based on the kinetic energy of the projectile. An object's kinetic energy in joules is determined by the formula 0.5 x mass (kg) x velocity^2, which means an object moving twice as fast has four times the kinetic energy. Which in turn means that if you wish to fire a railgun projectile with twice the muzzle velocity you need four times as much energy to fire it.
For example, if you want to launch a 1 kilogram projectile at a speed of 5000 m/s, the muzzle energy required is 0.5 x 1 x 5000^2, or 12.5 million joules, or 12.5 megajoules. If you double the projectile size, it will require muzzle energy of 25 MJ. However, if you double the velocity instead, the 1 kg projectile at 10,000 m/s will have a muzzle energy of 50 MJ. The most powerful real world railgun tested so far (at least that we know about) has a muzzle energy of 33 MJ. (US Navy last December).
The damage inflicted by a railgun is based on the kinetic energy of the projectile in MJ. For comparison purposes, one kilogram of TNT release 4.184 MJ of energy, so we can therefore rate a railgun both in the energy required to fire it and the TNT equivalent of a hit. So the 1 kg projectile moving at 5,000 km/s (a 12.5 MJ railgun) has the same destructive force as 3 kilograms of TNT. Increase the muzzle velocity to 92,000 m/s and that 1 kg projectile has the destructive force of 1 ton of TNT. Even that is a relatively slow velocity in Aurora terms of 92 km/s. Unfortunately, that also requires a railgun with a muzzle energy of 4,232 MJ.
That energy has to come from somewhere. 1 joule is equal to 1 watt for one second, so the 4,232 MJ of energy has to be generated as 4,232 Megawatts of electricity. That can be generated gradually and stored in capacitors or (for Newtonian Aurora) homopolar generators (HPG). So a 100 Megawatt reactor could generate enough energy to fire the railgun every 42.32 seconds, assuming a 100% energy efficiency - which is unlikely (but you can improve it through a new tech line :)). Other tech lines include the MJ you can store per ton of HPG and the reactor output in MW per ton.
All this is fairly theoretical at the moment. The railgun launch speeds are going to be a LOT lower than the light speed railguns in standard Aurora but the weapon will be completely different anyway. Actual speeds will depend on what I come up with for power generation and storage. In fact, I am likely to introduce the concept of an integrated power grid for ships. A ship will have reactors which generate power in MW. That will be stored in HPG, which are rated in MJ storage capacity. Any system on the ship can draw power from the HPGs. I will likely extend power requirements to weapons, active sensors, FTL drives and several other systems. A major design decision is going to be how you allocate power generation and power storage. Power storage in MJ is likely to be about 25-30x greater than power generation in MW on a per ton basis. So do you have a huge storage capacity that can sustain you in combat for a while but can only be slowly regenerated by your weak power reactors, or do you have limited storage but a high rate of power generation to feed power to energy-intensive systems, or somewhere in between.
With regard to the comparatively slow (in Standard Aurora terms anyway) speed of kinetic weapons, I am starting to believe that it may be prudent for ships to actually slow down if they are expecting combat. Otherwise, if your 50,000 ton battlecruiser is hurtling into the system at 20,000 km/s (20,000,000 m/s), then a caveman lobbing a rock into its path may be able to take it out. A stationary 1 kg object in the path of the ship will have the same effect as if the ship were struck by a 47 megaton thermonuclear device.
Interesting....
Steve
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a caveman lobbing a rock into its path may be able to take it out. A stationary 1 kg object in the path of the ship will have the same effect as if the ship were struck by a 47 megaton thermonuclear device.
That's actually one of the main issues with realistic combat at relativistic speeds. One of the others is that due to the power, fuel and speed requirements, a "missile" is almost indistinguishable from a "ship".
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That's actually one of the main issues with realistic combat at relativistic speeds. One of the others is that due to the power, fuel and speed requirements, a "missile" is almost indistinguishable from a "ship".
"sir, we have developped the PERFECT DEFENSE!"
"what is it?!"
"we have moved ALL THE GARBAGE OF THE PLANET in a 360° sphere around ourselves! the ships cannot pass without auto destroying themselves!"
"you officer need a medal for this! free-pollution world and extremely effective shield? marvelous!"
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Unfortunately that wouldn't work because the garbage most likely won't stop the missile. I guess it really doesn't matter if a destroyed or an intact missile hits you.
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I like the energy idea. However, have you thought of having heat brought into the game. Ie: needing to dissipate it via some means before the crew and fragile electronics boil away.
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I like the energy idea. However, have you thought of having heat brought into the game. Ie: needing to dissipate it via some means before the crew and fragile electronics boil away.
Yes I am looking at that. Just deciding whether it adds too much complexity :). I will probably add solar panels as well as an alternative to reactors. They would work well for sensor buoys or ships deployed as pickets within an inner system. Very prone to damage though. Also contemplating something I read in Fire, Fusion and Steel (the New Era version) about a type of shield diverting absorbed energy into the ship's power grid. Lots of options at the moment.
Steve
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if you fire MJs of energy out of a railgun, in a newtonian setting, won't that effect ship path and direction too?
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Increase the muzzle velocity to 92,000 m/s and that 1 kg projectile has the destructive force of 1 ton of TNT. Even that is a relatively slow velocity in Aurora terms of 92 km/s. Unfortunately, that also requires a railgun with a muzzle energy of 4,232 MJ.
Interesting....
Steve
The picture is not fully correct I think. The TNT charge will affect all directions, the kinetic penetrator only one direction. So you need much more TNT to have the same effect on the target as the penetrator has.
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if you fire MJs of energy out of a railgun, in a newtonian setting, won't that effect ship path and direction too?
Yes, it would, although the effect would be tracked as Newtons not Joules. Momentum isn't the same as kinetic energy (and this is a weird one to get your head around) so increasing the velocity of a projectile by x5, would require 25x more energy and would give the projectile x25 impact but, at least as I understand the physics, would only give the projectile 5x more momentum and have 5x the effect on the launching ship in terms of affecting its movement. This is because the force applied to the ship is equal to the velocity x mass of the propellant (the railgun shot), not 1/2 mass x velocity^2, which is kinetic energy of the railgun shot.
However, I haven't decided whether to include it yet. Once I have some railguns designed I will run the math and see how much of an impact (unintended pun!) it has.
Steve
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The picture is not fully correct I think. The TNT charge will affect all directions, the kinetic penetrator only one direction. So you need much more TNT to have the same effect on the target as the penetrator has.
True - I am only using the comparison to hlighlight the energies involved. I have been looking at this site an an idea for possible use with nuclear weapons in Newtonian Aurora: http://www.5596.org/cgi-bin/nuke.php
The web site allows you to enter a weapon size, explosion distance and armour strength. It calculates how much of a nuclear weapon's energy will be applied againt each cm^2 and what how much armour would be destroyed.
Steve
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if you fire MJs of energy out of a railgun, in a newtonian setting, won't that effect ship path and direction too?
As Steve said, it's the momentum that counts for the course change. It would probably be wise to ignore this effect, unless Steve wants to track the mass of the railgun ammo. The momentum of a projectile with mass M and kinetic energy K is sqrt(2*M*K), so for fixed K MJs of kinetic energy, the momentum goes to zero as the mass of the projectile goes down (and the muzzle velocity goes up).
A different way to say this is that keeping track of the momentum of the ammo treats the railgun as a reaction drive. This is true, but the "real" drive is going to be MUCH more efficient, and so the effects of the railgun should be negligible.
John
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wow, sounds like the wish list of features is comming on as well. looks like ship to ship combat is heading towards being slower and seriously closer to toe to toe. Question is are 5 second ticks going to be too long in these instances?
Also if you are revamping the weapons and energy systems any thoughts on separating laser generators from the turrets and just giving them an output power to divert to various turrets?
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Sounds like what we'll need is very fast lasers that vaporize incoming or stationary debris before it strikes the ship. If we extend that to weapons fire, we could say that making the projectiles out of different materials (much like armor) and making them faster would improve your combat effectiveness.
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Steve regarding sensors and electromanetic weapons. If you fire a rail or gaus-/coil-gun you could a ship on the other side of the system see the spike in the EM?
Also thanks for thinking about alternative ways of energy production and storage. It would be nice if i could build a ship without any generator whatsover but with a bank of batteries.
What about "computer"-controlled ships? I mean like in ships without a actual crew but with a HAL like computer. Any opinions on that?
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I am going to start using this thread to post mechanics changes, even minor ones, for Newtonian Aurora so there is a reference when it is available to play
Starting with active sensors
Active Sensors now have a power requirement in MW equal to five times their sensor strength. For example, for a size 3 (150 ton) active sensor with sensor strength technology of 21, the power requirement would be 315 MW. For continuous operation of its active sensors, a ship is going to need power generation capability equal to their total power requirement. However, that power is actually going to come from the ship's integerated power grid (total homopolar generator capacity) rather than direct from the reactors (or other power generation systems TBD), so an active sensor that was intended for occasional use only could be mounted on a ship with sufficient power storage capacity to operate it, even if the power generation capability is insufficient for continuous use. Because of this extra hull space needed for sensors, I am going to increase sensor strength so you can have a smaller sensor with the same strength as before.
Having explained all that, I am probably going to gradually remove hull spaces (HS) from Newtonian Aurora and replace them with tons instead (on the existing 50-1 basis). For a game where mass is so important, I think having everything in tons rather than hull spaces will be much more intuitive. So by the time the game is available, sensor strength is likely to be per ton, rather than per HS.
Steve
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- Build ships with an FTL drive and magazines.
- Build tugs which are all-engine and fuel.
- Using the tugs, accelerate the FTL ships to 100 000 km/s into the direction of the enemy home star.
- You can do this at your leisure in a system under your control. The high entry speed will
propel your ship to the enemy in a couple of weeks maximum.
- Once in the enemy home system, jettison the missiles. Using Sol as an example,
the missiles need about 8.3 hours to reach Earth, with a maximum needed course correction delta-V of 5000 km/s
(1AU/3 billion km*100 000 = 5000).
5000km/s in 8 hours should be doable with antimatter drives, judging the ion engine missile examples and estimating
fuel and payload. Also 5000 is the maximum. You could time the attack in a way that you do not need much course correction at all.
- The FTL ships drive into the sun or are lost in space.
- The defenders now have a time window of 8 hours before the drive-by nuclear holocaust. That means only defensive assets on and around the target planet are able to intervene.
This may work if you have surveyed the target system first. Otherwise, it is unlikely the ship and its missile are going to be on a course that allows them to intercept the target. They may end up on the far side of the system, heading outwards without enough fuel to slow down. The other possible problem will be that as sensors will almost certainly be FTL (to avoid horrendous complications), the defenders will have some time to throw a rock in front of the missiles.
One thing I am considering (and the above scenario is pushing me more in that direction), is to have some new type of sensor that can detect an object based on its momentum (the disturbance of space-time or some other technobabble).
Steve
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Steve regarding sensors and electromanetic weapons. If you fire a rail or gaus-/coil-gun you could a ship on the other side of the system see the spike in the EM?
Also thanks for thinking about alternative ways of energy production and storage. It would be nice if i could build a ship without any generator whatsover but with a bank of batteries.
What about "computer"-controlled ships? I mean like in ships without a actual crew but with a HAL like computer. Any opinions on that?
Detection of an energy spike is something I am considering.
Depends what you mean by computer-controlled. 'Remotely piloted' would be simple enough as I would replace crew quarters with some type of 'quantum entanglement device' that allows instant control over interstellar distances. 'Computer controlled' in the sense that you can't tell the ship what to do, would effectively be the same as creating an NPR ship on your side.
Steve
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mmm space is empty right? how about a sonar sort of thing? wouldn't trans-newtonian waves generated by objects moving in trans-newtonian environment go "back" faster than usual? like a bat-like sensor for catching flies.
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wow, sounds like the wish list of features is comming on as well. looks like ship to ship combat is heading towards being slower and seriously closer to toe to toe. Question is are 5 second ticks going to be too long in these instances?
Also if you are revamping the weapons and energy systems any thoughts on separating laser generators from the turrets and just giving them an output power to divert to various turrets?
Yes, five second ticks may be too long. I may add a one second option, or add sub-pulses to even small timesteps in combat.
I haven't even looked at lasers yet but they will likely be very different than standard Aurora.
Steve
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mmm space is empty right? how about a sonar sort of thing? wouldn't trans-newtonian waves generated by objects moving in trans-newtonian environment go "back" faster than usual? like a bat-like sensor for catching flies.
Active Sonar is very similar to active sensors in Aurora, at least in principle. However, the idea of 'waves' generated by objects is interesting. Perhaps objects moving above a certain velocity appear larger to active sensors, due to a detectable 'bow-wave' in spacetime :).
Steve
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Detection of an energy spike is something I am considering.
Depends what you mean by computer-controlled. 'Remotely piloted' would be simple enough as I would replace crew quarters with some type of 'quantum entanglement device' that allows instant control over interstellar distances. 'Computer controlled' in the sense that you can't tell the ship what to do, would effectively be the same as creating an NPR ship on your side.
Steve
I was actually thinking of something like a "Crew equivalent" thus [impending technobubble] some kind of installable computer with an expert system, machine learning algorithms etc. [/impending technobubble] that operates a ship instead of a crew but has trade offs say in reactiontime, energy-consumption or whatever.
For many things i would like to have "robotic"-ships because i cant see a couple of poor guys staying out in space for decades just to mine a asteroid, doing geosurveys or hauling infrastructure from planet to planet on no end.
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I was actually thinking of something like a "Crew equivalent" thus [impending technobubble] some kind of installable computer with an expert system, machine learning algorithms etc. [/impending technobubble] that operates a ship instead of a crew but has trade offs say in reactiontime, energy-consumption or whatever.
For many things i would like to have "robotic"-ships because i cant see a couple of poor guys staying out in space for decades just to mine a asteroid, doing geosurveys or hauling infrastructure from planet to planet on no end.
It's a interesting idea. The game-play issue would be coming up with something different enough for robotic ships that a significant decision was required as to whether to use them.
Steve
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Maybe if the crew of a ship feels like it's a suicide mission, they could just refuse to go? Like if you're sending a Geosurvey ship straight to the enemy homeworld, they won't go? But a robotic ship wouldn't care.
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Maybe if the crew of a ship feels like it's a suicide mission, they could just refuse to go? Like if you're sending a Geosurvey ship straight to the enemy homeworld, they won't go? But a robotic ship wouldn't care.
conscripts could become at risk of going rogue and becoming...tadah SPACE PIRATES!
and you could reduce the risk by adding officers to command those ships, (maybe call them commissars and have them carry a revolver)
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conscripts could become at risk of going rogue and becoming...tadah SPACE PIRATES!
and you could reduce the risk by adding officers to command those ships, (maybe call them commissars and have them carry a revolver)
There are plenty of reasons why a robotic ship could be a good idea. There have to be corresponding disadvantages though or it's not a decision :). This is probably better addressed in the suggestions thread though as it isn't specific to Newtonian Aurora and could equally be applied to normal Aurora.
Steve
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Playing as a machine race would be nifty. The population must be built with minerals. It needs maintenance and fuel to live. Can colonize a wider variety of worlds, including hard vacuum worlds. "Biology" research enhances the machines and makes them smarter, faster etc. Or it allows you to research and enhance specialist sub-types e.g. for high accelerations (newtonian and gravity), soldier robots, worker robots, fighter pilot robots, research robots...
Should be quite a different experience.
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There are plenty of reasons why a robotic ship could be a good idea. There have to be corresponding disadvantages though or it's not a decision :). This is probably better addressed in the suggestions thread though as it isn't specific to Newtonian Aurora and could equally be applied to normal Aurora.
Steve
well, there could be the risk of the ai going rogue and turning into a starswarm ship or even a self replicating tend toward extermination of living organism machine.
or there could be the "error 32" risk, or if it gets into a system with highly charged particles (nebulaes?) it risks frying itself. and hardware countermeasures and the like would actually become useful in "steeling" from this problems the technological ships.
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well, there could be the risk of the ai going rogue and turning into a starswarm ship or even a self replicating tend toward extermination of living organism machine.
or there could be the "error 32" risk, or if it gets into a system with highly charged particles (nebulaes?) it risks frying itself. and hardware countermeasures and the like would actually become useful in "steeling" from this problems the technological ships.
There's not much risk in a ship going rogue outside of the loss of the ship (and any relevant information it carried) and the potential risk of an extra armed combatant out there. Given that (outside of the starswarm) there don't exist any shipbuilding components, a rogue ship is on its own until it runs out of ordnance and fuel.
I think a better risk is something like the AI Revolt from Sword of the Stars. If the ships are built with actual AIs (instead of expert systems), a rogue ship that encounters other AI ships should be able to attempt to convince the new ships to join it. Less starswarm, more pirate.
Combining the two could be fun. If you encounter a derelict vessel and refuel it for your own use, you might end up with all your AI ships in orbit suddenly switching teams to the alien vessel that promised them a future that didn't involving chasing down comets billions of kilometers away using a single Nuclear Pulse engine.
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Playing as a machine race would be nifty. The population must be built with minerals. It needs maintenance and fuel to live. Can colonize a wider variety of worlds, including hard vacuum worlds. "Biology" research enhances the machines and makes them smarter, faster etc. Or it allows you to research and enhance specialist sub-types e.g. for high accelerations (newtonian and gravity), soldier robots, worker robots, fighter pilot robots, research robots...
Should be quite a different experience.
Well Steve Traveller: NE gives one possible drawback to AI ships ;)
Vampire fleets of revolted player AI ships would be like Precursors that appear in exactly the wrong places!
And one thing Aurora of any description needs is SPACE PIRATES!
Matt
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Well, as for AI ships, increased power requirements has been mentioned, but also increased vulnerability to microwave weaponry. If your 'computer core' gets hit it's game over for that vessel. I would consider these AI cores to harbor weak AIs, aka non-sentient AIs that operate within a known domain and pre-existing simulations and tunings.
I can support AI cores instead of crews for vessels with 'fire-and-forget' missions, like... missiles and fighters. Especially fighters, reducing life support means you can pack more guns on it. Your automated miner perhaps as well. In my view, all vessels already are packed with AI systems and so forth, just leaving high level command and functions to its crew. I would suggest that a ship with AI core count as possibly 80% crew training (maybe 50% with improvements in research?), to indicate the combination of customizable automation and highly trained crew can out-think and out-fight a weak AI. Additionally, AI ships won't ever receive commander bonuses, least not without the in-system quantum entanglement communication remote control Steve suggested, but that would mean it will not work without a commander in-system or without a backup AI core
As for an AI race, well, while they CAN survive in hard vacuum it is still a bad idea. Every time there is a solar flare there is a panic about our satellites and power stations and transmission lines, all for good reason (if overdone in some cases). What protects earth and its electronics is both the magnetosphere and the atmosphere. On a ship it can be assumed that shielding is part of the hull (certainly is for organic passengers), but on alien worlds radiation and temperature would still very much be a concern. Worlds with little atmosphere or little magnetosphere would need its citizens to include shielding into their design, greatly increasing their cost (perhaps modeled by infrastructure?). On warm worlds there is greater need for cooling systems and on cold worlds the efficiency of any moving parts can be greatly reduced through freezing (combination of humidity and cold). Additionally, on atmosphere-less worlds heat sinks would have little effect, greatly affecting the logistics of waste heat and temperature control. Perhaps through their feet? Though even that would be limited compared to worlds with atmosphere.
Slightly different topic, on FTL I recently ran across this, which seems very similiar to Newtonian FTL with similiar intended limits(biggest difference is instant travel).
http://www.well-of-souls.com/outsider/forum_ftl_tech.html
EDIT: As for not-always-on active sensors, I see that as a potential source of undesired micromanagement... What about if not enough power exists to run it constantly, it supports lower power or delayed modes? Lower power might be the ability to lower the sensor sensitivity in exchange for less power use. Delayed mode might be switching on the sensor for 5 minutes, off for 5 minutes to reduce power use, though in this case it will result in a delay of up to 5 minutes before a new contact is spotted, potentially fatal for warships but of less concern for expendable scoutships.
@Steve: Do you still use the email address listed in your forum account?
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I'd put this in a seperate topic, but as these pretain directly to Newtonian Aurora, I thought it would make more sense to post them here.
Now that we have ships with accelerations, what about having those limited by crew type/technology, etc. Races from high grav planets would have an advantage here, which is a fair tradeoff given that they have less planets to colonize in return. Essentially, at G levels above say twice the races natural maximum (ie, 3.4g for humans) an extra delay is added to order changes; until at around 6x (10.2g for humans), order changes are not possible. So you could program in a high acceleration manuever, but once it starts you cant do anything until its over. Obviously, AI cores might no have the same issue, but could have other downsides, like limits to crew bonuses, no commander bonuses, high power requirements, susceptibility to microwave and EW weaponry.
These effects on crews could be mitigated though technology, either through bioegineering your crews to be more grav resistant, or through some alternative method like gravitic reduction systems.
Regarding sensors from the last poster, a low power mode might be an option, along with a pulsed mode that could be automated. Ie, On 1min, off 2min, etc. If you're looking at sensor changes, I thought I'd bring up the ability to activate sensors independently of each other on a ship with multiple systems. Would make power management more interesting too.
Any plans to have passives require some low amount of power to run? Same for lifesupport etc.
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Everytime I visit this tread, I'm happy.
So many things I've wanted for so long, and now it all comes into place.
While we're talking about AI and realistic weapons, I'd like to raise a question:
Why do they work the way they do?
Kinetic Impact is fine, explosives, in the power range of strategic nukes, is also understandable.
But Lasers?
All I can think of is very high energy waves, like Gamma-Rays, to erode the Material; but that would pass straight through and thus have 200% armor penetration, or excessive heating of the target material, likely by means of lower energy, higher wavelength- beams.
As far as I can tell, while the effect might be abstracted as the same, the working would be different.
Will that have an impact?
Then there is stuff like EW.
As far as I can tell, an EMP is something that can be created, nukes for example could be used to such an effect, but microwaves are more used to fry living beings, and thus should more be an anti-crew weapon like flechettes and shot used on the ships and artillery of old (in game terms old).
It also raises the question of ship defenses.
Couldn't a ship employ a strong enough magnetic field to make projectiles whizz past?
Would it be possible to engineer "reactive armor", or in this case an automatic defense field, to split incomming projectiles to lessen their armor penetration?
And looking at modern nano-materials, like Graphene, might it be possible that an armor of the space era is a lot more sturdy than todays, but might suffer heavily from Heat and acid?
And now that weapons are actually effective based on their speed, is a shield a solid forcefield to stop them, will it be offensive and weaken/disintegrate them, or does it slow them down?
As for sensors, if you include an automatic "flickering" option to periodically light up space once every 10 seconds for five, it'd be too easy for combat purposes, as long as theres a single defensive sensor.
Maybe add a delay until you can use that sensor for targeting?
For the heat dissipation, sure, simplify it, you'll figure it out, you always did; but complexity wouldn't me much of an argument if you already have as complex things as powergrid management (I've been waiting on this for sooooo..... ), on the other side, todays prototype insulations are already able to seemingly dissipate heat waves into nothing by having pores smaller than IR-wavelength, and if FTL Aurora does still include forcefields/shields of sorts, a very high tech laser from heat-resistant material could use it's own heat to fuel it's fire. (Literally.^^)
Damn, I'm exited by this.
This is awesome.
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Few thoughts:
First, as to AI ships being more damaged from microwave weapons: Wouldn't a crewed ship be just as vulnerable? You knock out the computers on a spaceship and AI or crewed, you've just got a hunk of metal floating in space.
For weapons, at the kind of power you'd use for combat, lasers don't erode, they destroy. That kind of energy being transfered into the target has similar effects to a bomb going off. For example, a 100 megajoule laser (only 100x our current technology) delivered as a single pulse would be like detonating 25 kg of TNT. See http://www.projectrho.com/rocket/spacegunconvent.php#id--Laser_Cannon (http://www.projectrho.com/rocket/spacegunconvent.php#id--Laser_Cannon).
EMP is an artifact of nukes exploding in the atmosphere, explosions in space wouldn't have that effect.
I'm not sure about microwaves as a weapon. If you just emit them, the range is going to be awful and I'm pretty sure microwaves are easy to block (simple faraday cage). If you focus them, you've got a microwave laser (maser) and you've just got a lower powered laser.
I'm looking forward to the upgraded (or should I say finished :) ) bomb pumped lasers. One because I'm really picturing the Honor Harrington battles and two because they make a lot more sense. Why risk that last 50,000 km of point defense when you can explode early? It should also help with accuracy since you're not looking for a direct hit, just get in the vicinity and orient yourself properly before exploding.
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As to microwaves: In a book called something like "How to survive the robot rebellion" I read that microwaves have a similar effect on electronics as an EMP, only they aren't blocked by a Faraday Cage. So it sounds reasonable to me, although I lack the physical basics.
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As to microwaves: In a book called something like "How to survive the robot rebellion" I read that microwaves have a similar effect on electronics as an EMP, only they aren't blocked by a Faraday Cage. So it sounds reasonable to me, although I lack the physical basics.
They are blocked by faraday cages, it's what keeps your microwave oven from leaking radiation into your kitchen.
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Which is kind of the point here, a tinfoil-thick sheet of metal apparently stops them completely.
As for Lasers, that's a good read. If 100 MJ is 100x the power we can use right now, that would in Aurora-terms be the equivalent to a very small missile with nuclear warhead, as 1/100000 of the Hiroshima Bomb would already be equivalent to 150 kg of TNT; unless nuclear warheads now become more expensive and stronger, which I'd support, don#t get me wrong.
Additionally, a very interesting point in that text is the frequency of pulse, and how it interacts with the behavior of the resulting shockwaves in the object.
Beams that deliver the entire energy in one brust could be lethal, but it's very hard to gather that energy at once, so that would probably be rather high tech (A good point to limit weapon size in early games, using more energy at once becomes less size efficient), and behave more like a long ranged plasma-carronade.
Which raises another question, could a ship emit particles, smoke, so to say, to decrease the impact energy of lasers by means of burning to plasma and dissipating the energy over a larger area of armor?
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While it is true that strong magnetic fields CAN deflect charged particles or magnetically vulnerable materials, these would only work against say ion beams or kinetic weapons using magnetizable metals for instance. Plastic or ceramic ammunition would pass right through, and since it is not the composition of the material that matters but rather the mass for kinetic kill weapons, these should still be effective.
For shielding I normally consider it to be a handwavium mass effect style potential shield, capable of robbing momentum from kinetic attacks and even laser light (maybe a combination of two or more different shielding technologies working together?).
As for armor that disintegrates under heat makes sense against laser weaponry. These would give off superheated plasma AWAY from the hull WITHOUT spreading it over a larger part of the armor.
Regarding EMP and microwave weaponry, while microwave weaponry is effective against organics, it is MORE effective against sensitive electronics. The electronics for ship control systems, target prediction and all that can be created simply and with resistance to interference far easier than the complex electronics needed for an AI. For example, your AC would be less susceptible to an EMP than an unshielded CPU. Both do their duty but one is just so much closer to the limits of what is physically possible that interferences can be that much more destructive. A single voltage pulse through an AC electronics would likely do nothing, while on a CPU can destroy it.
As far as I am aware, your microwave is not shielded from microwaves with a Faraday cage, the door for instance is shielded by the fact that the holes in the grid is smaller than the microwave wavelength(1mm-1m). That isn't to say that shielding isn't trivial. Either way, we already have a researchable technology that can reduce the vulnerability of our sensors to microwave weaponry, makes sense that this would also be effective to shield AI cores.
Aurora microwave weaponry I consider a handwavium for any anti-sensor and anti-tech weaponry, including microwaves and directional EMP lasers(some kind of ion magnetic beam? Monopole laser?).
Revisiting my on-off strategy for sensors, adding a delay in exchange for lower power use, I am reminded of two things... First, a large amount of power in most systems is spent starting up devices. My university for instance prefers to keep air-conditioners on rather than switching them on and off evenings and mornings due to the peak load being greatly increased when you start them up. For this reason a 10 second on, 10 second off strategy for power saving won't save 50% of the power, though a 1 hour on 1 hour off might come close, though possibly in that case, 10 min on, 1 hour off would be even better. Note though that a delay of even a second at these distances can be fatal in combat. Your targetting is already lagged by 1 second at 300 000km due to the speed of light and your laser will only hit it in another 1 second, which is a 2 second delay at those ranges. With an additional sensor delay of 1 second you potentially decrease your accuracy by 33%. Same for missiles that are not equipped with their own sensors. I would consider this power saving strategy viable for scouts where absolute real-time isn't needed, but it is quite simply not practical for combat.
I am still in favor of rock-paper-scissors gameplay. Every advantage has a counter. Even if we have to step away from reality just a tad to enhance gameplay.
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As far as I am aware, your microwave is not shielded from microwaves with a Faraday cage, the door for instance is shielded by the fact that the holes in the grid is smaller than the microwave wavelength(1mm-1m).
That's one way to design a Faraday cage :) http://en.wikipedia.org/wiki/Faraday_cage#Examples (http://en.wikipedia.org/wiki/Faraday_cage#Examples)
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While it is true that strong magnetic fields CAN deflect charged particles or magnetically vulnerable materials, these would only work against say ion beams or kinetic weapons using magnetizable metals for instance.
Considering that both Railguns and Gauss-Guns propel mass by a means of magnetism, it is very unlikely to see projectiles entirely non-magnetic.
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Considering that both Railguns and Gauss-Guns propel mass by a means of magnetism, it is very unlikely to see projectiles entirely non-magnetic.
All it would take is a couple of guides that were pressed into the projectile. Once the magnetic field was removed they could be spun off by centrifical force leaving an non magnetic slug.
Brian
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All it would take is a couple of guides that were pressed into the projectile. Once the magnetic field was removed they could be spun off by centrifical force leaving an non magnetic slug.
Brian
It's even easier: Instead of making the projectile itself magnetic, use a sledge.
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That is what not educated people call a sabbot ;) . Anyway Magnetic fields against railgun slugs would have to be damn strong. Well the US army is developing a "pulse shield" - these things though need a damn huge amount of power (stored in big capacitors) to repel a relativly slow slug on a a short range. If you believe the telegraph (http://www.telegraph.co.uk/technology/news/7487740/Star-Trek-style-force-field-armour-being-developed-by-military-scientists.html).
well theres still the "iron-curtain (http://gizmodo.com/5417079/darpas-iron-curtain-detects-explodes-rpgs-from-a-moving-humvee)"
edit: or a sledge :P
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Idea for balancing AI warships, they never suffer maintenance failures until they reach their Maintenance Life, and there is no self-repair, even for maintenance failures. Also, rouge AIs in the conventional sense are kind of silly, but it would be cool if espionage teams could have a chance to subvert the AIs of any AI ships at the planet they are at. Also, the "pulse shield" would be a good way of implementing more realistic shields, maybe it could be an earlier technology than the current force fields?
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Actually, since we're going the power grid way, why don't we give engines a power requirement and make them use electricity rather than fuel?
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How's that supposed to work?
Sure, an Anti-Matter-drive would be an option at some point, but aside that, something still has to come out the exhaust.
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Was just thinking about the implications of all this for mines
In my last game I found some size 20 mines, loaded with 6 size 2 missiles to be very good at keeping warp points defended. Given the loss of warp points and the very limited range of the munitions in question it looks like the use of mines is going to change quite a lot.
The loss of warp points means that you can't just dump a couple and have the place covered. Perhaps you could instead, once you have done your grav surveys, have the marked likely entry points from nearby stars where you could then seed a number of mines? This might prove to be a pretty good counter to the stated drive by shootings - you enter real space at 100kks and slam into these things - ending your attack real quick.
Given the typically close range of mines for activation any launched missiles are going to have to have hugely inefficient engines to get them up to any sort of reasonable speed before hitting the target ship. Perhaps some different munition types are needed or a new mine system implemented.
One option may be the creation of mine fields:
Individual mines are now a lot smaller and perhaps are back to more classic explosives that release a ball of shrapnel. On the map you define and area to be covered and a density of mines to lay. Your mine layer then goes out and drops these mines. Area coverage would probably need to be pretty large!
Hostile ships then moving through the area would trigger the mines to explode and damage taken would be based on proximity to the field, density of the mine field, tech of the mine and the speed of the craft itself. Attacks would be resolved against all ships in a task group in the same area.
Thoughts?
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Hmm, with the added customizability of drones and mines and missiles, will it be possible to instead of mines, launch inert missiles. That is to say, they lay in space, till a hostile contact is detected, then fire their engines and engage. Mines with engines as it were.
This could prove to be a situation where minefields could still be useful even if you do not know with absolute certainty where the enemy will be. Pre-launching a large group of missiles in this way could one-up box launchers by a single ship being able to overcome a fleet's point defence, even if it needs plenty of preparation for it.
As for more typical mines... these can still be useful around planets and so as a large line of defence. The enemy can destroy your ships and PDCs from beyond the range of the mines, but they WILL need to come close in order to land any troops.
Minefields with an 'area' could be interesting, but would need an incredible amount just to cover a 1mil km radius, nevermind 50 million or 100 million that would be actually useful. Still, I remember this being in Stars! and being a valid tactic. Without some way of making minefield areas working at 100 million km radiuses (without the current all exploding against the first contact thing) I don't see classical mines as useful other than invasion force landing denial.
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Well you dont need as much mines. You can secure a sytem by 2 ways.
You set up patches of mines. Arrange them loosely in a ring or a (semi-)random grid. This way the enemy would have to asume you have a entire minefiled.
The more sophositicated assembly is a moving minefield. The most efficient path for such a field would be a circular one like being in orbit around a massive object. I propose you set up some small patches of mines to orbit a star. Supposed you have enough speed and a enough mines (you need more mines at lower speeds and higher radie to get the same amount of defence) you can put up a huge defence ring at compareable small costs.
Since everything that you chug out of your spaceship will have roughly the same speed and course as your spaceship the deployment of engineless mines works very well. Suppose you go from earth to Jupiter to perform a swingby and then another around the freaking sun your momentum could be pretty high. Give your mines a gentle push in the right direction (or some steering thrusters) and they would get into a defensive orbit for the virtual eternity ... that is if your calculations where right.
For a passive field you would need thin long "strip" that is perpendicular to the source of graviation. For small corrections (like avoiding spiralling into the sun or out of the system) you could still use your thrusters. Same goes for aiming at the enemys ship if you want a "active" minefield this would need sensors thought.
Damn you could use just some rubbish say a ton of compressed cat-litter or for simplicitys sake rocks. Shaped, hardened and rather dense projectiles would still be more effective.
The defense value depends on some things. Mostly on the speeds of your mines and the target. Also on the size and number the strips in a passive field respective on the number of packages on a single orbit and how good your sensors are. These sensors could themself be part of the "minefield" or could be stationary which i atleast would prefer.
It could also be dangerous to you. Blowing up enemy ships or old satelites (i am looking at you china) could create a cloud of spacejunk that could have effects from sanding of your paintjob up to making pretty speed holes into your hull.
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EDIT: As for not-always-on active sensors, I see that as a potential source of undesired micromanagement... What about if not enough power exists to run it constantly, it supports lower power or delayed modes? Lower power might be the ability to lower the sensor sensitivity in exchange for less power use. Delayed mode might be switching on the sensor for 5 minutes, off for 5 minutes to reduce power use, though in this case it will result in a delay of up to 5 minutes before a new contact is spotted, potentially fatal for warships but of less concern for expendable scoutships.
I have also come to the conclusion that "not-always-on active sensors" are a bad idea. Instead, systems such as active sensors that have a constant power requirement rather than the "large amount of power occasionally" requirement of weapons, will draw that power directly from reactors. So if you have a sensor that requires 250MW and you have a 400 MW reactor, the power from the reactor will run the sensor and the remaining 150 MW will be sent to the capacitors (homopolar generators) if there is capacity available. On the class summary, any system with a constant requirement, such as active sensors, will have that shown in Megawatts (MW) while systems with a requirement for energy from the HPGs, such as weapons and shields, will have that shown in Megajoules (MJ)
Steve
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I'd put this in a seperate topic, but as these pretain directly to Newtonian Aurora, I thought it would make more sense to post them here.
Now that we have ships with accelerations, what about having those limited by crew type/technology, etc. Races from high grav planets would have an advantage here, which is a fair tradeoff given that they have less planets to colonize in return. Essentially, at G levels above say twice the races natural maximum (ie, 3.4g for humans) an extra delay is added to order changes; until at around 6x (10.2g for humans), order changes are not possible. So you could program in a high acceleration manuever, but once it starts you cant do anything until its over. Obviously, AI cores might no have the same issue, but could have other downsides, like limits to crew bonuses, no commander bonuses, high power requirements, susceptibility to microwave and EW weaponry.
These effects on crews could be mitigated though technology, either through bioegineering your crews to be more grav resistant, or through some alternative method like gravitic reduction systems.
Regarding sensors from the last poster, a low power mode might be an option, along with a pulsed mode that could be automated. Ie, On 1min, off 2min, etc. If you're looking at sensor changes, I thought I'd bring up the ability to activate sensors independently of each other on a ship with multiple systems. Would make power management more interesting too.
Any plans to have passives require some low amount of power to run? Same for lifesupport etc.
Interesting idea about the crews G resistance. The order delay might not work because players would tend to cease acceleration before giving orders. Perhaps instead crew grade could be reduced while under high acceleration so a ship would fight less effectively.
Good point about individual sensors being on/off. I should add that to both standard and Newtonian at some point.
For the moment, I have no plans to use power requirements for passive sensors and life support. I am aiming to have power/energy requirements for major systems only.
Steve
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Railguns
Railguns have changed completely from standard Aurora. There are now six parameters in the design window:
Railgun Maximum MJ Per Ton: The muzzle energy in Megajoules (MJ) of the railgun is based on its size in tons (not HS as I am moving away from HS) multiplied by this number. So a 200 ton railgun with an MJ per Ton of 12, would have a muzzle energy of 2400 MJ. Damage in Newtonian Aurora will be calculated based on the MJ output of a weapon. For comparison, the recently tested US Navy railgun has a muzzle energy of 33 MJ. This is a tech line starting at 5 MJ per ton.
Railgun Energy Conversion Rate: The efficiency with which the railgun transfers energy stored in homopolar generators (HPG). If this was 35% for example, the 2400 MJ railgun would require 6857 MJ of energy to fire. This is a tech line starting at 25%
Railgun vs Projectile Maximum Mass Ratio: This is the ratio of the total railgun mass compared to the mass of the projectile. The kinetic energy of each shot is based on the muzzle velocity squared multiplied by half the mass of the projectile (real physics - not my formula). This means that greater velocity is more important than larger projectiles. Also, greater velocity makes fire control easier. So, the question becomes why not spend your muzzle energy on smaller, faster projectiles? Because with a smaller 'calibre' the actual rails become longer and narrower and there is a limit to the aspect ratio between 'calibre' and rail length. As Aurora doesn't really consider how 'long' something is, that design consideration is handled by this parameter. You can exceed the mass ratio if you wish (and therefore increase muzzle velocity) but your energy conversion rate is reduced by maximum mass ratio/actual mass ratio. I'll show an example of this later on. This tech line starts at a mass ratio of 100,000, which is a 1 kg projectile for a 100 ton railgun.
Railgun Heat Dissipation Rate: When a railgun fires, it generates a huge amount of heat. The parameter covers how rapidly the railgun cools down to the point at which another shot can be fired. It is based on the surface area of the railgun, which is based on its mass. The value of the parameter is how much MJ/s per square meter will be dissipated per second (assuming 1 ton = 1 cubic metre). Smaller railguns will have a greater surface area vs volume than larger railguns so they will cooldown a little faster. For example, if this parameter was 0.6 MJ/s and the railgun was 200 tons and 2400 MJ, the surface area would be 165.4, the dissipation rate would be 99.24 MJ per second and the total cooldown period would be 2400/99.24 = 24.18 seconds, rounded to 24 seconds. You can increase rate of fire by either researching this tech line, or you can also reduce the MJ per Ton parameter to create a less powerful but faster firing railgun. For example, changing it from 12 to 5, would create a 1000 MJ railgun that fired every 10 seconds (albeit at about 2/3rds of the muzzle velocity).
Railgun Size: The size of the railgun in tons
Projectile Mass in Kilograms: The size of the projectile, starting at 1 kilogram with 0.1 kg increments to 5 kg and then 0.5 kg increments. When you hit the mass ratio limit described above, if you wish to create a more powerful railgun while retaining as much energy efficiency as you can, then increasing the size of the projectile becomes the best option. However, if muzzle velocity is deemed more important than energy efficiency then increasing mass ratio would be more effective. The following examples assume MJ per Ton of 12, a 200k mass ratio, a conversion rate of 35% and a heat dissipation rate of 0.6 MJ per m2.
Below is a 200 ton railgun with a 1 kg projectile. This makes full use of the maximum mass ratio of 200k. Note that Vendarite is now the required material for kinetic energy weapons (also, the existing research field of missiles and kinetic weapons has been split into two separate fields). The railgun has a Muzzle Velocity of 69,282 m/s (69.3 km/s), which is the maximum that can be achieved with the available technology without sacrificing energy efficiency. While this doesn't seem to be a very high velocity compared to standard Aurora, bear in mind most ships at a similar tech level would require several hours of acceleration to reach this speed from a standing start and if they are moving faster, their own speed may (depending on the ship's heading) increase the relative speed of the projectile and increase its damage.
2400 MJ Railgun
Muzzle Energy: 2400 MJ Muzzle Velocity 69,282 m/s Cooldown Period: 24 seconds
Power Requirement per shot: 6,857 MJ Energy Efficiency: 35%
Mass Ratio: 200k Energy Efficiency Penalty: 0%
Railgun Size: 200 tons Surface Area: 165.4 Projectile Mass: 1 kg
Cost: 24 Crew: 20 HTK: 2
Materials Required: 24x Vendarite
Development Cost for Project: 240RP
Now lets look at two options for doubling the size of the railgun to 400 tons. The first has the same 1kg projectile size and the second has a 2kg projectile. Both will inflict the same damage and both take 30 seconds to cooldown, because their surface area to volume ratio has decreased. The former has increased the muzzle velocity to almost 100 km/s but at the expense of reducing energy efficiency to 17.5% and therefore requiring 27,429 MJ per shot. The second has the same 70 km/s muzzle velocity as the 200 ton version and requires 13,714 MJ per shot. BTW, you may be thinking why bother with a 400 ton 4800 MJ railgun and instead have two 200 ton 2400 MJ railguns. I'll explain that when I describe the new shield generators.
4800 MJ Railgun - 1kg
Muzzle Energy: 4800 MJ Muzzle Velocity 97,979 m/s Cooldown Period: 30 seconds
Power Requirement per shot: 27,429 MJ Energy Efficiency: 17.5%
Mass Ratio: 400k Energy Efficiency Penalty: 100%
Railgun Size: 400 tons Surface Area: 262.5 Projectile Mass: 1 kg
Cost: 48 Crew: 40 HTK: 4
Materials Required: 48x Vendarite
Development Cost for Project: 480RP
4800 MJ Railgun - 2kg
Muzzle Energy: 4800 MJ Muzzle Velocity 69,282 m/s Cooldown Period: 30 seconds
Power Requirement per shot: 13,714 MJ Energy Efficiency: 35%
Mass Ratio: 200k Energy Efficiency Penalty: 0%
Railgun Size: 400 tons Surface Area: 262.5 Projectile Mass: 2 kg
Cost: 48 Crew: 40 HTK: 4
Materials Required: 48x Vendarite
Development Cost for Project: 480RP
Here is a third option using a 1.5kg projectile, which is a compromise between the other two. Bear in mind these are just the options for two different sizes at one tech level. You will be able to create a lot of different designs, of different sizes, even at just one technology level. With multiple tech lines involved, there are many possibilities for railgun design.
4800 MJ Railgun - 1.5kg
Muzzle Energy: 4800 MJ Muzzle Velocity 80,000 m/s Cooldown Period: 30 seconds
Power Requirement per shot: 18,240 MJ Energy Efficiency: 26.32%
Mass Ratio: 266k Energy Efficiency Penalty: 33%
Railgun Size: 400 tons Surface Area: 262.5 Projectile Mass: 1.5 kg
Cost: 48 Crew: 40 HTK: 4
Materials Required: 48x Vendarite
Development Cost for Project: 480RP
I haven't worked through fire control yet for railguns but at the moment I am leaning toward tracking each projectile as if it were a missile with no maneuvering ability and checking if it occupies the same space as the target (or anything else that gets in the way) at the same time. If that is the case, there will be more chance of it intersecting a ship with shields than the same size ship without shields (see next post for shields). The actual firing of the projectile will be based on the course, velocity and acceleration rate of the target ship and an estimate of where it will be when the projectile arrives. Of course that means the best defence is small, random fluctuations in acceleration and heading. I need to get into the numbers to see how realistic this will be. Of course, a stationary target will make things much easier.
Steve
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Shield Generators
Shields have changed for Newtonian Aurora. There are three parameters in the design window.
Maximum Shield Energy Per Ton: This parameter is rated in Megajoules (MJ) and the tech line starts at 25 MJ per ton. This is the maximum shield energy that can be sustained by the shield generator. So if the Maximum Shield Energy Per Ton was 100 MJ and the generator was 50 tons, it could sustain a shield energy of 5000 MJ.
Shield Generation Rate: This is the rate in MJ/s per ton at which the shields can draw energy from the ship's homopolar generators (HPG) to replenish shield energy. The tech line starts at 0.1 MJ/s. For example, if this tech was 0.25 MJ/s, a 50 ton shield generator could replenish shield energy at 12.5 MJ/s.
Shield Generator Size: Between 10 and 500 tons. Each 10 ton increment adds a 1% bonus to maximum shield energy, on the basis that the larger installations are more efficient. So a 50 ton generator would have a 5% bonus.
Here is an example 200 ton shield generator using Maximum Shield Energy Per Ton = 100 MJ and Shield Generation Rate = 0.25 MJ/s
5250 MJ Shield Generator
Maximum Shield Strength: 5,250 MJ
Maximum Recharge Rate: 12.5 MJ/s Minimum Recharge Time: 420 seconds
Cost: 10.5 Crew: 3 HTK: 1
Materials Required: 10.5x Corbomite
Development Cost for Project: 1050RP
Multiple shield generators can be added to a ship, although they must be all of the same type. The Maximum Shield Strength of the ship is equal to their combined strength and is the total amount of incoming energy (damage) that the shields can withstand. However, as well as a maximum overall strength, a ship has a Maximum Point Strength for its shields as well. This is the maximum damage than can be absorbed from a single hit from a railgun or beam weapon. This depends on a combination of the size of the ship and the overall strength of the shields. The shields are assumed to encompass a spherical volume that has twice the radius of the spherical volume of the ship. In other words, if the ship is a 40 meter sphere, the shields are a sphere with an 80 meter diameter. For the purposes of shields (and armour), every ship is assumed to be a sphere, even if for RP reasons they are described as different shapes.
The point strength of the shields is equal to their maximum strength divided by the (surface area of the shields in m2/10). For example, the ship below is 4620 tons (ignore the EM Signature and beam fire control stats as they are placeholders). The total strength of the shields is 72,000 MJ and the surface area of the shields is 395.4. Therefore the point strength is 72,000 / 39.54 = 1820.94, rounded up to 1821 MJ. So the shields will absorb incoming fire, reducing their own strength by an equivalent amount in the process, but any hit above their point strength will only be reduced by that point strength. For example:
If the ship below was hit by a 1000 MJ railgun shot, its shields would absorb 1000 MJ and be reduced to 71000 MJ and no damage would penetrate.
If the ship below was hit by a 2400 MJ railgun shot, its shields would absorb 1821 MJ and be reduced to 70179 MJ. The other 579 MJ would be resolved against the armour
If the ship below was hit by a 4800 MJ railgun shot, its shields would absorb 1821 MJ and be reduced to 70179 MJ. The other 2979 MJ would be resolved against the armour
Resolution class Destroyer 3,620 tons standard 4,620 tons full load 161 Crew 886.5 BP
Armour 3-24 Sensors 1/20/0/0 Damage Control Rating 1 PPV 12
Maint Life 1.91 Years MSP 120 AFR 170% IFR 2.4% 1YR 43 5YR 639 Max Repair 100 MSP
Active Signature 92.4 Thermal Signature 225 EM Signature 10000/2160000
Rolls Royce 7500 KN Ion Drive (3) Total Power 22.5 MN Fuel Use 299.2 litres per hour Exp 10%
Full Load Acceleration 4.87 mp/s (0.5G) Hourly Acceleration 17.53 km/s Daily Acceleration 420.78 km/s
Standard Acceleration 6.22 mp/s (0.63G) Hourly Acceleration 22.38 km/s Daily Acceleration 537.02 km/s
Fuel Capacity 1,000,000 Litres Delta-V Budget (Full Load) 66,046 km/s Full Burn Duration 139.2 days
24 GJ Shield Generator (3) Max Strength: 72 GJ Max Point Strength: 1821 MJ Recharge Rate: 150 MJ/s
690 MW Stellarator Fusion Reactor (2) Total Power Output: 1380 MW Exp 10%
11 GJ Homopolar Generator (3) Total Power Storage: 33,000 MJ Recharge Time: 24 seconds
Odin 4800 MJ Heavy Railgun (1) Energy: 4,800MJ Velocity: 69,282 m/s Power Reqt: 13,714 MJ Cooldown: 30 secs
Thor 2400 MJ Railgun (1) Energy: 2,400MJ Velocity: 69,282 m/s Power Reqt: 6,857 MJ Cooldown: 24 secs
Beam Fire Control (1) Max Range: 192,000 km TS: 4000 km/s 95 90 84 79 74 69 64 58 53 48
R100 Active Search Sensor (1) GPS 10000 Range 100.0m km Resolution 100 Power Reqt: 500 MW
EM20 Passive Sensor (1) Sensitivity 20 Detect Sig Strength 1000: 20m km
This means that larger ships may have a greater total shield strength than their smaller opponent but may not necessarily have a greater point strength. Although given the reducing ratio of surface area to volume as ships become larger, larger ships will be more efficient in terms of point strength vs total strength. In a battle between two railgun-armed, shield protected ships, the ship that is able to penetrate the shields of its opponent more effectively is likely to prevail. In a sense, such a combat would resemble that of two WW1 dreadnoughts.
EDIT: One final point is that a ship with shields is easier to hit than one without because the shields are larger than the ship.
Steve
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Will there be seperate to-hit checks for shields vs armor?
For example, is it possible for my railgun to hit the enemy shields, pierce through due to overcoming the shield's maximum per-hit strength, but have the projectile physically miss the ship?
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Interesting. That means the detailed ship can hit itself from a maximum range of about 270 000 km. The time it needs to move itself out of the way of a projectile, shields included, is 3.9 seconds. Will "tracking speed" have any relevance in Aurora FTL?
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For example, if this parameter was 0.6 MJ/s and the railgun was 200 tons and 2400 MJ, the surface area would be 165.4, the dissipation rate would be 99.24 MJ per second and the total cooldown period would be 2400/99.24 = 24.18 seconds, rounded to 24 seconds.
Surely the efficiency of the railgun matters. A more efficient but higher power railgun that retains the same amount of energy as a less efficient lower power railgun would take the same amount of time to cool for the same tech and size.
eg.
50% efficiency with 2000MJ per shot = 4000MJ draw
33% efficiency with 1000MJ per shot = 3000MJ draw
Both of them, with the same heat dissipation and the same size, ought to cool at the same rate since they both retain 2000MJ of energy.
I suggest that the heat dissipation only applies to the portion of energy the railgun drew that did not go into the projectile.
EDIT:
I forgot to add that this is awesome! I look forward to seeing Newtonian Aurora!
Absolutely amazing detail.
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Here's a suggestion for railguns:
Have a railgun design for "special ammunition". Basically, railgun assisted launches. Can fire cargo bay stuff as well.
Have a special design of railgun able to launch things. Obviously this will have a much lower acceleration than normal railguns although they use the same calculations (the max accel a particular thing can withstand depends on what you're firing, might be a tech line?).
It'll need to calculate the length of the railgun and the acceleration on the object.
Thus, railguns could be "extended" in an additional field that increases mass but doesn't affect projectile and efficiency stats except by lowering acceleration by increasing the railgun's length. Say 1 ton per 10 meters. (and this likewise increases the area and thus the heat dissipation, a bit like adding mass for heat sinks)
Also, the railgun will have to be designed to launch that one thing only. (mineral packets can be "one thing" for all combinations, and the mass driver-railgun will have a designed weight per packet)
Obviously, railgun length will have to be calculated for ship sizes. Might want to check ship size and take the "calculated by weight" size or the railgun length, whichever is higher.
Also obviously, this applies to rail assisted hangar launches, missile launches, mass drivers and "engine-less missile" weapons (laser warhead missile with no engine, fired from railgun). Railgun launched escape pods... although why you would want that I have no idea.
And if the recoil is ever calculated, a "railgun" drive might be possible.
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A W E S O M E
Does that mean that Sensors can't be turned off?
Or that they always draw energy despite being shut down? (Electronics in active standby, so to say)
I also second the question if a Projectile can hit the shields but miss the ship.
I suppose minimum distance will be reduced massively?
Why shouldn't we use two types of shields? wouldn't those stats described just add up?
Also, will it be possible to specialize a Shield to be faster recharging, but less capacity, or the other way around? In essentially the same way that one could now specialize a ship to have massive weaponry fueled by batteries, but low endurance, or the other way around....
Suggestion/question: Given that projectiles are now calculated in the energy they contain, and Shields work on that principle as well, will hull strength change as well?
I always thought that quadrupling the HTK of Internal systems and the weapon damage, and multiplying armor thickness and amount by 2 would allow for more options, like large Mesons finally being better than small ones in some aspects.
But only now, in this gorgeous wet dream of strategy nerds, would it really make sense.
Will Armor strength be calculated in MJ as well?
Also, those systems described by various persons in this thread, of "Electric Armor"... will there be different armor types?
Essentially to allow stuff like a tank today, huge target, slow, expensive, but completely impervious to small projectiles.
On the other hand, those new systems described could allow for a lightweight, hard to hit ship that reduces the effect of one shot of ~(insert very high number here) MJ every 10 seconds to (insert very low number here), but would horribly fail in a hailstorm of railgun fire.
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As for special ammunition, missiles is the most obvious. A launch boost of 70km/s while not extreme would be welcome, though missiles I guess weigh a little more than 1kg so would propably be less under this system. Would the railgun mass be worth it though for a 70km/s bonus instead of just carrying 70km/s worth more fuel?
As for faster charging shields versus higher capacity...
That shield specifies 12.5MJ/s recharge rate. To recover from a 2400MJ hit (assuming all of it got absorbed) would take 192 seconds or 3.2 minutes. Considering they fire every 24 seconds and it is likely there is more than just one firing, they will quickly destroy the shields if you rely on passive tanking. A 100 MJ/s recharge is needed in order to recover from a single railgun's attacks firing at max rate, multiplied by several times for multiple railguns.
Now, would it be possible to increase your shield recharge rate by dumping your capacitor energy into it? In this case it can be a trade-off between shields and weapons, but the much greater recharge rate would make tanking possible. If implemented I can just imagine the ships with huge excess generators to take advantage of it, but I'm unsure whether it could be game-breaking. Perhaps transferring to shields at a max rate and with a certain inefficiency?
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The point penetration for shields is nice though. It makes building lasers at max size worth it. That is, if we were still playing normal Aurora.
Capital ship weapons vs puny frigate weapons. Instead of the forest of puny frigate weapons we see on capital ships now.
Still, the way Aurora handles laser PD, I'd still end up using a one-size fits all 15cm dual role laser.
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Hmmm if shots that are fired are handled like objects i could build my own mjoelnir-Railgun (From the P&P "Justifiers"). Imagine it a giant size Kilometer long railgun somewhere in position a bit outside of the earthorbit say a lagrane point. Some scout-ships out on the rim of the system and all need is to take aim at a certain position. The problem is that i need to know there my target is going and i can let rain red hot death on the enemy. At big enough ranges i dont even need to worry about cooling down. The "artillery" is back on the battlefield.
Edit: Do wee need to take ammo with us for the Railguns? I mean even if thousand slugs for the railgun weight just a ton its would be interesting take on realism.
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Ammo would certainly be nice, now that it's a true ballistic weapon.
Such a huge Artillery weapon would likely fail, at that distance the enemy could easily evade. More importantly, he could counterfire witht he smallest weapon available in his arsenal.^^
As for shields, I figured a modification that subsitutes generator power, aka force projection, for a hotwireing to the ships main batteries.
Btw, if shields not have an assigned size, would it, with very high tech, theoretically be possible to have a Shield Cruiser that flies ahead and covers the fleets advance for a minute?
Edit: Another question; How will shields handle Missiles?
I Imagine a nuclear blast should hit a larger portion of the shield, thus dealing more damage, but also being absorbed to a larger percentage?
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Citing the above example of 2 destroyers fighting at a range of 270 000 km, a missile with 180 mp/s accel (360kN engine example) needs 28 minutes to cross the distance, as compared to the 4 seconds of the rail gun projectile. 28 minutes is some time to shoot down a missile with railguns. And point defense guns probably have a rate of fire above the listed ones.
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Ammo would certainly be nice, now that it's a true ballistic weapon.
Such a huge Artillery weapon would likely fail, at that distance the enemy could easily evade. More importantly, he could counterfire witht he smallest weapon available in his arsenal.^^
I on the contrary think it could be rather effective. The slug has no signature of its own, thus has only minor mass and no EM or Thermal output. What would be vissible is the high EM and TH-Spike from the firing - this is like seeing the muzzleflash of a gun and then dodging the bullet.
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I on the contrary think it could be rather effective. The slug has no signature of its own, thus has only minor mass and no EM or Thermal output. What would be vissible is the high EM and TH-Spike from the firing - this is like seeing the muzzleflash of a gun and then dodging the bullet.
Except it's easy to dodge a bullet when you see the flash 4+ seconds before impact.
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Except it's easy to dodge a bullet when you see the flash 4+ seconds before impact.
Not when your maximum acceleration is under 1g, like the Resolution class DD Steve posted. In 4 seconds thats a maximum displacement of 50m from your projected vector, in simple terms a circle with radius 50m perpendicular to the vector from weapon to target. While its hard to estimate the sizes of the ships given we dont know their shapes, a modern wet navy Frigate in the 5000t range is much larger than that. If you use more than one weapon, you can easily 'bracket' the target buy shooting in such a way as to maximise hit probability at the expense of number of hits (analagous to the concept of ladder firing from the battleship era). This is probably where the 'forest of puny weapons' might make a comeback.
Now, if we had a fighter with say 4g acceleration, then the target area is closer to 300m in radius, and we have a problem. Anti-fighter size railguns might have a rather small EM 'pulse' when fired though.
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Antagonist:
Missiles need to take time to boost up to the required speeds though. In "short range" combat, missiles actually become rather worse than railguns/lasers.
That's where the railgun launcher comes into its own. Allows you to use missiles as well.
Not to mention, the railgun launcher can put some delta-v onto the missile at launch. This increases the size of your launch windows and thus the number of salvoes you can throw
When you are closing at angles approaching 180*, if you launch your missile too late, it can't cross the gap before the enemy has zipped past you.
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Suggestion/question: Given that projectiles are now calculated in the energy they contain, and Shields work on that principle as well, will hull strength change as well?
I guess you could do a "by ton" approach thus like a shield a ton of armor absorbs a certain amount of kinetic power say 2500 MJ deployed over the entire size of the ship. I thought wonder how armoring certain parts of the ship will turn out. I still would like to have additional armor on my engines and reactors because often enough they are made from literal explodium.
Also another question to Steve: You said a railgun needs to cool down - is there a way to hotwire (pun not intended) the rails with a cooling system? And will cooling be a problem if you are right next to star?
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Citing the above example of 2 destroyers fighting at a range of 270 000 km, a missile with 180 mp/s accel (360kN engine example) needs 28 minutes to cross the distance, as compared to the 4 seconds of the rail gun projectile. 28 minutes is some time to shoot down a missile with railguns. And point defense guns probably have a rate of fire above the listed ones.
As things stand at the moment, I think combat at those type of ranges will be railgun/beam weapon only. Missiles will probably be too slow to be effective.
Steve
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As things stand at the moment, I think combat at those type of ranges will be railgun/beam weapon only. Missiles will probably be too slow to be effective.
Steve
If effective missiles are faster than railgun projectiles (and much heavier), we're looking at kinetic kill vehicles.
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It may be a good idea to have something like "random evasive maneuvers" type of movement for fleet, that will prevent from being hit by gigantic projectiles from big distances. It's only additional type of movement that You can use when You suspect that something is shooting ;D It could reduce acceleration by 5% and also increase fuel usage. Also, it would be easier for small ship with small mass to slightly change course every few seconds. The fuel and acceleration penalty for capital behemoths could be much bigger.
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Also what would happen when a Task Group runs out of fuel? Does it keep on going forever?
Now this, is something to really worry about, because it could turn out to be a real game breaker.
A warning should sound or the game paused when either a ship or a fleet nears the fuel level when decelerate can't stop the ship, either that or make it automatic that the ship/fleet must decelerate when the available fuel supply is only enough to bring the speed down to nil speed. Otherwise, I fear that soon the galaxy will fill with (powerless) drifting ships/fleets with no hope of stopping, because the further they go, the less chances they have of rescue. They couldn't even scuttle the ship because their escape pods' momentum would turn them into mini comets if they were to be caught into the gravity of a neighboring star or (if they should go fast enough) endless drifting in a straight line, until they would leave the game galaxy altogether.
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Sounds absolutely fine to me.
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... make it automatic that the ship/fleet must decelerate when the available fuel supply is only enough to bring the speed down to nil speed.
Maybe some kind of check-box that if enabled will do that? Because there is possibility that Your tankers are coming, or You want to stop using enemy home-world ;D
EDIT: Do we really need fuel in the game? ???
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Maybe some kind of check-box that if enabled will do that? Because there is possibility that Your tankers are coming, or You want to stop using enemy home-world ;D
EDIT: Do we really need fuel in the game? ???
YES. Its one of the most critical peices of logistics, and its about to get even more critical. ;D
However, perhaps a checkbox to 'disable fuel usage' might be an option for those who dont want to fiddle with logistics, kind of like the 'no maintenance' option.
As for evasive manuevers, the best way be to simple be able to specify the amount of them, from say '2 degree zigzag every 2 hours' to ensure long range safety, to '5 degree course zigzag every 15 minutes' for more radical manuevers. I would prefer them to be definable, rather than some arbitary 'x% more fuel use' thing.
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I just stumbled onto this, and had to restrain myself from laughing maniacally. I apol
To preface the following comments, one of my hobbies is studying realistic space warfare. And I mean realistic. Aurora is about the only thing I can stand where spacecraft don't move in a Newtonian manner, and while I'm a huge fan of this already, it would be even better with more realism.
That said, I've studied quite a bit, which might be of some help.
First off, I've attempted to do something somewhat like this in spreadsheets, though on a tactical level. They can be found at the following links:
https://docs.google.com/leaf?id=0B3KjwvJFChTfNGYzNWNjNzEtMDQzZS00ZWIzLTkyMDItNDA5ZjY0MTY5YjI4&authkey=CJWd6dwB&hl=en_US&authkey=CJWd6dwB (https://docs.google.com/leaf?id=0B3KjwvJFChTfNGYzNWNjNzEtMDQzZS00ZWIzLTkyMDItNDA5ZjY0MTY5YjI4&authkey=CJWd6dwB&hl=en_US&authkey=CJWd6dwB)
https://docs.google.com/leaf?id=0B3KjwvJFChTfODU4OWZkNTQtOTllNy00NThlLWI1MjAtODk0ZDU0MzhiMjRj&authkey=CJjV9UE&hl=en_US&authkey=CJjV9UE (https://docs.google.com/leaf?id=0B3KjwvJFChTfODU4OWZkNTQtOTllNy00NThlLWI1MjAtODk0ZDU0MzhiMjRj&authkey=CJjV9UE&hl=en_US&authkey=CJjV9UE)
https://docs.google.com/leaf?id=0B3KjwvJFChTfMTU2NDk4OGMtOWZhMS00ZDk3LTg2YmYtMjU0NTRlNjU1NWU4&authkey=CMPwg80C&hl=en_US&authkey=CMPwg80C (https://docs.google.com/leaf?id=0B3KjwvJFChTfMTU2NDk4OGMtOWZhMS00ZDk3LTg2YmYtMjU0NTRlNjU1NWU4&authkey=CMPwg80C&hl=en_US&authkey=CMPwg80C)
https://docs.google.com/leaf?id=0B3KjwvJFChTfMDczZjZhNGUtYTc4Ni00YTc0LWIzNTYtZDE2YmY2ZjIzNDA1&authkey=CIvAseMI&hl=en_US&authkey=CIvAseMI (https://docs.google.com/leaf?id=0B3KjwvJFChTfMDczZjZhNGUtYTc4Ni00YTc0LWIzNTYtZDE2YmY2ZjIzNDA1&authkey=CIvAseMI&hl=en_US&authkey=CIvAseMI)
https://docs.google.com/leaf?id=0B3KjwvJFChTfNWVlY2M1NGMtN2FjMy00N2ExLTgwZGQtNmIwZGMwMDY1NWQw&authkey=CKOL_-sE&hl=en_US&authkey=CKOL_-sE (https://docs.google.com/leaf?id=0B3KjwvJFChTfNWVlY2M1NGMtN2FjMy00N2ExLTgwZGQtNmIwZGMwMDY1NWQw&authkey=CKOL_-sE&hl=en_US&authkey=CKOL_-sE)
Things that might be useful include a formula for projectile weapon tracking, though it's based on x&y position and velocity, not on headings and velocities. That might make the whole thing easier, though. I don't know, as I'm not a programmer (as anyone who looks at the sheets can tell).
One thing I would like to see is a different detection system. Realistically, you can't hide in space. http://www.projectrho.com/rocket/spacewardetect.php Period. Even having that as an option would be helpful, and even more so if there was some ambiguity. "We know there's a strength 100 thermal contact, and it's out there. We know how big it is, but not what it is." At the very least, add a non-removable "life support" thermal signature. Or even just as an option.
The FLT system sounds very interesting, and I look forward to testing it. One suggestion is to have well-surveyed routes produce slightly higher speed multiplication. This would be expensive, but allow "trade lanes".
Steve if i would have some sort of crazy overengineered ion-drive (like we usein present day probes) with enough fuel to reach relativistic speeds, would it be possible to snail my way into another system?
Ion drives aren't terribly practical for interstellar travel. The specific energy is too low to get the sort of speed required. Even a high-efficiency ion drive probably can't make more than 900 km/s total.
Slightly off topic but could be of interest. Just finished reading "through struggle, the stars" by John Lumpkin. Aside from being a pretty good read I thought it had an excellent take on combat in a Newtonian environment and has some very good points:
- Basically no one does head on attacks because the closing speeds given so much kinetic energy to any slugs that it's pretty much suicide for both sides.
- Missiles tend to get shot down a lot but when they do get through they are pretty devastating. These are also basically MIRVS with lots of flechettes.
- Rail guns etc are used to help command the combat space rather than trying to hit things in most cases ie fill a section of space with a lot of lead to stop your enemy moving there and limiting their ability to undertake evasive mans.
- Lasers are the main close in armament. There is also an interesting concept of an overall laser wattage that can be directed between the offensive lenses and the defensive ones which gives captains some interesting decisions as to how aggressive they want to be.
Anyway perhaps some food for thought!
This made me laugh. I haven't read the book, but I know he used the same sources I've studied. All are requested.
I really have doubts that this endeavor, while notable for seeing if it will actually work, will end up actually be more of a simulation than a game.
There's a difference?
I'll deal with the second half as I read it.
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I have a lot to post on missiles.
1. Why bother with warheads at the speeds in question? At 190 km/s relative (which sounds fairly low for Aurora) the kinetic energy is approximately equal to that of a modern nuke. And metal is a lot cheaper. This is particularly true for AMMs.
2. Laser warheads sound good, as do EMP warheads, submunition warheads, and sandcaster warheads. No, I'm not proposing them based on Traveller. They're an idea I came up with to damage laser optics.
3. My spreadsheet includes CBDR (constant-bearing, decreasing-range) tracking formulas.
4. It would be reasonable for any missiles that miss to disappear (unless you're tracking space debris). I say this because giving it 3x impact delta-V is incredibly wasteful. To the point of insanity. In a knife-fight it might happen, but that's fairly rare.
5. I also like the unification of kinetic projectiles and missiles.
6.
Yes, it would, although the effect would be tracked as Newtons not Joules. Momentum isn't the same as kinetic energy (and this is a weird one to get your head around) so increasing the velocity of a projectile by x5, would require 25x more energy and would give the projectile x25 impact but, at least as I understand the physics, would only give the projectile 5x more momentum and have 5x the effect on the launching ship in terms of affecting its movement. This is because the force applied to the ship is equal to the velocity x mass of the propellant (the railgun shot), not 1/2 mass x velocity^2, which is kinetic energy of the railgun shot.
However, I haven't decided whether to include it yet. Once I have some railguns designed I will run the math and see how much of an impact (unintended pun!) it has.
Steve
Don't bother. As the speed gets higher, the energy-to-mass ratio gets higher. At the sort of velocities you speak of, you're firing the smallest thing you can get a guidance system and thrusters into.
Also, if some sensors are going to be limited-use, it might make sense to set up sensors to be independently-activated.
And if that's going to happen, duty-cycle scaling might be a nice addition, too. This is mostly for surveiliance ships. You can only activate once every five minutes, but the range is x10 or more.
I also would like remote-piloting available. I personally believe that realistic space combat will be largely unmanned. As to why, see http://www.rocketpunk-manifesto.com/2011/03/space-warfare-xiii-human-factor.html (http://www.rocketpunk-manifesto.com/2011/03/space-warfare-xiii-human-factor.html). The biggest issue might be maintainence (as with FLT communications, it's not reaction time.) A robot vessel has a higher failure rate than a manned vessel, and "ages" faster, too. (I'm not terribly familiar with the details of how that works in Aurora.)
And if space pirates must be added, please give them an off switch. I really don't want to go there.
On the balance though, I'm incredibly excited about this. I've enjoyed Aurora immensely, and this looks to be far, far, better.
High-powered microwaves can produce a similar result to EMPs. And there are ways of making an EMP without the use of a nuke. Faraday cages only block them if they are sealed. If there are wires going in and out, then the current induced in the wires can still fry whatever's inside.
Particles to block lasers are not going to be terribly effective. They'll burn out too fast, or be heavier than armor.
While it is true that strong magnetic fields CAN deflect charged particles or magnetically vulnerable materials, these would only work against say ion beams or kinetic weapons using magnetizable metals for instance. Plastic or ceramic ammunition would pass right through, and since it is not the composition of the material that matters but rather the mass for kinetic kill weapons, these should still be effective.
A bigger problem is the velocities involved. That's going to be too high to make these terribly practical.
For shielding I normally consider it to be a handwavium mass effect style potential shield, capable of robbing momentum from kinetic attacks and even laser light (maybe a combination of two or more different shielding technologies working together?).
As for armor that disintegrates under heat makes sense against laser weaponry. These would give off superheated plasma AWAY from the hull WITHOUT spreading it over a larger part of the armor.
It's called ablative armor, and it also carries away more heat than conventional armor. Aurora already uses it, though. There's no "bounces off armor" mode.
Regarding EMP and microwave weaponry, while microwave weaponry is effective against organics, it is MORE effective against sensitive electronics. The electronics for ship control systems, target prediction and all that can be created simply and with resistance to interference far easier than the complex electronics needed for an AI. For example, your AC would be less susceptible to an EMP than an unshielded CPU. Both do their duty but one is just so much closer to the limits of what is physically possible that interferences can be that much more destructive. A single voltage pulse through an AC electronics would likely do nothing, while on a CPU can destroy it.
As far as I am aware, your microwave is not shielded from microwaves with a Faraday cage, the door for instance is shielded by the fact that the holes in the grid is smaller than the microwave wavelength(1mm-1m). That isn't to say that shielding isn't trivial. Either way, we already have a researchable technology that can reduce the vulnerability of our sensors to microwave weaponry, makes sense that this would also be effective to shield AI cores.
That is a faraday cage. It's just that the cage appears to be solid to things with a larger wavelength. A few weeks ago, I was in a faraday cage that was less than 10% metal by area. A tesla coil was arcing to it. I had my hand about 8 inches from the point of contact. Didn't feel a thing.
Minefields are going to be difficult. The sheer volume of space is enormous, and will defeat unguided munitions. And making them go faster doesn't work, either. They have to go at orbital velocity. A better plan is an honrverse-style pod defense system. Missile targeting might require an overhaul to make this all work, though.
One thing I would really like to see would be keel-mount weapons. The mechanics would probably be that the weapon in question is much bigger than normal, and you can only mount one per ship.
As I read the whole thing, I can't wait. If there's anything I can do to help, let me know.
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Hmm, as for missiles and shields... For lasers that make deep gouges in armor, the point strength determines the total shield at the point of impact. But what about missiles whos damage profiles are more 'craters'? Would these require 4x or more of the point strength to overcome in order to pierce the shield?
This can affect tactics quite a bit, for one thing it makes cratering the armor impractical without first eliminating the entire shield, since a single missile shot is unlikely to be able to pierce the shields. It also makes lasers more valuable since it will take less to pierce the shields, even if it then has difficulty piercing the armor... and multiple laser hits at same point is unlikely, so you need a laser that can with one shot pierce shields AND all layers of armor, which might not be possible except for weak ships. It might not even BE practical to kill a ship without first taking down the entirety of its shields.
On that front, what about special anti-shield weapons? Microwave maybe, but it already has a niche as a anti-sensor weapon (and maybe anti-AI as well), but it is a possibility.
For Faraday caging... yes, there will definitely we wires. Either the engine ports will be vulnerable, and the sensors definitely will be (EM sensors can't work inside a faraday cage). And internally shielding the AI might help to a degree, but not provide immunity since it will need wires to the rest of the ship. Such shielding can be a tech line, but should never be perfect.
As for cannot hide in space... yes, you are correct. The ship definitely will have a exhaust plume in Aurora of some description, since it has a Thermal signature. BUT... even so, I like the current system. This is a point where gameplay and fun should trump realism.
Back to minefields... the way Stars! worked was that if you lay minefield then any enemy ships passing through that exceeds a certain speed risks a % chance per turn of striking a mine. You can go slower to be safe and detect mines soon enough to avoid them. This suggests to me a VERY sparse dark minefield, and is something that can be considered for Aurora. From the comments I see others agree that mines will tend to be point denial instead of area denial, hence me thinking of ways it possibly can work as area denial. Possibly when laying them they will have a sparsity setting? And perhaps a one-shot laser warhead, allowing them to hit from range instead of having to make physical contact, or else engines that activate when close enough after which it acts as a missile. If you make the minefield VERY sparse you might even be able to seed the whole system, but it would require that the enemy be fast and even so only get hit a few times as it crosses the system. Non-newtonian materials and gravity manipulation can explain how they can keep a position in a system without being limited to an orbit or a lagrange point.
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I split the stealth discussion off into its own thread. Please use that one for stealth discussions.
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For Faraday caging... yes, there will definitely be wires.
Will there? Do optical fibres conduct?
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Will there? Do optical fibres conduct?
No, which is why there need to be wires, unless you want a seperate powerplant outside to power your sensors.
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I think we should reduce it to two or three kinds of handwavium and just abbreviate the rest, for example into "Metal", "Gas", "Rare Minerals" and "Fossil Fuels".
Question from the Stealth thread.
Why not simplify the resource system a bit that way, makes it easier to learn what is useful for what, and just a few materials of handwavium will be enough to justify anything they are used in.
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Question from the Stealth thread.
Why not simplify the resource system a bit that way, makes it easier to learn what is useful for what, and just a few materials of handwavium will be enough to justify anything they are used in.
Excuse me? We need 168 chemical elements to build thousands of different parts on multiple levels to build thousands of products, not handwavium. I'll never understand these gameplay people. Gameplay, yawn. This is Excel-in-Space, not Wing Commander.
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Excuse me? We need 168 chemical elements to build thousands of different parts on multiple levels to build thousands of products, not handwavium. I'll never understand these gameplay people. Gameplay, yawn. This is Excel-in-Space, not Wing Commander.
I absolutely love the quote, though I've done excel in space, and it was less complicated.
On the other hand, I'm also in favor of avoiding handwavium as much as possible. Not for gameplay reasons so much as suspension of disbelief, and logical consistency. I find it easier to accept a few pieces of handwavium that explain all the fun mechanics then it is to accept ten different types.
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I absolutely love the quote, though I've done excel in space, and it was less complicated.
On the other hand, I'm also in favor of avoiding handwavium as much as possible. Not for gameplay reasons so much as suspension of disbelief, and logical consistency. I find it easier to accept a few pieces of handwavium that explain all the fun mechanics then it is to accept ten different types.
You seem to be contradicting yourself. Do you want to avoid handwavium or do you find it easier to accept?
I say that we don't need to reduce the minerals down to only generic metal. This is meant to be complicated and hard to manage. ;)
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What I meant was that I didn't want 15 different types of handwavium in the game, particularly not if 3 will do. And honestly, we will be using existing materials for a long, long, time. And what if those are cheap, and the handwavium is rare. Maybe only found in traces on planets, which forces it to be mined from asteroids? Or something like that, at the very least. The lack of conventional materials does annoy me.
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I find it hard to believe that one or two new elements would allow for FTL travel, energy fields, super efficient fuels, extra strong armor, Meson Cannons and so on.
I mean, we don't have one or two elements that accomplish such a huge range of possibilities on their own now, why would a new one be able to do all that? Easier to imagine an entire class of elements with those possibilities I think.
This is all on the assumptions in the game though, I imagine IRL much of this may become possible with conventional tech. However if we accept the base setting of Aurora using these elements, than it is easier to accept a lot of them rather than a couple.
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It would be nice if there were "normal" materials like iron, steel, aluminum, etc. and then "special" minerals like we have now for the stuff like the sensors, FTL and the power plants. Mines would be able to produce both types, but produce the normal types faster than the specials types.
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Let's see.
The New technology we need is: A super-hardened, at least somewhat heat-resistant material, which could be an alloy of handwavium and metal, for reuseable Railguns, ablative armor, etc.
One new material that allows for FTL sensors, probably some quantum stuff, which might mean a certain amount of stored energy, so it could double for shield systems and the like as well, if we want so. So 2 or 3 so far.
Then something to facilitate new energy phenomena/Space-time bending/opening of new dimensions... whatever.
Which could also be used shields/sensors, but is most likely required for the FTL travel.
Meson cannons are essentially particle accelerators shooting packets of a specific type of Hadron, and it is beyond me why specifically that would deal any damage, but let's not discuss that yet.
So, in short, if spread correctly, I see no problem with 3-4 Handwavium materials that I'd hope to be rare, and using abstracted base materials for the rest of the building.
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Let's see.
The New technology we need is: A super-hardened, at least somewhat heat-resistant material, which could be an alloy of handwavium and metal, for reuseable Railguns, ablative armor, etc.
One new material that allows for FTL sensors, probably some quantum stuff, which might mean a certain amount of stored energy, so it could double for shield systems and the like as well, if we want so. So 2 or 3 so far.
Then something to facilitate new energy phenomena/Space-time bending/opening of new dimensions... whatever.
Which could also be used shields/sensors, but is most likely required for the FTL travel.
Meson cannons are essentially particle accelerators shooting packets of a specific type of Hadron, and it is beyond me why specifically that would deal any damage, but let's not discuss that yet.
So, in short, if spread correctly, I see no problem with 3-4 Handwavium materials that I'd hope to be rare, and using abstracted base materials for the rest of the building.
I'm in complete agreement. For one thing, current materials aren't going to go away. For another, handwavium is best when applied as sparingly as possible while still getting the desired effect.
Don't get me wrong. Steve has done a fantastic job with his handwavium, and it's about the only thing I can stomach that doesn't use newtonian movement. However, the number of elements is a bit daunting.
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Armour and Shields
The general principle for armour remains the same in Newtonian Aurora, although the specifics have changed. Rather than the abstract nature of armour in standard Aurora, Newtonian Aurora measures armour thickness in centimeters and calculates the amount required based on the surface area of the hull. For the purposes of armour, shields and chance of weapon impact, the hull is assumed to be spherical and each ton of displacement is 10m3. So a ship of 5918 tons would have a volume of 59,180 m3, which is a sphere of approximately 48m in diamater. The surface area is 7344 m2 so a layer of armour 1 cm thick would mass 73.44 tons (rounded to 73). If the armour thickness is increased to 3cm, the hull volume is 60,690 m3 (including the armour), surface area is 7468 m2, sphere diameter is 49m and armour tonnage is 224. All this information is shown in the armour section of the class window. Each cm of armour means 1 row of armour boxes. The width of the armour is equal to the diameter of the sphere, which is 49 in the latter case. Armour is rated in the amount of megajoules required to destroy one box. For example, High Density Duranium Armour is rated at 80 MJ per box while Ceramic Composite Armour is 125 MJ.
The total amount of armour boxes in Newtonian Aurora is now greater for the same tonnage of armour in Standard Aurora but probably less than twice as much. So a ship that used to have 3 layers of armour would now have 5-6 layers for about the same tonnage. It's not an exact conversion though as Standard Aurora uses the concept of Armour Strength to require less tonnage for the same number of boxes at higher armour levels. That concept doesn't exist in Newtonian Aurora where you will always need the same tonnage of armour for the same number of boxes. Better armour in Newtonian Aurora is more resistant to damage though. Damage is rated in Megajoules rather than an abstract damage rating so 1 box will subtract a set number of megajoules from the total damage amount, rather than 1 box stops 1 damage.
The way in which damage is applied to armour is still basically armour boxes removed due to damage but the way in which the boxes are selected will change. Assume for the purposes of these example, there are no active shields. Lasers (which are totally different than standard Aurora and I will cover the details in a later post) will affect an area of armour depending on the diameter of the beam when it hits the target. The megajoule output of the laser will be divided between the number of armour boxes covered by the beam, which means once the beam widens to a certain amount, it will only warm up a large section of the armour rather than vapourising a smaller section. For example, if the armour is rated at 100 MJ and the laser output is 1200 MJ, it could penetrate 4 layers of armour by three columns if the beam is only 3 boxes wide, or penetrate two layers by six columns if the beam is 6 boxes wide, etc. If the beam is 13 or more boxes wide, it wouldn't damage the armour because the megajoule damage per box is less than 100. The width of the beam will depend on the range between firing ship and target and on the wavelength of the beam in nanometers (more on that in the forthcoming laser post). Lasers won't be able to affect more than half the width of the armour (one whole side of the ship) so any beam width beyond that will be wasted.
Kinetic weapons such as railguns will punch a hole one box wide straight through the armour. If they penetrate through the entire armour belt, they will damage a limited number of systems depending on the size of the ship and then potentially punch their way out again, damaging armour from the inside outwards. Of course, it will be much harder to hit with a railgun due to the speed of the projectile but the potential for damage is much greater, especially if the target ship is moving at high speed.
Nuclear weapons in Newtonian Aurora are area-based and missiles may be set for proximity detonation. If a ship is close enough to be within the blast radius, any damage that penetrates the shields will be applied to half the width of the armour, which will be the side of the ship facing the explosion. To determine the damage applied per box, the total MJ output of the explosion (which for 1 megaton would be 4,184,000,000 Megajoules - ouch!), is applied across the total surface area of a sphere with a radius equal to the range from the ship to the detonation point. The total energy output for 1 square metre of that explosion at the given range (or maybe 2 m2 - haven't decided yet) will be applied to each affected armour box. This isn't quite as bad as it sounds unless you are very close to the explosion because the rate at which damage falls off for nuclear detonations in space is far higher than in atmosphere.
For example, if you are 500 meters from a 200 kiloton detonation (which is a 1 ton warhead at tech level 3), the total damage applied per armour box will be 266 MJ. At 100 meters though it is 6659 MJ per box, which wouldn't be good. And yes, this means it is possible to take out a ship with a single missile if you get close enough, so I suggest anti-missile defence should be a priority :). I thought a lot about this but decided to go with the realistic option. Lets face it - if the Nimitz took a direct hit from a 200 KT nuke, it would be in some difficulty. Don't forget though that you can also use nuclear detonations defensively and a single small nuke could take out a lot of attacking missiles with a proximity detonation. Also missiles will generally be slower than in Standard Aurora. Targeting will be different too but I will cover that in another post.
Another example. A 1 megaton nuke would cause 83 MJ per box at 2000 meters, 332 MJ at 1000 meters, 1331 MJ at 500 meters and 5327 MJ at 250 meters. At 100 meters it would be 33,295 MJ per box!! Definitely need to keep the location of any fleet bases and shipyards a very closely guarded secret! In fact, I think dispersing shipyards may be a good idea. In a way, I am designing Newtonian Aurora without a really detailed idea of how the combat is going to play out. I am trying to create realistic systems and then I will see how everything interacts and how that drives tactics. It will be fun to find out :)
Other types of warhead will include laser heads and shrapnel heads, although I haven't designed those yet.
Shield Update
Although I have already explained the basics of shields, the changes I have made to armour (see below) will slightly affect the details but not the general principles. Shield radius will now be equal to 1.25x armour radius, so shields will be much closer to the hull and will not make the ship significantly easier to hit. Shield Area is also now in square meters rather than the abstract size I used in my earlier post and the point strength is equal to total area divided by 200. In effect, I am assuming that the energy contained in 200m2 of the shields will be applied against any single kinetic strike.
Although the maximum strength that can be applied against a kinetic strike is the point strength, a laser strike with a beam diameter greater than one will affect a greater area of the shields and will require greater energy to penetrate. I'll cover this in the laser post. Against a nuclear detonation, the amount of energy that will strike the shields will be equal to the square meter damage at that range mutliplied by (armour width*0.625). This is because half the ship will be affected and the shields are 25% wider than the hull, so half the armour x 1.25, which is all the armour x 0.625.
Note: In reality, the damage to armour and shields would be greater because the ship has height as well as length. In effect I am assuming a strip of the ship 1 meter high is all that is hit by the blast. However, the game is 2D, it's complicated enough already and nuclear weapons don't really need the extra help so I am happy to live with that simplification. In addition, some parts of the ship would actually be slightly closer to the explosion than others so the damage should vary across the hull. I am not going to include that complication either.
Example of shield and armour calculation
A ship of 4884 tons has 6cm thick armour and 72 GJ shields. The hull volume is 48,840 and the spherical diameter is 45 meters. The surface area is 6461m2, which is multiplied by 0.06 for 6cm of armour, giving 388 tons of armour. The armour is 6 layers by 45 columns and is Ceramic Composite with a strength of 125 MJ per box. The radius of the shields is 25% greater than for the armour, which gives a surface area of 10,096m2. The 72 GJ total shield strength (72,000 MJ) is divided by (10096/200), to give a point strength of 1426 MJ.
Steve
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Except it's easy to dodge a bullet when you see the flash 4+ seconds before impact.
True, assuming you can track the path of the bullet. Otherwise you might dodge into it :). Railgun rounds will likely be too small to track on sensors, at least as things stand at the moment.
Steve
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It may be a good idea to have something like "random evasive maneuvers" type of movement for fleet, that will prevent from being hit by gigantic projectiles from big distances. It's only additional type of movement that You can use when You suspect that something is shooting ;D It could reduce acceleration by 5% and also increase fuel usage. Also, it would be easier for small ship with small mass to slightly change course every few seconds. The fuel and acceleration penalty for capital behemoths could be much bigger.
There will be some type of random evasion. I need to get into the calculations before I figure out exactly how it will work. I am already thinking that stationary bases will be a bad idea. Even a 'base' is going to need some type of maneuvering capability. Also - Hide Your Shipyards!
Steve
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I kinda like it, missiles will no longer be king, thanks to the extended flight times and just generally lower accuracy as well as improved railgun and laser damage, but you still want to use them because of the unmatched damage potential.
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Does that mean that Sensors can't be turned off?
Or that they always draw energy despite being shut down? (Electronics in active standby, so to say)
You can shut them down and they won't draw energy. In effect, power will be used for sensors if they are active. If not, that power will be sent to the batteries (HPGs) if there is capacity.
I also second the question if a Projectile can hit the shields but miss the ship.
I suppose minimum distance will be reduced massively?
I have changed this now so that shields are much closer to the ship. I probably won't bother now with a "hit shields, miss armour" scenario.
Steve
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I kinda like it, missiles will no longer be king, thanks to the extended flight times and just generally lower accuracy as well as improved railgun and laser damage, but you still want to use them because of the unmatched damage potential.
I'll see how it plays out but I think missiles with a nuclear warhead will be a distraction you can't ignore rather than a serious threat to a well defended fleet. They will be effective though in an anti-missile role. It may be different for missiles with other types of warheads, depending on the range from the target at which they can detonate and still be effective. I'll see how it works out when I get into the maths.
Steve
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In a way, I am designing Newtonian Aurora without a really detailed idea of how the combat is going to play out. I am trying to create realistic systems and then I will see how everything interacts and how that drives tactics. It will be fun to find out :)
I applaud this attitude. We are honestly unsure how this sort of thing will work in reality, and it's going to be highly dependent on the technological parameters involved. Keep up the good work.
For lasers, I have a better equation for beam radius at target then the conventional one:
Radius =(range (m) *SQRT((1.22*wavelength (m)*beam quality)^2+(jitter (radians)*mirror diameter (m)*2)^2))/mirror diameter (m)
Beam quality is a dimensionless number that is the ratio of the spot size to the diffraction-limited spot size. For Aurora, it's going to be very close to 1, but still might have a significant impact.
Jitter is probably going to be measured in (tens at most) nanoradians. 250 is my guess for a near-to-mid future model. This would help reign in large mirrors, as the spot size converges to jitter*range.
I'll see how it plays out but I think missiles with a nuclear warhead will be a distraction you can't ignore rather than a serious threat to a well defended fleet. They will be effective though in an anti-missile role. It may be different for missiles with other types of warheads, depending on the range from the target at which they can detonate and still be effective. I'll see how it works out when I get into the maths.
Steve
Missiles are not a serious threat to a well-defended fleet now, at least in my games. I will admit to being killed by long-range missiles a few times early in my career, so I may be going overboard.
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I might be drooling in my pudding right about now.
Sweet.
I somehow expect it to get worse anytime, but it gets better. :D
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What would be nice is if you could have more parameters for armour. Like if you could make it so that armour was more resistant to lasers, but cost more minerals, or was denser, but again, cost more minerals.
It would also be nice to be able to have multiple types of engines on a ship at once. A really fuel efficient, slow burning engine for getting up to speed to go FTL, and a really powerful, fuel-hungry engine that is used when the ship is under attack for emergency (de)acceleration.
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It would also be nice to be able to have multiple types of engines on a ship at once. A really fuel efficient, slow burning engine for getting up to speed to go FTL, and a really powerful, fuel-hungry engine that is used when the ship is under attack for emergency (de)acceleration.
The problem with that is that the engines not currently in use are basically dead weight.
I already have a solution to this however, and it needs no extra game mechanics. Build the ship with the fuel hungry engines, and then build a seperate 'ship' thats just fuel efficient engines and fuel storage. Tractor the first ship with the second. When you get into combat, deploy your combat ship, leaving the dead weight behind.
I just hope we can turn off engines on tractored ship, otherwise this wont turn out as well as it could.
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Your "Dead weight" will speed into the enemy while your combat ship decelerates fast enough. ;D
I'd really like multiple speed options as well.
However, this could simply be the installing of thrusters.
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The thing is, there's nothing stopping you from using both types of engines at the same time.
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The thing is, there's nothing stopping you from using both types of engines at the same time.
Except the fact that, in that case, you'd likely be better off with a single, more balanced engine design?
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I guess it will depend on the exact formulas that Steve uses.
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By a strange turn of fate, I happen to have an equation for spacecraft with two engines.
You begin by finding the mass ratio for each engine (M1 and M2), and the tank fraction as a fraction of remass (T1 and T2). Be warned. If they are both close to or above 2, the equation doesn't work. Also, each engine is assumed to burn all remass while the others tanks are full.
Payload includes everything that's not tanks and remass.
total mass = (M1*payload)/(1-(T1*(M1-1))-((1-(1/(M2/(1-(T2*(M2-1))))))*M1))
Just in case Steve was actually considering adding it.
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Steve, I was wondering, as missile explosion will be much more dangerous, will ship explosion (when destroy) have a dangerous impact if the rest of the fleet is close enough? Does fleet dispertion will be taken into acount?
Also, you mention stationary space station might be to easy of a target. There could be "fortress shields" as in Nexus the Jupiter incident, or even Eve online. They could be permanently turned on but regenerate extremely slowly. This would avoid a single direct hit from very far, but let a siege fleet the possibility of destroying the station.
Overall, this looks so exciting, and all the things you describe look like the game I have been hunting down for so long. Thanks!
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Steve, I was wondering, as missile explosion will be much more dangerous, will ship explosion (when destroy) have a dangerous impact if the rest of the fleet is close enough? Does fleet dispertion will be taken into acount?
Also, you mention stationary space station might be to easy of a target. There could be "fortress shields" as in Nexus the Jupiter incident, or even Eve online. They could be permanently turned on but regenerate extremely slowly. This would avoid a single direct hit from very far, but let a siege fleet the possibility of destroying the station.
Overall, this looks so exciting, and all the things you describe look like the game I have been hunting down for so long. Thanks!
Ship destruction is giving me a lot to think about. For example, there wouldn't be many stationary wrecks because any wreckage would have the same general velocity and heading as the destroyed ship. I think instead I will have several individual pieces of wreckage from a ship, with slightly diverging courses depending on the method of destruction. Each piece would contain minerals for scrap and potentially one or more intact components. You would have to detect them, chase them down and tractor them for salvage. They may also create something of a navigational hazard for other ships, especially fast moving ones. Or maybe the wreckage would be relatively intact if the ship was rendered a mission kill in some way, rather than complete destruction. Life support failure perhaps. Reactor failure could be far more catastrophic and result in an explosion that could damage other ships directly, rather than through debris.
Some type of huge shield is possible, although it would have to be truly gargantuan to resist very high speed projectiles or close-range nuclear detonations. Perhaps something planetary-based might be possible. I haven't given this area a lot of thought so far.
Steve
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What about shields that are electro magnetic in nature, that tend to be further from the station then closer. Projectiles tend do be metallic in composition the job of the this shield is to not stop but change the course of the object, so if it can deviate it to miss the station.
Also if the station is orbiting a planet, it would not be stationary. Neither is the planet stationary, with all the influences of space from solar currents to gravity from other planets, long range projectiles that do not have course changing thrusters would more then likely miss. Firing the projectile would cause micro shift in angles in any particles direction so I doubt it would hit. It be like hitting a coin 20km away with a computer stabilised rifle, still not an easy thing to do.
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I wasn't too taken with the idea of Newtonian Aurora when I first heard about it, but the more I hear the more I like!
That said I'm wondering how (if) fighters and other small craft will work in Newtonian Aurora? Because the way I'm reading it now is that they won't, or at least not in a manner we are at all familiar with.
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What about shields that are electro magnetic in nature, that tend to be further from the station then closer. Projectiles tend do be metallic in composition the job of the this shield is to not stop but change the course of the object, so if it can deviate it to miss the station.
Also if the station is orbiting a planet, it would not be stationary. Neither is the planet stationary, with all the influences of space from solar currents to gravity from other planets, long range projectiles that do not have course changing thrusters would more then likely miss. Firing the projectile would cause micro shift in angles in any particles direction so I doubt it would hit. It be like hitting a coin 20km away with a computer stabilised rifle, still not an easy thing to do.
The perturbations on a planetary scale will be very minor (not an issue). But, yes, projectiles will have to be guided.
On another note, I'm skeptical of the whole "navigation hazard" thing. Yes, a wreck could be dangerous, but only if you're stupid. Collision detection in space is easy, due to "constant bearing, decreasing range". Just burn a little bit in any direction, and you're safe. Projectiles can track, which makes dodging iffy. I wouldn't bother tracking objects for navigation purposes beyond a few seconds, on the assumption that past that point, they will have moved the few kilometers needed to be safe.
That said I'm wondering how (if) fighters and other small craft will work in Newtonian Aurora? Because the way I'm reading it now is that they won't, or at least not in a manner we are at all familiar with.
You are entirely correct. Space fighters in a Newtonian environment are just plain silly, as the vessel is made less manuverable, and you need 4 times the delta-V.
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You are entirely correct. Space fighters in a Newtonian environment are just plain silly, as the vessel is made less manuverable, and you need 4 times the delta-V.
This part I do not understand, this means that missiles would be less manoeuvrable, based on the logic above the smaller the object the less manoeuvrable they are.
Perhaps I am missing something and need to be explained, my thought was the less mass the easier it is to manoeuvre, as it doesn't require quite as much thrust
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Also just a throw away line and I am sure people would call me a crack pot. And I am far from an astrophysicist, so you can take my niavity.
http://discovermagazine.com/2008/aug/18-nothingness-of-space-theory-of-everything
This article talk about temporary particles in a vacuum and dark matter. What if 100 years from now power can be derived from dark matte or capture the temp particles, would that mean you could produce and engine that used space as fuel?
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Well, without the fighter engines from regular Aurora, fighters are right out in my book.
Except for the fact, that they are harder to detect due to size, there is simply no advantage over a ship, ´cause, well, a fighter is a spaceship is a spaceship.
If I wanted my fighter to have anything close to what a fighter is meant to have in terms of accel, it would probably have to be 90% fuel/engine. Add in life support and a small firecon and there are perhaps 10 tons for weapons left on a 200t fighther.
I don´t think this would be a winning setup :)
Reduce engine/fuel, and you have a fighter with the same performance stats as a regular warship, just a lot more fragile, so what´s the point?
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Why can't fighters use rather large missile engines?
I cannot see how you can have missiles but not have fighters. A fighter is basicly and engine, fuel and a weapons system. There is no food storage, galley, rec facilities, toilets, showers etc etc etc. Even if they were the same acc speed as a spaceship they would be highly more manoeuvrable, due to not having all the items above.
I cannot see how you can deploy manoeuvrable missiles and not deploy fighters, it like a whole segment of physics is ignored. Even if the fighter engines could accelerate the same as a warship, I still see it usefulness, in the ability to manoeuvres into a position to attack the ship.
On a side note, since now have newtonian physic, wouldn't things like turret placement be critical. Even fighting on a 2D plane, you could place turrets on the rear, top, side, bottom. But placement is important as you could only fire that direction each placement is important example.
Say you place 2 on top, and the enemy is in the rear, only one might be able to fire. I don't see the idea of going to the trouble of Newtonian physics but you can still fire all your weapons, no matter the direction of the enemy.
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Well, any fighters become rather pointless when you consider putting an extra stage on your missiles: it has almost all the advantages of a pilot, but without the disadvantages of needed a human pilot and the massy life support, being acceleration-limited by the human inside and not being able to put anything useful (I do not count the pilot as useful) in the centre of mass.
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Well, any fighters become rather pointless when you consider putting an extra stage on your missiles: it has almost all the advantages of a pilot, but without the disadvantages of needed a human pilot and the massy life support, being acceleration-limited by the human inside and not being able to put anything useful (I do not count the pilot as useful) in the centre of mass.
A pilot give you options a second stage missile cannot, such as change target, abort target without destruction of ordnance, direct to another fleet and engage. Let along the other which is fit weapons other then a missile such as a beam weapon, or something else using it as a sensor scout. You cannot do any of those things with a longer range missile that I can think of.
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A pilot give you options a second stage missile cannot, such as change target, abort target without destruction of ordnance, direct to another fleet and engage. Let along the other which is fit weapons other then a missile such as a beam weapon, or something else using it as a sensor scout. You cannot do any of those things with a longer range missile that I can think of.
These are all things a computer can do better then a pilot. There is no point in space fighters - they are way too expensive. And I guess the ordnance is less expensive then the propulsion mass required to maintain a fighter.
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All of you assume that a Fighter is equivalent to a Bomber.
This is not the case.
I can totally see a small space craft with a few rocket thrusters, able to evade incoming fire while shooting railgun slugs at the enemy from a medium distance.
You also assume a fighter is necessarily manned.
Well, call it a drone, then.
In current Aurora, you can use multistage missiles as well, it's just a tiny difference in expenditure that will result from Newtonian physics.
As for bearing, if I remember correctly, Steve has said on multiple occasions that that would turn it too much into a tactical simulation as opposed to strategy. Just the same as it's 2D, after all.
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RE: fighters
Presumably, you want to recover your fighters. That means fighters have to have enough fuel to get out there, stop, get back and stop again.
Missiles (or suicide fighters) will only need to get there. If they miss, they miss.
4x delta-v requirement makes fighters carry too much fuel.
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Send fighters.
Wreck enemy.
Follow and pick them up again.
Profit.
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Hey would still need to stop.
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This part I do not understand, this means that missiles would be less manoeuvrable, based on the logic above the smaller the object the less manoeuvrable they are.
Perhaps I am missing something and need to be explained, my thought was the less mass the easier it is to manoeuvre, as it doesn't require quite as much thrust
I should have been more clear. I was comparing them to missiles.
A missile has to go out and kill its target. A fighter has to accelerate to get to the target, decelerate to a stop, then kill the target and go back to the mothership.
The statement about "less manuverable" also applied as compared to missiles. The extra mass of the human and his stuff hinders acceleration.
All of you assume that a Fighter is equivalent to a Bomber.
This is not the case.
I can totally see a small space craft with a few rocket thrusters, able to evade incoming fire while shooting railgun slugs at the enemy from a medium distance.
You also assume a fighter is necessarily manned.
Well, call it a drone, then.
In current Aurora, you can use multistage missiles as well, it's just a tiny difference in expenditure that will result from Newtonian physics.
At medium distance, you can either evade or you can't, and there's no reason that a conventional ship couldn't if a "fighter" can.
I'm in favor of drones, but what makes a fighter is recoverability. That tacks on delta-V somewhere in the system.
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The fighter would be harder to hit, and would probably be able to (de)accelerate faster than a ship.
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Well, fighters would likely have much higher acceleration than regular ships, so they would be capable of evading things at shorter distances then a larger ship. They would also likely be harder to hit in general, as it seems size now matters.
As for the delta-v things, while true, one has to remember that theres no reason that the return trip has to be made at the same speed, or than you couldnt use a series of slingshots to get back if fighting in close proximity to a planet/moon.
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Hmmn, just thinking about those fighter engines, Steve has already given missile engines a better power to weight ratio than ship engines due in part to the fact that the missiles don't need access hatches and maintenance space etc.
Potentially you could extend this reasoning to fighter engines and provide them with a benefit of power to weight v ships engines with a restriction on repairs. Ie you can only carry out repairs in a hanger deck.
I know this departs from the single engine design parameters further but with these benefits aligned with the current benefits of larger engines being more efficient than smaller ones it could help to address the issue of the fighters becoming redundant due to large delta V requirements when compared to missiles.
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Well, fighters would likely have much higher acceleration than regular ships, so they would be capable of evading things at shorter distances then a larger ship. They would also likely be harder to hit in general, as it seems size now matters.
As for the delta-v things, while true, one has to remember that theres no reason that the return trip has to be made at the same speed, or than you couldnt use a series of slingshots to get back if fighting in close proximity to a planet/moon.
This assumes that evasion is a serious part of combat. It isn't. For one thing, random course changes to throw off laser targeting take almost unbelievable amounts of delta-V. Fighters might be able to pull it off, but why? What good does it do them?
Kinetics will track their targets. Period. So you have to disable them, then dodge a little bit. No advantage to fighters.
The second point is true, but if you still take a performance hit compared to missiles. And slingshotting only works if you're not going that fast, and in a very specific place. Also, you need a planet. That sounds silly, but think about it. Going around an enemy planet is a good form of suicide, and what if there's no planet at all?
Actually, why do you want fighters at all? To extend the range of the launching ship? That's not going to work, as you can make longer-range missiles instead, and far more cheaply. To scout? Drones work just as well, and they can be small and expendable. To have dogfights in space? Go ahead, but don't pretend it's realistic.
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Also just a throw away line and I am sure people would call me a crack pot. And I am far from an astrophysicist, so you can take my niavity.
http://discovermagazine.com/2008/aug/18-nothingness-of-space-theory-of-everything
This article talk about temporary particles in a vacuum and dark matter. What if 100 years from now power can be derived from dark matte or capture the temp particles, would that mean you could produce and engine that used space as fuel?
This has been a common science fiction idea for years (for example Charles Sheffield's stuff). The problem is in the paragraphs about 1/3 of the way down the 2nd page - if you can pull energy from the vacuum, then that means the vacuum is unstable and can go into a different state, where the laws of physics would be different and we'd all die.
As an example of this, think about two populations of (fresh water) fish - "A" that's living in water that's 5 degrees C and "B" that's living in water that's -5C. In both cases, there's thermal energy in the water. In case "A" the fish can try to extract that energy by rearranging the water into ice. The problem is this doesn't work - the "water" state is the stable one. In case "B", it will work - you'll get energy out of the water by turning it into ice. The problem is that water likes (energetically) to be in the "ice" state at -5C, and the ice crystal you just made will grow until the whole pond is made out of ice and the fish die because the physical properties of water are very different from those of ice. If you say "vaccuum" everywhere I said "water", then you've got the argument on the 2nd page....
CAVEATS:
1) Experts will notice that I was being a little fast and loose about energy vs. free energy above. The general argument remains the same, though.
2) There's always the very small chance that some of what we think are very basic physical principles (like the 2nd law of thermodynamics) might not apply at these small scales/high energies. If so, something weird might come out of it.
3) If the vacuum is "choppy" (think waves on water), then there might be a way to extract energy from the chop. I suspect it would be difficult to get much out, though.
John
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http://en.wikipedia.org/wiki/Vacuum_energy
there have been some theories about extracting energy from vacuum and some experimental observations too.
but I maintain the position that one doesn't really have to make physics works too much in a game.
just imagine the mess of communicating orders to ship that travels at relativistic speeds :P
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The idea about better power ratios for fighter engines at the expense of in-space maintenance is a good one.
This assumes that evasion is a serious part of combat. It isn't. For one thing, random course changes to throw off laser targeting take almost unbelievable amounts of delta-V. Fighters might be able to pull it off, but why? What good does it do them?
Kinetics will track their targets. Period. So you have to disable them, then dodge a little bit. No advantage to fighters.
The second point is true, but if you still take a performance hit compared to missiles. And slingshotting only works if you're not going that fast, and in a very specific place. Also, you need a planet. That sounds silly, but think about it. Going around an enemy planet is a good form of suicide, and what if there's no planet at all?
My understanding is that evasion will be a big part of 'beam/kinetic' combat in newtonian aurora. Im not aware of any kinetics that can track fighters, only missiles can do that, and they still have to hit, which is where ECM or other defences come into play, along with good acceleration.
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Why can't fighters use rather large missile engines?
Missile Engines
Engine Technology: Exactly as ship-based engines. However, the base value of power is doubled on the basis that missile engines have no radiation shielding or maintenance access requirements.
Missile engine technology would not be prudent for manned spacecraft as the missile engine is designed to be used precisely once. There are a number of things one can afford to have an engine do if you never intend to have that engine be used again.
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Missile engine technology would not be prudent for manned spacecraft as the missile engine is designed to be used precisely once. There are a number of things one can afford to have an engine do if you never intend to have that engine be used again.
Yes, my point was that fighter engines could get for example 150% instead of the 200% of missiles to reflect the difference to a standard ship engine. Then follow this with the idea that the fighters 25 ton engine is substantially more efficient than a missile's 2 ton engine and you should get to a point where fighters are a worthwhile launch platform alternative.
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Well, without the fighter engines from regular Aurora, fighters are right out in my book.
Except for the fact, that they are harder to detect due to size, there is simply no advantage over a ship, ´cause, well, a fighter is a spaceship is a spaceship.
If I wanted my fighter to have anything close to what a fighter is meant to have in terms of accel, it would probably have to be 90% fuel/engine. Add in life support and a small firecon and there are perhaps 10 tons for weapons left on a 200t fighther.
I don´t think this would be a winning setup :)
Reduce engine/fuel, and you have a fighter with the same performance stats as a regular warship, just a lot more fragile, so what´s the point?
You can have fighter engines in Newtonian Aurora. If you read the engine post at the start of this thread, there is an option to increase thrust at the expense of fuel efficiency and you can also create 50 ton engines, which is the same size as a fighter engine in Standard Aurora. Instead of Commercial/Military/FAC/Fighter engines there is now a more detailed engine design process which allows you to create all four and everything in between.
'Beam' fighters may be possible in Newtonian Aurora because the smallest railgun is only 25 tons (0.5 HS). While it isn't very powerful, you could get the fighter up to a decent speed before firing and the projectile will gain the launch speed of the fighter. Of course, that fighter may struggle to change direction or decelerate before it reaches the target, especially as it will have to get fairly close for a good chance of a hit. The other option may be simple 'iron bombs'. Just a pair of 1000 kg chunks of iron under the wings. Get in close and let them go at a few hundred km/s. They would be devastating. A 1 kg railgun projectile is bad enough.
Steve
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Certainly.
I suppose the discussion is mainly why not to use guided missiles instead to pick up velocity and crash those into the target.
Now I suppose having a sphere 3 meters in diameter with strong thrusters buzzing around your ship, unmanned of course, and shooting a small laser, railgun slug, or Microwave your direction, will most certainly provive a distraction, if not as good of one as a volley of nukes, which might be cheaper.
The one thing that I fear might break the system (not just fighters, the newtonian system)from being fun is excessive speed making kinetic projectiles a bit too effective.
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Certainly.
I suppose the discussion is mainly why not to use guided missiles instead to pick up velocity and crash those into the target.
Now I suppose having a sphere 3 meters in diameter with strong thrusters buzzing around your ship, unmanned of course, and shooting a small laser, railgun slug, or Microwave your direction, will most certainly provive a distraction, if not as good of one as a volley of nukes, which might be cheaper.
The one thing that I fear might break the system (not just fighters, the newtonian system)from being fun is excessive speed making kinetic projectiles a bit too effective.
Kinetic projectiles will be extremely effective, as will nuclear weapons :). I forsee a return of the Nuclear Space Mine used by the Original Series Romulans against the Enterprise and the Agamemnon against the Minbari :)
I think I may have to revisit sensor technology to make it easier to detect small objects. However, it will be difficult to get hits with kinetic projectiles unless you are at close range, or the target is following a predictable course.
With regard to fighters vs missiles. A fighter can be far more selective about changing targets and is more able to adapt to a rapidly changing tactical situation.
Steve
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I think I am going to make shields just slightly larger than the ship rather than 25% larger. It is adding too many unnecessary complications that the damage that can hit the shields may not hit the ship, or worse still that only part of the damage that hits the shields may hit the ship. Much easier to have the same damage applied against both.
Steve
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Wait. Are kinetics (coilguns, railguns, etc.) going to be unguided, or just have minimal tracking capability?
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Wait. Are kinetics (coilguns, railguns, etc.) going to be unguided, or just have minimal tracking capability?
How could they track? Without an engine they have no means of altering course, unlike in the atmosphere. If they have an engine, they're no longer kinetics, but a missile.
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It's called thrusters. My definition is based upon the primary means of giving them velocity, not on being unguided.
Unguided kinetics are very impractical. See http://www.rocketpunk-manifesto.com/2010/11/home-away-from-home.html?showComment=1289267698643#c759139992445967698 (http://www.rocketpunk-manifesto.com/2010/11/home-away-from-home.html?showComment=1289267698643#c759139992445967698) for more details.
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It's called thrusters. My definition is based upon the primary means of giving them velocity, not on being unguided.
Unguided kinetics are very impractical. See http://www.rocketpunk-manifesto.com/2010/11/home-away-from-home.html?showComment=1289267698643#c759139992445967698 (http://www.rocketpunk-manifesto.com/2010/11/home-away-from-home.html?showComment=1289267698643#c759139992445967698) for more details.
Yes, but the railgun ammo is only going to be a few kilograms. Not really enough to put on thrusters, at least not without greatly increasing the size, which will slow it down significantly.
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You could fit a halfway-decent guidance system and some thrusters on something that size today. We have guided mortar rounds in that size range, and all the machinery isn't going to cut lethality at all. Aurora is more advanced, and if you look at the link, you'll see why unguided kinetics are a bad idea.
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You could fit a halfway-decent guidance system and some thrusters on something that size today. We have guided mortar rounds in that size range, and all the machinery isn't going to cut lethality at all. Aurora is more advanced, and if you look at the link, you'll see why unguided kinetics are a bad idea.
Thats because mortar rounds only need a simple system such as fins to guide them, whereas a kinetic in space requires an engine and delta-v reserve.
EDIT: Also, your article deals with hitting things at rather extreme ranges; 2 minutes is a long time. I expect kinetics will be faster than 'realistic' in Newtonian Aurora for the sake of gameplay, and as a result the evasion window will be smaller. Also remember Aurora is 2D, so its easier to 'bracket' targets with kinetics. Again, not realistic, but as long as the gameplay is fun and self-consistent, who cares. I trust Steve will get it right.
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You will need some sort of fuel. And that will take up most of the space I was talking about earlier. I don't think that guided projectiles will be worth it until you get some extremely powerful and efficient engines.
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You will need some sort of fuel. And that will take up most of the space I was talking about earlier. I don't think that guided projectiles will be worth it until you get some extremely powerful and efficient engines.
And what do you think Aurora's engines count as?
My point is simple. Even a very low-powered guidance round is vastly more effective then a non-guided round. I'll do some math on this.
Let's say a projectile has 1G acceleration (10 m/s2) and 100 m/s of delta-V, with a flight time of 10 seconds. During that time, it can deflect in a circle with a radius of 500 meters. Farther, let's say that the ship we're facing has a cross-section of 100 m. (I'm going to work both as lines, because this is Aurora). The guided round has a total target cross-section of 1000 m, and it's actually more like 1100 because of the size of the ship. The unguided round only has 100 m, so a guided round is 11 times as effective. For a 10-second flight time. And I don't think it would be serious trouble to build a guided round with 100 m/s of delta-V, and 1G acceleration, along with a basic guidance system.
11 times. Remember that. The picture gets even worse in 3D.
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This has been a common science fiction idea for years (for example Charles Sheffield's stuff). The problem is in the paragraphs about 1/3 of the way down the 2nd page - if you can pull energy from the vacuum, then that means the vacuum is unstable and can go into a different state, where the laws of physics would be different and we'd all die.
As an example of this, think about two populations of (fresh water) fish - "A" that's living in water that's 5 degrees C and "B" that's living in water that's -5C. In both cases, there's thermal energy in the water. In case "A" the fish can try to extract that energy by rearranging the water into ice. The problem is this doesn't work - the "water" state is the stable one. In case "B", it will work - you'll get energy out of the water by turning it into ice. The problem is that water likes (energetically) to be in the "ice" state at -5C, and the ice crystal you just made will grow until the whole pond is made out of ice and the fish die because the physical properties of water are very different from those of ice. If you say "vaccuum" everywhere I said "water", then you've got the argument on the 2nd page....
CAVEATS:
1) Experts will notice that I was being a little fast and loose about energy vs. free energy above. The general argument remains the same, though.
2) There's always the very small chance that some of what we think are very basic physical principles (like the 2nd law of thermodynamics) might not apply at these small scales/high energies. If so, something weird might come out of it.
3) If the vacuum is "choppy" (think waves on water), then there might be a way to extract energy from the chop. I suspect it would be difficult to get much out, though.
John
Scientist also originally said that breaking the speed barrier was an impossibility. Flight was impossible. And nothing could move faster then light. The word 'nothing' was the optimum word here, but there is a possibility that something does. Scientist change there reasons and definitions the more they understand the more they learn they do not understand.
What if they do succeed and it doesn't destroy the universe. Then science changes again. That why I smile a naysayers including no in space stealth people. Human do not hold the mysteries of the universe and I doubt we ever will. I believe the universe will have an infinite amount of mysteries to answer.
I was reading another article a theory about creating an optical bubble, to hide things. IR is just another form of light transmission. I think "never say never" cause when you do someone always ends up with egg on there face.
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Scientist also originally said that breaking the speed barrier was an impossibility.
Not as a physical impossiblity. As an engineering one. And not by the time they started to get good data.
Flight was impossible.
No, manned flight was impossible. And nobody said it was a scientific impossibility, either.
And nothing could move faster then light.
That hasn't been proved yet, and I for one am highly skeptical. The probability that there's some error is still very much present.
The word 'nothing' was the optimum word here, but there is a possibility that something does. Scientist change there reasons and definitions the more they understand the more they learn they do not understand.
What if they do succeed and it doesn't destroy the universe. Then science changes again. That why I smile a naysayers including no in space stealth people. Human do not hold the mysteries of the universe and I doubt we ever will. I believe the universe will have an infinite amount of mysteries to answer.
I was reading another article a theory about creating an optical bubble, to hide things. IR is just another form of light transmission. I think "never say never" cause when you do someone always ends up with egg on there face.
I can say that under our current understanding of how the universe works, the law of conservation of energy will hold. If it doesn't, then everything goes out the window.
Read this link before we go any farther. http://www.projectrho.com/rocket/respectscience.php (http://www.projectrho.com/rocket/respectscience.php)
Think it over carefully, and remember that just because it might be possible doesn't mean it is.
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Let's say a projectile has 1G acceleration (10 m/s2) and 100 m/s of delta-V, with a flight time of 10 seconds.
You see? That's why I wanted railguns that could launch stuff, not just mass packets.
Railgun launched missile is what you are talking about there.
Then again, there might also be a problem about launching a fusion torch drive at a humoungous accelerations a railgun imparts.
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Scientist also originally said that breaking the speed barrier was an impossibility. Flight was impossible. And nothing could move faster then light. The word 'nothing' was the optimum word here, but there is a possibility that something does. Scientist change there reasons and definitions the more they understand the more they learn they do not understand.
What if they do succeed and it doesn't destroy the universe. Then science changes again. That why I smile a naysayers including no in space stealth people. Human do not hold the mysteries of the universe and I doubt we ever will. I believe the universe will have an infinite amount of mysteries to answer.
I was reading another article a theory about creating an optical bubble, to hide things. IR is just another form of light transmission. I think "never say never" cause when you do someone always ends up with egg on there face.
Ummm I didn't (intend to) say never - that's what caveat number 2 was about. That being said, given everything we know today (including quantum field theory, which is where the vacuum energy stuff comes from) and applying the correspondence principle, the odds of it being possible to suck energy from vacuum fluctuations in a non-catastrophic way are VERY small. Something very fundamental, like the 2nd law, would have to be violated.
Two more things:
1) Science (scientific models, actually) doesn't change; it extends the accuracy and extent of the phenomena it describes - this is the correspondence principle. http://en.wikipedia.org/wiki/Correspondence_principle (http://en.wikipedia.org/wiki/Correspondence_principle) (note that the wikipedia article isn't very good - it leads off applying the principle only to quantum mechanics when in fact it applys to all scientific models).
2) As an amusing side note, quantum field theory predicts that if tachyons (particles which travel faster than light) exist then the vacuum is unstable and we're back in the "different state" catastrophe situation.
John
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One can assume that a missile, the engine and fuel, have less mass than a solid projectile of the same size, thus, a guided projectile would require a larger caliber railgun to fire a projectile of the same kinetic energy.
Additionally, given other factors of space combat, there is a great range of possibilities affecting the efficiency of weapons.
If your ship is going 150k anyways, the 70 you might get from the railgun could be substituted for slightly larger projectiles, and you'd be directly firing guided missiles.
Especially on ranges that have 30+ seconds slight time anyways.
However, one could assume to use the maneuvering engines to give additional thrust, yet still the gain would be too marginal.
If, instead, the range of the engagement is within just a few hundred kilometers, a guided projectile does not measurably increase the hitrate, while reducing the firerate(or damage output).
And wouldn't a defensive nuke be able to blind/damage a guided projectile, thus eliminating the advantage?
What about electronic warfare/decoys to simulate a ship shortly, maybe not able to confuse a ship-board sensor, but the small homing device of the projectile? Direct guidance might result in delay and thus give up part of the advantage, while directed ECM will food the guidance of such a small projectile that will have to be either conductive, and thus magnetic, allowing pulse magnet fields to alter it's course and damage electronics, or not, in which case it's not shielded from a medium-powered, and a lot faster-fireing, microwave laser to take it out.
Sure, these a re all very small caveats, but;
Given that a guided bomb is quite probably several hundred times more expensive than a chunk of metal, and more prone to failure, it raises the question if it wouldn't be drastically more economic, if less effective, to just mount more guns and fire a storm of standard pellets. Or leave out the railgun in favor of boxlaunchers.^^
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Wait. Are kinetics (coilguns, railguns, etc.) going to be unguided, or just have minimal tracking capability?
At the moment they are unguided. Guided kinetics will be missiles with a shrapnel warhead, or maybe a solid warhead. I am sure I will include some type of hybrid missile-railgun combination at some point.
Steve
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Given that a guided bomb is quite probably several hundred times more expensive than a chunk of metal, and more prone to failure, it raises the question if it wouldn't be drastically more economic, if less effective, to just mount more guns and fire a storm of standard pellets. Or leave out the railgun in favor of boxlaunchers.^^
Some form of lower velocity shotgun type weapon is definitely a possibility. In fact, throwing a large rock out the back of the ship into the path of a fast-moving enemy ship could be effective given the right circumstances. Different weapon types are going to be effective in different situations and in some of those situations high tech vs low tech may be far less of an advantage than in standard Aurora.
Steve
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It's worth considering that its entirely possible that ships may be moving faster than the kinetic projectiles and the closing speed is what determines damage, rather than just the speed of the projectile. The chance of avoidance may also be more affected by the ship speed than that of the projectile. The railgun may be used just to get the projectile into the path of a ship, rather than shooting directly at it.
I am considering the idea of a "debris cloud" (name not definite) which would be an area of space with a given diameter, that has x number of objects with y size. If you fly through the cloud then I will calculate the chance of you striking one of those objects and the damage will be based on the size of the object and the impact speed. That debris cloud could also be moving and expanding at the same time. This is probably how the shrapnel warhead will be modeled. I may also handle nebulae in the same way, with the whole system as a debris cloud of dust particles with the chance of occasional larger objects. Shields will work but will be degraded by constant impacts. Or you can move slow enough that the vast majority of impacts will be below the armour threshold.
Steve
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Why does everyone keep calling these things missiles? It's far more akin to a guided artillery shell.
Several things to keep in mind:
1. My example above was a minimal example. Doubling the acceleration and delta-V makes it 21 times as effective, and so on.
2. We're dealing with the far future, and fairly rudimentary guidance systems. The system from the original sidewinder missile should work, with proper modifications. That's pretty cheap.
3. The mass of the engine and guidance system does not subtract from lethality. They hit with the rest of the projectile, and do damage. And there's not a lot of remass used at the delta-Vs I've mentioned, even with cold gas.
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I guess you guys discuss using the casimir effect to "create" energy. Actually it is experimentally proven (see this article on TechReview (http://www.technologyreview.com/blog/arxiv/26813/)) that you can turn a virtual photon into a real one. ATM you put more energy into then you get out thought. If it can used to "produce" power *shrugs* no clue ask the guys who did the experiment.
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RE: vacuum energy
Of note is Noether's Theorem. To produce energy from nothing, you need to be doing something that is not time symmetric. (and 2nd law does not count)
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Cost of a Sidewinder Missile: ~85k $. Cost of a 80kg chunk of pure Iron: roughly 6k $ (actually a bit less). Foolproof radarguidance seekers are quite probebly 10x the cost of an old IR missile.
The main point here is that the missile is very likely to be larger, and anything with thrusters and guidance IS a missile for that matter.
As such, you need larger guns.
Additionally, a laser-based DIRCM is pretty affordable, and can not stop projectiles, but eliminate the advantage of homing rounds.
As said, in the case where the projectile flies for over 30 seconds, given the starting velocity of the ship of possibly a 100km/s, using guided kinetic missiles will be more likely to succeed, as in the same room of a railgun, a few dozen can be fired at once, overwhelming countermeasures.
Edit: Given the extreme electromagnetic forces required to accelerate a Projectile to 70+ km/s in the brink of a second, a guided projectile with it's own terminal guidance would require electromagnetic shielding, further increasing the cost. I'm starting to think that you could just mount an extra gun for every 10 guided projectiles you fire.
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Some form of lower velocity shotgun type weapon is definitely a possibility. In fact, throwing a large rock out the back of the ship into the path of a fast-moving enemy ship could be effective given the right circumstances. Different weapon types are going to be effective in different situations and in some of those situations high tech vs low tech may be far less of an advantage than in standard Aurora.
Steve
given the combination of ship speed and projectile speeds and enemy speeds, fire control will have an hard time to find firing solutions and the correct angle of lead to shoot at.
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Some form of lower velocity shotgun type weapon is definitely a possibility. In fact, throwing a large rock out the back of the ship into the path of a fast-moving enemy ship could be effective given the right circumstances. Different weapon types are going to be effective in different situations and in some of those situations high tech vs low tech may be far less of an advantage than in standard Aurora.
The Lost Fleet series had some interesting ideas about this sort of thing. Basically one of the main weapons for the ships was a ton of ball bearings that got fired into the path of an enemy ship to take down shields through multiple hits. I guess slamming into 5000 1 inch diameter chunks of metal is going to give any shield a battering.
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Why does everyone keep calling these things missiles? It's far more akin to a guided artillery shell.
Because artillery shells guide themselves by slightly changing their flight dynamics. Things which guide themselves by throwing out reaction mass behind them are called Rockets or Missiles. And in modern vernacular rockets generally refer to an unguided version.
It seems to be that your hangup is the assumption that missiles have to explode, when that is not the case. You can have "kinetic kill" missiles which are basically your "guided artillery shells" that solely do damage by ramming. These could get up their speed solely through their own engine (and the initial velocity of their firing ship), or get an initial boost by being fired from a rail gun.
There are three other variants of missiles being discussed:
Nuclear Missiles, which detonate at the end of their flight leaving a large sphere of damage.
Shrapnel Missiles, which create some combination of kinetic kill warheads, either modeled individually or abstracted as some sort of cloud.
Bomb-pumped lasers, which funnel their explosion as some sort of directed laser beam burst.
Any and all of these missiles could theoretically be shot out of a railgun to get an initial kick. (Hmm, it would probably be too complicated, but maybe missiles could have a "maximum" acceleration value, so that non-missile slugs could be shot out of a railgun faster than kinetic kill missiles, which would be faster than Nuclear and Shrapnel Missiles, which would be faster than Bomb-Pumped lasers. That's probably unnecessary bookkeeping though.)
Of course you could imagine still more forms of missiles, especially when you consider staging, and Steve has stated that these current missiles will also completely envelope the earlier "drone" and "buoy" categories.
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Because artillery shells guide themselves by slightly changing their flight dynamics. Things which guide themselves by throwing out reaction mass behind them are called Rockets or Missiles. And in modern vernacular rockets generally refer to an unguided version.
I disagree, but will bow to general terminology. Whatever you call them, guided projectiles are more effective.
It seems to be that your hangup is the assumption that missiles have to explode, when that is not the case. You can have "kinetic kill" missiles which are basically your "guided artillery shells" that solely do damage by ramming. These could get up their speed solely through their own engine (and the initial velocity of their firing ship), or get an initial boost by being fired from a rail gun.
The hangup is nothing of the sort. I'm fully aware of the potential of kinetic-kill weapons.
The definitions I have been using are based entirely on the method by which the weapon gains the majority of its Delta-V. If it uses a rocket, then it's a missile. Any form of kinetic projectile is referred to as a kinetic.
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I’m not sure if Newtonian Aurora suggestions should be going in this thread or in the Suggestions section, but my gut says to keep the Newtonian stuff here.
I’ve been thinking for quite some time (actually done itsy bitsy pieces of my own game about it) about attacking things in space far away from you. This is how I believe that the automatic form of weapon targeting should be accomplished:
When a Fire Control targets an enemy and is about to fire it should calculate (using its projectile speed, whether light speed for a laser, or some smaller value for a plasma bolt, slug, or inert missile) where the enemy would be at the point the projectiles would hit it if the enemy drifted. We will call this the target point. It should then estimate the target bracket in a simplified way, calculate the distance travelled under the targets estimated maximum acceleration (probably whatever the highest acceleration you’ve seen the class accomplish thus far) in the time between the firing time and the impact time. It would add this distance to each direction to get the total width of the target bracket.
Let’s say that the leftmost part of the bracket is called 0, the center (“target point”) is 50, and the rightmost edge of the bracket is 100.
The Fire Control would then look at all the beams under its control (a quad turret would count as four) and divvy up the shots as follows:
Beams: Target Spots
1: 50
2: 25, 75
3: 0, 50, 100
4: 20, 40, 60, 80
5: 0, 25, 50, 75, 100
6: 14, 28, 43, 57, 71, 86
7: 0, 16, 33, 50, 67, 83, 100
Etc, etc.
Now if this bracket represented the offset in the angle the firing ship had to aim its beams than you have the firing solution for that one ship. If you had multiple fire controls on the same ship with the same weapon (maybe just same projectile speed) they could also sum their beams together to best divvy up their shot spread. It’s all coming from the same ship so the same angle offsets would work.
However this wouldn’t be the easiest way to optimize target spread amongst a whole fleet. The easiest way I can see to do that is for the target bracket to not refer to the angular offset, but to instead find that maximum evasion distance from earlier, and then draw a line from your fleet’s current position to your target’s estimated position (assuming drift). Your target bracket now becomes a shorter line perpendicular to this line from your fleet, with a length of twice the evasion distance and centered on this fleet line.
Now count up your beams and divvy up the targets along this new line, and you can use that to get a firing solution for your whole fleet.
For example, a fleet of five ships with two quad turrets each could now cooperate to evenly distribute there 40 shots among the (reasonable approximation of the) entire region their target ship could be when their projectiles reach him.
I think that the same system would be useful for targeting launched missiles (either launched slowly or fired from a railgun). This would naturally make your missile salvo spread out, helpful to conserve losses from your enemies’ defensive nuclear explosions, and ensure that at least some of your missiles will be on a very close vector to your enemy when they light up for final course correction.
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That firing solution looks very much like a torpedo spread in a submarine.
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Let’s say that the leftmost part of the bracket is called 0, the center (“target point”) is 50, and the rightmost edge of the bracket is 100.
The Fire Control would then look at all the beams under its control (a quad turret would count as four) and divvy up the shots as follows:
Beams: Target Spots
1: 50
2: 25, 75
3: 0, 50, 100
4: 20, 40, 60, 80
5: 0, 25, 50, 75, 100
6: 14, 28, 43, 57, 71, 86
7: 0, 16, 33, 50, 67, 83, 100
Etc, etc.
Like the thought, but you'd probably want to change those numbers to something like.
From -10 Size Deviations to 10 SD, where 0 SD is on a straight line centered through the target ship's heading at 0 acceleration, and one Size Deviation is the target ship's diameter.
From that, you get:
1 beam weapon: 0SD
2: 1/2 SD, -1/2 SD
3: 1SD, 0SD, -1SD
4: 1 1/2 SD, 1/2 SD, -1/2 SD, -1 1/2 SD
etc...
If targetting range is still limited to 5 lightseconds, then you don't really need this though. You'd want to put as many points of damage as possible within the target window, and it's not going to change that much.
Using Steve's Daring Class from the first post, it's got a size of 6873 Tons. That's 68730 m3, or approximately 109m diameter.
The most it can accelerate at 21.83 m/s2. Looking at a 1 dimensional line, at 5 seconds the center of the ship can be at most 117.15m off from where it would be with no acceleration.
So you can look at this from a table standpoint:
| Time | Max Ship Deviation(s) |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 1 |
| 7 | 2 |
| 8 | 2 |
| 9 | 3 |
| 10 | 3 |
| 11 | 4 |
| 12 | 5 |
| 13 | 6 |
| 14 | 7 |
| 15 | 8 |
Remember, this is for a military ship with midgrade engine tech. Higher engine tech would be tougher to hit when accelerating, just as lower tech is easier -- the Atlas freighter from the first post doesnt' hit 1SD until 8 seconds.
So I can see why 5 lightseconds distance was the max range for regular Aurora, and I can see how that may not change.
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But the spread system scales at any range. (There should probably be some sort of "Expected projectile hits" number when your FCs calculate a system before you tell them to fire. If the number is .0003 it's probably not worth the energy, if the number is .37, and at the speeds involved one shot would cripple or destroy the enemy... fire away!)
If the ship is so close to you that it actually can't get away (aka the "Evasion Distance" is less than the target's radius) then whether or not you spread or not doesn't matter, all of your shots will hit regardless.
(This is assuming that Steve keeps his "any hit does armor damage at random location" methodology. If he actually starts keeping track of where the ship gets hit, than you wouldn't want to spread if a hit was guaranteed, so that all shots hit as close together as possible. I sort of hope he keeps the current simple solution, but the ships will have actual facings now, so who knows.
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I sort of hope he keeps the current simple solution, but the ships will have actual facings now, so who knows.
They do? I guess I missed something, quote pls?
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They do? I guess I missed something, quote pls?
No quote as such. But with Newtonian Physics you have to have a thrust vector. At the very least whenever a ship's engine is on it has a facing. However he's still stated 360 degree sensors and made no mention of turrets pointing or not pointing at a target, so it seems like he is still ignoring all facing mechanics except for the required thrust vector. (Which I think is wise).
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Yup, he repeatedly said we won't go into facing, as this at it's core is still a strategy game and not a tactics simulation.
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No quote as such. But with Newtonian Physics you have to have a thrust vector. At the very least whenever a ship's engine is on it has a facing. However he's still stated 360 degree sensors and made no mention of turrets pointing or not pointing at a target, so it seems like he is still ignoring all facing mechanics except for the required thrust vector. (Which I think is wise).
Well I thought it would be something like that, just wanted to be sure.
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But the spread system scales at any range. (There should probably be some sort of "Expected projectile hits" number when your FCs calculate a system before you tell them to fire. If the number is .0003 it's probably not worth the energy, if the number is .37, and at the speeds involved one shot would cripple or destroy the enemy... fire away!)
If the ship is so close to you that it actually can't get away (aka the "Evasion Distance" is less than the target's radius) then whether or not you spread or not doesn't matter, all of your shots will hit regardless.
Not only would you want to hit, but you'd also want to have the most hits, though. So if you had 1 shot, you'd take it down the center. For 2, you'd split it fairly close to the center. For three, four.... continue on. But say you have 20? I'd still cluster my shots around the center, probably looking fairly bell-curve shaped. Putting 4 massive alloy rods through a ship is better than putting just one. Because, as the saying goes: "There is no overkill. There's just 'Open Fire' and 'I need to reload'."
That being said, we may be being a little silly. Looking deeper, it probably isn't worth it to compute it. Straight up hit/miss is tough enough.
Take the Daring class again. At 1,400,000 km away (current max beam), that 109m diameter equates to 0.016 arcseconds, roughly 1/2 the apparent size of Eris (http://en.wikipedia.org/wiki/Eris_(dwarf_planet)). At that range, 21.83 mps2 acceleration can result in a deviation of 237m diameter from projected location with no acceleration. That equates to approx the same apparent size as Eris.
On a 1 dimension line, that's a target that's 45.86% of the area. On a 2 dimensional area, that's a target that's 21.03% of the area. I don't know which is used for computing hit/miss chances, but since in current Aurora you can stop on a dime, I don't think it's taken into account.
Now, granted we're talking about a game about spaceships which does involve some handwavium, but that's awfully precise to hit at that range. And even more so at greater ranges. If you double the range, you halve the apparent size of the ship, but double the potential deviation. If you quadruple the range (5.2m km), you have 0.004 arcseconds of target to hit in .130 arcseconds of potential, or approx 3%. Going backwards, at 1m km you're aiming at a .022 arcsec target in a .025 arcsec field, so pretty good odds to hit. And at 60k km, that target is .37 arcsecs big, or the approx apparent size of the asteroid Ceres. And at 595km (same as Hubble) that ship would be the same apparent size as Jupiter, and visible to the naked eye.
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Not only would you want to hit, but you'd also want to have the most hits, though. So if you had 1 shot, you'd take it down the center. For 2, you'd split it fairly close to the center. For three, four.... continue on. But say you have 20? I'd still cluster my shots around the center, probably looking fairly bell-curve shaped. Putting 4 massive alloy rods through a ship is better than putting just one. Because, as the saying goes: "There is no overkill. There's just 'Open Fire' and 'I need to reload'."
I'd rather a 100% chance of hitting them once than a 25% chance of hitting them four times. If you cluster all of your shots around the center you will only hit your target at all if he coasts or starts accelerating at 10% of his maximum or so. If he starts accelerating at full thrust in either direction (or just keeps accelerating if his engines are already on) you will miss him every time.
Take the Daring class again. At 1,400,000 km away (current max beam), that 109m diameter equates to 0.016 arcseconds, roughly 1/2 the apparent size of Eris (http://en.wikipedia.org/wiki/Eris_(dwarf_planet)). At that range, 21.83 mps2 acceleration can result in a deviation of 237m diameter from projected location with no acceleration. That equates to approx the same apparent size as Eris.
On a 1 dimension line, that's a target that's 45.86% of the area. On a 2 dimensional area, that's a target that's 21.03% of the area. I don't know which is used for computing hit/miss chances, but since in current Aurora you can stop on a dime, I don't think it's taken into account.
Now, granted we're talking about a game about spaceships which does involve some handwavium, but that's awfully precise to hit at that range. And even more so at greater ranges. If you double the range, you halve the apparent size of the ship, but double the potential deviation. If you quadruple the range (5.2m km), you have 0.004 arcseconds of target to hit in .130 arcseconds of potential, or approx 3%. Going backwards, at 1m km you're aiming at a .022 arcsec target in a .025 arcsec field, so pretty good odds to hit. And at 60k km, that target is .37 arcsecs big, or the approx apparent size of the asteroid Ceres. And at 595km (same as Hubble) that ship would be the same apparent size as Jupiter, and visible to the naked eye.
Right, and while you are waiting for my spaceship to get close enough to you to look like the size of Jupiter, I'll start spraying the sky with flak at 30 light seconds out (because this isn't Aurora remember, it's Newtonian Aurora).
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I thought that I needed to put my claim that firing in a spread like this would greatly increase your effective range, so I wrote up the following script.
(This is C#, but it should be easy to port elsewhere if anyone else wants to fiddle with it)
Errr... Nevermind, it's actually quite too large to really post. PM me if you want it.
The basic purpose of the program, was that for the scenario of an enemy ship coasting right towards you, with a set evasion acceleration and diameter.
You have a settable number of weapons, with specific muzzle velocity, fire rate, etc, etc.
The program calculated the range at which the target couldn't dodge your bullets anymore. It then started "shooting" at that target as fast as possible until it reached that range. For each shot it calculated the expected number of hits, and then at the end it told you how many expected "extra hits" you had from the early spread shooting. This depended a huge amount on the different conditions. In each scenario I tweaked the initial separation so that you start shooting right around when you have .01 expected hits per shot. I figured a 1% chance was as good an arbitrary starting point as any.
My target ship was the Daring class, 21.83 m/s2 acceleration, 109 meter diameter, approaching at 15k km/s.
My first example weapon system was a ship that had 8 railguns firing a 1kg projectile at 40 km/s (800 MJ) every 5 seconds.
Under these conditions you have a "can't miss range" of 33.6k km. That gives you time for a single shot 2.23 seconds before the target hits you. Albeit if you are still alive for that shot it will completely ruin your target. However if you start firing when you have a 1% hit chance that gives you an extra 60 seconds. That's 12 extra shots (of 8 slugs each), unfortunately odds are only one and a half extra slug impacts, and probably in that last ten seconds.
That didn't really help much, although the 164 million GJ of pain is nothing to sneeze at. (Keep in mind most of that kinetic energy would blow right out of the back of the ship though, Hmm, which really means you need more smaller slugs, if each of the slugs broke into 500 pieces 2-3 seconds before impact that would be a different ballgame)
Obviously we are going to need a less pathetically slow muzzle velocity to have more extra shots with the target approaching so fast. Lets jump straight to a laser. Or to be more precise, eight 800 MJ lasers.
At this point our "range" becomes approximately 2.23 light seconds, around 700k km. However we hit the 1% hit chance at 20 million kilometers, so we actually start firing at over a light minute away! Now at this point we may actually be leaving the bounds of a reasonably designed ship (we won't know until Steve give us more examples) because we are starting so early that we have 22 minutes of sustained shooting ahead of us. Who knows if that's reasonable. Anyways, all of this early shooting gives us 76 expected extra hits on the target, and starting at 2 million km we are guaranteed to hit every time. That's a total of 60.8 GJ of damage done. That's doesn't sound all that impressive considering that the example shield Steve has shown us was 72 GJ strong, but in a fight with numbers that would change things up. 10 ships on each side and focus firing would probably kill off 3-4 of the enemies before they got "in range".
I'd like to keep doing more examples, but it's super late here. Basically sometimes the early shooting helps a lot, sometimes it doesn't, but it's going to help a lot often enough (especially if you are doing things like fleeing from the enemy to keep them at range longer) that it's probably a good "most common" firing method.
Edit: One more example, since that 22 minutes of firing kept bothering me. If you wait until you have a 10% chance of a hit you starting shooting at 6.3 million km and only have 7 minutes of sustained shooting, but you'll still get 70 extra hits on them.
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I'm going to point out (again) that the expected range on a kinetic hit goes up significantly if you switch to guided projectiles, whatever you wish to call them. They now have their own hit cross-section, which greatly increases the chances of a hit.
But, yes, firing weapons will almost have to be in spreads. Though there are two caveats here:
1. Projectiles might now have to deal with PD systems, which means that firing 1 is useless.
2. It would be helpful to be able to cluster your projectiles under various assumptions. The most common are no thrust and current course. I have equations for both in the spreadsheets I posted links to.
One other thing I question is the 100 kg/m3. AV:T used 250. I'm not saying Steve's wrong, but they did a lot of research, and that number is comparable to modern jets.
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I guess laser tech could go one of two ways for improving hits: 1) A high number of small pulses every second with the spread of shots as discussed or 2) a single pulse that lasts for a longer perriod that follows a tracked path around the target.
I agree that it would make sense to have "guided" projectiles that improve individual to hit chances rather than lots of dunmb projectiles for when you are engaging and more distant ranges
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I'm going to point out (again) that the expected range on a kinetic hit goes up significantly if you switch to guided projectiles, whatever you wish to call them.
Those calculations are the next thing I'm adding to the script. ;)
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If targetting range is still limited to 5 lightseconds, then you don't really need this though. You'd want to put as many points of damage as possible within the target window, and it's not going to change that much.
Using Steve's Daring Class from the first post, it's got a size of 6873 Tons. That's 68730 m3, or approximately 109m diameter.
The most it can accelerate at 21.83 m/s2. Looking at a 1 dimensional line, at 5 seconds the center of the ship can be at most 117.15m off from where it would be with no acceleration.
I have been considering something along these lines, although it isn't final yet. My maths are slightly different so I'll post my thoughts here in case I am heading down the wrong track.
For a ship that can accelerate at 20m/s, there is more deviation than you might think. During the 1st second its speed increases by 20 m/s and it moves 20m further than without acceleration. During the 2nd second, it accelerates to 40 m/s faster but now it has moved 60m further than without acceleration. During the 3rd second, it increases to 60m/s faster and has now moved 120m more than without acceleration. By five seconds, it is now 300m from its projected non-acceleration point. It could also decelerate instead and be 300m behind where it would be without acceleration.
A ship of 68,730m3 is 50.8m in diameter (using the formula Radius = CubeRoot(3/4 Volume/Pi).
Using 1D only, before the five seconds starts, the ship occupies a line 50m long. After potential accel or decel, the entire width of the ship is contained within a line 650m long (the original 50m plus deviation of 300m either way). Assuming random accel/decel and a random shot, there is a 50/650 or 7.7% chance of a hit.
Using 2D and assuming the ship may modify its course left or right, there is an area within which the ship can be located. For ease of calculation, let's assume that is a circle with a 325m radius, whch has an area of 331,830m2. The ship itself occupies an area of 7853m2, so there is a 2.36% of the ship being hit randomly.
Of course, if this was really 2D then moving left or right on a course perpendicular to the firing ship doesn't matter because the shot would be in the same plane and just hit earlier or later. On a closing course, accel or decel wouldn't matter as the shot would hit earlier or later. However, in reality the ship would be maneuvering in 3 directions so using an area (instead of a volume) as a possible location is a reasonable compromise between reality and playability.
The other matter to consider is that the player may wish to apply some intelligence to his firing solution. For example, if the enemy ship has been under constant acceleration on the same bearing for an hour, he may wish to fire only at the exact predicted location based on current course and acceleration. Or he may wish to allow for speed changes but not course changes, or accel but not decel, or course changes without speed changes, or any combination of the above. He may also wish to apply different criteria to each fire control, or even each weapon, to bracket the target but still emphasise one option over the other (three weapons assume constant accel and one weapon assume random accel/decel and course changes for example).
So at the moment I am leaning toward the following:
1) Player specifies the parameters for the firing control using three checkboxes: Allow for possible Accel, Allow for possible decel, Allow for course change.
2) Aurora calculates the area in square meters, or line in meters if no course change is specified, or dot if no checkbox is checked, covered by that firing solution, and selects a random point within it (or along it).
3) The exact coordinates of that point are recorded, down to 0.1 meters.
4) Based on the speed of the projectile, the exact time of arrival (within 0.0001 seconds) at that point is recorded.
5) At the moment in time the projectile reaches the specified point, the location of the ship is checked to see if the location of the shot lies within the area of the ship.
6) Because the exact point in time will be partway through a sub-pulse and resolution of this will take place after movement, the location of the ship at the exact point in time will be calculated based on its heading and speed during the sub-pulse.
This means that a shot could actually miss even if the bearing would mean the shot would hit the target ship a fraction of a second later. However, because we are using an area rather than a volume, you have a higher chance to hit than you should have which compensates for this possibility. I haven't tested (or even coded) this yet but this is looking the most likely at the moment, unless someone comes up with a reason this won't work, which is entirely possible :). This avoids tracking individual projectiles on the map but also excludes the chance of hitting something else. I could also check any other nearby ships to see if they are in the target location instead, although this is extremely unlikely and may not be worth it.
For shrapnel warheads, which may involves a lot of objects and may be an area denial weapon as much as a anti-ship weapon, I will probably use a debris cloud approach with a chance to hit something when you pass through the cloud (or the cloud passes a ship)
Steve
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Alright, I took a short lunch and added calculations for shooting missiles. I used Steve's latest example missiles and used them to build what I think is a missile that matches them in terms of tech. It's 1 kg, and .9 of that is the engine, the last bit is fuel. It has an acceleration of 216 m/s2.
I then shot them out of that first example ship. 8 shots every five seconds, 40km/s muzzle velocity.
The real question for this situation is when you want to start firing your thrusters. Not because you will run out of fuel, not with the current setup if I've done my math right, but because if you turn on your thrusters too early your enemy may have time to shoot your missiles out of the sky. Too late and the missiles don't have time to correct much.
As with the target ships's acceleration, none of it is ever used to slow down or speed up with relation to the ship, just to match the target's motion perpendicular to the line of approach.
| Burn Time (s) | 1% Accuracy Range (m km) | Extra Volleys | Expected Hits |
| 0 | 1 | 12 | 1.5 |
| 1 | 1.6 | 21 | 4.5 |
| 2 | 2.9 | 37 | 13.7 |
| 3 | 4.0 | 52 | 22.7 |
| 4 | 5.4 | 72 | 32.9 |
| 5 | 6.8 | 90 | 42.4 |
| 6 | 8.13 | 108 | 52.2 |
| 7 | 9.4 | 126 | 62.5 |
| 8 | 10.7 | 142 | 71.9 |
| 9 | 12.1 | 160 | 81.9 |
At 9 seconds of burn time we have surpassed 76 expected hits from the laser example. Not only that, but each of the laser hits were minor annoyances, while each of these hits would bore through a ship like swiss cheese.
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One other thing I question is the 100 kg/m3. AV:T used 250. I'm not saying Steve's wrong, but they did a lot of research, and that number is comparable to modern jets.
Traveller (at least for Fire Fusion and Steel) used 71 kg/m3 so there are other figures out there. It is admittedly an abstract figure, especially since a carrier or freighter is going to be lower than 100kg/m3 while a FAC or fighter is probably the other way. One fairly significant factor in that decision was also making ships larger and easier to hit. There is also a length figure for ships in Newtonian Aurora on the class summary. This is entirely for RP purposes (as sphere diameter is used for targeting and the number of armour columns is equal to the diameter in meters ) and is based on an assumed ovoid shape with a 2.5-1 ratio of length to width. This ratio gradually decreases for smaller ships, down to 1.25-1 for fighter sized. See below for some examples. Part of the rationale behind the 100 kg/m3 was to achieve ships that seemed to be about the right size, based on little else but gut feel :). I could have assessed each component individually for mass vs volume but that would be a lot of work and I think the gameplay benefit would be minimal.
For example:
Atlas class Freighter 9,343 tons standard 34,843 tons full load 28 Crew 381.1 BP
Length 220m Armour 1-88 Sensors 1/1/0/0 Damage Control Rating 1 PPV 0
Resolution class Destroyer 3,895 tons standard 4,895 tons full load 186 Crew 951.3 BP
Length 103.5m Armour 6-46 Sensors 1/20/0/0 Damage Control Rating 1 PPV 16.92
Agincourt class Scout 4,612 tons standard 6,062 tons full load 204 Crew 692.9 BP
Length 120m Armour 3-48 Sensors 18/24/0/0 Damage Control Rating 1 PPV 0
Steve
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Alright, I took a short lunch and added calculations for shooting missiles. I used Steve's latest example missiles and used them to build what I think is a missile that matches them in terms of tech. It's 1 kg, and .9 of that is the engine, the last bit is fuel. It has an acceleration of 216 m/s2.
At the moment, missiles are a minimum size of 1 ton while unguided projectiles can be as small as 1 kg. I realise we have smaller real world missiles at the moment. This is partly based on the sensor model, which will allow the detection of missiles but not projectiles, and partly because of the firing rates of available energy weapons. If I allow lots of tiny missiles, I will need to change the sensor model and either allow lots of tiny energy weapons or extremely fast-firing energy weapons and I am not sure the added complexity will produce additional gameplay benefits. That doesn't mean I won't do it; just that I am not convinced about it yet.
Steve
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For a ship that can accelerate at 20m/s, there is more deviation than you might think. During the 1st second its speed increases by 20 m/s and it moves 20m further than without acceleration. During the 2nd second, it accelerates to 40 m/s faster but now it has moved 60m further than without acceleration. During the 3rd second, it increases to 60m/s faster and has now moved 120m more than without acceleration. By five seconds, it is now 300m from its projected non-acceleration point. It could also decelerate instead and be 300m behind where it would be without acceleration.
Your math is off. The correct formula for displacement is x=.5at^2+vt. So in the first second, it will move 10 m, then 40 m, then 90 m, and so on.
Of course, if this was really 2D then moving left or right on a course perpendicular to the firing ship doesn't matter because the shot would be in the same plane and just hit earlier or later. On a closing course, accel or decel wouldn't matter as the shot would hit earlier or later. However, in reality the ship would be maneuvering in 3 directions so using an area (instead of a volume) as a possible location is a reasonable compromise between reality and playability.
Given the sort of flight times and accelerations under discussion here, any counting of movement in line with the projectile is superfluous.
The other matter to consider is that the player may wish to apply some intelligence to his firing solution. For example, if the enemy ship has been under constant acceleration on the same bearing for an hour, he may wish to fire only at the exact predicted location based on current course and acceleration. Or he may wish to allow for speed changes but not course changes, or accel but not decel, or course changes without speed changes, or any combination of the above. He may also wish to apply different criteria to each fire control, or even each weapon, to bracket the target but still emphasise one option over the other (three weapons assume constant accel and one weapon assume random accel/decel and course changes for example).
That would be nice. If it was me, and I knew there were enemy nearby, I'd probably go for semi-random course changes to throw pure unguided kinetics off.
I have a different means of tracking the target, which probably only works for guided munitions. (I'm honestly not trying to get everyone to do that. It's just how it works. This is better for longer ranges, but I already had it available.)
In space flat space, an inertial object that is going to impact will appear to be closing on a course of constant bearing and decreasing range. If the target is assumed to be inertial, then give each projectile a limited stock of delta-V, and keep track of the target's maneuvers. If they run over the limit, then the projectile isn't going to hit. (Or it won't hit if the target displaces out of its way.) You can do the same if you assume the target to be constantly accelerating. You just use a different baseline, using delta-V when the target doesn't burn in the expected direction. It's not perfect, but do you really expect a tiny guidance system to be terribly optimized.
A worked version of this can be found in my spreadsheets.
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I have been considering something along these lines, although it isn't final yet.
(snip)
Steve
My maths were mostly using long remembered formulas and wikipedia... probably should have stated that.
Related question: Will there be a difference between ship and fleet movements within this? Will "random maneuvers" be applied on a ship-by-ship basis, where Ship A and Ship B in the same fleet can have the same course and be considered part of the same entity, but have different dV with respect to targeting? If this is the case, would accidental collisions be possible?
From what it looks like, shotgun type weapons are not yet planned aside from the area-burst missile/mine. Would new weapons be created for such a role, or others adapted (plasma carronade, etc).
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At the moment, missiles are a minimum size of 1 ton while unguided projectiles can be as small as 1 kg. I realise we have smaller real world missiles at the moment. This is partly based on the sensor model, which will allow the detection of missiles but not projectiles, and partly because of the firing rates of available energy weapons. If I allow lots of tiny missiles, I will need to change the sensor model and either allow lots of tiny energy weapons or extremely fast-firing energy weapons and I am not sure the added complexity will produce additional gameplay benefits. That doesn't mean I won't do it; just that I am not convinced about it yet.
Steve
Hmm, good point. As far as the sensor portion of it goes, one way to do this would be to let Thermal Sensors give locks to the Fire Control. That way even very small missiles would probably be visible once their engines started.
Your math is off. The correct formula for displacement is x=.5at^2+vt. So in the first second, it will move 10 m, then 40 m, then 90 m, and so on.
And the reason your math was off was because it looks like you were using the acceleration to calculate the velocity at each second, and assuming that velocity stayed constant over the entire second.
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Your math is off. The correct formula for displacement is x=.5at^2+vt. So in the first second, it will move 10 m, then 40 m, then 90 m, and so on.
I should have mentioned that in Newtonian Aurora, course changes and accel changes take place before movement. The formula above relies on steady acceleration over the time period.
Steve
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And the reason your math was off was because it looks like you were using the acceleration to calculate the velocity at each second, and assuming that velocity stayed constant over the entire second.
That is how it works in the game, which I thought I had mentioned somewhere in the thread but I probably haven't :). I could change it to a constant accel, rather than accel before movement, but it makes things harder to model, especially for interceptions, and for players to visualise. Overall velocity increase is the same either way.
Steve
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Related question: Will there be a difference between ship and fleet movements within this? Will "random maneuvers" be applied on a ship-by-ship basis, where Ship A and Ship B in the same fleet can have the same course and be considered part of the same entity, but have different dV with respect to targeting? If this is the case, would accidental collisions be possible?
From what it looks like, shotgun type weapons are not yet planned aside from the area-burst missile/mine. Would new weapons be created for such a role, or others adapted (plasma carronade, etc).
There are formations within Newtonian Aurora, as there are in standard Aurora, and it would be a good idea to use them if an opponent is using area effect weapons such as nukes. If ships are not in formation, they will essentially be in the same location and will use the same evasive manoeuvres. They will both be hit by nearby area effect weapons and they could be hit by separate beams from the same laser warhead but they will be hit individually by single shot weapons such as railguns and lasers. If you want to ships to follow independant evasive course then they need to be in formation or in separate task groups.
Ship launched shotgun weapons will be added at some point. I just haven't done them yet.
Steve
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By five seconds, it is now 300m from its projected non-acceleration point. It could also decelerate instead and be 300m behind where it would be without acceleration.
Whilst I know you are not dealing with facing it strikes me that any ship that wants to decelerate instead is going to need to spend some time flipping over and realiging itself before actually starting to decelerate. I'm not sure how fast one could expect a ship to flip over but it would feel right to me that, when dealing with relatively close combat - say 10 light seconds or less, then a target ships only real option is to change levels of acceleration or cease to accelerate. Similarly it would be constrained over the level of movement it could achieve on different axis of movement as well. This would therefore reduce the number of locations you would possibly need to shoot at.
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I just realised the targeting is more complex than I thought because the railgun projectile will have the momentum of the firing ship as well as its own velocity, which complicates the calculations. Time to learn some new maths I think :)
Steve
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given the combination of ship speed and projectile speeds and enemy speeds, fire control will have an hard time to find firing solutions and the correct angle of lead to shoot at.
;D
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Yes, the math is somewhat complicated. However, its in my spreadsheet, and I'll post a copy later.
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1) Player specifies the parameters for the firing control using three checkboxes: Allow for possible Accel, Allow for possible decel, Allow for course change.
2) Aurora calculates the area in square meters, or line in meters if no course change is specified, or dot if no checkbox is checked, covered by that firing solution, and selects a random point within it (or along it).
3) The exact coordinates of that point are recorded, down to 0.1 meters.
4) Based on the speed of the projectile, the exact time of arrival (within 0.0001 seconds) at that point is recorded.
5) At the moment in time the projectile reaches the specified point, the location of the ship is checked to see if the location of the shot lies within the area of the ship.
6) Because the exact point in time will be partway through a sub-pulse and resolution of this will take place after movement, the location of the ship at the exact point in time will be calculated based on its heading and speed during the sub-pulse.
This means that a shot could actually miss even if the bearing would mean the shot would hit the target ship a fraction of a second later. However, because we are using an area rather than a volume, you have a higher chance to hit than you should have which compensates for this possibility. I haven't tested (or even coded) this yet but this is looking the most likely at the moment, unless someone comes up with a reason this won't work, which is entirely possible :). This avoids tracking individual projectiles on the map but also excludes the chance of hitting something else. I could also check any other nearby ships to see if they are in the target location instead, although this is extremely unlikely and may not be worth it.
That sounds like a great way to calculate Meson hits, because them doing damage at a single point without passing through the space before or after that point seems to be how you've fluffed their ability to bypass armor, but for slugs, particle beams, lasers, etc, I would try to go for a compromise between that and modelling their trajectory for the entire journey. Maybe find their exact position half a second before expected impact, and half a second after target impact, and modelling them fully along that line.
Actually, instead of modelling a constant time before and after the impact point, you'd probably want to model the necessary time based on flight time of the projectile and the acceleration of the target, to eliminate the possibility of a ship simply accelerating towards their enemy with the knowledge that their bullets would all blink in behind them as long as he moved fast enough. If you just said "half a second on either side of impact time" that would work close in, but for really long range shots the enemy may be able to move in before the "projectile existence point".
Obviously that's more of an issue with a railgun than it is with a laser.
Their are two cases that I could still see as possible hangups with even the longer period of projectile modelling:
The possibility of putting up clouds of flak to, for example, shoot down missiles that you don't know are their but might be. This could fixed simply enough if "shrapnel clouds"--unlike projectiles--are modeled throughout the entirety of their trajectory (or at least until they disperse past a critical threshold.
The last one is the possibility of trying to destroy kinetic projectiles before they hit you, which may be important considering how much damage they can do. Other kinetic projectiles and beams would probably be useless for this because of targeting, but low yield missiles may not be.
If you see his muzzle flashes and know how fast his bullets are (which you may or may not) then you know the general place he is going to be shooting at to hit you. That means you also know about where his bullets will be along their entire path. Which means you could put some nuclear explosions along that path to try to vaporize those projectiles.
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on a slug based space warfare, deflection chaffs would be of extreme importance. it require far less energy to deflect a projectile just enough than to resist it or to destroy it.
a wedged slug, smaller and of similar speed, could intercept the enemy shoot halfway. it has to deviate it of just some deciradian, after all.
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on a slug based space warfare, deflection chaffs would be of extreme importance. it require far less energy to deflect a projectile just enough than to resist it or to destroy it.
a wedged slug, smaller and of similar speed, could intercept the enemy shoot halfway. it has to deviate it of just some deciradian, after all.
Yeah, but that only works if you either have very, very dense chaff clouds (and if you are able to put up that much projectile mass on the defense, why can't your opponent due so on offense?) or you have to actually be able to see these little 1kg slugs coming, aim at them, and shoot at them, and I'm assuming that's impractical at most velocities slug could be coming at.
Now that first criticism works for my proposed idea as well, do you really have the ability to spend a nuclear missile for every salvo your enemy fires at you, if the answer is yes, is that really the most efficient use of your nuclear missiles? On the other hand, you may not have enough to stop every salvo, but if you can determine which salvos are the ones that have the highest chance to hit you, that may be enough. If you spend 5 nuclear missiles to live three minutes longer and fire another 35 missiles at your opponent than that was a good use of your resources.
Still, I have no idea whether it's a plausible scenario, it was just the only scenario I could think of which would be ruined by "teleporting bullets", so I thought I'd bring it up for discussion.
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I support trying to find a closed form instead of simulated way of detecting slug hits. Tracking individual slugs would be adding yet another performance hit on an already loaded combat engine.
One possibility though might be a kind of binary search... aka calculate the vector of your shot. Let time pass till it hits the half-way mark, recalculate time of impact and where in the new area of the ship the vector will strike. Let time pass till a subpulse around halfway of flightime, repeat till the time increments is 5 secs or less, then perform final calculation. If at any step the projectile is well far enough out of the hit area, toss it and mark it a miss, even if the miss is actually only reported later, but no need for further tracking.
This kind of comprimise might allow higher accuracy in simulation compared to the suggested endpoint calculation, without adding TOO much overhead... (handful of subpulses are calculated versus position update every subpulse). Of course, the ideal would still be a calculate-once form as Steve suggests, but it should be tested.
As for detecting the projectile... I find that unlikely with Aurora tech. If its unguided it will emit no thermals, and even if it is guided thermals can't lock a targeting solution. It has no EM to speak of and its mass and thus gravity distortion is negligible compared to even the smallest missiles. It IS possible to detect the firing of a mass driver realistically, considering the huge amount of magnetic forces used to accelerate a slug, but I'm unsure whether such a detectable EM pulse is implemented. (Might be fun for a 'oh smeg' moment? It will however destroy stealth for attacking ships) Even if the shot launch was detected however, I'm unsure that enough resolution is possible to determine the exact vector of the slug, though it might provide an ETA (if the velocity of the slug is known, either prior engagements or a guess from the MJ of the shot.) Such a warning could be useful for saving fuel with evasive maneuvers, since you can coast until under fire. Then again, much less useful against lasers. Your warning of a laser attack IS the laser striking your hull.
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Some type of huge shield is possible, although it would have to be truly gargantuan to resist very high speed projectiles or close-range nuclear detonations. Perhaps something planetary-based might be possible. I haven't given this area a lot of thought so far.
So I was thinking about this and I thought of two different types of shield to protect against kinetic (and possibly other?) defenses.
These were my goals for the defense:
- Provide some sort of defense that would protect slow things that can't dodge (planets, moons, shipyards) from instant and unstoppable death in a universe where an average ship (like the Daring) does enough damage on impact to match the explosion of every single one of the nuclear weapons currently on earth going off simultaneously. One thousand times...
- Not make such shields invulnerable (especially for shipyards, orbital habitats, or anything smaller).
- Have some sort of plausible-ish handwavium explanation, hopefully.
So what we want is something that protects against higher energy/velocity impacts more than those of smaller impacts. We want to make a planet relatively safe from genocide asteroid strikes, but not safe from a low-yield planetary bombardment. If this shield is knocked out by a low-yield planetary bombardment from orbit, and the planet is then genocided by an asteroid attack, that's ok. There was some sort of orbit battle that you lost, and the planet was destroyed, totally different from a small invisible object moving at relativistic speeds killing you out of nowhere.
And if a hidden foe is still sniping you from the outskirts of the solar system between the Uber shield taking the high energy hits, and your normal shield and armor of the PDCs taking the lower yield hits, hopefully you'll at least have time to look or the attacker, or evacuate, or something before the kill strike. Anything that feels a little more fair to the player.
Not only must it be more effective at blocking the higher energy strikes, but it should also take less damage from the higher energy strikes. It has to be handwaved as transmitting that energy somewhere else, if an asteroid causes the shield a million times more damage than a shell it's still the best weapon, and we are trying to de-incentivise those genocidal weapons.
Idea 1:
The best way to avoid taking damage from being hit by something is to not be hit by something. Now these things we're worried about can't dodge, and the faster the projectile is going the further out you need to be to deflect it... How about you just don't get hit by it. Instead of deflecting it spatially deflect it into hyperspace. It'll pop out of space when it hits your shield, and pop back into space on the other side of the shield.
Mechanics: The shield senses the warped spatial time of relativistic movement. Maybe it starts out at a 20% chance at warping things moving 1% of c (3000 km/s) and goes up from there, I don't know. The total energy each deflection takes is proportional to the amount of time the object needs to be warped times it's mass, ie the faster the object the less time it needs to be warped and the cheaper warping it is, but you can't just send a bunch of bb bullets either.
This shield could be an installation like the Planetary Observatories, one that is very expensive and takes a lot of personnel to run, so you can't just spam them on defensive outposts everywhere. Maybe they protect orbiting shipyards and orbital habitats, but not orbiting ships, or maybe there is also a (very very large, possibly less effective) component one so you can put it on Orbital Habitats, and you could add the same thing to shipyards somehow.
There could be some research lines for them "Warp Chance", "Warp Power per Second", "Recharge Speed", and "Capacitor Size per Facility" to increase the likelihood of blocking attacks and decrease the energy cost of doing so.
I need to do a little more math to vet whether my second idea may work.
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(if the velocity of the slug is known, either prior engagements or a guess from the MJ of the shot.)
That is probably how you'd have to estimate that, but keep in mind that you're only going to see the MJs (or a portion of them) that were wasted. The more efficient the enemy's railgun is the less MJ you'll see for an equivalent shot.
On the other hand, once (if?) you see a shot whizzing by or hitting a friend, if you can extrapolate from that the velocity and mass of the slug, you then have a very, very good idea of how efficient their railguns are.
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This is sort of a confusing idea, I hope that I explain it reasonably.
Idea 2: Another way to go would be some sort of shield that wasn't based on the kinetic energy of a strike, but merely its momentum. I'm not as sure about the mechanics of this one, but I like the idea because I think it would scale naturally in that you could apply the mechanics to ships or planets and it would naturally be less effective on ships.
If we require conservation of energy and momentum, but handwave everything else, then a kinetic round that hits your shield could be absorbed with a burst of energy and a shift in the momentum of the ship. Let’s ignore the energy for now, maybe it's expelled at 100% efficiency, maybe not. The momentum change would be applied to the ship over a short period of time (extended by research) to get the total acceleration. Maybe the device has a maximum acceleration tolerance, and anything that goes over that starts damaging the device or other parts of the ship. Maybe the device expels momentum up to its maximum acceleration (venting off the kinetic energy from the slowdown) but after that doesn’t affect the projectile’s speed anymore.
Lets take a look at the Daring impact again. We'll say it's empty after all the thrusting, so the mass is 6,873 tons and it's moving at 80,366 km/s. Lets look at two possible collision targets, the first is a large capital ship at 45k tons. The next is the moon, at 7.348E19 tons. That's a change in velocity of 12274k km/s for the capital ship, and 7.517E-9 m/s for the moon. If the device changes velocity smoothly over the course of a second that's also their acceleration. Obviously the capital ship is dead, which is what we want, and the Moon’s acceleration is a good ballpark number for the Earth Acceleration of an example acceleration that we want the device to be able to handle just fine.
Now lets do an example of something small that we want to hurt a ship, and see if it would still hurt the ship if it had this device (IE, would the acceleration be over that 8E-9 m/s^2 that we are saying didn't break the moon’s version.)
Let’s say a 1kg shell from the Daring hits our capital ship on its way in. The shell is also going 80,366 km/s. Change in velocity to the capital ship would be 1.79 m/s. A one second transition period gives a 1.79 m/s2 acceleration, much much higher than the earlier acceleration to the moon, so that’s good. For a less ridiculous impact lets say that same projectile hits at only 40km/s, that leads to an acceleration of 8.89E-4 m/s2. That’s still a lot higher than that the 8E-9 from earlier. Something in between those, 1E-7, 1E-6, is probably a good starting point for a closer look at how the mechanics of this would work..
Lastly for this method I would say that multiple hits at once should all add their accelerations together, and if the time interval gets large enough (say 10 seconds) then the earlier accelerations should still be counted against the device if later objects hit during the interval.
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how about short range melting of slugs with lasers? this could reduce damage instead of negating.
also, heating only one part of the slug may very well change its trajectory, like how laser propulsion would work (ablation, see http://en.wikipedia.org/wiki/Laser_propulsion#Ablative_laser_propulsion).
by the way, current tanks defends from kinetic weapons by explosive strap on. Reactive armor may work as well in this context.
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Reactive Armor would be a way to decrease the force of the projectile by spreading the damage over a bigger patch of armor, but it's only a benefit if you can prevent the projectile from breaching into the inside, which will be pretty hard unless you also have shields and are not flying in the direction of the enemy.
Though Steve has repeatedly shown his discontent for different armor types by ignoring such suggestions^^.
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Reactive armor tends to work by disrupting the shaped charge and subsequent cone of molten metal that makes up armor piercing weaponry these days. Against a small hunk of iron, it's not going to have any noticable effect.
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And the reason your math was off was because it looks like you were using the acceleration to calculate the velocity at each second, and assuming that velocity stayed constant over the entire second.
That is how it works in the game, which I thought I had mentioned somewhere in the thread but I probably haven't :). I could change it to a constant accel, rather than accel before movement, but it makes things harder to model, especially for interceptions, and for players to visualise. Overall velocity increase is the same either way.
It's actually not that hard to model constant acceleration - you simply have to take the average of the initial and final V for each time step to give the average velocity for that time step. So for your 20 m/s^2 (note the units: (m/s)/s ) example accelerating for 3 seconds, for the first time step the ship has V_i = 0, V_f = 20m/s for an average velocity of 10m/s * 1 second travel = 10m. The second time step it's got V_i = 20m/s, V_f = 40m/s for an average velocity of 30m/s * 1 second = 30 additional meters or a total of 40 meters. For the third step it's V_i=40m/2, V_f=60m/s, average = 50m/s* 1 second = 50m, total = 90m. Note that this also works for the full 3 second interval: V_i=0, V_f=60m/s, average = 30m/s*3seconds = 90m., and is consistent with A*t^2/2.
For me, applying dV at the beginning of the timestep causes suspension of disbelief problems - if all the dV is really happening at the beginning, then you've got infinite acceleration going on. Plus the formula for figuring things out for extended burns (spanning multiple time steps) becomes complicated and makes the distance traveled depend on the time step. If you're thinking that most of a ship's time will be spend "coasting", plus making max accel a meaningful performance attribute of ships, then I would recommend calculating the burn time for a dV (t=dV/A) then subtracting the "distance lost accelerating" (= t*dV/2 = dV^2/(2A)) from the formula where all the dV is applied at zero time.
John
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As for detecting the projectile... I find that unlikely with Aurora tech. If its unguided it will emit no thermals, and even if it is guided thermals can't lock a targeting solution. It has no EM to speak of and its mass and thus gravity distortion is negligible compared to even the smallest missiles. It IS possible to detect the firing of a mass driver realistically, considering the huge amount of magnetic forces used to accelerate a slug, but I'm unsure whether such a detectable EM pulse is implemented. (Might be fun for a 'oh smeg' moment? It will however destroy stealth for attacking ships) Even if the shot launch was detected however, I'm unsure that enough resolution is possible to determine the exact vector of the slug, though it might provide an ETA (if the velocity of the slug is known, either prior engagements or a guess from the MJ of the shot.) Such a warning could be useful for saving fuel with evasive maneuvers, since you can coast until under fire. Then again, much less useful against lasers. Your warning of a laser attack IS the laser striking your hull.
It's going to heat up quite a bit from launch anyway. As for firing, if the enemy fires spreads, you can't tell where they will go. And you've pinpointed the issues of laser dodging vs. projectile dodging.
Reactive Armor would be a way to decrease the force of the projectile by spreading the damage over a bigger patch of armor, but it's only a benefit if you can prevent the projectile from breaching into the inside, which will be pretty hard unless you also have shields and are not flying in the direction of the enemy.
Though Steve has repeatedly shown his discontent for different armor types by ignoring such suggestions^^.
Reactive armor would be useful because it would basically serve as a "whipple bumper" with a large standoff distance, counterbalanced by limited use.
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It's going to heat up quite a bit from launch anyway.
This is true, some portion of the waste energy from the launch will heat up the rail gun, and some will heat up the projectile. Steve could model this, and the subsequent cooldown. Then, at least at first, projectiles would be visible, at least to thermal sensors.
Reactive armor would be useful because it would basically serve as a "whipple bumper" with a large standoff distance, counterbalanced by limited use.
To clarify for those unfamiliar with the term "whipple shields" are shields for high velocity impacts that are based on the fact that at high speeds even hitting something thin and weak can begin breaking down and deforming the impacting projectile, so that when it hits the hull itself some of the impact energy has been absorbed, and the projectile itself has been destroyed and as such spreads more of it's kinetic energy around a larger section of the hull, making it easier to stop.
They are currently used on man-certified space stations and spacecraft, and consist of a very thin aluminum shell (think soda can thin) spaced a few millimeters from the rest of the hull (which is slightly thicker than a soda can).
The problem with applying this idea to the game is that I think many of the projectile impacts are going to go at velocities where this isn't useful anymore. When you are deflecting paint chips at 6-7 km/s like our space station is, then that the destroyed and spread out paint chip can still be stopped by the hull. Once you start getting hit by things going a thousand times faster than that they will probably go entirely through your ship no matter what. You are better off minimizing the cross section of the projectile when it does so. (Of course at that speed a projectile isn't going to deform and spread much, even if the spacing of the whipple shield is meters instead of mm, so this is probably something that won't hurt for high velocity impacts, and will help for low velocity ones.
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But the Whipple Shield concept could work if extended to planetary size to protect against genocidal kinetic strikes, call it a large energy shield extending some thousands of KM from the planet, not strong enough to block attacks or prevent ships from just barging through it and bombarding at close range, but able to deflect or slow long range kinetic strikes into uselessness or near uselessness.
And of course, the equipment needed to produce the shield is far too bulky for ships, restricting its use to colonies only.
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If the Energy Whipple Shield is implemented to prevent long range kinetic strikes from killing your planet, make it do this:
Reduce momentum of any incoming object by a set %. (requiring energy that scales to the square root of the momentum dissipated)
This happens at a circle a few kkm from the planet. And doesn't apply to anything shot out under that limit.
In which case, the planetary shield also serves as a ship-catcher, allowing you to brake civilian ships and thus save on delta-v budget (and fuel for that and the fuel for that fuel etc.)
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No, that's not how whipple shields work. For one thing, penetration peaks at around 1 km/s. A projectile going at 10 km/s plus will tend to explode instead of penetrating. The whipple shield disrupts it farther out, limiting damage.
I'm not sure where the handwavium shield came from. And I honestly don't know how it would interact with large projectiles.
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The "handwavium shield" is a brainstorming by various community members to find somehting that prevents GFFP, as thats something Steve generally tries to achieve.
Now I've always been an advocate of making orbital bombardment more varied, but I certainly agree that unlimited weapon range doesn't end well in respect to this topic.
As such, there needs to be a sort of Shield that either makes attacks above a specific range ineffectual, or slow down all projectiles with either a very high mass or speed or a combination thereof, but is not feasible on the average warship.
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From what I am given to understand the Whipple Shield works not by outright stopping a projectile, but causing it to deform or fragment so it either misses the target or doesn't hit with enough force to do serious damage, the shield I propose also does that, I realize it is not an actual Whipple Shield but we are imaginative folks here and probably can accommodate the stretch.
I've been pondering it more and it could actually be a tech line, with successive techs slowing incoming by more and more. It could also be an installation built on the planet, likely expensive, and difficult or impossible to move, this means you probably wouldn't be putting one on all your asteroid mining colonies, and new colonies would be vulnerable until they are built up enough to make one themselves, this would give those who do want genocidal strikes the ability to do so while still keeping main industrial centers relatively protected and forcing new tactics.
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I'm guessing at the velocites in Aurora, a Whipple Shield doesn't care what material the impactor is made from (although a solid iron object is different than a micrometeorite).
The more important question is, what if my rail gun projectile has a Whipple Shield of its own? Would that negate your whipple shield? Will there be an arms race of trace-buster-buster-busters?
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Here's a tip:
Use Lasers.
And if that doesn't work:
Use nukes.
certainly cheaper than rapidfiring partially guided projectiles with their own shield generator....^^ ::)
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I think people are looking way to deep. It is suppose to be a war game not starship simulator
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Which is why we do all the simulation right now, so afterwards you just need to know the rules instead of the physics.
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Steve,
what about acceleration of ships concidering human being? What I mean is, will there be "inertia compensate" stuff (sorry, I don't know the english word). Like in Honorverse?
I imagine a module that would allow stronger acceleration with tech upgrades. If that module get destroy and if the ship is accelerating, it could kill everyone aboard, if they don't stop engines fast enough or something.
Thanks,
Gea
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@ First post: There are some typos,
Because as I read it you are using 'fuel efficiency' and 'fuel use' as interchangable,
they are inverse properties of the same engine property. It is clear what you want to say, but at some point you are writing:
...and decreasing thrust can provide huge savings in fuel efficiency
Where you obviously mean either a 'saving in fuel use' or an 'increase in fuel efficiency'.
Interesting effort though.
It would be so awesome if you'd create a game that actually works, proving the universal idiom that realistic space games are impossible false.
In truth though: the dogfighting in Frontier was very much more like jousting than in the original ELITE. :/
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I'm going to be the advocate of simplicity here. It might be something like being a snowball in hell, but it's my position ;D
Evasive maneuvers: All ships should have an evasive maneuvers option; when active ships do not change velocity at all on the strategic level (it can be assumed they are making completely random course changes in such a way that long term they all cancel out) but it uses fuel as if it was running engines at full burn. Note that this totally precludes slowing or accelerating, yet another reason to slow down before battle.
For firing accuracy: I wouldn't suggest modelling each projectile's path. Instead, when firing, have two choices "Dead Sight" and "Compensate for Evasion". Dead Sight is 100% accuracy if the target maintains course, 0% if it evades (for simplicity, this should be if the target activates evasive maneuvers and is capable of evading before the shot lands; assume that any non-random movements can be predicted, including planets in their orbit); compensate for evasion gives an accuracy value based on the formulas mentioned in previous posts; the area of the ship vs the area where the ship could be in based on its ability to maneuver. The shots hit with this accuracy rate regardless of if the target is evading or not. The projectiles may or may not actually travel, depending if they're interceptable by point defense (Lasers and other lightspeed beams probably shouldn't need to be modeled, but railgun shots I could see going either way. )
For guided projectiles: More of an advanced feature, but if added I see them basically working like missiles (return of torpedoes?). They'd need to be more expensive/less efficient stat wise because they have to be tough enough to withstand the magnetic fields and acceleration of railgun launch, and you'd of course need a railgun to launch them rather than just a missile tube. They'd probably also need a fairly large minimum size (maybe reduced by tech?). This last would have some interesting effects; they'd be more efficient in extremely large railguns (which would also serve to reduce their firing rate) and make them much more accurate in situations where fleets were approaching each other at high speed and a boost from the railgun was not as necessary. They could serve an interesting role as a mid-range weapon between missiles and beams.
Deflection shields: Kind of taken by surprise on this one, but it seems to have advocates. My suggestion: They take the place of normal shields, but instead of absorbing energy they deflect attacks that would otherwise be "glancing hits". Mechanically, they reduce the ship's area by a % for the purpose of accuracy calculations, since shots that are dead on or nearly so don't get deflected. I could see this being a ruins or invader tech.
One problem I see with this system: Against non-evading targets projectiles have effectively infinite range. While in some ways this makes sense even for moving targets (you can probably predict how a freighter will move) there probably needs to be some (reasonably long, maybe 20m km) limit on targeting. Or else you could fire at things like inhabited planets or shipyards from outside the system.
It would also make surprise attacks devastatingly effective, but I don't see this as a problem :P
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Thats the entire point, in space, there is no range.
As such, we're discussing a possibility for large handwavium shields to prevent planets from being victimized by this.
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As such, we're discussing a possibility for large handwavium shields to prevent planets from being victimized by this.
Or mutually assured destruction.
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Or mutually assured destruction.
Mutually assured destruction only works with some limiting assumptions. The important one here that any entity can detect an attack against them in transit, and launch their own unstoppable attack at that time.
Depending on the form of attack you may not have more than ten or fifteen minutes notice, or less. And you probably won't know who shot the bullets that are coming. In this scenario the best course of action is to immediately destroy any enemy colony you come across. You have to kill them just in case they turn out to be hostile later on, and you have to do it before they learn where your colonies are so that they can launch their own invisible attack.
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Thats the entire point, in space, there is no range.
As such, we're discussing a possibility for large handwavium shields to prevent planets from being victimized by this.
While planets are an issue, they're not the only problem here. Shipyards and anything else immobile would be completely helpless, and since fuel will be an issue no one will be using evasive maneuvers full time, so you could in theory launch a volley from the outer system at a defense fleet. Defense doesn't need to be any harder than it already will be with these mechanics.
If instead we assume the guns have a small degree of inaccuracy to them (not enough to effect normal combat scenarios, but enough to miss a stationary ship many millions of km away) and give them a capped range/decreasing accuracy with range, then you need dedicated stealth ships to pull off sneak attacks with impact weapons. Which I think makes for more interesting tactics.
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Hello!
I'm a fan of Aurora! Anxiously waiting for Newtonian version. Its unparalleled realism is something I have been wishing to see in 4X for many years.
Now, talking about realism. Everything is great, except one thing. Explosive weapons in space. Explosives work so good on Earth because we have atmosphere. Shock wave (main force of explosion) is pressure and there is no pressure in vacuum. Even direct hit of a nuke in space would be considerably less effective than on Earth. Area effect nukes? Only if you talk about EMP. Kinetic weapons much, much, much more effective, if one needs physical damage.
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One could indeed assume that it would be a lot more effective to simply fill a missile with heavy material to improve its raw kinetic power.
However, you could also think about a missile that pierces armor thanks to an armored head and then explodes *inside* the ship. Internal explosion + breach of hull = ouch.
External explosions are, that's true, a lot less effective without atmosphere.
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@ Bremen:
About the problems with stealth, see the very long discussion in this subforum; It also covers complex economics if you're interested.
@Vex:
As you might have not read in this thread, Steve has already calculated that in his internal wisdom; maybe not perfectly, but close enough.
Nukes will fall off at distance^4, instead of ^2;
For example, if you are 500 meters from a 200 kiloton detonation (which is a 1 ton warhead at tech level 3), the total damage applied per armour box will be 266 MJ
As you can see, the damage at range is pretty darn low, for a warhead of roughly 13x Hiroshima.
For further Information,
You might be interested in this:
http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion (http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion)
http://video.google.com/videoplay?docid=-1070486738375276219# (http://video.google.com/videoplay?docid=-1070486738375276219#)
It would be interesting to have EM damage on nukes, though.
Sure, a kinetic missile would be more effective, but a kinetic missile also needs a very high speed.
A Laser missile would probably be the most effective option.
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Hello!
I'm a fan of Aurora! Anxiously waiting for Newtonian version. Its unparalleled realism is something I have been wishing to see in 4X for many years.
Now, talking about realism. Everything is great, except one thing. Explosive weapons in space. Explosives work so good on Earth because we have atmosphere. Shock wave (main force of explosion) is pressure and there is no pressure in vacuum. Even direct hit of a nuke in space would be considerably less effective than on Earth. Area effect nukes? Only if you talk about EMP. Kinetic weapons much, much, much more effective, if one needs physical damage.
Actually, rather the opposite. The "explosion" of a nuke is caused by its heating of the atmosphere. Without atmosphere, the radiation keeps traveling until it hits a hull, and then heats the hull, quite possibly explosively. A direct hit by a nuke in space would be, if anything, *worse* than a direct hit by a nuke in atmosphere.
And besides, it's being modeled by the book physics. A nuke will have a (probably realistic) amount of energy, in MJ, and apply that energy to anything in range with a realistic model. Let's do a thought experiment.
A 1 megaton nuke (probably pretty small, considering the technology in Aurora) has an energy release of 4,184,000,000 MJ. If it detonates in contact with the hull of a ship, roughly half would be applied to the hull (Slightly more than radiate into space, and probably a small but noticeable amount would pass entirely through). Lets say 2 billion MJ applied to the ship. Assuming the ship were made of pure iron (unlikely, but steel's properties vary by composition) it would take roughly 700 MJ to melt 1 ton of iron, so in theory a contact 1 MT nuke could melt a 2. 85 million ton ship (about 28 Nimitz class aircraft carriers). Of course, that energy wont be distributed evenly, and some parts of the ship will be outright vaporized while others might remain intact. But I think it's safe to say that a contact explosion with such a weapon would instantly destroy anything but the largest and best protected Aurora spacecraft. So I suspect we'll see something like the Honorverse here, where laser heads and other standoff weapons are used, because point defense and evasion makes getting a contact missile hit nearly impossible, but if one does happen it's incredibly destructive.
For ranged detonations, the damage will indeed fall off quickly. Some quick math, allowing for 100 MJ per square meter being the minimum to take damage, means that for an unshielded ship to take no armor damage from a 1 MT nuke, it would need to be 1,826 meters away. That's tiny by current Aurora standards, admitedly, but makes for a much larger target than a kinetic weapon trying to impact the hull itself.
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While planets are an issue, they're not the only problem here. Shipyards and anything else immobile would be completely helpless, and since fuel will be an issue no one will be using evasive maneuvers full time, so you could in theory launch a volley from the outer system at a defense fleet. Defense doesn't need to be any harder than it already will be with these mechanics.
If instead we assume the guns have a small degree of inaccuracy to them (not enough to effect normal combat scenarios, but enough to miss a stationary ship many millions of km away) and give them a capped range/decreasing accuracy with range, then you need dedicated stealth ships to pull off sneak attacks with impact weapons. Which I think makes for more interesting tactics.
This is a good way to make it impossible to snipe non-evasive ships from hundreds of millions of kilometers away, but doesn't help you with hitting planets.
If you have the accuracy to hit the Daring (109 m diameter) from a million-kilometers away, then you have the accuracy to hit Earth from 117 trillion kilometers away. That's over 780 au away, around 20x farther out than Pluto.
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The more I think about it, the more I think the only way to defend a planet is either handwavium (atmosphere/planetary shield blocking long range attacks) or rely on bombarding them being an atrocity of some sort (but what about automated mining bases?).
I had a day to think about the weapons we've seen so far, and I've been trying to predict what roles each weapon type will serve.
Missiles will (as previously discussed) be almost useless at close range. They'll be the only remotely feasible long range weapon, though probably nowhere near as effective as they are in current Aurora. It looks like they'll be further subdivided into laser/shrapnel warheads, with better accuracy but less damage, and contact nukes which will serve demolition/coup de grace roles and possibly area denial/area point defense. One idea I'm toying with is a suicide ship that dives into a fleet at high speed and deploys a multi-gigaton superbomb/mine when enemies are within the area effect; how effective this could be remains to be seen. A large missile with a large number of tiny, contact fused parasite missiles could be interesting as well, since even a tiny warhead would inflict massive damage on an impact hit. These could be the bane of massive battleships, and a reason to bring along smaller escort craft to guard them.
Railguns, I theorize, will be particularly suited to punching above your weight class. Defenses like shields and armor will be more effective on larger ships, since they're generated based on volume/weight but spread over the surface area. They'd be what you want on fighters or gunboats, since smaller scale lasers would have more trouble penetrating heavy shields and armor. On the other hand, their range is greatly diminished based on the evasion ability of the target, so they'd be limited against smaller, more agile ships. If point defense is effective against them (My suggestion is not; even if you melt a rock heading towards you, or vaporize it, it still has the same kinetic energy, and at short ranges railguns will probably be used at deflection will be more difficult) they'll favor multiple smaller weapons as well.
Lasers care much less about how fast your target is moving, since they move at the speed of light. It is possible to evade a laser (though obviously you wont see it coming), but only at *much* longer ranges than a railgun. Instead, the range of lasers will probably be limited by dispersion, IE the range at which they wont do even a single point of damage to a hull plate. They'll be the weapon of choice against small targets and missiles. They won't necessarily have a longer effective range than railguns, but within that range they'll be much harder if not impossible to evade with speed alone.
Torpedoes or theoretical railgun/missile hybrids depend on implementation, but if they work like I suggested (railguns with fairly large minimum projectile size) they would be a medium range weapon, very accurate, very damaging, but with massive launchers and probably slow reload speeds, making them exceptionally vulnerable to point defense. A successful hit with one would probably be crippling though, and they may or may not have limited ammo, so I predict a lot of maneuvering in order to minimize/maximize how long fleets will remain at torpedo range.
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Some thoughts on the whole defending a planet:
- Create a tech that is similar in line to planetary sensors except that they provide a detection range for ships in hyperspace. These would be very large installations that are very hard to build on anything but a large industrial planet. The sensor would provide an estimated exit point and time for the contacts allowing defending fleets to move to defend.
- PDCs in space. Basically a means to build space bound weapon platforms that have the faster rate of fire etc of a PDC, can only operate in orbit but allow the construction of platforms with significantly more defensive systems on compared to a ship.
- Gravity distortion generators. Similar to a PDC in space, basically an automated platform with a good length shelf life. Once you have mapped the system in question this allows you to build an move the platforms to areas in the system that distort the mapped gravity fields. Ships jumping into the system will then be subject to either the original levels of variation in location on jump in or could be pushed off axis. Hence an attacking fleet that came in at serious speed could have a real change of being out of position and unable to deliver that massive volley.
- Planet shields feel very high tech to me. Maybe an interim would be shield generators that protect a certain number of population and facilities in a more localised field.
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Asteroids
On a completely different note I was also thinking today that it would be very nice if I could go and grab some of those asteroids and push them into an orbit around one of my planets so they can be far more easily exploited.
Also quite like the idea of being able to mine out some of the larger roids, give them some spin and a decent internal atmosphere and create something a bit different to just sticking more infrastructure on them.
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Steve you are suing sliding scales for the size of drives if i got that right. Will it be possible to do the same with the other components too? It would be nice if i could add quarters for exactly 262 people or for starbases (if they make it in) livingspace for 322k people. I dont hate micromanaging this stuff but at times it gets a little bit annoying if i want to build a orbital hub for 2.5 mil people because i have to click so often.
Also are there any plans to add the need for power to populations? In my oppinion its a bit unrealistic that i can support 300 mil people somewhere at the edge of a system where energy is rather sparse if you wont go the nuclear route and even then fuel is limited or uneconmic (unless you have enough cheap Hydrogen for Fusion).
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As for preventing long-range bombardment of planets one possible solution is to have random variances in the solar wind be enough to throw projectiles off enough to make hitting any thing at more than 20m k imposable with a guidance system that could be detected and thus intercepted I also like the idea of being able to detect incoming ships in hyperspace or at least have a ship transitioning form hyper to regular space leave a large EM or Thermal "hyper footprint making it possible to tell if ships are entering or exiting form the system
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Some initial thoughts on accuracy:
Railgun Size: 200 tons Surface Area: 165.4
, assuming a sphere, has a radius of 3.63m. Length double to 7.2m, call it 10m for some order of magnitude calculations. Unlikely to be 100m long though, but the point remains.
Steve's 4800MJ railgun has a Muzzle velocity of 100,000 m/s, which I like because its a round number.
To hit a target 1,000,000m away, the flight time is 10 seconds. All discussion below assumes the target, an enlarged Daring class ship, is stationary.
The projectile must accelerate from rest to 100,000m/s along a distance of 10m, and then fly for 1,000,000m. Any deviation along the 10m length in the rails will be magnified by 100,000 by the the projectile hits the target. And this is not just limited to the rails, but also the relationship between where the rails are pointing, and where the targeting computer thinks they are pointed, which could be affected by defelction caused by heat, or large accelerations. The quality of the shot could also affect its path: if it does not have a homogenous density, then it might be subject to uneven acceleration. This might affect missiles etc which are not supposed to be solid iron. I am on shaky ground with the maths here though.
The shot can obviously deviate if the target is large enough, but a 100m Daring is 1:10,000 of the 1,000,000m range, so there is only a limited opportunity for shots to deviate and still hit.
Similar logic can be applied to long distance plant bombardment. In theory you can arrive at the edge of the solar system, aim, and launch, then be long gone before the shots arrive at the planet.
However, this assumes that you know with great accuracy the orbit of the planet, which requires you to know its mass, and the mass of the sun. And how fast it perihelion advances. And any influence from other large planets, for example Jupiter. Or any large moons.
Although Aurora doesn’t consider gravity (yet), it would have to be considered in reality, as the target planet might not be directly in line with the sun on our side of the solar system.
Size of earth is 12,742km from wiki, or 10,000km by order of magnitude.
Orbit of Uranus is 3,004,419,704km, again from wiki, or 1,000,000,000km by order of magnitude. So the target is 10 times smaller than the Daring in proportion, or a diameter 1:100,000 of the range. While the shots might have the range, they have a small target to hit.
Solar wind might also have an impact, as would sunlight itself, and any dust or debris in the system.
From here (http://en.wikipedia.org/wiki/Rifle) and here (http://en.wikipedia.org/wiki/Minute_of_arc) a modern rifle is accurate to 1 arc minute over 100m, or nearly 3cm over 100m. For order of magnitude calculations, we can round that to 1cm over 100m, or .01m over 100m, or 1:10,000.
All this, and I conclude:
A railgun shooting 1,000,000m to hit a target 100m wide is about the same accuracy as our modern rifles.
A railgun shooting the earth from Uranus is about 10x more difficult than current technology, assuming a straight shot. As soon as the planets are moving, things get much more difficult. In theory if the system has been grav surveyed then you would have this information, but it would need to be accurate to allow a 1:100,000 shot.
All this to say, that really if Steve wants a range limit of railguns and interplanetary bombardment, there is enough (dodgy?) physics to justify it.
Let me know if my maths and physics is off here, as it has been a while since I had to think like this.
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I haven't read all the essays in this thread so this might be posted before. But what about mire controls?
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wut?
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Mire: noun
1.
a tract or area of wet, swampy ground; bog; marsh.
2.
ground of this kind, as wet, slimy soil of some depth or deep mud.
I can only assume a mire control is some form of installation to produce or remove swampland, why this should be something specifically for Newtonian Aurora I do not know. I suppose it is possible there is a misspelling, but I think I am happy with my definition.
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All of your math is right, but we come to different conclusions, mostly because you assume a reasonable engagement range for shooting a Daring to be a million meters and I considered a reasonable range to be a million kilometers. At that point it becomes trivially easy to target planets and whatnot as well.
You (and others) have mentioned solar wind, third body gravity perturbations, etc as possible things to throw off aiming. Solar wind at the least isn't going to affect anything at all. Solar wind only effects modern satellites to appreciable levels in the long term, and satellites are very low-mass vehicles in comparison to most objects, and their solar panels gives them a fairly high surface area. This force would be completely negligible for a high density slug.
Now third body gravity is a completely different beast, you can't really make comments on how much it will affect a slug in all situations, because everything will depend so much on each specific trajectory and how close it passes to how many planets of what mass. That said, if you are not firing from a planets orbit, or at a planets orbit (/planet) and your slug doesn't go too close to a planet (within a few million kilometers) there once again wouldn't be a lot of difference.
Even if one of those things was true (and lets face it, it often will be, as most of what we are worried about is destroying shipyards, orbital habits, or attacking populations directly) those are the sorts of effects that are actually very easy to calculate. With close observations determining the masses of bodies from their orbital trajectories is easy stuff, and TN ships will have better sensors and computers than we do. Between visual observations and black body thermal release I'm thinking that the larger system bodies would be mapped within minutes of entering a system, even if many moons took longer. Also the handwave for our active sensors is that they are somehow measuring the mass/gravity of objects directly, through the bend of space time or somesuch. I'm guessing that even in a handwaved "stealth mode" these active sensors would probably be able to pick out planets and moons right away.
Now, while that effect can be calculated, it is true that such affects do serve to expand the uncertainty of a projectile, because the forces on it are different depending on where it is, meaning that instead of smoothly increasing its distance from the target trajectory based on its initial inaccuracy, the rate of gaining inaccuracy increases. I suspect, though, that that effect will be very small, simply because our projectiles are moving very fast.
The scenarios that I am mostly worried about have some other caveats as well. I am not assuming that a ship is leisurely orbiting the Sun around Uranus and then firing 100 km/s shells. If that was the case there wouldn't be much worry, those (1 kg) shells are only hitting with 1.2 tons of TNT of force (5 GJ) and more importantly it will take something like 10 years of time for those projectiles to hit the earth. At those slow speeds third body gravity perturbations, etc, etc are very important, you'd probably still be hitting planets, but not shipyards. However I am more assuming the scenario where someone jumps in 10-20x past Pluto, then accelerates to a good speed of 15k km/s or something like that (or comes from warp at that speed, or comes into Pluto, then slowly moves away, then turns around to accelerate back).
If your projectile is moving at that speed it only takes 4 days for it to get to Earth, and while that sounds like a lot it doesn't affect the accuracy at all. As long as you aren't shooting super close to any planets you are in the clear. More importantly in that situation you aren't actually shooting at a target (say) 5e9 km away. The image of a cone of inaccuracy from a shot is only valid in the reference frame of the shooter. The shooter is shooting at where the target will be, if the planet is approaching him at 15k km/s and he shoots at 100 km/s then the projectile will be in flight for a little over 3.83 days. In that amount of time the projectile travels just over 33 million km. From the ship's perspective it's shooting at a target 150 times closer than it really is.
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I guess the accuracy debate comes down to what drift is more proportional to: distance or time. Both will have an effect, but one is likely to dominate.
If drift is proportional to distance, then there is a fairly hard range ceiling. This is the scenario JimiD describes. It mostly includes pointing errors.
Time drift is caused by things like the aforementioned gravitational perturbations, solar wind, and light pressure. There are lots of things that can cause a body in space to drift, but the only one that would be of any real interest is third bodies, and those don't matter over short enough ranges. At the sort of speeds we're dealing with, space can be approximated as flat with a very high degree of accuracy.
Distance drift will tend to dominate here, but I expect that we're looking at something at least an order of magnitude better then modern rifles. They get microradian (~.2 arcsecond) accuracy with modern laser weapons.
As an aside shooting stuff in space is a good bit easier then on Earth. There are fewer variables, and more can be computed ahead of time. Things like perturbations can be compensated for with a good enough computer. That's not to say I'm recommending unguided slugs for long-range work. I'm saying that time drift causers like wind are less variable.
As another aside, I'm fairly certain that solar wind pressure is negligible compared to light pressure. I've never heard of a physical solar wind sail. Magnetic sails are another issue.
There are several ways of dealing with the RKV problem. One is that, seeing as you have FTL sensors, RKVs are not as stealthy as they are in reality. They're just very fast. I've read that objects at relativistic velocity tend to give off hard radiation, which would foil attempts at stealth. Another idea is to have the radiation surge upon leaving hyperspace roughly proportional to the speed. That way, you can make an RKV, but it will be seen.
As for stopping one, if you throw a ball bearing at it, it will tend to die. And if the ball bearing is off-center, the ablating RKV will push the rest off course.
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That's just it though, distance drift and time drift aren't different things, it's the same amount of drift for the same reasons. The only time they appear to be different is when you get your reference frame transformations wrong. Instead of thinking of the ship approaching the planet, and shooting at a planet 5 trillion kilometers away, think of a ship sitting motionless in space (which it is, from its frame of reference) with a planet 5 trillion kilometers away coming towards you. That ship isn't shooting at the planet 5 trillion kilometers away, it is shooting at where that planet is going to be, which is only 33 million kilometers away.
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That's just it though, distance drift and time drift aren't different things, it's the same amount of drift for the same reasons. The only time they appear to be different is when you get your reference frame transformations wrong. Instead of thinking of the ship approaching the planet, and shooting at a planet 5 trillion kilometers away, think of a ship sitting motionless in space (which it is, from its frame of reference) with a planet 5 trillion kilometers away coming towards you. That ship isn't shooting at the planet 5 trillion kilometers away, it is shooting at where that planet is going to be, which is only 33 million kilometers away.
I will admit that you are correct, so far as impecision in the physical pointing of the weapon is concerned. However, that isn't where most of the error will lie in this case. Most of the error will come from inaccuracies in where you choose to point it, which are going to be significant at half a light year. Even if you're shooting at a planet, determining exactly where you are and how fast you're going relative to the planet is a significant task. While you aren't terribly likely to miss your target, the planet may not be there when it hits.
The same applies when you're at a more reasonable distance. There's only one error that is proportional to the fraction of velocity the projectile travels on its own.
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That's not even a difficult task using today's technology.
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That's not even a difficult task using today's technology.
Precisely enough for weapons targeting? At half a light year? Over a short time period? Mounted on a ship?
Really?
Maybe the planet example is overkill, but dismissing all pointing error as being in the physical precision of the laying of the weapon is wrong. Other factors will come into play. I can guarantee you that shooting at something 100,000 km away with a 100 km/s coilgun while going at 100 km/s is not the same as shooting at the same thing with the same coilgun at a range of 50,000 km while you're stationary. Yes, the laying error is the same, but all the other variables are different.
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If your engines are on you would have more trouble due to ship vibrations. If your engines are off you are always stationary.
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That's not what I meant. What I did mean (and I assumed it would be implied from context) is that you were stationary relative to the other vessel.
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That's not what I meant. What I did mean (and I assumed it would be implied from context) is that you were stationary relative to the other vessel.
Why does it matter if your other target is moving, acceleration is the only thing that matters. If your target is moving at constant velocity you know where it's going to be, whether or not that constant velocity happens to be zero doesn't matter.
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Why does it matter if your other target is moving, acceleration is the only thing that matters.
I would have to say I don't think that is entirely true. If either of you are moving relative to the other on anything but a head on or directly away from each other you are going to have more variables and inaccuracies to deal with ie:
- How good are your sensors in calculating exactly how fast you are going compared to one another?
- What about the time lag from sensors to gun control to turrets and accounting for that?
- What about the momentum built up by the turret itself as it moves to a firing solution and impac this has when stopping the turret?
- What about timing accuracy of exactly when you need to fire the round for the intercept?
- What about the consistency in the launch velocity of the round - does it change as the ship draws power to other systems that impacts the feed to the coil gun?
At the ranges we are talking about, moving v stationary is going to have an impact and for ship v ship a relatively big one. I therefore like the expectation of the mechnics that even when on a constant bearing and speed there is a chance of missing and when you get to more significnat range they are going to have to be smart rounds to help cope with the multitude of inaccuracies that will build up in the system v the theoretical position.
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Why does it matter if your other target is moving, acceleration is the only thing that matters. If your target is moving at constant velocity you know where it's going to be, whether or not that constant velocity happens to be zero doesn't matter.
You do understand that there is a limit to what sensors can determine, right? Yes, assuming ideal circumstances, velocity doesn't matter. But let's do some math:
Assuming the sensors are accurate down to 1 cm/s, and a flight time of 1 day (86,400 seconds). The target will be off of its estimated position by about 864 m, assuming flat space. That might be enough to hit, depending on the size of the target. And the accuracy of said sensor will scale with distance. Let's assume that we're shooting at a target that's stationary relative to us at 8.64 mkm with a weapon that has a muzzle velocity of 100 km/s, with the given sensor. Our target position error radius is 864m, or 100 nradians. But what if we approach the target with a velocity of 100 km/s relative, and launch at 17.28 mkm. The flight time is the same, but now our velocity error is 2cm/s, and the target circle has a radius of 1,728 m. If we look at that over launch distance, the angular error is the same.
The point of all this is simple. There is going to be just as much if not more error built in from your sensors as there is from your gunlaying itself. And to clear up any confusion, I use gunlaying to denote the precision with which your weapon can physically be pointed.
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You do understand that there is a limit to what sensors can determine, right? Yes, assuming ideal circumstances, velocity doesn't matter. But let's do some math:
That's all reasonable and correct, but note that even in your situation velocity of the target doesn't matter. A 1cm/s sensor error will result in a 864m error radius regardless of whether one of the ships is moving with respect to the other or not.
I think that having two types of inaccuracies, sensor inaccuracies that depend on distance at firing time, and gunlaying inaccuracies that depend on the flight time of the projectile, would be reasonable mechanics, however I don't really see a mechanism that would degrade firing solutions based on the relative velocities, except of course for how the relative velocities impact the flight time.
Also the modelling of the sensor accuracy may be a good way to resolve the (odd IMO) issue with Thermal and EM sensors not giving targeting solutions. Maybe in Newtonian Aurora they each could, but the position and velocity accuracy of those passive sensors are an order of magnitude below an Active sensor of the same tech level.
I would have to say I don't think that is entirely true. If either of you are moving relative to the other on anything but a head on or directly away from each other you are going to have more variables and inaccuracies to deal with ie:
- How good are your sensors in calculating exactly how fast you are going compared to one another?
This is an issue whether your target is stationary or not, if your target is stationary with respect to you but your sensors have a velocity error margin that tells you that the target isn't stationary than you are in just as much trouble.
- What about the time lag from sensors to gun control to turrets and accounting for that?
That would be a very, very small time lag, and I have no idea why Steve would model it. That said it would be easily accounted for by the targeting software, as this time lag would be constant on a dedicated communications line, which I assume you would have between the Fire Control and weapons.
- What about the momentum built up by the turret itself as it moves to a firing solution and impac this has when stopping the turret?
There aren't any facings in Newtonian Aurora, so this doesn't have relevance for the game, in "real life" the same effect would happen when moving your guns to point at a stationary target, and this sort of conservation of momentum problem is accomplished by every one of our present day satellites with a reaction wheel every second.
- What about timing accuracy of exactly when you need to fire the round for the intercept?
This is a trivial problem to solve with pencil and paper to an arbitrary tolerance. It's not a time-consuming problem either.
- What about the consistency in the launch velocity of the round - does it change as the ship draws power to other systems that impacts the feed to the coil gun?
I'm assuming that the power activities of the main weapons are relatively isolated from the rest of the ship, the sort of electrical setup that would cause the other systems to interfere with firing would also cause firing the gun to interfere with the rest of the ship. This would be apparent right away, as the first shot fired would probably short out every electrical device on the entire ship.
Note that this is different from the power supplies of the ship being overtaxed such that the weapon capacitors are charged slowly, but that doesn't really seem to be a targeting problem.
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This is an issue whether your target is stationary or not, if your target is stationary with respect to you but your sensors have a velocity error margin that tells you that the target isn't stationary than you are in just as much trouble.
But when you are both staionary you would not need to take velocity data from the sensors so that error would not be consistent.
In any case my previous list of points was not a list of things for Steve to try and model it was a simple justification as to why, when there is movement involved, your shots will be less accurate than when there is no movement involved; even when that is at a constant speed.
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But when you are both staionary you would not need to take velocity data from the sensors so that error would not be consistent.
How do you know that you are stationary to your target if your velocity readout isn't telling you zero? If you have some sort of secondary, more accurate velocity sensor that tells you that the target is stationary and you can ignore your velocity readout, then why aren't you always using that secondary sensor?
In any case my previous list of points was not a list of things for Steve to try and model it was a simple justification as to why, when there is movement involved, your shots will be less accurate than when there is no movement involved; even when that is at a constant speed.
Phrased in another way. How do you match speed with your target (to get the stationary scenario that your weapons theoretically operate best at) without using your velocity readout?
Yeah, but if you are not going to model the effects, and they are very small effects, or effects that can be easily compensated for as part of normal operations, then the best thing to do is say that those effects aren't there.
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Yonder
I understand where you are coming from with the constant errors in sensors but the whole point of the discussion was comparing accuracy of stationary to non stationary hence ignoring it when you were in that theoretical situation.
All the differences are tiny, the whole point is that at the ranges and accuracy requirements we are talking about you are going to have to be infinitesimally accurate in order to score a hit. That means, rather than try and model all of those tiny variances, you introduce a simple error in you hit chance to simulate all of these tiny problems.
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That's just it, you don't have to be infinitesimally accurate. There is a finite, though precise level of accuracy that you have to accomplish, and that level of accuracy has already been surpassed in the modern day. From laser rangefinding the moon and further bodies, to putting millions of transistors on tiny chips, to mapping Earth's irregular gravitational field we already do things that require really precise measurements. If you do the math you find that today's fidelity instruments are enough to do these operations already.
Lets say you are trying to genocide a small body, like the size of a moon, and your sensors were off by 1 cm/s per 10m km. (An earlier example, and according to Webb and Jones this is already in the low-performance range of commercially available inteferometers in a vacuum: http://books.google.com/books?id=dVOz6v5icxkC&pg=PA1741#v=onepage&q&f=false) We will also assume that we begin by approaching at 15,000 km/s with guns shooting at 100 km/s, with a gunlaying inaccuracy of .2 arcseconds (What byron claimed was modern laser accuracy).
If we shoot from 1e10 km away (around 60 AU, 50% again past Pluto's average distance from the sun) then it will take 7.665 days for our projectile to hit. That means that from our perspective we are shooting at something 66.2m km away. Our gunlaying inaccuracy gives us an error of 66.2 kilometers, and our sensor inaccuracy adds another 66.2 km of inaccuracy (a coincidence that arose from our round numbers, we are firing at 100km/s and our sensor inaccuracy is 100 times more than our gunlaying inaccuracy). That means that our total maximum inaccuracy, if each of our systems had the maximum amount of error, and they were each wrong in the exact same direction, would be 132.4 km. The moon has a radius of 1738 meters, it's easily genocided.
In fact, we could even do this with a gun with the accuracy of a modern high-accuracy hunting rifle, which top out at "sub minute of angle" or 3milliRadians. At that point we add the 66.2 km of sensor accuracy to 19264.1 km of gunlaying error. Our maximum error range is now 19330 km and considerably higher than the moons radius, or even higher the Earth's 6378 km radius, but our Astronaut with a deer rifle sitting on the space shuttle refitted with TN engines is still hitting the planet a non-trivial amount of the time with no other technological modifications.
And that's just a handheld rifle, it took me awhile of searching before I could find a single reference to the angular error of any larger guns, but I finally found a reference on Jane's ( http://articles.janes.com/articles/Janes-Ammunition-Handbook/76-mm-APFSDS-T-ammunition-for-Rooikat-armoured-car-South-Africa.html ) showing that a South African tank which entered production in 1983 has an accuracy of .3 mils, or milliRadians. This is an order of magnitude better than our rifle and at 1992.6 total error we are now always hitting the Earth, and reliably hitting the Moon. All with today's technology.
You're not going to be able to avoid Genocide with realistic accuracy penalties, or any sort of reality/physics based approach. We would either need to drastically lower the delta-Vs and some other capabilities of the ships (a ship which had difficulty making a 3,000 km/s attack run would be much less dangerous than the current Daring, which can can easily make a 15,000 km/s attack run) but I don't think that you would be able to do so without increasing the travel times and assorted logistical complexities so much that you were negatively impacting the game. We're either going to have to do some sort of handwaving defense mechanism, or just have the AIs not try to genocide the player. (A player could genocide in a pinch, but if the dust mechanics weren't changed any sort of attack on this scale would probably make any planet hurt in this way inescapably cold for thousands and thousands of years.)
I would expect a Trans-Newtonian (or whatever we'd be calling it) culture to start out with instruments an order of magnitude or so more accurate than ours, possibly even more. If the tech progression followed similar scaled improvements to the rest of the tech tree then within 30-40 years of game time races might even have the the accuracy to destroy shipyards and orbital habitats in the above scenario (which remember, was 50% farther out than Pluto).
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I agree that we can reliably hit a planet at long range. My question is if it is practical. You're not looking at genocide with the accuracy in question. You're looking at ecocide. And at something on the order of .05c, that requires probably megatons. There is no way to launch anything smaller then an asteroid unguided at those sort of ranges. I'm skeptical of unguided weapons at any range, but long range is by far the worst. It's quite easy to avoid targeting. I doubt you can get really good accuracy with passive sensors, and if you get lased, put on about 5 cm/s.
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Well, so planets probably are save from anything but dedicated weapons, against which someone will have to find a solution.
Homing weapons can be countered by simple countermeasures, and guided weapons will give away the gunners position.
Both of those are also expensive.
Shipyards are another ballgame.
How can we prevent those from being wrecked several Au out?
I suppose it would be logical to only have a skeleton drydock up there, which is easy to just shoot through without hitting, and assemble the components on the surface; that at least weakens the problem.
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If we shoot from 1e10 km away (around 60 AU, 50% again past Pluto's average distance from the sun) then it will take 7.665 days for our projectile to hit. That means that from our perspective we are shooting at something 66.2m km away. Our gunlaying inaccuracy gives us an error of 66.2 kilometers, and our sensor inaccuracy adds another 66.2 km of inaccuracy (a coincidence that arose from our round numbers, we are firing at 100km/s and our sensor inaccuracy is 100 times more than our gunlaying inaccuracy). That means that our total maximum inaccuracy, if each of our systems had the maximum amount of error, and they were each wrong in the exact same direction, would be 132.4 km. The moon has a radius of 1738 meters, it's easily genocided.
I think I understand your logic here but doesn't it assume that your ship itself is flying a perfect course to the planet at the point of firing your weapon and as a result the error component is only in the aiming? I would have thought that you might expect a similar error in the ships navigation as well which would then introduce the largest error in targetting?
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I agree that we can reliably hit a planet at long range. My question is if it is practical. You're not looking at genocide with the accuracy in question. You're looking at ecocide. And at something on the order of .05c, that requires probably megatons. There is no way to launch anything smaller then an asteroid unguided at those sort of ranges. I'm skeptical of unguided weapons at any range, but long range is by far the worst. It's quite easy to avoid targeting. I doubt you can get really good accuracy with passive sensors, and if you get lased, put on about 5 cm/s.
It could just be a couple of nuclear missiles minus engines and targeting. IE. unguided nuclear shells
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Dear All,
New to Aurora forums. Been playing for a year though. Some thoughts on the matter of extreme range planetary bombardment. I don't mean to offend, but though it is an attractive option, isn't it rather impractical?
Now imagine WE'RE all hostile aliens just entering the solar system and about to target earth with extreme range ballistic bombardment. Remember we would have VERY little pre-existing astrogravitational data on the system. What? Take time off for detailed survey in a hostile system with active defenders??? Given that our firing location is just beyond the orbit of PLUTO;-
Our problems are, assuming we can even manage to LOCATE EARTH from so far away (what a miracle that was!):-
1) All newtonian sensor data is an image of the past thanks to the speed of light limit. It takes approx 4 to 7 hours for light to travel from SOL to PLUTO; but EARTH moves at approx 108,000 km/hour around the sun. Thats like a 430K km to 750K km difference by the time we are pointed at it. Sure, lets LEAD THE TARGET, but that only takes us to the next problem:-
2) To "lead" the target is difficult given the extreme time lag, because we would need to know the object's EXACT astrogravitational movements, a study that will take years (365. 25 days???) of observation. But remember, the earth MAY NOT take the EXACT SAME path around the sun for each year due to the following problem:-
3) Predicting the exact planetary orbit given its many variations due to gravitational effects from other solar system bodies and "wobbling" due to LUNA. Then you need to study the intricate sequence of planetary alignment, but planetary alignments are kinda unique each year so you would need to study and predict ALL the significant solar system bodies to predict their effects on earth orbital variations.
4) Okay now thats done, we ALSO need to factor in the gravitational effects of all those solar system bodies ON THE PROJECTILE, including all other minor bodies that are possibly in the way (planetoids, asteroid belts, comets). Assuming we've done that, next:
5) What about the effects of solar wind and its unpredictable variations blowing on the projectile? We'd have to study SOL's internal structure, internal convections, solar flares, solar spot activity. Not to mention that solar wind interaction with the magnetosphere of each major body may have a small effect. Also, we must assume that:
6) The further away the target is, the more unreliable the sensory data (degree of uncertainty increases with range). Remeber there are such things, (no matter how minute) as gravitational lensing of light rays, interference from nearby gravity centres, diffraction, echoes, interference from solar wind (and especially actively from defenders), etc. So we roughly know where a planet WAS to the nearest +/- XXX km, but that may not be precise enough.
7) Finally we'd have to hope there are no collision whatsoever (not even a glancing blow) with micrometeorites / space dust / comets / asteroids (unlikely) that will put our projectile off course. Natural stuff are easily avoided (except the space dust and small stuff), but what about:
8) The last problem is a valid counter-defense in response to any such projectiles that we might launch. Moving at relativistic speeds, even a collision with a human-seeded "cloud" of floating micro-debris in space early on is enough to veer the projectile sufficiently off-course. Heck those humans could have already pre-emptively put up millions of square kms of those defensive stuff along the "predicted" optimal line of fire the moment they detected our ships warping in-system. Remember we're fighting in THEIR territory now, an unfamiliar battleground they have extensively studied and know very well more than we do.
9) And would you think they'd just let us conduct an accurate system survey in peace? Heck, bouncing all those EM signals in every spectrum off every major solar system body , blasting and lighting us up with all sorts of EM/sensor energy. Putting up false "ghost images". Partial cloaking of earth itself? I'm sure that'd have a profound effect on the accuracy of any survey.
Better we crack out those MK III 100 MSP self-guided drone missiles with the 999 radiation yield dirty warheads??? At least their courses are self-correcting with minimal sensor time-to-target (plus other interferences to be avoided) lag.
Regards,
Sam
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I haven't read the recent posts in detail yet but based on a quick skim... :)
Firstly, bear in mind the issue we are looking at is not just game-related but one that humanity will have to face for real at some point in the future, even if the firing ship is one human nation firing at another.
In Aurora terms I think it would be reasonable to assume that a ship with advanced technology way out beyond Pluto would still have a reasonable chance of hitting something as large as a planet. I haven't yet decided what parameters would affect such a long-range shot but I will read the previous posts in detail before I do. For the sake of argument, lets assume its possible. However, the debate should not really be about whether it is possible but if it is practical.
For starters, if you want a really high velocity shot, then your ship needs to be moving fast before it fires. You can either enter the system at high speed, or accelerate after you arrive. If you arrive slowly, it would takes years for the interstellar journey, so lets assume you arrive at a reasonable speed. If you haven't surveyed the system, you are very likely going to arrive on a course that doesn't allow the shot. You could even arrive on the far side of the system facing the wrong way. In that case, lining up the shot is going to take a while. But, lets assume you eventually manage to line it up without being attacked by the defenders.
Next there is the question of do you really want to destroy the population anyway? In standard Aurora, it is fairly easy to wipe out a planet with nukes. It doesn't happen too often though because you would like to either steal the industry or use the planet afterwards. While a massive kinetic strike wouldn't result in radiation, it would result in a LOT of dust and it would destroy any industry.
Finally, there is the chance of the defenders intercepting the projectile. Anything moving at extremely high speed could be destroyed by throwing a pebble in its path. It wouldn't be too hard to intercept the projectile with some type of debris field from a shrapnel warhead, or you could simply detonate a large nuclear warhead nearby. Aurora has FTL sensors so you may be able to detect it in time to intercept it. A small object such as a 1-2kg railgun projectile would be virtually impossible to detect with normal Aurora active sensors. However, as I mentioned earlier in the thread, I am considering adding some type of new sensor that detects an object based on mass x speed. That would probably allow detection of even small objects with a very high velocity.
So in summary. Lining up the shot won't be easy. It would be unusual that you would want to destroy the ecosphere of a planet and the defenders would probably be able to intercept the shot anyway.
Steve
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The question on my mind though, is could they intercept a thousand shots? I assume a railgun projectile is cheaper than a nuke for example, so for planetary attacks long range bombardment still works, simply to remove defenders ammo if nothing else.
I find for me, when I invade a planet, the desire to keep the infrastructure intact drops rather quickly as the shipyards keep pooping out little ships that annoy me, or as the ground war just keeps grinding along. There are a number of RP reasons to annihilate a population as well. not to mention the special NPRs seem to love doing it when they get a chance,
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So in essence you would station some shrapnelclouds in orbit around your planet and it should stay save enough?
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We already have that kind of shrapnel cloud^^
No, a permanent debris field would be hard to maintain, expensive, and spread to thin.
However, a Shrapnel-field fired in the direction of an attacker would be able to disintegrate a large amount of projectiles.
Which is a good point, finally getting back to the actual gameplay implications.
The Ammo is an interesting point, I think kinetic weapons should cost ammo with the power they have now, and massively so.
Though I suppose a 10 Ton Magazine could already store 8000 1 Kg projectiles.
For planetary bombardment, it might make a difference.
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I think one issue that gets consistently overlooked in this thread (though I admit to not reading it all) is the effect of atmosphere on kinetics. Any 1kg projectile, or even 100kg projectile travelling at those speeds will be vaporised even by the relatively thin atmosphere in high orbit, or at least break up enough that damage becomes minor. Larger, slower projectiles are more resilient (and presumably might even be worth shielding, though if thats sensible gameplay wise is for Steve to decide), but also easier to intercept.
Here's an interesting little calculator and an even more interesting peice of documentation on how its calculated for those of you interested;
http://impact.ese.ic.ac.uk/ImpactEffects/
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Wow, thats a great page. :D
Just let it calculate the effects of a 1 feet projectile the density of iron, at 5° angle and 10000km/s, and the airburst (the projectile would vaporize in the stratosphere) has a strength of 2.08 x 1013 joules. Decent, but that's a large projectile, probably the size of a guided slug, and the energy would spread over a few kilometers. Looks like it might be more damaging to the environment than Industry. The site doesn't calculate if a projectile of this high speed, but this small size, would actually make an impact at ground level at all, it's probably meant for asteroids and not space warfare.^^ ;)
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Yes, but the energy and damage calculations are still valid and interesting.
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It could just be a couple of nuclear missiles minus engines and targeting. IE. unguided nuclear shells
Yes, you could do that. However, the yield would have to be in the gigatons. And the cost of a guidance system is minimal compared to the cost of the nukes themselves. Not to mention that you can target the nukes for maximum damage. Hit the big concentrations, and have the rest die off or revert to savagery.
My comments to the general debate:
1. I've read that something entering the atmosphere at 100 km/s will ablate at around 200 m/s. This is not a good number for planetary bombardment. You're sort of restricted to using asteroids. The best you can hope for with anything smaller is to dump energy into the upper atmosphere. That's not terribly useful.
2. Passive shrapnel clouds are a bad idea. See my post on space mines. (Passive, as in 'constantly there').
3. Nukes. Enough said.
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But like you said, engines take up alot of mass and when they fire, they're visible.
A 'missile' that is a reentry sheild + warhead is alot smaller and thus much less visible. At least until it starts reentry, but it's too late by then.
It could even look like a meteor.
EDIT: there are enough of those that you can't go shooting them all down. Although after the first such nuclear holocaust, you bet anything larger than a baseball on course for a colony is going to get shot at.
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But like you said, engines take up alot of mass and when they fire, they're visible.
A 'missile' that is a reentry sheild + warhead is alot smaller and thus much less visible. At least until it starts reentry, but it's too late by then.
It could even look like a meteor.
EDIT: there are enough of those that you can't go shooting them all down. Although after the first such nuclear holocaust, you bet anything larger than a baseball on course for a colony is going to get shot at.
How visible the engine is depends on what type it is. If all you need is a few hundred m/s, then cold gas works well, and is very hard to see. Note: It is not practical for anything but guidance.
The problem with the meteor idea is that it would probably take a year or more to set up. You have to come in from an undetectable range, and then change into an orbit that makes the projectile look like a meteor.
Now that I think about it more, even that won't work. Anything coming toward a city gets shot at, and that goes double for anything that isn't behaving like a meteor (tumbling, etc.).
As for size, given modern technology (which I know isn't true, but nuclear physics don't change) you simply can't fit a nuclear weapon in an object the size of a baseball. IIRC, that's about the size of a critical mass, not counting any explosives or anything. You'd probably need something a bit bigger. And an object that size will likely decelerate high in the atmosphere. If it doesn't, it's suspicious. And anything suspicious gets shot at.
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I think I understand your logic here but doesn't it assume that your ship itself is flying a perfect course to the planet at the point of firing your weapon and as a result the error component is only in the aiming? I would have thought that you might expect a similar error in the ships navigation as well which would then introduce the largest error in targetting?
Very true. Probably the best way to look at it is that you have launched your ship towards your target, and then the projectile you shoot is the course correction. In my above example the projectile traveled 66.2 km away from the ship after it was fired, that means that the vector of the firing ship has to pass withing 66.2 km of the target, as the largest course correction you could have would be if the ship fired at a right angle to its course. Doing the math is actually looks like that's the highest precision task of that entire maneuver, the maximum error of 66.2 km from 1e10 km away comes out to 6.62E-9 radians, 220,000 times more accurate than that South African tank cannon. I used to have some info on course corrections for a satellite mission that involved lots of planet flyby's, if I can track that down and do some math I may be able to find a ballpark number for modern space trajectories to go with the modern laser range finder and gun accuracies I found.
Now we certainly wouldn't be able to get the sort of accuracy required in my above example directly out of hyperspace, but if you came out of hyperspace at around 1E10 km, and then course corrected for the next few billion kilometers, shooting at around Uranus or Neptune, then I think you'd be back in business.
Dear All,
New to Aurora forums. Been playing for a year though. Some thoughts on the matter of extreme range planetary bombardment. I don't mean to offend, but though it is an attractive option, isn't it rather impractical?
Now imagine WE'RE all hostile aliens just entering the solar system and about to target earth with extreme range ballistic bombardment. Remember we would have VERY little pre-existing astrogravitational data on the system. What? Take time off for detailed survey in a hostile system with active defenders??? Given that our firing location is just beyond the orbit of PLUTO;-
Our problems are, assuming we can even manage to LOCATE EARTH from so far away (what a miracle that was!):-
1) All newtonian sensor data is an image of the past thanks to the speed of light limit. It takes approx 4 to 7 hours for light to travel from SOL to PLUTO; but EARTH moves at approx 108,000 km/hour around the sun. Thats like a 430K km to 750K km difference by the time we are pointed at it. Sure, lets LEAD THE TARGET, but that only takes us to the next problem:-
2) To "lead" the target is difficult given the extreme time lag, because we would need to know the object's EXACT astrogravitational movements, a study that will take years (365. 25 days???) of observation. But remember, the earth MAY NOT take the EXACT SAME path around the sun for each year due to the following problem:-
3) Predicting the exact planetary orbit given its many variations due to gravitational effects from other solar system bodies and "wobbling" due to LUNA. Then you need to study the intricate sequence of planetary alignment, but planetary alignments are kinda unique each year so you would need to study and predict ALL the significant solar system bodies to predict their effects on earth orbital variations.
4) Okay now thats done, we ALSO need to factor in the gravitational effects of all those solar system bodies ON THE PROJECTILE, including all other minor bodies that are possibly in the way (planetoids, asteroid belts, comets). Assuming we've done that, next:
5) What about the effects of solar wind and its unpredictable variations blowing on the projectile? We'd have to study SOL's internal structure, internal convections, solar flares, solar spot activity. Not to mention that solar wind interaction with the magnetosphere of each major body may have a small effect. Also, we must assume that:
6) The further away the target is, the more unreliable the sensory data (degree of uncertainty increases with range). Remeber there are such things, (no matter how minute) as gravitational lensing of light rays, interference from nearby gravity centres, diffraction, echoes, interference from solar wind (and especially actively from defenders), etc. So we roughly know where a planet WAS to the nearest +/- XXX km, but that may not be precise enough.
7) Finally we'd have to hope there are no collision whatsoever (not even a glancing blow) with micrometeorites / space dust / comets / asteroids (unlikely) that will put our projectile off course. Natural stuff are easily avoided (except the space dust and small stuff), but what about:
8) The last problem is a valid counter-defense in response to any such projectiles that we might launch. Moving at relativistic speeds, even a collision with a human-seeded "cloud" of floating micro-debris in space early on is enough to veer the projectile sufficiently off-course. Heck those humans could have already pre-emptively put up millions of square kms of those defensive stuff along the "predicted" optimal line of fire the moment they detected our ships warping in-system. Remember we're fighting in THEIR territory now, an unfamiliar battleground they have extensively studied and know very well more than we do.
9) And would you think they'd just let us conduct an accurate system survey in peace? Heck, bouncing all those EM signals in every spectrum off every major solar system body , blasting and lighting us up with all sorts of EM/sensor energy. Putting up false "ghost images". Partial cloaking of earth itself? I'm sure that'd have a profound effect on the accuracy of any survey.
Better we crack out those MK III 100 MSP self-guided drone missiles with the 999 radiation yield dirty warheads??? At least their courses are self-correcting with minimal sensor time-to-target (plus other interferences to be avoided) lag.
Regards,
Sam
You don't need to sit around watching the Earth's orbit for a year to know where it's going to be. From a snapshot of the current positions and velocities of the solar system bodies, you can then just propagate out their positions from that point forward. Gravity is a well understood force, and can be easily modeled. Almost immediately after arriving in a new system you will have a very accurate measurement of that Star's mass due to measuring the change in velocity of your ship, giving you the gravity acceleration, and from their (and the distance to the sun) you have the mass.
You can similarly, trivially, and almost immediately measure the mass of any planet with a moon you find, by observing the acceleration on the moon. A slightly more thorough examination would let you find the barycenter that that planet and its moons were rotating around, which would give you the mass of all of the bodies.
The only thing that would give you trouble is a planet with no moons, in that case the only way to measure its mass (except for using our sensors which somehow actively probe and detect the gravity of all objects, which I am pretending we don't have) is to examine the wobble of the sun, which does take time. While you gather that data you'll just have to use a placeholder mass based on its size and type.
So shortly (how shortly depends on how long it takes you to find all the planets, in Aurora this has always been done instantaneously upon entering a new system) you have all the information you need to propagate all of the non-trivial gravity effects for every body in the entire system. The last bit you need is the star's luminosity so you can calculate light pressure, as well as the velocity and density of the hydrogen in the solar wind. Direct observation of the star will quickly give you that.
With this information you can begin propagating the positions of all of the planets and moons in the solar system over time. Accurately, and quickly.
I have to stress again that we do this today. We have thousands of satellites up there right now, and a lot of them have to stay in fairly particular places, or we have to know where they are, or where they are going to be. We don't have to wait until they are there, we can look at where they were in the past, and then calculate their trajectory including all of the affects that you have mentioned (and more) that you seem to think are impossible or difficult to account for.
This program: http://www.agi.com/products/by-product-type/applications/stk/stk-for-space-missions/ is one which is used to do those sorts of calculations, this is a list of the forces that it models when calculating a satellite's (Earth-orbiting) trajectory.
1. Two-body gravity
2. Gravity correction for the irregularities of the Earth's gravity field, primarily due to it being an oblate spheroid, but also due to the fact that it doesn't have a continuous density over the entire volume. This is accomplished by using corrections calculated by earlier space missions which meticulously measured the gravity over Earth. Depending on the gravity file the Earth is broken up into a couple dozen or several thousand sectors.
3. Drag, which is based on density which can be calculated in a variety of ways. The better models take into account the current strength of the magnetic field, the current solar activity, and some other variables to model how the atmosphere balloons outwards as it heats up during the day. If you really care you can also use high-altitude weather forecasts to compensate for windspeed when calculating the drag.
4. Third-body gravity from the sun and moon, and if you're really anal, Jupiter and Venus. You could do the others if you wanted to, but there is really no point.
5. The solar radiation pressure from the light emitted by the sun, as well as the solar wind. Of course this also entails modelling when you are being shaded from the sun by the Earth or the Moon.
6. The light coming from the Sun is only part of the battle, there is also a lot of light that bounces off the Earth and pushes you, and you have to measure how much light that was using the shape of the Earth and a model of its albedo.
7. It also models radiation pressure of the light being emitted by the Earth, as in the IR light being emitted as black body radiation.
8. Then you have outgassing, the mass that is from a satellites surface that throws it off course. The largest offenders of these are fuel or cryogenic tanks, which always have some amount of leakages.
9. Lastly the satellite might even have an engine, which also has to be modeled when it fires.
We've had the ability to model all of that stuff for more than 20 years, and the problem we are talking about here is way simpler, since we really just care about the sun and planet gravity. SRP is meaningless for a dense slug, and we won't be near any bodies long enough to worry about Drag or gravity field irregularities.
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As for size, given modern technology (which I know isn't true, but nuclear physics don't change) you simply can't fit a nuclear weapon in an object the size of a baseball. IIRC, that's about the size of a critical mass, not counting any explosives or anything. You'd probably need something a bit bigger. And an object that size will likely decelerate high in the atmosphere. If it doesn't, it's suspicious. And anything suspicious gets shot at.
It depends on the material (uran plutonium ...) you use and how much preasure your explosives can create if you use a nuclear shaped charge (normally its a hollow ball of your nuclear material with multiple explosive packages on its oute side). Iirc and i am no nuclear physicist higher pressures meant that you need less material for the critical mass.
The davy Crocket nuclear shell was 53 kilograms by a length of 40 cm and a diameter of 27cm (in 1950). You have a low yield though. Said shell goes to 1 Kilotons.
I would guess a shell about the size of a soccer-ball would be possible if you have modern tech and some tinkering spirit. Dont forget till 2003 it was forbidden in the USA to research mini-nukes so that we didnt see any such small nukes isnt that surprising for me.
There was also the idea (some say a idea from the ####es) of using two shaped charges (the same kind as in heat ammunition just with uranium) facing each other with tritium/deuterium in between. The high pressure and energy of the 2 uranium-streams hitting each other would have been enough to generate a short but brief fission+fusion reaction (fizzle) that boosted the yield of the explosion. Still the yield would be far lower then the yield of "Little boy". Depending on what you want to hit say just critical infrastructure like powerplants, train-stations, water-reserves or whatever it would be enough.
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It depends on the material (uran plutonium ...) you use and how much preasure your explosives can create if you use a nuclear shaped charge (normally its a hollow ball of your nuclear material with multiple explosive packages on its oute side). Iirc and i am no nuclear physicist higher pressures meant that you need less material for the critical mass.
The davy Crocket nuclear shell was 53 kilograms by a length of 40 cm and a diameter of 27cm (in 1950). You have a low yield though. Said shell goes to 1 Kilotons.
I would guess a shell about the size of a soccer-ball would be possible if you have modern tech and some tinkering spirit. Dont forget till 2003 it was forbidden in the USA to research mini-nukes so that we didnt see any such small nukes isnt that surprising for me.
And a soccer ball is a bit bigger then a baseball. Though I do question strategic warheads of that size. Antimatter, on the other hand...
What happened in 2003?
There was also the idea (some say a idea from the ####es) of using two shaped charges (the same kind as in heat ammunition just with uranium) facing each other with tritium/deuterium in between. The high pressure and energy of the 2 uranium-streams hitting each other would have been enough to generate a short but brief fission+fusion reaction (fizzle) that boosted the yield of the explosion. Still the yield would be far lower then the yield of "Little boy". Depending on what you want to hit say just critical infrastructure like powerplants, train-stations, water-reserves or whatever it would be enough.
I've heard some stuff about the #### program, but I'm not sure that was exactly how it worked, and I don't think it scales down that well. Maybe I'll look it up later.
Very true. Probably the best way to look at it is that you have launched your ship towards your target, and then the projectile you shoot is the course correction. In my above example the projectile traveled 66.2 km away from the ship after it was fired, that means that the vector of the firing ship has to pass withing 66.2 km of the target, as the largest course correction you could have would be if the ship fired at a right angle to its course. Doing the math is actually looks like that's the highest precision task of that entire maneuver, the maximum error of 66.2 km from 1e10 km away comes out to 6.62E-9 radians, 220,000 times more accurate than that South African tank cannon. I used to have some info on course corrections for a satellite mission that involved lots of planet flyby's, if I can track that down and do some math I may be able to find a ballpark number for modern space trajectories to go with the modern laser range finder and gun accuracies I found.
This is what I was talking about with the sensors. You can't expect yourself to be on a perfect intercept course. You have to determine your relative velocity experimentally, and that takes time, particularly with a passive sensor. Is putting a guidance system in the projectile really too much to ask?
As for corrections, I'll look them up in the morning. However, expect them to be absolutely negligible over a few days, particularly as most of that time is spent in deep space.
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And a soccer ball is a bit bigger then a baseball. Though I do question strategic warheads of that size. Antimatter, on the other hand...
What happened in 2003?
True put extrapolated into the future with TN tech i could see kiloton tennisballs. Every explosive is usefull exspecaily one that can obliberate a block of houses while being the size of an soccer or even baseball, its just a tool thought. Such small weapons could work well in planetary warfare if it ever gets refined.
In 2003 the US-senat removed alaw that did forbid the research and development of mini-nukes the congress though watered that down to just research. I forone think that nukes at all should be forbidden so i am not happy about it either way.
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I should have been more clear. I was comparing them to missiles.
A missile has to go out and kill its target. A fighter has to accelerate to get to the target, decelerate to a stop, then kill the target and go back to the mothership.
The statement about "less manuverable" also applied as compared to missiles. The extra mass of the human and his stuff hinders acceleration.
At medium distance, you can either evade or you can't, and there's no reason that a conventional ship couldn't if a "fighter" can.
I'm in favor of drones, but what makes a fighter is recoverability. That tacks on delta-V somewhere in the system.
well a few points on fighters one is that technically you could use theorized nuclear engines to easily power them (once miniaturized) assuming that, like conventional jet engines of today, they do not rely on a flow of particles to move the fighter. Secondly on regards to maneuverability, multiple nose and wing thrusters easily mitigate the effects of using a conventional maneuvering flap (like all planes today). Thirdly what do you think fighters are? Spacious luxury craft? They're already 98% engine.
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I just realised the targeting is more complex than I thought because the railgun projectile will have the momentum of the firing ship as well as its own velocity, which complicates the calculations. Time to learn some new maths I think :)
Steve
Finally got this sorted out. I can now predict the correct launch angle for the shot (or if the shot isn't possible) based on the heading and speed of the two ships and the speed of the projectile, taking into account the momentum of the firing ship being added to that of the projectile. The eventual solution was based on a combination of suggestions on here, on the sfconsim-l board and on the stackoverflow forum.
Essentially I looked at the shot from the frame of reference of the firing ship (idea from Isaac Kuo on sfconsim). By giving the target ship the combined vectors of both ships, I could predict the angle of a shot from a stationary firing point against a moving target using a quadratic equation provided by Jeffrey Hantin on the stack overflow forum. Then I took the x,y velocities of that shot (which is firing at the wrong place because in reality the actual target ship isn't moving with the combined vectors of both ships) and combined them with the x,y velocities of the firing ship to give me the actual x,y velocity of the projectile, including velocities from both launch angle and firing ship momentum. The addition of the firing ship momentum will now send the projectile into the path of the target ship.
This means I am going to track the projectile on the map like a missile so you can see its progress. It also means it might hit something else instead, including your own ships if you aren't careful about firing position (line of battle reborn?). If the processing overhead gets too high because of the number of projectiles I might look at this again.
Steve
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well a few points on fighters one is that technically you could use theorized nuclear engines to easily power them (once miniaturized) assuming that, like conventional jet engines of today, they do not rely on a flow of particles to move the fighter. Secondly on regards to maneuverability, multiple nose and wing thrusters easily mitigate the effects of using a conventional maneuvering flap (like all planes today). Thirdly what do you think fighters are? Spacious luxury craft? They're already 98% engine.
1. What do you mean, do not rely on the flow of particles? There are no reactionless drives planned as far as I know.
2. And maneuverability is far more then pointing the nose. It's related to acceleration.
3. Supporting a human is going to tack on at least 5 tons, if not more. And it means you absolutely have to get it back.
There are only two situations I can see any type of fighter being practical, and neither applies here:
1. A war breaks out that neither side is prepared for, so they throw some parts together to make what is basically a fighter. It's likely to be manned.
2. You have a highly effective engine that is too expensive to use in missiles. (Fusion torches spring to mind.) Instead, you use a lancer, which is almost certainly unmanned.
Steve:
Just have them go away if they miss. Space is so vast that the chances of a hit are negligible, particularly if the ship in question has any form of radar. Unguided projectiles will be harmless unless they can hem the target in, while a good guided round will either hit or be out of fuel, not to mention being "dumb".
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Well one could theorize that transnewtonian elements could be used to generate gravity fields/wells. Given that you can generate this field at some point in space you achive movement of your ship by generating a strong field somewhere right in front of you. But that gets to scifi for me. Thats the same category as riding waves of spacedistortions etc.
I could see fighters as computercontrolled drones. Like the vulturedroids in the Star wars sequells these guys thought were remotecontrolled and slowed down in the reactiontime if there were to many droids running on the same mainframe. Iirc thats why a six year old shrimp could kill that battleship.
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Well one could theorize that transnewtonian elements could be used to generate gravity fields/wells. Given that you can generate this field at some point in space you achive movement of your ship by generating a strong field somewhere right in front of you. But that gets to scifi for me. Thats the same category as riding waves of spacedistortions etc.
Steve has given no indication that he's even considering this.
Oh, and jet engines do rely on the flow of particles. They just get most of the particles from the surrounding air. I know you weren't the one who suggested it, but I thought I'd clear it up.
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If a fighter ever were to be manned, I'd expect it to be a brain hotwired to a computerframe.^^
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Steve has given no indication that he's even considering this.
Oh, and jet engines do rely on the flow of particles. They just get most of the particles from the surrounding air. I know you weren't the one who suggested it, but I thought I'd clear it up.
1. What do you mean, do not rely on the flow of particles? There are no reactionless drives planned as far as I know.
2. And maneuverability is far more then pointing the nose. It's related to acceleration.
3. Supporting a human is going to tack on at least 5 tons, if not more. And it means you absolutely have to get it back.
There are only two situations I can see any type of fighter being practical, and neither applies here:
1. A war breaks out that neither side is prepared for, so they throw some parts together to make what is basically a fighter. It's likely to be manned.
2. You have a highly effective engine that is too expensive to use in missiles. (Fusion torches spring to mind.) Instead, you use a lancer, which is almost certainly unmanned.
Steve:
Just have them go away if they miss. Space is so vast that the chances of a hit are negligible, particularly if the ship in question has any form of radar. Unguided projectiles will be harmless unless they can hem the target in, while a good guided round will either hit or be out of fuel, not to mention being "dumb".
1. A jet engine doesn't rely on atmospheric molecules to go (except for the oxygen required for ignition) therefore it is just as effective, if not more so, in space. 2. Yes quite, hence wing thrusters which can counter-act the forward force of the engine when changing direction, it would be a bit sloppy but it would theoretically work. 3. Take a que from starwars' tie-fighters the cabin doesn't necessarily have to maintain some form of homeostasis if the pilot's suit can. Now for your statements on the practical uses of fighters: a fighter is a reusable weapon with alot more damage potential then missiles, also fighters act as good defense ships, easily destroying when gathered en masse. secondly if you designed a highly expensive and/or advanced engine you wouldn't use it on a measly fighter it would go to a stealth ship or something very important or experimental. Also id like to added something someone said earlier in the topic, a fighter doesn't just stop at a ship and attack it, think of it like strafing runs every time it's ready to attack it makes a run. To Bryon now: do mean for the use of combustion or for the purpose of thrust from pushing off of them?
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1. A jet engine doesn't rely on atmospheric molecules to go (except for the oxygen required for ignition) therefore it is just as effective, if not more so, in space.
If you take a jet engine, and remove the "requirement of oxygen to ignite" you have a rocket engine. I am with Byron in being confused as to how either jet or rockets are supposed to accomplish thrust without "particle flow".
2. And maneuverability is far more then pointing the nose. It's related to acceleration.
3. Supporting a human is going to tack on at least 5 tons, if not more.
2. To expand on that, maneuverability for a "real" spaceship would be based on how quickly you could point your engine in the direction you need it (what Scoop was referring to) and then how powerful that engine is. In NA we are ignoring facing, meaning that only the second factor is important.
3. 5 tons is probably more than is really necessary for a high tech fighter. The F22 is 19tons empty, and I highly doubt that a fifth of that is life support. A high altitude fighter really has all of the life support considerations as a space ship as well, aside from radiation, and that's not too much of a penalty because high-performance electronics are even more vulnerable to radiation than humans are, so you need to shield against it regardless. In a 200-300 ton fighter the mass devoted to life support would be pretty inconsequential, the real new consideration is that you are now limited to 6-7 gs, for any length of time, and 9-10 for very short bursts. That's a pretty huge constraint on something that relies on acceleration to survive. (Of course 250 years into the game when you have genetically engineered fighter pilots that can withstand 70g's... Lol, although 250 years in the game your fighters may very well need more than that to be competitive).
This is what I was talking about with the sensors. You can't expect yourself to be on a perfect intercept course. You have to determine your relative velocity experimentally, and that takes time, particularly with a passive sensor.
I quoted an actual textbook citing today's sensor technology and used that in my example, it also just doesn't take that much time to determine this stuff.
Is putting a guidance system in the projectile really too much to ask?
It kinda sounds like you are just throwing up all sorts of objections because you really want every single projectile to have a guidance system. I know that projectiles with guidance systems are better. If you go back a couple pages I did lots of math showing how much your range was extended by launching projectiles that were guided. I am with you on the guided projectiles. That said, there are some times when you don't need guided projectiles. All I'm saying is that when you are shooting at a target that is 6378 km across and can't dodge out of the way, you don't need guided projectiles. I'm not standing here and claiming that you can snipe a 20m fighter with 10g's of acceleration from Pluto with dumb slugs, I will let you take care of that with your missiles.
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A jet engine doesn't rely on atmospheric molecules to go
*shudder* You are aware of conservation of momentum, yes?
So, then, without a mass going in the opposite direction, how do you accelerate *any* mass?
This is basic physics that even a non-physicist (like me) should be aware of.
Take a que from starwars' tie-fighters
Star Wars is hardly a source for hard science fiction.
Even if a fighter would be designed that was able to attack and return, it would better be flown by a computer.
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This means I am going to track the projectile on the map like a missile so you can see its progress. It also means it might hit something else instead, including your own ships if you aren't careful about firing position (line of battle reborn?). If the processing overhead gets too high because of the number of projectiles I might look at this again.
Steve
I would take the estimated flight time of the projectile, and calculate the trajectory for some multiple of that (with a minimum calculation time for close in fighting) this would cover most of the cases that are remotely plausible for the projectile to hit something else, firing at a ship and hitting another ship in the squadron, firing at a ship and hitting a squadron right in front of it performing missile defense, firing at a new enemy missile salvo and hitting the firing ship behind the missiles, firing at ships leaving orbit to intercept you and hitting the planet behind them.
And of course all of the vice-versas for those scenarios.
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I would take the estimated flight time of the projectile, and calculate the trajectory for some multiple of that (with a minimum calculation time for close in fighting) this would cover most of the cases that are remotely plausible for the projectile to hit something else, firing at a ship and hitting another ship in the squadron, firing at a ship and hitting a squadron right in front of it performing missile defense, firing at a new enemy missile salvo and hitting the firing ship behind the missiles, firing at ships leaving orbit to intercept you and hitting the planet behind them.
And of course all of the vice-versas for those scenarios.
That sounds like a good idea. I was trying to decide when to eliminate a projectile without waiting until it left the system :)
Steve
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Crap, I was like totally ninja'd 3 times.
Edit: 4 times.
@byron:
I've calculated it several times, and posted it; guided railgun slug would be excessively more expensive and have a higher minimum size; Thus it is likely they are not used when they don't have to be used, planetary bombardment is one of those few occasions, I mean, if you can't hit a PLANET with a slug, chances are you won't be mentally able to construct a guided projectile.^^
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First, let me make one thing clear. I'm not claiming that space fighters are completely impossible. I can come up with a few scenarios that could justify their existance (even a manned version). None of those scenarios are applicable here.
I'm claiming that they are completely impractical when judged by the following criteria. What is the most effective way, in terms of both money and firepower, to destroy the target?
1. A jet engine doesn't rely on atmospheric molecules to go (except for the oxygen required for ignition) therefore it is just as effective, if not more so, in space.
Do you really believe this? Do you have any clue as to how a jet engine works? I'm guessing no, so look it up. Please.
2. Yes quite, hence wing thrusters which can counter-act the forward force of the engine when changing direction, it would be a bit sloppy but it would theoretically work.
Yes, it is possible to turn quickly. As I recall, my original point is that a fighter is not that much more maneuverable then a larger ship. It still stands. What makes fighters possible today is that they work in a different fluid medium relative to ships. Now ask yourself when what the last time you saw a real combat speedboat. (I'm not referring to special ops stuff. A warship the size of a speedboat. And I do know about missile craft. Note that only coastal navies use them.)
3. Take a que from starwars' tie-fighters the cabin doesn't necessarily have to maintain some form of homeostasis if the pilot's suit can.
True. Now spend a couple of days in a space suit, and tell me how it feels. Not to mention that without a human, you have no acceleration limits and you can skip things like reactor shielding and all the stuff that helps the human interface with the fighter. Most of the stuff they cut out of UAVs isn't the oxygen system. It's the cockpit itself.
Now for your statements on the practical uses of fighters: a fighter is a reusable weapon with alot more damage potential then missiles,
Really? How much more damage potential? To be blunt, why add another stage, and a heavy, expensive one at that. Given that the definition of fighter includes "carried aboard a larger ship" why not instead spend the money on a missile ship and missiles? You do save some money on reusability, but there are several problems. First, a lot of the cost savings of fighters dry up when you take combat losses into account. Yes, a fighter dropping a bomb is cheaper then using a cruise missile. Provided you don't lose the fighter. Second, fighters will tend to have low throw weights. A missile ship of a given size/cost will be able to outpunch a carrier of the same size/cost's wing. And this is space. There's no such thing as maximum range.
also fighters act as good defense ships, easily destroying when gathered en masse.
Could you explain this better? It sound like "if you have enough fighters, you can destroy stuff easily". The same is true of any warship. We're comparing fighters to those other designs on a mass/cost basis.
secondly if you designed a highly expensive and/or advanced engine you wouldn't use it on a measly fighter it would go to a stealth ship or something very important or experimental.
What? You completely missed the point. Let's say that we're using magnetic-confinement fusion, and the torches are very high-performance, but also have a fairly high minimum size and are expensive. You simply can't put one on a missile. However, the performance is too good to let it go, as the new drive renders chemfuel missiles useless. So you strap a bunch of kinetics to a torch, and you have a lancer. It's used like a fighter, because you have to try to bring the engine back, and the performance is good enough to justify that. I'm not sure how to explain it any better.
Also id like to added something someone said earlier in the topic, a fighter doesn't just stop at a ship and attack it, think of it like strafing runs every time it's ready to attack it makes a run.
Do you have any idea what we're talking about? This is Newtonian Aurora. By definition, multiple strafing runs are out. Why? Because they're far less efficient then one strafing run. If you have a set amount of delta-V, it behooves you to use as much as you can at once.
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To the various people who keep advocating unguided weapons for planetary bombardment:
Yes, it is possible to hit a planet from way out with an unguided weapon. The question is why? To do damage to a planet-sized target, you're looking at throwing asteroids. Normal railgun rounds are going to be next to useless, unless you use them in the same mass as the previously-mentioned asteroid.
So if you're going to do it, use nukes. You could probably end civilization as we know it by nuking the biggest 10 cities on the planet with a few megatons each. Drop those same 10 few megatons on random spots, and we just get mad. (Presuming we have the tech to respond). Trying to use unguided weapons on a planet is less efficient (provided you want to remove the occupants as a threat, not xenocide them) then doing so with guided weapons.
All I'm saying is that when you are shooting at a target that is 6378 km across and can't dodge out of the way, you don't need guided projectiles.
This is entirely true. However, you will never be shooting at the earth as a whole. At least not under the circumstances given.
I've calculated it several times, and posted it; guided railgun slug would be excessively more expensive and have a higher minimum size; Thus it is likely they are not used when they don't have to be used, planetary bombardment is one of those few occasions, I mean, if you can't hit a PLANET with a slug, chances are you won't be mentally able to construct a guided projectile.^^
I'm not so sure about excessively more expensive. It will be more expensive, but if it costs 5x as much, and is 10x as effective (not to mention needing smaller magazines) then it's still worth it. The only time unguided rounds will be used is when the kill radius is larger or similar in size to the CEP. And that means you need a planet-sized kill radius.
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Normal railgun rounds are going to be next to useless, unless you use them in the same mass as the previously-mentioned asteroid.
Well, unless guided rounds get cold gas for drives, they're going to be visible. More visible at least.
They just have to be "beneath notice" until they hit the atmosphere. At which point, given they are travelling at a few kkm/s, it's too late.
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First, let me make one thing clear. I'm not claiming that space fighters are completely impossible. I can come up with a few scenarios that could justify their existance (even a manned version). None of those scenarios are applicable here.
I'm claiming that they are completely impractical when judged by the following criteria. What is the most effective way, in terms of both money and firepower, to destroy the target?Do you really believe this? Do you have any clue as to how a jet engine works? I'm guessing no, so look it up. Please.
Yes, it is possible to turn quickly. As I recall, my original point is that a fighter is not that much more maneuverable then a larger ship. It still stands. What makes fighters possible today is that they work in a different fluid medium relative to ships. Now ask yourself when what the last time you saw a real combat speedboat. (I'm not referring to special ops stuff. A warship the size of a speedboat. And I do know about missile craft. Note that only coastal navies use them.)
True. Now spend a couple of days in a space suit, and tell me how it feels. Not to mention that without a human, you have no acceleration limits and you can skip things like reactor shielding and all the stuff that helps the human interface with the fighter. Most of the stuff they cut out of UAVs isn't the oxygen system. It's the cockpit itself.
Really? How much more damage potential? To be blunt, why add another stage, and a heavy, expensive one at that. Given that the definition of fighter includes "carried aboard a larger ship" why not instead spend the money on a missile ship and missiles? You do save some money on reusability, but there are several problems. First, a lot of the cost savings of fighters dry up when you take combat losses into account. Yes, a fighter dropping a bomb is cheaper then using a cruise missile. Provided you don't lose the fighter. Second, fighters will tend to have low throw weights. A missile ship of a given size/cost will be able to outpunch a carrier of the same size/cost's wing. And this is space. There's no such thing as maximum range.
Could you explain this better? It sound like "if you have enough fighters, you can destroy stuff easily". The same is true of any warship. We're comparing fighters to those other designs on a mass/cost basis.
What? You completely missed the point. Let's say that we're using magnetic-confinement fusion, and the torches are very high-performance, but also have a fairly high minimum size and are expensive. You simply can't put one on a missile. However, the performance is too good to let it go, as the new drive renders chemfuel missiles useless. So you strap a bunch of kinetics to a torch, and you have a lancer. It's used like a fighter, because you have to try to bring the engine back, and the performance is good enough to justify that. I'm not sure how to explain it any better.
Do you have any idea what we're talking about? This is Newtonian Aurora. By definition, multiple strafing runs are out. Why? Because they're far less efficient then one strafing run. If you have a set amount of delta-V, it behooves you to use as much as you can at once.
1. you're right
2. you're right
3. why would pilots spend 3 days in a spacesuit? if it was a long-rane exploratory fighter or something or other it would be designed wth that in mind.
4. Basically over time and as technology advances a fighter would be able to care more munitions than a single rocket.
5. basically fighters are a cheap area defense craft easily based at pdc's
6. once again, you're right, I guess i misinterpreted the statement
7. I didn't necessarily mean more than one run per payload, I was stating how the attack happened. I believe someone stated that a fighter works by going to within firing range of a ships, firing, then going back.
also sorry for giving short answers my pc is acting up again.
also should this whole fighter subject have its own topic?
finally, even if fighters aren't 'practical' will they be possible in newtonian aurora?
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Well, unless guided rounds get cold gas for drives, they're going to be visible. More visible at least.
They just have to be "beneath notice" until they hit the atmosphere. At which point, given they are travelling at a few kkm/s, it's too late.
Um, if they go into atmo at that speed, they explode harmlessly. An object entering at 100 km/s ablates at 200m/s. I shudder to think about what 1000km/s will do.
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Well aiming at planets with railguns makes sense when the planet has stuff that orbits it. I for once would like to have railgun-armed satelites up there. Altought the orbiting code would have to be rewritten. Shipyards, terraformers, massdrivers (last line of defense?) and Observatories come also to mind.
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Um, if they go into atmo at that speed, they explode harmlessly. An object entering at 100 km/s ablates at 200m/s. I shudder to think about what 1000km/s will do.
They have handwavium heat shields. Duranium armour is what... 1 inch thick? And it can survive a size 1 contact nuke (2.5ton TN warhead) to protect whatever is behind it.
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I'm not so sure about excessively more expensive. It will be more expensive, but if it costs 5x as much, and is 10x as effective (not to mention needing smaller magazines) then it's still worth it. The only time unguided rounds will be used is when the kill radius is larger or similar in size to the CEP. And that means you need a planet-sized kill radius.
From a few pages back:
Cost of a Sidewinder Missile: ~85k $. Cost of a 80kg chunk of pure Iron: roughly 6k $ (actually a bit less). Foolproof radarguidance seekers are quite probebly 10x the cost of an old IR missile.
Now, let's ignore what else I wrote there and do a proper calculation:
The price of the "Missile" is dependent on several factors of technological advance:
1. It's a bit cheaper due to replacing the explosive with solid metal.
2. The electronics are going to be a LOT more sophisticated, and expensive, as we'll need to miniaturize them; 85kg is too big.
3. Fuel efficiency can be expected to go up drastically, so more space for the above.
Let's assume for now that all of the above +material savings cancel each other out, so the missile would still be around 80k$
4. We need to develop a suitable electromagnetic shielding to prevent the insane Electric field of a Railgun able to accelerate an 8kg projectile to 50+kps in a timeframe measured in nanoseconds.
While this will be food for thought, let's still assume it adds nothing to the cost AND still allows the projectile to actually track anything.
5. With technological advance, production might get streamlined (though we're already basing this off a missile in production for over 50 years), let's reduce the assumed cost by another fourth, which would be roughly 60k $.
After expending it's fuel, the projectile will very likely still have more than 7500 grams of impact weight, a bit less than a solid slug, which would probably be a bit more dense and thus the same railgun could fire a heavier unguided slug, but I'm not too sure about the mechanics, so I'll ignore this altogether, correct me if I make wrong assumptions.
Now, I compare this guided projectile to a simple 8kg slug of iron, or let's use one of the handwavium materials, and assume it's a bit more expensive, like, exactly 600$ for 8 kg (yes, I bend the numbers a bit for easier calculation, but so far not in my favor as far as I can see).
In direct comparison, we can now assume that a guided slug is roughly 100x more expensive than an unguided projectile.
Don't get me wrong here, please, I still think that this would absolutely be worth it, even if it's just 10x more efficient, the higher killspeed and reliability would indeed be worth it in a fleet battle, and one can assume that a single railgun of that size would cost upwards of 10 Millions, maybe more in the range of 50.
However, there's two other paths the thread:
First, for planetary bombardment, I can see that commanders would avoid what essentially amounts to shooting money at the enemy.
Second, the biggest cost factor, and at that calibre also a significant size and low firerate, would be the railgun.
The War Ministry could probably save a lot by building a ship roughly half the size, let it accelerate for a day, and instead fire those projectiles from box launchers;
Which offers the additional benefits of less size restrictions, and less required electronic shielding on the projectile.
I'm not advocating against guided rounds, I'm advocating against railguns for dispensing them in medium range battles.
Other stuff:
@jseah:
Look thorugh this thread for the new armor and nuke mechanic.
Armor will be 1 cm/ layer now, and a 1 ton contact nuke would probably evaporate a capital ship.
Though I'm really looking forward to realistic atmospheric mechanics; While this will mean more weapons can do harm in an earth atmosphere, it will probably also mean that against thinner atmosphere, those weapons will do less;
Also, do planets have a proper size, now that ranges seem to calculated in meters instead of 10000 km?^^
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Well aiming at planets with railguns makes sense when the planet has stuff that orbits it. I for once would like to have railgun-armed satelites up there. Altought the orbiting code would have to be rewritten. Shipyards, terraformers, massdrivers (last line of defense?) and Observatories come also to mind.
But they are not the size of a planet. You will target those separately. Again, unguided weapons will only be used when the CEP is of the same order of magnitude as the lethal radius. I still have nothing short of asteroids/nukes where that is remotely true.
They have handwavium heat shields. Duranium armour is what... 1 inch thick? And it can survive a size 1 contact nuke (2.5ton TN warhead) to protect whatever is behind it.
These are of almost the same order of magnitude (I'll look it up later). And those mechanics have changed.
UnLimiTeD:
I'm thinking of the most basic IR guidance system possible, working on CBDR principles. If you design the thing from the start for mass production, and build it cheap, I think your costing is quite high, at least by a factor of 5 or so. That's just a guess, however.
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As said, an AIM-9 Missile costs over 80k $, and those have been in massproduction for over 50 years now; I can't believe they could be produced much cheaper and no one has done it by now.
Such a thermal guidance can be shut down by a single flare, those simple systems are nearly useless in modern aerial warfare, if every opponent was on todays tech level.
I mean, those are over 50 year old tracking systems, and we'd have to get that simple technology down in size by a factor of 10, and shield them against several mj of electrical current; I don't get how it could get any cheaper.
A GUIDED round would be a lot cheaper, yes. But that also gives your opponent a valid target id, and requires an active firecontrol to keep connection with the projectile, which results in limited range.
Why not just omit the railgun?
Sure, less power, but also drastically cheaper, and around 10x the salvo size. For stationary targets, it's as good as it gets. Hell, you could empty your toilet in that direction.
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You can build these weapons cheaper. It does not make sense though because research and re-eqiment costs would be massive. The machines, computers heck it even goes down to the weapon-platforms like the older Phantoms and harriers would have to be changed. Its more a case of "never change a running system". Take a completly new IR sensor, sure it has more range has a better resolution etc. but it has tradeoffs and these even if they are small can be substantial. This new sensor might need a different current so you change the board layout to get that. The new power-lines and the size/weighting difference of the chip need you to recalculate the weight-profile of the rocket, half the algorithms might be changed so your rocket still hits. Furthermore the software might be incompatible, the higher resolution of the sensor might not even bring a benefit if your cpu cant handle its precision. I could go on.
Another thing is that you to mass-produce order in Bulk. Or atleast that is how it was done 50 years ago. This has the advantage that you may have stocked 3 Million IR sensors. same goes for other parts. And since they did cost you money you build as many weapons as possible from them. A dollar in the hand is still better then a dollar wasted on recycling. As long as people buy your bombs.
And the bulk of the money goes iirc anyway into the explosives and the fuel.
Every modern lowclass car has more and better tech and manufacturing behind hit then your 80K missile but in the end it makes no difference.
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As said, an AIM-9 Missile costs over 80k $, and those have been in massproduction for over 50 years now; I can't believe they could be produced much cheaper and no one has done it by now.
That depends on the magnitude of the production. The AIM-9X seemed to be at about 600/year. Given that 600 rounds might be a single ship's load, you would be producing a lot more. And length of production has very little to do with it, as most upgrades reset the clock on it.
Such a thermal guidance can be shut down by a single flare, those simple systems are nearly useless in modern aerial warfare, if every opponent was on todays tech level.
I mean, those are over 50 year old tracking systems, and we'd have to get that simple technology down in size by a factor of 10, and shield them against several mj of electrical current; I don't get how it could get any cheaper.
The 50s version, yes. The modern version, not so much. I perhaps oversimplified it. However, I don't see the system taking anything more then today's sidewinder, and we're looking at decades if not centuries of improvements in computers. I'd estimate the guidance system at less then $1000. As for the rest of the stuff, it's pretty much a tank of gas, some tubing, and some valves. Shielding would cost, but Faraday cages are quite effective.
A GUIDED round would be a lot cheaper, yes. But that also gives your opponent a valid target id, and requires an active firecontrol to keep connection with the projectile, which results in limited range.
True. But for medium-short ranges, it might be quite effective.
Why not just omit the railgun?
Sure, less power, but also drastically cheaper, and around 10x the salvo size. For stationary targets, it's as good as it gets. Hell, you could empty your toilet in that direction.
I'd think you might want a little bit of delta-V. Getting your ship pointed just so would be a pain.
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Do you really believe this?
Do you have any clue as to how a jet engine works?
Do you have any idea what we're talking about?
While the above is extremely mild by the standards of most internet forums :), for the Aurora forums this might be construed as getting slightly personal. Lets keep everything perfectly civil, even if you believe someone doesn't understand some of the principles involved in the discussion.
Steve
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To the various people who keep advocating unguided weapons for planetary bombardment:
Yes, it is possible to hit a planet from way out with an unguided weapon. The question is why? To do damage to a planet-sized target, you're looking at throwing asteroids. Normal railgun rounds are going to be next to useless, unless you use them in the same mass as the previously-mentioned asteroid.
So if you're going to do it, use nukes. You could probably end civilization as we know it by nuking the biggest 10 cities on the planet with a few megatons each.
Pretty much this entire post confuses me. When you talk about "doing damage to a planet sized target" it makes me think that you are talking about actually breaking the planet into a bunch of pieces Death Star style. We are just talking about making the biosphere unlivable for the current unpleasant occupants.
You compare normal railgun rounds to asteroids, and describe railgun rounds as "completely useless", however the typical railgun slug we have been talking about has been 1 kg, and a sizable--but not enormous-- asteroid could mass 200 million times that much. Maybe we can explore projectiles in between those two extremes?
The jump from here to choosing nuclear explosions as your weapon of choice is odd, the fact that you speak of "a few megatons" as something catastrophically powerful that would end civilization with a couple applications is just weird when juxtaposed with your dismissal of gigaton kinetic impacts in the paragraph before.
As an example if you take the impact effects site posted Elouda posted ( http://impact.ese.ic.ac.uk/ImpactEffects/ ). If we plug in a 10.6 meter diameter iron meter going 15,000 km/s (I keep using that speed because it is a very comfortable attack speed for the low-tech example destroyer Daring) we get a projectile that masses 5 tons, equivalent to a size-2 missile. According to the site this projectile explodes as a 60 Gigaton airburst. Also according to this site this will pretty much demolish any building and kill most people within 100 km, but it will continue doing damage out past that.
Now lets talk more about this site, I read the included research paper so that I could understand why the results it was giving me didn't seem destructive enough. We go beyond the bounds of what these equations can do in a couple of ways. The big one is that all of the equations for how strong projectiles are and how easily they break up are based off of meteors. Even iron meteors aren't going to be as strong as machined iron, there are going to be all sorts of imperfections in these naturally occurring objects that cause them to break apart faster than a slug of manufactured Iron, let alone manufactured Steel, or Tungsten, or Uranium, or Duranium. (Protip, in the paper they state that the relationship between density and structural strength they use comes from these meteors, they say that it is only accurate for up to the 8000 kg/m3 iron density, so plugging in Tungsten densities (19300) or other materials won't be accurate).
Obviously a railgun slug would be much more durable than a meteorite, especially one made out of TN materials, so it would start breaking up far later than calculated by this site. The next problem is that they don't model anything after the airburst. Roughly half of the energy of an incoming object is expelled by the airburst, in a more typical collision, (for example our 5 ton iron meteorite at 50km/s) the remaining portion of the energy is only .6 Megatons of explosives, a fairly useless amount of energy when you are spreading it over 7-8 km drop zone. However when you are talking about a 15000 km/s entry you can no longer just ignore that energy, it's another 60 Gigatons in the strewn field, at that point all of the fireball effects are still going to occur, however at the site it doesn't model any impact or fireball effects if there is an airburst.
So that site gives a 5000 ton projectile a 60 Gigaton explosion, and there are many ways in which that's an extremely conservative estimate. I don't understand why sending a similar 5000 ton projectile to impart a 10 megaton explosion is a more desirable alternative.
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Pretty much this entire post confuses me. When you talk about "doing damage to a planet sized target" it makes me think that you are talking about actually breaking the planet into a bunch of pieces Death Star style. We are just talking about making the biosphere unlivable for the current unpleasant occupants.
I understand that, and if that really is your goal, that is fine. However, ecocide is kind of extreme. I will admit that it can be done with less mass then I believed, but it's still the only practical use of this technique.
The jump from here to choosing nuclear explosions as your weapon of choice is odd, the fact that you speak of "a few megatons" as something catastrophically powerful that would end civilization with a couple applications is just weird when juxtaposed with your dismissal of gigaton kinetic impacts in the paragraph before.
What I said was that putting a few megatons on Earth's major cities would probably end civilization, while normal railgun rounds (which are going to be high-atmosphere kiloton to megaton range airbursts) are not going to do much. Even the below-mentioned calculation would be pretty much pointless if it hit something like 80-85% of Earth's surface. Over water, it might sink a few boats, but given breakup at 20 kilometers, I don't even know how much tidal wave there would be. If it hits a desert, there would be bad climatic effects, but no mass death. It works a lot better if it detonates over New York.
As an example if you take the impact effects site posted Elouda posted ( http://impact.ese.ic.ac.uk/ImpactEffects/ ). If we plug in a 10.6 meter diameter iron meter going 15,000 km/s (I keep using that speed because it is a very comfortable attack speed for the low-tech example destroyer Daring) we get a projectile that masses 5 tons, equivalent to a size-2 missile. According to the site this projectile explodes as a 60 Gigaton airburst. Also according to this site this will pretty much demolish any building and kill most people within 100 km, but it will continue doing damage out past that.
It will not kill most people. 5psi is a good estimate for destroying buildings. I duplicated this, and got 17 psi. That is nowhere near lethal. It would destroy the area, but everyone would not be dead.
Now lets talk more about this site, I read the included research paper so that I could understand why the results it was giving me didn't seem destructive enough. We go beyond the bounds of what these equations can do in a couple of ways. The big one is that all of the equations for how strong projectiles are and how easily they break up are based off of meteors. Even iron meteors aren't going to be as strong as machined iron, there are going to be all sorts of imperfections in these naturally occurring objects that cause them to break apart faster than a slug of manufactured Iron, let alone manufactured Steel, or Tungsten, or Uranium, or Duranium. (Protip, in the paper they state that the relationship between density and structural strength they use comes from these meteors, they say that it is only accurate for up to the 8000 kg/m3 iron density, so plugging in Tungsten densities (19300) or other materials won't be accurate).
Obviously a railgun slug would be much more durable than a meteorite, especially one made out of TN materials, so it would start breaking up far later than calculated by this site. The next problem is that they don't model anything after the airburst. Roughly half of the energy of an incoming object is expelled by the airburst, in a more typical collision, (for example our 5 ton iron meteorite at 50km/s) the remaining portion of the energy is only .6 Megatons of explosives, a fairly useless amount of energy when you are spreading it over 7-8 km drop zone. However when you are talking about a 15000 km/s entry you can no longer just ignore that energy, it's another 60 Gigatons in the strewn field, at that point all of the fireball effects are still going to occur, however at the site it doesn't model any impact or fireball effects if there is an airburst.
So that site gives a 5000 ton projectile a 60 Gigaton explosion, and there are many ways in which that's an extremely conservative estimate. I don't understand why sending a similar 5000 ton projectile to impart a 10 megaton explosion is a more desirable alternative.
I really question if a site like that can properly model what is going on. The calculator in question is designed to model asteroid impacts, which, IIRC are generally below 50 km/s. It is not built to deal with an object entering the atmosphere at .05 C. From what I understand (http://www.rocketpunk-manifesto.com/2010/09/space-warfare-xii-surface-warfare.html?showComment=1286896414619#c7359830619437874742) an object entering at 100 km/s will have about 240 m ablated before it hits the ground. Assuming it doesn't break up. I have no idea how something at 15,000 km/s behaves, but it isn't going to be "an asteroid at 50 km/s but a lot faster".
While the above is extremely mild by the standards of most internet forums :), for the Aurora forums this might be construed as getting slightly personal. Lets keep everything perfectly civil, even if you believe someone doesn't understand some of the principles involved in the discussion.
Steve
My apologies. I could not believe that someone thought a jet engine was reactionless.
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*sigh* I won't continue past this but I did not believe that, I thought that a jet engine did not require anything past oxygen for ignition, I took our advice and looked it up, obviously I was wrong and I apologize for responding without knowledge, but regardless my point was that a capable space fighter engine could be built.
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Completely different question, and I don't know if it's come up in the thread already: Are NPRs still going to have infinite fuel in this? It's not that big a deal in normal Aurora, but it seems like a gamebreaking advantage here. Of course, the combat AI will probably be even more exploitable than it is now, but I don't think forcing the player to use AI exploits to stay competitive is a good idea.
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Completely different question, and I don't know if it's come up in the thread already: Are NPRs still going to have infinite fuel in this? It's not that big a deal in normal Aurora, but it seems like a gamebreaking advantage here. Of course, the combat AI will probably be even more exploitable than it is now, but I don't think forcing the player to use AI exploits to stay competitive is a good idea.
The AI will be keeping track of fuel. Otherwise, as you say, they would have a completely unrealistic advantage.
Steve
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Cross-post from the fighters thread:
Yonder has pointed out that the engines in Newtonian Aurora are so efficient their exhaust velocity exceeds the speed of light. The reason that this issue has arisen was that I was using standard Aurora as a baseline for likely speeds when instead I should have been looking at the physics involved from scratch. After further reflection, it occured to me that if I restricted the game to exhaust velocities below the speed of light, which is only reasonable in a game where realistic physics are supposed to be important :), it would actually slow everything down without having to change engine thrust. This is relatively straightforward as I just need to change the fuel efficiency tech line and adjust accordinly. I have therefore ensured that the most efficient possible engine at max tech level does not have an exhaust velocity beyond that of light speed and have worked backwards from there.
Fuel consumption has increased by 10x at low tech levels and 15-20x at higher tech levels (compared to before). Which means for the same amount of fuel a ship's Delta-V budget has dropped by 90%. Obviously, this will have a significant impact on the game. It also solves some of the issues around very high speed kinetic impacts (which were devastating because I was breaking the laws of physics in terms of how easily ships could achieve very high speeds :))
Steve
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Cross-post from the fighters thread:
Yonder has pointed out that the engines in Newtonian Aurora are so efficient their exhaust velocity exceeds the speed of light. The reason that this issue has arisen was that I was using standard Aurora as a baseline for likely speeds when instead I should have been looking at the physics involved from scratch. After further reflection, it occured to me that if I restricted the game to exhaust velocities below the speed of light, which is only reasonable in a game where realistic physics are supposed to be important :), it would actually slow everything down without having to change engine thrust. This is relatively straightforward as I just need to change the fuel efficiency tech line and adjust accordinly. I have therefore ensured that the most efficient possible engine at max tech level does not have an exhaust velocity beyond that of light speed and have worked backwards from there.
Fuel consumption has increased by 10x at low tech levels and 15-20x at higher tech levels (compared to before). Which means for the same amount of fuel a ship's Delta-V budget has dropped by 90%. Obviously, this will have a significant impact on the game. It also solves some of the issues around very high speed kinetic impacts (which were devastating because I was breaking the laws of physics in terms of how easily ships could achieve very high speeds :))
Steve
Due to this change I have increased FTL speed multipliers by 5x on the basis that overall speeds will be much lower. I have also slowed research and shipbuilding a little as expansion is going to take a lot longer than before. I'll probably make some other economic changes as well to simulate the slower overall growth compared to standard Aurora
Steve
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I think I'm going to miss In-System Hyperdrives. ::)
But that'll certainly improve combat.
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Is the fuel power/efficiency algorithm going to remain the same?
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Is the fuel power/efficiency algorithm going to remain the same?
Yes, that will remain the same. I have started replacing the term "Base Fuel Efficiency" with "Fuel Consumption per MN per hour". They are both the same thing but the latter is more descriptive.
Steve
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That is going to change things quite a lot!
Would it be worth having a look at engineering spaces and ship endurance as well. I can see a need for ships to be able to go longer between refits with these changes.
So I take it this will also significantly slow down missiles and make slug throwers and lasers even more balanced
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That is going to change things quite a lot!
Would it be worth having a look at engineering spaces and ship endurance as well. I can see a need for ships to be able to go longer between refits with these changes.
So I take it this will also significantly slow down missiles and make slug throwers and lasers even more balanced
It may not slow missiles down as much as you might think. Mainly because acceleration rates haven't changed and missiles will be used at relatively short distances (compared to the distances that ships will travel) so while it will limit the top speed of missiles overall, it may not limit them very much within likely engagement ranges because they were unlikely to reach their theoretical top speed anyway, unless used at extreme range.
Slug throwers and lasers will certainly be more effective overall though because average ship speeds will drop dramatically, making them far easier to hit.
Steve
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But in turn take less damage from kinetic projectiles.
Any plans on having a Fuel compression tech line?^^
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I don't think it will affect missiles that much, the example missiles that I was working with when I wrote that script calculating hit chances ended up with burn durations far less than the expected flight time of the missiles. (Although part of that was because flight times were shorter because the enemies were approaching at .05c).
The only time when this will really change missile behavior that much is probably very long distance sniping, where you may have been able to burn for the week or two required to get up to speed.
But in turn take less damage from kinetic projectiles.
Any plans on having a Fuel compression tech line?^^
Hmm... That tech line wouldn't do all that much, as ships are designed based on mass, not volume, so making the fuel denser wouldn't change anything. With one exception... The size of the ship actually does matter now for getting hit. If a ship had 50% fuel by mass (or more) then you may start getting noticeably smaller ships with denser fuel. (This may have minor benefits in decreased armor weights as well).
However I don't think you'd get a very noticeable affect this way, since the doubling the density of the fuel would halve the volume, but that would only shrink the length of the ship devoted to fuel by .125%, and in 2-D space the odds to hit you are based off of the length of your ship, not its cross-sectional area.
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I think I'm going to miss In-System Hyperdrives. ::)
Speaking of which, will it be possible to hyper from one star of a binary system to another, if they're small and distant enough that their hyper limits don't overlap?
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Steve, in NA could you change some of the names of stats to match scientific notation? For example right now in Aurora your "Engine Efficiency" stat is actually a consumption, though looking in the just posted Rules thread it seems like you may indeed have changed that to Consumption in NA.
You do, however have "Engine Power" which is actually a thrust. I noticed this because I was trying to calculate the power output of the engines in order to compare them to the power required to fire weapons, I was just wondering how much higher performance our engines would be than the rest of the craft.
BTW, looking at the latest Resolution:
Ve = 27070 km/s
Thrust = 22.5MN
Engine Energy: 3.04 E8 MW
Reactor Energy: 1.38 E3 MW
Engine/Reactor Ratio = 2.2E5
Now that seems like a pretty huge discrepancy, but rockets produce crap tons of energy, way more than could safely harnessed for any other purposes other than movement, so it's not the same as comparing a car or ship or an aircraft. We can compare it against another spacecraft though!
SpaceShuttle:
Ve = 4.423 km/s
Thrust = 6.51 MN
Engine Energy = 1.44 E4 MW
Reactor Energy = .021 MW
Engine/Reactor Ratio = 6.9E5
Wow, I was actually not expecting anywhere that close to a match. Obviously there is a huge amount of wiggle room for something like this, I was just hoping that the ratios would be within two orders of magnitude of each other, and they totally are, so sweet. (Of course comparing the ratio of specific power, or power/mass of the reactor/engine, would be more illuminating, but unnecessary IMO. I also can't do that anyways because I don't know the mass of the Resolution's Reactor and Engines.
Speaking of that rule page, I'm really glad to have it because I have been bouncing all around the different threads looking for your mechanics and design examples. Could you post the most recent variants of the Daring, Resolution, the Fighter, and those missiles you designed to the Rules thread as well?
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Yes, I have changed to fuel consumption per MN per hour rather than engine/fuel efficiency. As you mentioned, I really should change Engine Power to Thrust as well.
Steve
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Thrust can be increased by up to 300% of normal and decreased to 10% of normal if you have the prerequisite techs.
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Fuel Consumption per MN +300%, you would have something similar to the FAC engine in Aurora
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I've two question on engines, based on those lines:
does the tech requirement means that FAC engines are available only much later in game now? they become comparable only at the max tech, if that +300% is indeed the max researchable.
what about comparable fighter engines thrust?
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I've two question on engines, based on those lines:
does the tech requirement means that FAC engines are available only much later in game now? they become comparable only at the max tech, if that +300% is indeed the max researchable.
what about comparable fighter engines thrust?
A FAC Engine doesn't exist as such any more but you can produce an engine with double normal thrust when you research the "Max Engine Thrust Modifier +100%" tech, which is 15,000 RP. The fighter equivalent would be the "Max Engine Thrust Modifier +200%" tech, which is 60,000 RP. The fuel consumption multiplier penalties in Newtonian Aurora are much lower than in Standard Aurora.
This may not be as significant as issue as you might think. I would suspect that designing a fighter will be a balance between high acceleration and an acceptable Delta-V budget, so you may not want the max engine boost anyway. In fact, you might design a small, long endurance 'fighter' with an engine that has a negative thrust modifier.
Steve
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Steve can yo outline how NPR will make decissions on the size of theyr engines and weapons? Ai is a small hobby of mine so it would be pretty nice to know how they wll handle this "problem".
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You say that the current FTL rules are that you come in between 100% and 110% of the hyper limit if the system is surveyed, and within 100% and 170% of the system if it isn't surveyed.
What do you think of having a target radius instead? So if you ordered the ship to jump to 3x the hyper limit it would come in from 295-305% for a surveyed system, and 265-335% for a non-surveyed system.
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I suspect that Tankers will play a much larger role in the game now.
Still hoping for either a component miniaturization tech line, or at least for an independant research line for Tractor Beams, with successive tech levels reducing the size/mass of the Tractor Beam equipment.
... I'm thinking primarily of Tractor-locked, jettisonable fuel pods, at this point.
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And right as I posted that you added another post to the rules page.
Re-reading your Railgun rules I realized that your heat-dissipation mechanics were a little contrary to "real life".
The heat generated by each railgun shot which needs to be dissipated is currently equal to the power of the railgun. If I read you right a 1000 MJ railgun with 25% efficiency would generate 1000 MJ of heat which needed to be dissipated. The way to do that which would be more realistic is to have the waste energy be the component that heats the railgun. That way in the above case the railgun draws 4000 MJ from the homopolar batteries, transfers 1000 MJ of that to the projectile, and the remaining 3000 MJ heats the railgun and needs to be dissipated.
If you did this there would now be two techniques which increased the rate of fire, the Heat Dissipation Rate and the Efficiency. For example lets say that our railgun dissipates 100 MW, in the above 25% efficiency scenario it would take 30 seconds to fully dissipate and be ready to fire. If you then increased the efficiency to 30% you now only pull 3333 MJ from the batteries, not only that, but you only heat your railgun with 2333 MJ, meaning that you are now ready to fire in 23.3 (25 in the game) seconds.
If you did this though you may want to cap the efficiency techs at below 100% though, otherwise you won't be producing any heat and your railguns will be able to fire as quickly as you can push power into them (which may not be a bad thing, gameplay-wise).
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And more rule postings to re-read!
Have you thought about having a "Shield Hardness" tech line for the point strength? Instead of having the rule that "200 m2 of shield contributes to each single hit", that 200 could be a quantity improved with research. Maybe at first the shields energy can only travel from the closest 100m^2, up farther and farther and farther.
Another question on the Point strength. Is the equation MaximumShieldEnergy * 200 / ShieldSA, or CurrentShieldEnergy * 200 / Shield SA. In other words, during a fight if the 'Total Shield Strength' has been weakened by 50%, has the 'Point Shield Strength' gone done by half as well?
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Hmm, wouldn't that mean that shields never deplete?^^
Also,
5250 MJ Shield Generator
Maximum Shield Strength: 5,250 MJ
Maximum Recharge Rate: 12.5 MJ/s Minimum Recharge Time: 420 seconds
Cost: 10.5 Crew: 3 HTK: 1
Materials Required: 10.5x Corbomite
Development Cost for Project: 1050RP
As far As I've read, shields gain a bonus of 1% per ton, so shouldn't this one, at 200 tons and the tech specified on that page before, have 6000 MJ of Power?
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Are you planning a "Linear Accelerator" installation, that could be constructed at airless bases (eg: Luna, or Asteroids) to augment the Delta-v of small ships and Fighters?
It could have a tonnage limit based on size (ie: on the number of installation levels), and a MN limit based both on size and on the available energy from the base's reactors.
This idea would allow the construction of more effective dedicated Fighter Bases, but could not be easily adapted to Carriers... thus giving LBA (Land Based Air) its traditional historical advantage over NA (Naval Aviation).
Also,As far As I've read, shields gain a bonus of 1% per ton, so shouldn't this one, at 200 tons and the tech specified on that page before, have 6000 MJ of Power?
1% per 10 tons.
Each 10 ton increment adds a 1% bonus to maximum shield energy...
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You have 'Align To and Jump' command, will you also have an 'Align To' command as well?
Or maybe have a conditional order that is 'Align To xx'. That way you could be in combat outside the hyper limit being chased, so you align out but keep on fighting until the last moment - then jump out.
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A lack of survey information could also result in the ship arriving slower or faster than expected, although within 30% of departure speed, and correspondingly earlier or later than expected. Because the ship is out of contact, you will be unable to determine the likely arrival point ahead of its arrival
This could make an interresting gamble for operations where time is crucial. The abillity to be at a destination before you actually should arrive there is pretty valueable. Depending on distance it might mean that you can get hours if not weeks of additional time out of a jump. This could be used for a number of things.
Steve will shields/armor acount the solar-wind? As in would getting to near to a star vaporize your armor/shields?
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Steve can yo outline how NPR will make decissions on the size of theyr engines and weapons? Ai is a small hobby of mine so it would be pretty nice to know how they wll handle this "problem".
I haven't even thought about it yet. I think I will probably scrap the code I already have in terms of NPR ship design and start from scratch :).
Steve
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And right as I posted that you added another post to the rules page.
Re-reading your Railgun rules I realized that your heat-dissipation mechanics were a little contrary to "real life".
The heat generated by each railgun shot which needs to be dissipated is currently equal to the power of the railgun. If I read you right a 1000 MJ railgun with 25% efficiency would generate 1000 MJ of heat which needed to be dissipated. The way to do that which would be more realistic is to have the waste energy be the component that heats the railgun. That way in the above case the railgun draws 4000 MJ from the homopolar batteries, transfers 1000 MJ of that to the projectile, and the remaining 3000 MJ heats the railgun and needs to be dissipated.
If you did this there would now be two techniques which increased the rate of fire, the Heat Dissipation Rate and the Efficiency. For example lets say that our railgun dissipates 100 MW, in the above 25% efficiency scenario it would take 30 seconds to fully dissipate and be ready to fire. If you then increased the efficiency to 30% you now only pull 3333 MJ from the batteries, not only that, but you only heat your railgun with 2333 MJ, meaning that you are now ready to fire in 23.3 (25 in the game) seconds.
If you did this though you may want to cap the efficiency techs at below 100% though, otherwise you won't be producing any heat and your railguns will be able to fire as quickly as you can push power into them (which may not be a bad thing, gameplay-wise).
Yes, I think someone else has mentioned this as well, earlier in the thread (unless that was you too :)). I will make a change along these lines when I get back to looking at railguns and lasers. Recently I have been concentrating on the missile design code.
Steve
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Steve will shields/armor acount the solar-wind? As in would getting to near to a star vaporize your armor/shields?
I have been considering some type of occasional particle impact for fast moving ships, with the frequency based on distance travelled and local particle density and the impact energy based on relative speed and particle size. This is how I might model nebula systems, or more localised dust clouds. I hadn't considered solar wind or temperature but now you have mentioned it I will look into it at some point.
Steve
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Solar wind and temperature may more easily be modeled as static values based on size/number of stars in a system if it gets too confusing. Certain technology thresholds to not take damage, otherwise, hope you brought enough reactors/armor.
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Got one more question:
How will the new system account for the difference between weight and volume?
Considering a 20k ton Ship often costs less than 6k Minerals, even assuming theres an equal amount of abstracted away standard materials (sadly^^) and air and whatever, they are likely to be a third lighter.
I assume an empty freighter will will weight less than 10k tons with that system, and then load another 25 for travel?
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On AI: Would it be possible to code this as a script? An external open source bit of code that gets loaded and run at runtime. One that others can customize.
I ask since AI is not your speciality, yet is one of the complaints about current NPRs, and will be even worse with the much more complex system.
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Got one more question:
How will the new system account for the difference between weight and volume?
Considering a 20k ton Ship often costs less than 6k Minerals, even assuming theres an equal amount of abstracted away standard materials (sadly^^) and air and whatever, they are likely to be a third lighter.
I assume an empty freighter will will weight less than 10k tons with that system, and then load another 25 for travel?
As I understand it, current Aurora works not with mass, but more with displacement. That´s how a freighter that can carry 25.000 tons of stuff around, "weights" 40k no matter if full or empty.
Of course, with Newtonian Aurora, this would have to change, I guess.
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Got one more question:
How will the new system account for the difference between weight and volume?
Considering a 20k ton Ship often costs less than 6k Minerals, even assuming theres an equal amount of abstracted away standard materials (sadly^^) and air and whatever, they are likely to be a third lighter.
I assume an empty freighter will will weight less than 10k tons with that system, and then load another 25 for travel?
Volume, which is used for armour and shield size and for targeting, is based on the full load mass of the ship. Current ship mass, which is used for acceleration rate, is based on the standard mass plus anything being carried by the ship, such as fuel, ordnance, cargo, colonists, etc.. Your guess on the empty freighter is almost spot on, based on the design in my test game. The base design is less than 10k but the full load mass is another 26k because the ship is also carrying 1000 tons of fuel.
Atlas class Freighter 9,393 tons standard 35,393 tons full load 28 Crew 431.1 BP
Length 220m Armour 1-176 Sensors 1/1/0/0 Damage Control Rating 1 PPV 0
MSP 8 Max Repair 37.5 MSP
Active Signature 707.86 Thermal Signature 375 EM Signature 0/0
Cargo 25000 Cargo Handling Multiplier 5
Commercial Ion Drive (5) Total Power 37.5 MN Fuel Use 1299 litres per hour Exp 2%
Full Load Acceleration 1.06 mp/s (0.11G) Hourly Acceleration 3.81 km/s Daily Acceleration 91.54 km/s
Standard Acceleration 3.99 mp/s (0.41G) Hourly Acceleration 14.37 km/s Daily Acceleration 344.93 km/s
Fuel Capacity 1,000,000 Litres Delta-V Budget (Full Load) 2,979 km/s Full Burn Duration 32.1 days
Steve
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On AI: Would it be possible to code this as a script? An external open source bit of code that gets loaded and run at runtime. One that others can customize.
I ask since AI is not your speciality, yet is one of the complaints about current NPRs, and will be even worse with the much more complex system.
Interesting idea. The current AI is scripted to a certain extent. There are various NPR actions and various NPR ship types. Each ship type has a list of actions to consider in order of priority. Which actions a ship type considers and the order of those actions is very easily changed.
Steve
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So, does that mean that the aforementioned Freighter will also cost nearly 10k Minerals?
Because otherwise, it seems way less dense than 'solid metal' and should obviously be even lighter.
Or where is the mass coming from?
I remember that in current Aurora, a Ship is often around 1/4th of it's mass in mineral price.
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So, does that mean that the aforementioned Freighter will also cost nearly 10k Minerals?
Because otherwise, it seems way less dense than 'solid metal' and should obviously be even lighter.
Or where is the mass coming from?
I remember that in current Aurora, a Ship is often around 1/4th of it's mass in mineral price.
The freighter is 431.1 BP so it will should require 431.1 tons of minerals (although I occasionally forget to match up the minerals to the cost in the DB). The rest is assumed to be made of up 'normal' easily accessibile materials.
Steve
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Well, then shouldn't be assumed that those materials not all have the same density?
Like, Air inside, or various alloys used for whatever?
That would allow for lightweight builds or the like.^^
Currently, a fully loaded ship seems to have the same weight as displacement, and I find that hardly believable.
Higher level armor for example should weight a bit more (on average).
As for armor, if a laser just warms up a ship from being too weak, will several lasers hitting in the same increment be able to penetrate?
It probably wouldn't have an effect on kinetics.
After all, you're factoring heat in weapons.
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Well, then shouldn't be assumed that those materials not all have the same density?
Like, Air inside, or various alloys used for whatever?
That would allow for lightweight builds or the like.^^
Currently, a fully loaded ship seems to have the same weight as displacement, and I find that hardly believable.
Higher level armor for example should weight a bit more (on average).
As for armor, if a laser just warms up a ship from being too weak, will several lasers hitting in the same increment be able to penetrate?
It probably wouldn't have an effect on kinetics.
After all, you're factoring heat in weapons.
I could have different volumes and densities for each component but that would be a lot of work to add a level of complexity that probably doesn't add a lot in terms of gameplay. I have to draw a line somewhere.
I won't be modelling the combination of several lasers hitting nearby. The beams could be many metres wide and figuring out exactly where they overlap would be a lot of work. If they need to overlap to have an effect they are extremely weak anyway and losing an extra few boxes of armour in one layer isn't going to make a huge difference to a battle. Anything I spend time on means I am not spending time on something else and I have to try and use my (unfortunately limited) time to work on things that will have the most significant impact on gameplay.
Steve
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Read the post on missile warheads. Awesome beyond words.
When Newtonian Aurora comes out, the first thing I will be doing is designing a war fleet designed to throw a huge volley of nukes and going out fishing.
I can already imagine the feeling of getting that one glorious contact nuke off and wiping out an entire dreadnought or space station.
1x Lancelot Anti-ship missile detonates at 0 range
Radia 005 is hit by *ridiculous* GJ of damage at *ridiculous* MJ per square meter
Radia 005 is destroyed
Then again, that could happen to me too. =| Poor poor freighters.
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There should be some special message when you do so much damage with a nuke that the ship no longer exists in any form.
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There should be some special message when you do so much damage with a nuke that the ship no longer exists in any form.
Pretty much impossible, at least with a nuclear device. Maybe if you had a significant quantity of antimatter you could release enough energy to completely vaporize a whole ship, but with a nuke you're going to have to settle for taking chunks out of it.
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A contact megaton nuke on a 50 meter vessel?
I don't think you'll get all the bits, but they'll be very very tiny bits.
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Proper nukes! I really wonder how this will turn out in the end. How much damage can these nuclear missiles absorb before being mission-killed?
A normal 10 gram 7,62mm bullet that hits at 1000 km/s has an energy of 5000 MJ. A ton of TNT. I foresee guided kinetic missiles having much better performance than explosive warheads except maybe in a close orbit environment. Or shrapnel warheads! Imagine a thousand 10 gram bullets released at a relative velocity of 2000 km/s, say at 50000 meters distance. Each hits with 20000 MJ. Each needs 25 milliseconds to reach the target. Altogether they do 20 000 000 MJ of damage. Not good.
You can only stop all these threats with more nuclear proliferation. Each ship squadron will pack multi-gigatons in ASMs and AMMs.
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Pretty much impossible, at least with a nuclear device. Maybe if you had a significant quantity of antimatter you could release enough energy to completely vaporize a whole ship, but with a nuke you're going to have to settle for taking chunks out of it.
Now imagine these tiny tiny bits of highly irradiated junk go down on a low-athmosphere world with an active colony. Atleast i dont want to be where this spacejunk goes down.
These calculations also show how dangerous nukes are and hack i am afraid that humanity could come to a sudden violent end. Also the effects on electronics sound good the *spoiler* might have !!fun!! with them.
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What about adding in a random chance that Ship A could be in the shadow of Ship B when Ship B gets smacked by a nuke?
Therefore, no damage is applied to Ship A even though it is theoretically inside the damage range of the nuke.
Make sense?
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What about adding in a random chance that Ship A could be in the shadow of Ship B when Ship B gets smacked by a nuke?
Therefore, no damage is applied to Ship A even though it is theoretically inside the damage range of the nuke.
Make sense?
Why theoritcly? Actually you could calculate blast-shadows iirc. its not even that hard.
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Steve,
Will there be something about acceleration compensators, like in honorverse. It could be a new component that would have a max acceleration tech line and a max ship size tech line (or such). If it get destroy in a fight, or out of power for some reason and the ship is accelerating, then every one aboard would get kill but the ship would be almost undamaged and could be thug back and reused. There could even be an emergency "stop accelerating" probability. The ship would then have to use human possibility of acceleration until reparation are made.
Obviously missile and such wouldn't need that component.
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I think acceleration compensation would be intrinsic to the Antigravity Minerals bit. Tho damage to the antigrav systems might be interesting.
Many of the new/changed mechanics are interesting and seem like they would be portable to Aurora or Aurora II. Hrmmm...
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I can't wait for it! Steve, this keeps getting better.
Antimatter warheads are more trouble then they're worth. It really doesn't matter if the ship is in tiny pieces or big ones, and they're tricky to handle.
I don't want acceleration compensators. This isn't honorverse, much as I like that setting, and we won't see the same sort of velocities they use. If exhaust velocity is limited to c, I for one am not building ships that will routinely go above about .1 c. Why not? It's simply too expensive in terms of delta-V.
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Seems ships must be very well defended anyway, and are slow. Six centimeters of armor looks very thin. Half a meter of armor, that's what I want to use.
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Well given that most modern space-constructions are just tinfoil wrapped around a frame made from Hollow aluminium pieces its actually pretty solid.
Steve how will you handle secondary explosions? Say if a railgun-slug rips through a drive which causes catastrophal results? Especially with such things as gascooled Reactors or even magazines filled with nukes it could be devasting.
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Seems ships must be very well defended anyway, and are slow. Six centimeters of armor looks very thin. Half a meter of armor, that's what I want to use.
According to the rules post about armour, that would be equivalent to 25 layers of armour in Aurora.
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Can I caution against completely removing missile agility? If I'm reading things right, a maneuvering missile will have 100% accuracy on any target with a slower acceleration than the missile; which is to say, any target. It would seem more realistic (or at least, more reasonable) if there was a chance for a sufficiently nimble ship to dodge missiles. One assumes the missile has to be aligned in the direction of thrust, IE it shoots a rocket out the back, so it would make sense if there's a delay to adjust course. Not to mention this makes proximity detonations more useful; I don't imagine a missile going for a contact hit is much harder for PD to shoot down than one 250m out, at the speeds we can expect to see.
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The thing is, unless a ship has missile efficiency engines, which it won't, a ship will never out-accelerate a missile.
Similarly, ships cannot turn faster than missiles for the same reason.
And as a missile approaches a ship, the ship becomes easier and easier to target. (and so does the missile) You can't hide the engine of a MN-range drive from nearly pointblank range, ECM or no.
The only thing ships have more than missiles is fuel efficiency. So for missiles of a specific design fired a certain time-of-flight away from a ship, it cannot compensate for the ship's delta-v with its onboard fuel and still acheive its desired final velocity.
And missiles in cruising mode for part of the journey have a lower final velocity and more time for the target ship to jink and force your missile to burn fuel to course correct.
I think there will be a maximum effective distance of missile use against a target that knows you are launching and can jink. (depends on time-of-flight * target max acceleration / missile delta-v for course correction)
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Every fleet in the system within the 10 MJ range limit, regardless of race, is checked in order of increasing range from the detonation, to see if the beam intersects the hull of any ships in that fleet. If it does, the actual ship is determined randomly from among those that could be hit.
Why are you choosing a random enemy ship instead of the closest one? If you did the closest ship for beam weapons then maybe you could have a formation editor so that we could keep our heavier armored ships in the front lines to run interference.
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Finally plowed through the 30+ pages of this and the other 6 of the fighter thread.
I have enjoyed reading this and look forward to this becoming a reality. (Pun intended)
Keeping handwavium to only a few elements instead of many will simplify the economics profoundly from what I can see, but the ship dynamics might make up for this in spades. Just ensuring your design can get from point A to B will no longer be a given. Especially if it comes in slightly off heading after a 'jump'.
I complement the catch on exhaust velocity. Increasing the mass comsumed was a very good fix.
I like the idea that planet killers will be more difficult, but expect that ships specifically designed as such could still rear thier nasty heads. Reality has its nasty side.
The flip side to this is that reality is much more difficult than some would indicate. Statements that a shot at the earth would be easy from outside Neptune at the drop of a hat just aren't realistic. The old statement that where math is precise it doesn't describe reality, and where math describes reality it is not precise applies here. You can land on the moon, you can get satellites in orbit, you can dock at the ISS, but these all have months of math double and triple checked and based off of decades of measurements. And even with all of this accumulated data, just check how closely we could predict the crash sites of the last couple satelites that came down.
Getting data from Neptune to Earth will take hours (1/2 a day) just to get an accurate ranging. Longer if you 'jumped' in farther out. Getting the mass on the star, planets, etc is not an easy process at that range. You can measure the star's acceleration but you will need to first get accurate measurements of the distances, realative velocities. etc which will take hours again and will likely be measuring values only a tiny fraction of the velocities/accelerations involved. If you have a week or two, it would be a fairly simple ordeal to take the shot (depending on how accurately you can maneuver your ship). Otherwise go for guided munitions.
And on the idea of a guided railgun projectile, I don't buy it. If you can design a sensor that could withstand the acceleration of the shot, it could withstand being hit with a fair portion of that level of energy. We can make (semi) guided munitions for artillery, but none of it will be acheiving anywhere close to the G's of those railguns. It isn't just a little more than the breaking strength of any known material, it is an order of magnitude bigger. Just build a missile. (That would be my opinion.)
Those would be my thoughts, but I have made up my mind that if this ever comes off the drawing board I will have to make the kids give up some of their computer time because dad will have finally found a game HE wants to play. :D
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And on the idea of a guided railgun projectile, I don't buy it. If you can design a sensor that could withstand the acceleration of the shot, it could withstand being hit with a fair portion of that level of energy. We can make (semi) guided munitions for artillery, but none of it will be acheiving anywhere close to the G's of those railguns. It isn't just a little more than the breaking strength of any known material, it is an order of magnitude bigger. Just build a missile. (That would be my opinion.)
I don't think it would be that hard. If you have solid-state systems (and yes, I'm fairly certain that some thruster systems can be made that way) then it will be able to take any accleration the slug itself can handle.
As for nukes going off when hit:
This is the biggest misconception around about nuclear weapons. They absolutely, positively, will not detonate under any but the most controlled conditions. Most modern designs are one-point safe, which means that even if one of the two detonators gets set off, it doesn't blow up. A railgun projectile won't even cause that.
It might, however, cause radiation casualties to the crew.
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And on the idea of a guided railgun projectile, I don't buy it. If you can design a sensor that could withstand the acceleration of the shot, it could withstand being hit with a fair portion of that level of energy. We can make (semi) guided munitions for artillery, but none of it will be acheiving anywhere close to the G's of those railguns.
This has already been tested, several years ago. An Army (not Navy) Railgun test launched a projectile at 40 G's, after which the projectile went through a pre-programmed manoever.
Granted, this didn't involve sensors, but the technology has advanced since then and will continue to advance.
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Guided will be easy, if expensive.
Homing is a lot harder.
As for nukes going off:
No, they wouldn't, but if a ship is hit by a nuke, and evaporated, it is quite possible that stored nukes will be set off, resulting a way bigger explosion.
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Guided will be easy, if expensive.
Homing is a lot harder.
As for nukes going off:
No, they wouldn't, but if a ship is hit by a nuke, and evaporated, it is quite possible that stored nukes will be set off, resulting a way bigger explosion.
Nuclear weapons are never at a risk of sympathetic detonation: the triggering mechanism is far too precise. At worst, you'll get a fizzle.
Antimatter weapons, on the other hand...
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The old statement that where math is precise it doesn't describe reality, and where math describes reality it is not precise applies here.
That would be important if our officer's were doing the math with pencil and paper. Luckily they will have computers.
You can land on the moon, you can get satellites in orbit, you can dock at the ISS, but these all have months of math double and triple checked and based off of decades of measurements.
The trajectories for all of those scenarios, and more, can be calculated in seconds with modern computers and modern commercially available software, like this one: http://www.agi.com/products/by-product-type/applications/stk/stk-for-space-missions/
There are a lot of things that need to be done to prepare for an ISS rendezvous, having every one hanging around waiting for a supercomputer to finish a 90 day calculation is not one of them.
It's true that there are decades of measurements that go into the models that predict these movements, however those decades are for incremental improvements. For example breaking Earth's gravity field up into 2450 pieces rather than 800 pieces, or making density 80% accurate instead of 78% accurate (yeah, density is the killer, everything else is really straightforward, not density.) Also, a lot of those incremental improvements are for things that need ridiculous levels of accuracy. Shooting down a GPS satellite doesn't need the Earth to be into 2450 pieces, knowing where GPS satellites are precisely enough that they can help with the positions and timings needed for an experiment comparing the speeds of photons and neutrinos, that needs more accuracy.
And even with all of this accumulated data, just check how closely we could predict the crash sites of the last couple satelites that came down.
That's all because even the best models for density aren't all that great, also helped along by the fact that those satellites were out of control and tumbling, making calculating their Cd or Area at any time also tricky. I have been ignoring the inaccuracy of density models in this thread because Steve isn't modeling density, and the vast majority of Aurora combat happens more than 400km above the Earth's surface, so it seems silly to base the accuracy for all long-ranged shooting on that one case.
And on the idea of a guided railgun projectile, I don't buy it. If you can design a sensor that could withstand the acceleration of the shot, it could withstand being hit with a fair portion of that level of energy. We can make (semi) guided munitions for artillery, but none of it will be acheiving anywhere close to the G's of those railguns.
In ten seconds of googling the first reference I found to shooting a rocket out of a gun was the Russians doing it in their T-72 tanks back in 1985. I'm sure it was done in various other situations earlier. In fact I am pretty sure that Gerald Bull successfully shot rockets out of his enormous cannons in Project Harp back in the 60s. His first tries failed as the propellant deformed on firing, but I believe he was able to get the propellant to survive when he slowly filled the tank of (dry) propellant with salt water so that all of the voids in between the propellant grains were filled. Unfortunately I was not able to find any citations to back that up. You are assuming that there have been no electronic or material advancements to partner with the rail gun advancements. You are right that shooting an Excalibur out of one of these railguns would convert it to paste, but we aren't talking about doing that.
It isn't just a little more than the breaking strength of any known material, it is an order of magnitude bigger.
Acceleration doesn't directly compare against "breaking strength" so I don't know what you are talking about here. Also you haven't given any breaking strengths of the material you are talking about, and honestly in my mind "Order of Magnitude Bigger than modern technology" has been my ballpark comparison for every "trans-newtonian" starting tech.
All that said, I actually would approve of lower acceptable muzzle velocities for shrapnel, kinetic, etc, etc warheads. (Or even G requirements if Steve wanted to model Railgun length) These could either be individual tech lines, or simply static multipliers. For example.
Projectile muzzle velocity modifiers:
<list>
<li>Slug: 1.0</li>
<li>Kinetic Missile: 0.8</li>
<li>Shrapnel Missile: 0.7</li>
<li>Conventional Missile: 0.5</li>
<li>Nuclear Missile: 0.3</li>
<li>Laser Rod Missile: 0.2</li>
</list>
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Regarding the safty of nukes i want to point you at two incidents that happend in the 60s. Number 1. (http://"http://en.wikipedia.org/wiki/1961_Goldsboro_B-52_crash") Almost made a big crater into the beautiful landscape of Goldboro in North Carolina. The second (http://"http://en.wikipedia.org/wiki/1966_Palomares_B-52_crash") almost sank spain.
Anyway the newer Bombs are far saver thanks double and dripple point explosives still a thread thought if the computer screws up and arms these guys. What might be also interresting is the recovering of nukes from the enemys wreckage or if you could arm those boys from affar. Imagine a *Spoiler* putting its eggs into one of your disabled cruisers which tiggers the bombs proximity sensor.
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It's not known what happens when you explode a thermonuke next to another thermonuke. There is no reason to assume that the fuel inside will NOT take part in the reaction.
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Hmm, well, I suppose there was no reason so far to detonating a 250 kton Fusion Bomb next to an ammo storage containing multiple other nukes.
No one quite knows if fusion "spreads", we don't have too much reliable info on what happens inside stars; it can be assumed, though, that most of it would be blasted away as the sun only "works" in it's core.
I high energy Laser, on the other hand, might be able to partially ignite a nuke, even though that would possibly only wreck the ammo storage.
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Well given that most modern space-constructions are just tinfoil wrapped around a frame made from Hollow aluminium pieces its actually pretty solid.
Steve how will you handle secondary explosions? Say if a railgun-slug rips through a drive which causes catastrophal results? Especially with such things as gascooled Reactors or even magazines filled with nukes it could be devasting.
I intend that reactors may explode in Honorverse-style, although I haven't written any code yet. I am not an expert but I understand that nuclear weapons are difficult to detonate accidentally. In fact, they can be difficult to detonate on purpose :). Perhaps a low chance might be fun for the occasional catastrophic hundred megaton blast. If I class some weapons as anti-matter, they might be considerably more temperamental. One reason for avoiding anti-matter might be its unfortunate tendency to explode at inconvenient times :)
Steve
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Why are you choosing a random enemy ship instead of the closest one? If you did the closest ship for beam weapons then maybe you could have a formation editor so that we could keep our heavier armored ships in the front lines to run interference.
It's not a random enemy ship within range. Its a random ship within the closest fleet to the blast. All ships in the same fleet will have the same coordinates, so I will assume they are stacked vertically. I would imagine that formations will be used a lot more in Newtonian Aurora but in that case each 'escort TG' will be in its own fleet.
Steve
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I intend that reactors may explode in Honorverse-style, although I haven't written any code yet. I am not an expert but I understand that nuclear weapons are difficult to detonate accidentally. In fact, they can be difficult to detonate on purpose :). Perhaps a low chance might be fun for the occasional catastrophic hundred megaton blast. If I class some weapons as anti-matter, they might be considerably more temperamental. One reason for avoiding anti-matter might be its unfortunate tendency to explode at inconvenient times :)
Steve
Maybe early AM drives/reactors need more maintenance, and in case of a failure, a percentage of the AM in the ship will detonate. Fission or Fusion reactors shouldn't detonate catastrophically and take the whole ship with it, vital components can be damaged enough for the ship to be given up.
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Both Fission and Fusion weapons tend to be rather stable; just look at how a 2 stage fusion weapon works - to get the second stage to detonate requires careful design of the shape and materials in the bomb, even though theres a second nuke going off right next to it. Likewise both fission and fusion power plants tend to be rather inert, and its almost impossible to get a modern nuclear reactor to detonate just by damaging it.
Antimatter is a whole different game though. One thing I always thought would be interesting is having antimatter be a trade-off development, instead of just 'more of the same', ie a fusion drive with better ratings. Using AM would no doubt give you better power outputs and energy densities, but the dangers and costs associated with using and manufacturing it might make high efficiency fusion drives viable alternatives, especially in settings with multiple factions who dont want the stuff being proliferated.
So my suggestion is to split it off from the regular drive and weapon progressions, instead being a seperate tech line and warhead type that becomes available later, with its own dangers and possibly costs (maybe special AM only fuel refineries).
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You could directly use antimatter as fuel, thus generating enormous output at the chance that the entire ship spontaneously evaporates.
Sounds like good afterburners to me.^^
As a suggestion, if you'd ever think about it, first make the rest working :D I can hardly wait.
Also, how will you aquire Anti-Matter in the first place?
You can't mine it....
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Particle accelerators with a track running around the world, or alternatively, an accelerator in an orbital ring, would give you the sort of energies needed for serious AM production. This is why I was saying it would be expensive.
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I believe that Anti matter is produced naturally in the Van Allen Belts around earth and also found in larger quantities in the much bigger radiation belts around planets such as Jupiter. I could be possible to harvest these belts.
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Possibly you could have a antimatter plant component, that takes a lot of minerals to build (neutronium?), but can provide antimatter for the ship it's on. Probably be very explosive.
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Regarding the safty of nukes i want to point you at two incidents that happend in the 60s. Number 1. (http://"http://en.wikipedia.org/wiki/1961_Goldsboro_B-52_crash") Almost made a big crater into the beautiful landscape of Goldboro in North Carolina. The second (http://"http://en.wikipedia.org/wiki/1966_Palomares_B-52_crash") almost sank spain.
Anyway the newer Bombs are far saver thanks double and dripple point explosives still a thread thought if the computer screws up and arms these guys. What might be also interresting is the recovering of nukes from the enemys wreckage or if you could arm those boys from affar. Imagine a *Spoiler* putting its eggs into one of your disabled cruisers which tiggers the bombs proximity sensor.
I'm aware of both of those, and neither had a serious chance of causing mass destruction. The only bomb that was ever in service that would have behaved like that was little boy. (Admittedly, any gun-type nuke. However, those were generally only used in artillery shells.)
It's not known what happens when you explode a thermonuke next to another thermonuke. There is no reason to assume that the fuel inside will NOT take part in the reaction.
There are two problems with this statement. First off, we have no evidence it will explode. Second, do you know anything about nuclear physics? Fusion is quite difficult to initiate compared to fission, which only happens in properly working bombs. Otherwise, we would have fusion power now.
I intend that reactors may explode in Honorverse-style, although I haven't written any code yet. I am not an expert but I understand that nuclear weapons are difficult to detonate accidentally. In fact, they can be difficult to detonate on purpose :). Perhaps a low chance might be fun for the occasional catastrophic hundred megaton blast. If I class some weapons as anti-matter, they might be considerably more temperamental. One reason for avoiding anti-matter might be its unfortunate tendency to explode at inconvenient times :)
Steve
Antimatter would be a good alternate warhead, too. It's expensive and dangerous, but has a very high energy density. As for reactors, if you have enough plasma, then losing containment (which is what happens in Honorverse) would be a bad thing. There's also a lot of energy stored in the bottle's magnets. Possibly a minute or more's worth. And if that all lets go at once...
You could also use antimatter-initiated fusion, which puts probably several kilotons of boom on each ship in an unstable form.
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So, would shooting a blast of Anti-matter at a planet result in an EMP on the surface from the resulting explosion?
Or will it all dissipate way too high in the thinner regions of the ionosphere?^^
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There are two problems with this statement. First off, we have no evidence it will explode. Second, do you know anything about nuclear physics? Fusion is quite difficult to initiate compared to fission, which only happens in properly working bombs. Otherwise, we would have fusion power now.
I did not say that the secondary bomb will "detonate" in the sense of a controlled reaction. I said that the fuel inside could well contribute to the first reaction. If you have nuclear fuel next to a neutron source like an H-Bomb, a reaction will occur, so secondary effects are in the realm of possibility for Newtonian Aurora. I am talking about the difference between "cannot explode when chucked out of a plane in an unarmed state" and "vast stockpile of thermonuclear weapons suffers direct hit by another thermonuclear warhead". This is enough for my sense of realism.
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So, would shooting a blast of Anti-matter at a planet result in an EMP on the surface from the resulting explosion?
Or will it all dissipate way too high in the thinner regions of the ionosphere?^^
No.
Yes.
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I did not say that the secondary bomb will "detonate" in the sense of a controlled reaction. I said that the fuel inside could well contribute to the first reaction. If you have nuclear fuel next to a neutron source like an H-Bomb, a reaction will occur, so secondary effects are in the realm of possibility for Newtonian Aurora. I am talking about the difference between "cannot explode when chucked out of a plane in an unarmed state" and "vast stockpile of thermonuclear weapons suffers direct hit by another thermonuclear warhead". This is enough for my sense of realism.
Again, I'm going to say the effect will be negligible. I could almost see some effect on the fission cores, but I expect that effect to be minor, as there aren't going to be enough for major energy release before the plutonium is blown apart. You might get the equivalent of a conventional missile exploding out of it. As for fusion, it really isn't going to do anything. Hitting fusion fuel with neutrons does next to nothing, and certainly won't induce mass fusion. And contrary to earlier statements we do know enough about nuclear physics to have a fair idea of how this sort of thing would work.
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I suppose no one will actually test it, either. ::)
Well, let's just assume that short of a high energy laser hit, nothing noticeable will happen.
As in, the starting explosion blows the ship apart anyways.
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Seconding that nukes would not sympathetically detonate under any reasonable circumstances. The missiles might well explode when their conventional trigger charges go, but it would just be a smallish normal explosion. That happens to be radioactive.
As for antimatter; I remember in the Starfire books there was mention that warships carried fission/fusion (I forget) warheads under normal circumstances, but could be armed with special antimatter weapons during wartime in areas where battle was imminent; the antimatter weapons were considerably more effective but no one wanted to fly around with them because even a tiny glitch (which *would* happen eventually) destroying the ship. This could kind of be an interesting mechanic; you can choose to load a ship with antimatter missiles, but if it has a maintenance failure of the magazine (even if it has the supplies to repair it) the component explodes for extremely high damage.
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Let's just agree to disagree then. Even though it hurts me that there is somebody wrong in the internet. :-*
(Btw the properties of antimatter are unknown too, because we can only observe singular particles. Who knows what will happen when you have a slab of frozen antihydrogen in your weapon. Can't really assume that there is going to be a multimegaton explosion)
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Well, considering that when antimatter and matter meet, all their mass is converted to energy, a multi megaton explosion is a safe bet.
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Let's just agree to disagree then. Even though it hurts me that there is somebody wrong in the internet. :-*
(Btw the properties of antimatter are unknown too, because we can only observe singular particles. Who knows what will happen when you have a slab of frozen antihydrogen in your weapon. Can't really assume that there is going to be a multimegaton explosion)
Please learn more about nuclear physics before you say this kind of thing. By definition, matter and antimatter will turn into energy when they meet. The only way you wouldn't get an explosion is if there was some form of barrier formed, and that has been proposed. From my reading, though, that's not likely to happen on weapon scales.
For more information see:http://www.yarchive.net/space/exotic/antimatter_bomb.html (http://www.yarchive.net/space/exotic/antimatter_bomb.html)
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The bigger issue with antimatter is actually getting it all to annihilate. For example - If you have a block of antimatter, the portion that makes contact first will annihilate and the energy released (the explosion) will blow the rest of the block away before it can contact the target. Sort of like a super-destructive bouncy ball!
Also kicking a dead horse, but nukes will not sympathetically detonate.
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As discussed in the link byron posted, shaped implosion devices ejecting matter onto a suspended AM core would result in good annihilation ratio; once the core grows above a certain size, its no longer as efficient, at which point you use two smaller ones, etc.
No doubt this can be represented adequately with various level of AM warhead tech...
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The bigger issue with antimatter is actually getting it all to annihilate. For example - If you have a block of antimatter, the portion that makes contact first will annihilate and the energy released (the explosion) will blow the rest of the block away before it can contact the target. Sort of like a super-destructive bouncy ball!
You obviously didn't read my link. However, I'll post the summary, because I'm feeling nice. The above analysis is true for large masses (cosmic scale) but not for masses on the scales in question here. The boundary layer will likely be on the same order of thickness as the deposition length for the reaction products, which is on the order of hundreds of meters. That means that a warhead would be unaffected.
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The main thing I can read from that article, as I have already argued in the case of homing Slugs, is the inconsiderate cost.
Such an Anti-Matter Warhead would have the sole advantage over a nuclear warhead of massively saving space.
Costwise an entire magazine of 10 Ton nuclear warheads would probably still be noticeably cheaper.
Would it be possible to channel an Anti-Matter Explosion into a Laser Rod as well?
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AM warheads vs nukes are basically like missiles vs beams in Aurora 5.53.
Immensely higher cost and complex logistics.
But packing far far more destruction into the same weight to eke out another order of magnitude more firepower per ton.
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Missiles in current Aurora are logistically and economically more demanding, but offer more range, burst damage, and firepower/ton.
AM warheads would be economically more demanding, even more so, and offer drastically higher burst damage and firepower/ton, and logistics would be pretty easy, in the sense of; you only have a few.
Additionally, keep in mind that a single lucky railgun hit could kill an opposing ship, so the benefit might be less in most circumstances, while a single hit on an AM core would result in the sure annihilation of the ship while the same hit in a nuke magazine, and be it 10x the size, would only destroy part of your ammo.
Tl;dr
Yes, but with higher costs and less potential gain.
A pure specialization option.
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Dont forget that AM also means AM drives for said ships and missiles, which is where the real advantages would come from in my opinion; an AM drive be it ship or missile sized would have much higher output than a fusion one, and this would mean an edge tactically.
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AM catalyzed fusion drive, ditto power core.
AM warheads.
Higher fuel efficiency (more range), higher speeds, higher firepower per ton.
One lucky hit penetrating armour means your ship blows itself up.
Tactical advantage in every area except defence.
AM warheads alone could serve as exceedingly expensive, but correspondingly more effective, anti-missiles.
Given that M/AM reactions are far more powerful than fusion warheads, the kill radius of AM anti-missiles is increased by alot. So your interception chance against incoming missiles is much higher and you kill more of them.
By the time the missiles have broken through your AMM umbrella, you'd have no more AM warheads left.
Or at least, so you hope. =) Good luck to you if you don't...
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To high risk given the obscene costs. You could just create a half dozen more ships that more slower.
As a booster, thus a small amount, I can probably see it.
Also, for double the detonation range, you need what, 4x the power?
So it would definitely not be cost effective to use them as amms.
It's ultimately a very late-game tech, highly efficient, extremely expensive, and with barely containable risks, from spontaneous combustion during movement to extreme vulnerability to enemy hits.
Once there's the money, it'll be used, but it'll take decades until that money can't be spend elsewhere.
Also, the weapons are pretty pointless against planets.
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Not sure how an AM warhead is 'pointless' against a planet. I can't think of a better way to eradicate surface targets and completely wipe out electronics with EMP than an AM bomb. And theres no fallout, just lots of second-hand irradiated material.
Also, I think 'spontaneous combustion' during movement might is an exxageration; I might see early drives being prone, but mature AM drives would probably not be any worse than a fusion torch maintenance wise (combat damage is a different matter).
The Dread Empire's Fall triology is a series set in a late-AM era universe, and theres some interesting ideas for storing AM there, like anti-hydrogen being stored in small pellets capable of self-containment, meaning that unless caught in an explosion they're rather safe.
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The way it's pointless against a planet is that yes, the effect is huge, it will probably blow a few mountains away and blanket the good part of a continent, taking a measurable part of the local atmosphere with it, but also a measurable part of your empires yearly income.
For the same price, you could unload a few hundred small nukes on the planet, engineer a bioweapon against the inhabitants, or just drop a few armygroups to take the planet the old-fashioned way.
Sure it's possible.
It just doesn't make sense.
Far less so than in space, the planet doesn't run away, you can get as much conventional ammo as you like.
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Please can we avoid statements such as "Please learn more about nuclear physics before you say this kind of thing" or "Do you know anything about nuclear physics?". By all means, reference your own expertise on a subject but please avoid any denigration of anyone else's knowledge.
Thanks,
Steve
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That would be important if our officer's were doing the math with pencil and paper. Luckily they will have computers.The trajectories for all of those scenarios, and more, can be calculated in seconds with modern computers and modern commercially available software, like this one: http://www.agi.com/products/by-product-type/applications/stk/stk-for-space-missions/
True, and how long has it taken to put all that together.
It wasn't in a few hours. The data and programs took a long time to generate.
And even with modern computers, the 'fudge factor' still exists. If we could calculate these things exactly, we wouldn't still be guessing most asteroids' orbits. We would also be able to fire two part 'penetrators' at comets and asteroids from Earth orbit. Trust me, we still need to make a LOT of course corrections on the way to shoot something as big as an asteroid that we have been watching for years.
As for breaking strengths of material, I actually am an engineer and physicist so I have a pretty good idea on this one. If we are assuming a projectile leaving a railgun at perhaps 10km/s (is this acceptable?), and assuming it is shot from a ship with a diameter of 50m with the whole length of the ship used for the driver, it will leave the barrel in .01 seconds after first acceleration assuming even acceleration of the projectile. One G is an acceleration of appox 10m/s/s. The projectile from this gun just withstood 1 MILLION G's of acceleration stress.
Google the load strength of any material known per mass, and see if it will withstand 1,000,000 times its mass in load.... You will find that NOTHING comes remotely close. Let alone a piece of machinery with the fine calibration to make in course adjustments. Every known material in this gun would be reduced to its component atoms (most likely). Some dense materials might reach degenerate matter levels of compaction if your railgun had a high enough muzzle velocity. (The thought of shooting unstable degenerate matter at something so that it detonates might be fun though...).
On the thought of nukes suffering sympathetic detonation, not likely at all. The only case I might see was if a ship had one prepped for launch and for some insane reason had the thing armed in the launcher - and then the vessel was hit. Otherwise, not going to happen. If it was unstable enough to detonate under inadvertent acceleration/heating/etc, I wouldn't want it on MY ship...
And I don't know if this would go in a suggestions thread or here, (this is the only group of threads I have spent much time on game-wise), but I think most all of the missiles should have the option to default to a kinetic kill if you choose not to arm them. A several ton intact nuclear/conventional/shapnel warhead hitting a ship at km/s velocities isn't going to look a lot different than a big old chunk of metal doing the same thing. Using a nuke this way might be an expensive waste, but might be attractive if you have a bunch of small ships near the target - or perhaps your colony on a moon with no atmosphere to protect them - or an orbital habitat. Just a thought.
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My apologies. I will say that it annoys me when people talk about things they apparently have no knowledge of. I say apparently because statements made are completely inaccurate.
I'll ask: how would one indicate that a commentor does not know what he is talking about?
Procyon:
50m is absurdly short for a realistic 10km/s coilgun anyway. Based on what I remember, 1 km is more likely.
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The way it's pointless against a planet is that yes, the effect is huge, it will probably blow a few mountains away and blanket the good part of a continent, taking a measurable part of the local atmosphere with it, but also a measurable part of your empires yearly income.
For the same price, you could unload a few hundred small nukes on the planet, engineer a bioweapon against the inhabitants, or just drop a few armygroups to take the planet the old-fashioned way.
Sure it's possible.
It just doesn't make sense.
Far less so than in space, the planet doesn't run away, you can get as much conventional ammo as you like.
I tend to agree with this after a fashion. The latest and best tech isn't really necessary against a static target. Not that you couldn't use it, but most folks would prefer to use up the older stuff first. (Hence the fact we are still burning up 70's era munitions in the middle east.)
This is probably the biggest reason we don't upgrade our arsenal of ICBMs every few years. Decades old missile are still plenty accurate enough to hit a city with a nuke. We can do much better now, but what would be the point?
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My apologies. I will say that it annoys me when people talk about things they apparently have no knowledge of. I say apparently because statements made are completely inaccurate.
I'll ask: how would one indicate that a commentor does not know what he is talking about?
Procyon:
50m is absurdly short for a realistic 10km/s coilgun anyway. Based on what I remember, 1 km is more likely.
True, probably longer in reality. Just basing it off of the ship designs I have seen here giving the ships diameters in the 45 to 50m range. Even if we stretch the ship to twice that long we are still talking a quarter million G's. I hesitate to think of how big a ship would have to be in NA to have a diameter of close to a km.
And no offense taken. I was just giving the credentials of mine.
EDITTED
Removed this statement as I also don't have my glasses here at this station and BADLY misread what was on your post. Ooops
As for knowing what to say to someone that seems to be 'misinformed', I simply show what I have as information and ask if they have any sources to support what they claim. Works well enough here with my coworkers. A lot of times they actually bring me something interesting and educational. (Sometimes it is just plain funny to read also.)
A professor of mine once told me that there is something to be learned in everything, even if it was only that there was nothing to learn there.
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My apologies. I will say that it annoys me when people talk about things they apparently have no knowledge of. I say apparently because statements made are completely inaccurate.
I'll ask: how would one indicate that a commentor does not know what he is talking about?
Well, an option to seriously consider is not to indicate at all that a person doesn't know what they are talking about. In my experience, implying that someone is an idiot does not make them particularly receptive to your counter-argument. Put forward your own opinion and back it up with whatever factual sources you can. In many cases, the other person will accept your evidence and change their mind. If they continue to disagree in the face of what you believe is overwhelming evidence, then you are never going to change their mind anyway. Just agree to disagree and end the discussion.
Steve
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My first successful missile test for Newtonian Aurora. A Terran Federation Vanguard class destroyer launched a Sabre Nuclear Anti-Ship Missile with a laser head at a stationary Chinese destroyer near Venus. It just seemed fitting based on my campaign histories that a Chinese destroyer should be the first to experience a nuclear attack in Newtonian Aurora :). At the time of launch, the Vanguard was ten million kilometers away on a heading of 342 degrees at a speed of 242 km/s. The missile began with the same speed and heading as the Vanguard and an acceleration of 40 m/s. After launch, the destroyer began a braking manoeuvre at 5.46 m/s with the intention of decelerating to rest and then returning to Earth. The missile gradually drew away from the ship as their acceleration rates changed. By the time it intercepted the destroyer it was moving at close to 1000 km/s. As the destroyer was stationary, the 500 kiloton warhead detonated just ten meters away. All nine x-ray lasers generated by the detonation hit the target ship and eviscerated it. The wavefront from the explosion was academic but devastating nontheless :)
However I forgot to include the destruction code so the target ship is still there even though all its armour and systems are gone :)
(http://www.pentarch.org/steve/Screenshots/Nuke.PNG)
This isn't a real campaign btw - just a basic setup for various weapon tests.
Steve
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Steve: Nuke test looks very cool.
I suppose I got carried away by abuse of the burden of proof fallacy. My apologies.
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Steve
Congrats on the first missile test! Must be great to start to see your hard work coming together - can't wait to have a look myself!
You mentoned previously that you had a survey ship up and running and doing a geo survey of sol. With the new fuel consumption changes it would be interesting to see a comparison of the time it will now take to do the survey compared to current Aurora. As a quick test I just ran the following ships round sol with no stops for fuel or resupply and no officer assigned to reduce survey time.
Tribal class Survey Ship 1,600 tons 162 Crew 357 BP TCS 32 TH 80 EM 0
2500 km/s Armour 1-12 Shields 0-0 Sensors 1/1/0/2 Damage Control Rating 4 PPV 0
Maint Life 22.85 Years MSP 558 AFR 5% IFR 0.1% 1YR 2 5YR 31 Max Repair 100 MSP
Nuclear Pulse Engine E8 (2) Power 40 Fuel Use 80% Signature 40 Armour 0 Exp 5%
Fuel Capacity 200,000 Litres Range 281.3 billion km (1302 days at full power)
Geological Survey Sensors (2) 2 Survey Points Per Hour
This design is classed as a Military Vessel for maintenance purposes
That ship took 8.56 years (ignoring the outlying comets), I'm asuming an equivalent tech Newtonian ship is going to take an order of magnitude longer and have massively higher fuel consumption?
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Steve
Congrats on the first missile test! Must be great to start to see your hard work coming together - can't wait to have a look myself!
You mentoned previously that you had a survey ship up and running and doing a geo survey of sol. With the new fuel consumption changes it would be interesting to see a comparison of the time it will now take to do the survey compared to current Aurora. As a quick test I just ran the following ships round sol with no stops for fuel or resupply and no officer assigned to reduce survey time.
Tribal class Survey Ship 1,600 tons 162 Crew 357 BP TCS 32 TH 80 EM 0
2500 km/s Armour 1-12 Shields 0-0 Sensors 1/1/0/2 Damage Control Rating 4 PPV 0
Maint Life 22.85 Years MSP 558 AFR 5% IFR 0.1% 1YR 2 5YR 31 Max Repair 100 MSP
Nuclear Pulse Engine E8 (2) Power 40 Fuel Use 80% Signature 40 Armour 0 Exp 5%
Fuel Capacity 200,000 Litres Range 281.3 billion km (1302 days at full power)
Geological Survey Sensors (2) 2 Survey Points Per Hour
This design is classed as a Military Vessel for maintenance purposes
That ship took 8.56 years (ignoring the outlying comets), I'm asuming an equivalent tech Newtonian ship is going to take an order of magnitude longer and have massively higher fuel consumption?
Based on my testing so far, surveys are going to take a LOT longer unless you support your survey forces with several fuel tankers (and in that case you will need to produce the fuel in the first place). As you estimated, many years for a geological survey for example. In my test game, a geo survey ship has surveyed the inner planets and perhaps a third of the asteroid belt in one year. This is an interesting dynamic because it means that survey information is far more valuable than in the past and an Empire will have to seriously consider its survey strategy, rather than simply trying to survey everything.
Steve
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I could have different volumes and densities for each component but that would be a lot of work to add a level of complexity that probably doesn't add a lot in terms of gameplay. I have to draw a line somewhere.
Steve
I know you've probably reached a decision there, but for the sake of argument, I'm not quite dropping it yet. :D
I can accept the argument that modeling the density of materials would go too far, in the same sense that you didn't want to incorporate regular materials for the sake of not getting it overly complicated.
However, you could easily abstract it.
Given the current code, you could just reduce the mass of the ship by a percentage, based on an arbitrary value, for example the weight to volume ratio of a space shuttle.
Given the raw data here (http://history.nasa.gov/SP-4225/diagrams/shuttle/shuttle-diagram-4.htm), I've calculated a base value for it, using the following assumptions:
As length, I picked 32 meters, which is close enough given it's obviously not a cube, and omits part of the fins and all that jazz.
Given the rather inaccurate data provided by that site, I just assumed it to be 5x5 in height and width, which is probably a rather generous assumption.
With 32*5*5 (I have this mad feeling of totally missing something right now), I got a total of 800 cubic meters; given that I fully expect to miscalculate something here, let's just assume half of it.
However, the full load of the shuttle seems to be, according to wikipedia, around 109 tons.
So, to take the middleground between what is in game now and the cheap calculation I just pulled off, you could reduce the weight of a ship by roughly 35%.
This would change the given freighter from:
Atlas class Freighter 9,393 tons standard 35,393 tons full load 28 Crew 431.1 BP
Length 220m Armour 1-176 Sensors 1/1/0/0 Damage Control Rating 1 PPV 0
to:
Atlas class Freighter 6,105 tons standard 32,105 tons full load 35,393 tons volume 28 Crew 431.1 BP
Length 220m Armour 1-176 Sensors 1/1/0/0 Damage Control Rating 1 PPV 0
Now, I obviously don't know too much about the subject, but I think this wouldn't be too much coding effort, and as with the exhaust problem before, you could just change the fuel consumption to account for that; In this case it would probably go down a bit again.
Though, now that I think about it, crew spaces should probably handle only half as many persons after that model, maybe 2 or 3 per ton.
As for railguns, does that mean we'll have to expect the muzzle velocities to go down by an order of magnitude? After all, a somewhat similar change was enacted on engines to keep with the realism.
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Based on my testing so far, surveys are going to take a LOT longer unless you support your survey forces with several fuel tankers (and in that case you will need to produce the fuel in the first place). As you estimated, many years for a geological survey for example. In my test game, a geo survey ship has surveyed the inner planets and perhaps a third of the asteroid belt in one year. This is an interesting dynamic because it means that survey information is far more valuable than in the past and an Empire will have to seriously consider its survey strategy, rather than simply trying to survey everything.
Steve
It might be more economic to use drones with Geo-sensors. Sol has 428 System objects. If i assume that a geosurvey drone cost as much as a Thermal-sensor-buoy (~ 0.06x Tritanium 0.375x Boronide 0.75x Uridium) plus a small drive as first stage (lets asume thats an additional 1/10th materials) i get to:
1.1*428*0,06 = 28.248 Tritanium
1.1*428*0,375 = 176,55 Boronide
1.1*428*0,075 = 35,31 Uridium
Given that the drive does not need to be that fast you could make savings on the fuel. But going with 1500 liters you would need 642000 Liters.
You would still need a launching platform though which would give this approach some additional base-costs. Also one should remember that 428 Sol-object include ~300 asteroids and most people tend to ignore them. You could also repurpose these buoys as surveillance system if you add some passive thermal sensors. In asteroid-belts this could double as early warning system.
edit: Oh and gives you a timeadvantage if you can start these buoys in a 1minute increment.
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I suppose their geo sensors should be made less effective, or drone geo sensors should require a special tech, or ship-based geological surveys will never be used. Unless that is exactly what Steve wants.
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I'm pretty certain they will have the same efficiency by size as regular ship sensors, which is to say, they'll survey a lot.
I can see a good speed-advantage in drones, but not cost-wise.
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I can see a lot of advantage to buoys. The survey ship won't have to decelerate at each target - the buoy will decelerate itself. Buoys were the first thing to pop to mind when thinking about surveying under a newtonian scheme.
Furthermore, it's looking like fuel efficiency/fuel carried will be the limit on survey ships, not sensor efficacy. Ironically better sensor tech would improve buoys way more than it would improve ships... assuming you can just make a lighter buoy, anyway.
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I'm pretty certain they will have the same efficiency by size as regular ship sensors, which is to say, they'll survey a lot.
I can see a good speed-advantage in drones, but not cost-wise.
It doesn't seem to cost a large amount of resources to build the drones, but fuel might indeed be the problem. Though I suspect Steve will increase Sorium availability to account for the greatly increased fuel use. Either that, or the RNG will be able to really screw the player over.
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As I calculated above, the ships really *should* be a third lighter, under the most unfavorable conditions.
This could be easily abstracted by reducing the fuel cost a bit again, given the calculation that might it go higher was based on the shown mass, which is actually the volume.
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As I calculated above, the ships really *should* be a third lighter, under the most unfavorable conditions.
This could be easily abstracted by reducing the fuel cost a bit again, given the calculation that might it go higher was based on the shown mass, which is actually the volume.
The shuttle is not the best example to use. It operates under entirely different constraints from a typical NA vessel. I already asked Steve about density, using numbers from AVT.
Crewing shouldn't really go above around 1/ton and 1/2-3 tons is more accurate.
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If it is possible to reclaim drones, you could just fire them from Earth use 50-90% of the fuel to get to and stop at the target, then the rest to get back. You wouldn't have to worry about the cost of lots of new drones. Of course, fuel would be an issue, but you could make it have lots of fuel and go very slowly between multiple targets before returning to refuel.
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Actually the question would be to which extend buoys or drones can be programmed? What would you need essentially? Atleast "Moveto" and "Survey object". If Steve feels fancy he could even write a up a code that calculates how much the rocket would need to accelerate/decelerate 2times to get there and back again (minus the Oldman, Lizardchicken and the sequels McGuffin).
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The shuttle is not the best example to use. It operates under entirely different constraints from a typical NA vessel. I already asked Steve about density, using numbers from AVT.
Crewing shouldn't really go above around 1/ton and 1/2-3 tons is more accurate.
Certainly agree with you.
The numbers I calculated were a compromise between current Aurora, where mass=weight, and an (albeit bad) reallife example; indeed, a compromise heavily shifted to current Aurora.
In the same vein, the crew housing would only be changed in the general direction of realism;
This would save Steve a bunch of work, as he'd only need to use one general multiplier for now.
Sure, ultimately, the best solution short of calculating material densities would be to have A specific size to weight ratio for every ship parts, with crew compartments and empty fuel tanks being rather light, and engines being rather heavy;
But he's got so much awesome stuff to get his head around, I suppose we should be happy with what we get, so I figured a small change has a lot higher chances of being easy to implement, and thus be well recepted.
On second thought, my calculation obviously had the error of not factoring armor, which would be 100% weight.
This could actually be interesting, an Armored ship will become noticeably slower, but not necessarily much bigger.
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i think the problem is not just the effort involved, but that it's adding complexity and additional numbers for players to deal with. So there needs to be discernable gameplay benefit.
Armor adding to mass but not volume is interesting though. Hmm-mm.
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Certainly agree with you.
The numbers I calculated were a compromise between current Aurora, where mass=weight, and an (albeit bad) reallife example; indeed, a compromise heavily shifted to current Aurora.
In the same vein, the crew housing would only be changed in the general direction of realism;
This would save Steve a bunch of work, as he'd only need to use one general multiplier for now.
Sure, ultimately, the best solution short of calculating material densities would be to have A specific size to weight ratio for every ship parts, with crew compartments and empty fuel tanks being rather light, and engines being rather heavy;
But he's got so much awesome stuff to get his head around, I suppose we should be happy with what we get, so I figured a small change has a lot higher chances of being easy to implement, and thus be well recepted.
On second thought, my calculation obviously had the error of not factoring armor, which would be 100% weight.
This could actually be interesting, an Armored ship will become noticeably slower, but not necessarily much bigger.
I just don't get why you're bringing it up at all. He's decided on a density, and you're asking him to change it. And I will remind you that things like average density are highly variable, based on setting. If you're going with a highly nautical model, then it will have densities that are somewhere above .5. AVT used .25, and I could see something nearer to life using .15 or so. The point is that Steve has made his decision, so stop badgering him about it.
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Byron, you need to stop jumping down people's throats. He's bringing it up because he wants to discuss it, in the thread for discussion about Newtonian aurora.
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Steve has made the decision that he doesn't want to simulate material density.
I on the other hand argue for a weight multiplier that would simulate a ships structure not being from pure, solid metal, no matter what the actual material would be.
His argument was that calculating densities was too much work.
Thus, I created a simple, though not very accurate, calculation that should be nearly no work, and would get close enough to the truth to be a valid description.
It's fine if you disagree, but if he does, be so kind and let him tell me himself, because he certainly didn't so far.
After all, he changed fuel consumption to match valid exhaust velocities based on 100% weight, he could just simulate 70% weight be reducing that by 30% again.
@Hali; That's pretty much my motivation, thanks for summing it up so coherently. :)
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True, and how long has it taken to put all that together.
It wasn't in a few hours. The data and programs took a long time to generate.
What does the time that the program took to generate have to do with anything? Unless you are arguing that every time a firing solution needs to be calculated the Midshipmen will have to develop the software to calculate the shot from scratch? As far as the data for the models, that does take time to collect, however even on immediate arrival to the system you have a lot of information available to you for reasonable simulations.
And even with modern computers, the 'fudge factor' still exists. If we could calculate these things exactly, we wouldn't still be guessing most asteroids' orbits. We would also be able to fire two part 'penetrators' at comets and asteroids from Earth orbit. Trust me, we still need to make a LOT of course corrections on the way to shoot something as big as an asteroid that we have been watching for years.
Guessing asteroids orbits is a fundamentally different problem though. You aren't trying to guess where things will be in an hour, or three hours, or a week, you are trying to guess where things are going to be (in the case of Apophis) 32 years later.
I am not sure exactly what shooting 'penetrators' at comets and asteroids has to do with this. There are a lot of reason we are not destroying asteroids, and a lack of knowledge of orbital mechanics isn't one of them. We don't have orbital weapons platforms for one, which is in my mind the biggest thing missing from that plan.
If we did have huge orbital cannons, however, it would be a lot easier to hit comets with those than what we are doing now. Take the Stardust mission, our piddly little weak modern engines took it out of Earth orbit in the beginning of 1999. It came around Earth again in 2001 for a gravity assist (once again because of our piddly little Earth engines), it didn't get to its comet until 2004, five years after it was launched. So yes, a five year mission does require quite a bit of course correction. If that asteroid interception was made with a slug launched at 40km/s then it would have hit within a few days, long before a problematic amount of uncertainty could accumulate.
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Steve, have you put any thought into divorcing the active and passive part of the active sensors? I often have a "watchship" with both active sensors and enormous Thermal and EM sensors. It would be neat if the "EM Sensitivity" part of the Active Sensor strength could take advantage of the purpose built EM sensors on the ship.
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Steve has made the decision that he doesn't want to simulate material density.
I on the other hand argue for a weight multiplier that would simulate a ships structure not being from pure, solid metal, no matter what the actual material would be.
Um, the density he's assuming is something on the order of .5 tons/cubic meter. Metals start above 2 ton/cubic meter, and go up from there. What you're asking for is a lower density.
For some reason, I can't find the original discussion on the topic. I asked too, and he said that he liked the number he had.
I have been thinking about a reasonably simple way to model a ship's density, and I'll post the results in a bit.
What does the time that the program took to generate have to do with anything? Unless you are arguing that every time a firing solution needs to be calculated the Midshipmen will have to develop the software to calculate the shot from scratch? As far as the data for the models, that does take time to collect, however even on immediate arrival to the system you have a lot of information available to you for reasonable simulations.
Reasonable simulation and able to hit a planet with an unguided projectile are fundamentally different things. I'm in agreement with him on this. For that sort of thing, you need very accurate models of the star system involved. One of the reasons for midcoure corrections is to allow them to largely ignore those sort of perturbations.
I am not sure exactly what shooting 'penetrators' at comets and asteroids has to do with this. There are a lot of reason we are not destroying asteroids, and a lack of knowledge of orbital mechanics isn't one of them. We don't have orbital weapons platforms for one, which is in my mind the biggest thing missing from that plan.
He's talking about missions like Deep Impact, where they hit the comet with a penetrator to see what was inside. His point is that if we had the sort of models you refer to, we could just shoot them out from earth orbit, instead of having to make course corrections on the way.
If we did have huge orbital cannons, however, it would be a lot easier to hit comets with those than what we are doing now. Take the Stardust mission, our piddly little weak modern engines took it out of Earth orbit in the beginning of 1999. It came around Earth again in 2001 for a gravity assist (once again because of our piddly little Earth engines), it didn't get to its comet until 2004, five years after it was launched. So yes, a five year mission does require quite a bit of course correction. If that asteroid interception was made with a slug launched at 40km/s then it would have hit within a few days, long before a problematic amount of uncertainty could accumulate.
That's not true, though. Wild 2 has a diameter of 5 kilometers. At closest, it comes within about 7.2*10^7 km of earth. Your penetrator would take about 500 hours, or nearly three weeks to get there. If there was a sideways drift for whatever reason of an average of 1.39 mm/s, the penetrator would miss. That sort of drift could occur from any number of sources. Hitting a planet is easier because the planet is bigger.
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My thoughts on component density:
First, I want everyone to understand. I do not want this in the first version of Newtonian Aurora. It looks wonderful as is, and I don't want Steve to delay getting it ready. This is merely my suggestion for how to implement a relatively simple density system.
Divide all components into one of the following categories:
1. Armor: Infinite density. In reasonable cases, the volume of armor is negligible.
2. Habitation: .15-.25 tons/m3. This is any place that humans spend a bunch of time. Crew quarters, bridge, flag bridge, passengers, troop transport bays, cryo modules. I'm not sure what to do about drop bays.
3. Fuel. I'm not qualified to comment on the density of exotic and currently unknown substances.
4. Void spaces. .25 tons/m3 fully-loaded. Hangar bays and cargo holds.
5. Equipment: .75-1 tons/m3. This covers everything that doesn't fall into another category. Engineering, weapons, electronics, engines, terraforming modules. Anything that is mostly metal.
I tried to keep the number of types low to limit complexity. This is just an idea for future designs, and the numbers will probably have to be changed.
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I have been thinking about FTL travel and deep-space sensors, and realised that something is wrong. If we can create sensors that can see enemy ships travelling in a certain radius, how come we lose contact with our ships going FTL?
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His argument was that calculating densities was too much work.
Thus, I created a simple, though not very accurate, calculation that should be nearly no work, and would get close enough to the truth to be a valid description.
It's not just work to code in, it's work for players. There needs to be some gameplay value from it other than more details is better. Personally, armor having zero (or very low) volume is the only thing I can see having gameplay value. And it's simple/straightforward.
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It's not just work to code in, it's work for players. There needs to be some gameplay value from it other than more details is better. Personally, armor having zero (or very low) volume is the only thing I can see having gameplay value. And it's simple/straightforward.
More work for players? How? This would be hard-coded in, and all you would see is that for a given mass, you get a bigger cargo ship then warship.
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I know you've probably reached a decision there, but for the sake of argument, I'm not quite dropping it yet. :D
I can accept the argument that modeling the density of materials would go too far, in the same sense that you didn't want to incorporate regular materials for the sake of not getting it overly complicated.
However, you could easily abstract it.
Given the current code, you could just reduce the mass of the ship by a percentage, based on an arbitrary value, for example the weight to volume ratio of a space shuttle.
Given the raw data here (http://history.nasa.gov/SP-4225/diagrams/shuttle/shuttle-diagram-4.htm), I've calculated a base value for it, using the following assumptions:
As length, I picked 32 meters, which is close enough given it's obviously not a cube, and omits part of the fins and all that jazz.
Given the rather inaccurate data provided by that site, I just assumed it to be 5x5 in height and width, which is probably a rather generous assumption.
With 32*5*5 (I have this mad feeling of totally missing something right now), I got a total of 800 cubic meters; given that I fully expect to miscalculate something here, let's just assume half of it.
However, the full load of the shuttle seems to be, according to wikipedia, around 109 tons.
So, to take the middleground between what is in game now and the cheap calculation I just pulled off, you could reduce the weight of a ship by roughly 35%.
This would change the given freighter from:to:
Atlas class Freighter 6,105 tons standard 32,105 tons full load 35,393 tons volume 28 Crew 431.1 BP
Length 220m Armour 1-176 Sensors 1/1/0/0 Damage Control Rating 1 PPV 0
Now, I obviously don't know too much about the subject, but I think this wouldn't be too much coding effort, and as with the exhaust problem before, you could just change the fuel consumption to account for that; In this case it would probably go down a bit again.
Though, now that I think about it, crew spaces should probably handle only half as many persons after that model, maybe 2 or 3 per ton.
As for railguns, does that mean we'll have to expect the muzzle velocities to go down by an order of magnitude? After all, a somewhat similar change was enacted on engines to keep with the realism.
Already built into Newtonian Aurora is that the volume of a ship in cubic metres = 10x mass in tons. This is will be too low for some ships and too high for others but it will suffice as an average. As a comparison, Traveller TNE uses volume m3 = 14x mass in tons. Of course, mass will change significantly during the game based on how much of the maximum fuel load is carried or whether a cargo ship is actually carrying any cargo, so the volume - mass ratio of a ship will change a lot during the normal course of play.
I could calculate individual volume - mass ratios for every component but my reasons for not doing so are as follows:
1) It would be a lot of work, especially in terms of the research required to create reasonable ratios for each component. If I was not going to research it enough to come up with reasonable ratios then what would be the point.
2) Even though different components would have different mass ratios, ships tend to use the same type of components. Engines, armour, weapons, crew quarters, fuel, etc. So even though the individual components may vary, warships would probably have similar average mass-volume ratios anyway.
3) When you see the TCS of a ship with a fixed mass-volume ratio for its full load mass, you will have a reasonable idea of the capability of the ship. Otherwise, I would just display the diameter of the contact in metres, which to most players wouldn't be that useful. They would like an idea of what they are facing. If they were an experienced naval officer, they may know how TCS generally related to possible mass ranges for different ships of different nations. However, they aren't and most players will want 'Sensor Reading' = 'General Idea of Ship Capability', and in Aurora terms 'Ship Capability' is closely related to mass. If they need to know mass they need to know how volume relates to mass without a lot of calculations.
4) Most importantly, having different mass ratios for different components wouldn't significantly affect gameplay. Players are unlikely to design their ships any differently based on the mass/volume ratio of the components. If you want an escort DD then you will pick the components you need and select engines based on how much mass you need to propel. You won't care about the volume during design. Volume changes will affect the chance of a hit but not by a great deal and certainly not enough for you to make different decisions during design, especially as it is likely that ships of a given role, such as warships, would probbaly have similar mass-volume ratios anyway.
5) With 4) in mind, I really don't want to expend a lot of effort on something that might add more realism but would have very little impact on gameplay. Gameplay in this context being the addition of difficult decisions related to the volume of a component.
Volume is included because I am using it as a baseline for to hit chances and the impact of nukes. It isn't intended to have a significant effect in gameplay.
Steve
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I suppose their geo sensors should be made less effective, or drone geo sensors should require a special tech, or ship-based geological surveys will never be used. Unless that is exactly what Steve wants.
There isn't any difference between ship geo sensor tech and missile geo sensor tech. There is simply geosurvey tech, which is based on a rating per ton. That will be the same whether it is a on a missile or a ship.
Steve
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I can see a lot of advantage to buoys. The survey ship won't have to decelerate at each target - the buoy will decelerate itself. Buoys were the first thing to pop to mind when thinking about surveying under a newtonian scheme.
Furthermore, it's looking like fuel efficiency/fuel carried will be the limit on survey ships, not sensor efficacy. Ironically better sensor tech would improve buoys way more than it would improve ships... assuming you can just make a lighter buoy, anyway.
Yes, buoys will be very useful and yes, fuel efficiency and capacity will be vital for long-range survey ships.
Steve
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Actually the question would be to which extend buoys or drones can be programmed? What would you need essentially? Atleast "Moveto" and "Survey object". If Steve feels fancy he could even write a up a code that calculates how much the rocket would need to accelerate/decelerate 2times to get there and back again (minus the Oldman, Lizardchicken and the sequels McGuffin).
Bear in mind there are no drones or buoys in Newtonian Aurora in the same sense as Standard Aurora. There are only missiles. However, you can send a missile on a zero-zero intercept, which means it will accelerate and then decelerate to rest, so you can create a 'single stage survey drone' with an engine, reactor and sensor, or you can deploy a missile with a reactor but no engine as a second stage. Unlike Standard Aurora though, you will still need a zero-zero intercept because the second stage will start with the same momentum as the first stage.
Steve
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Steve, have you put any thought into divorcing the active and passive part of the active sensors? I often have a "watchship" with both active sensors and enormous Thermal and EM sensors. It would be neat if the "EM Sensitivity" part of the Active Sensor strength could take advantage of the purpose built EM sensors on the ship.
I did consider it. In the end I went the simplified version, partly because fire controls use the same component type and design process as active sensors and I didn't want to have active sensors and fire controls to be sharing the same receiving antennae, as that isn't the case in reality. It might also mean I would have to account for the receiver picking up reflected pulses from other transmitters. In the end I decided a single combined unit was a lot less trouble :). BTW I recently posted the updated active sensors in the Rules thread.
Steve
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I have been thinking about FTL travel and deep-space sensors, and realised that something is wrong. If we can create sensors that can see enemy ships travelling in a certain radius, how come we lose contact with our ships going FTL?
In this version of Aurora, ships in FTL enter 'hyperspace', which is a different dimension. Sensors (or even communications) cannot penetrate hyperspace from normal space and normal sensors don't work in hyperspace. Ships in hyperspace can't even see each other. In fact, in the game you lose contact with your own ships while they are in hyperspace. They return to your control when they return to normal space.
Steve
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Whoops, didn't know you already calculated it that way.
My bad.
In that case, I really have nothing senseful to add, aside from +1 that armor adds more weight. Why?
More Info to the player. ;D Ship size+ exhaust + speed = armor Strength.
Just kidding, I'm happy already.
Another question:
Will there be Hyperspace sensors? X-D
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I'm fairly sure Steve pointed out that there won't be in his post directly above yours.
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Steve
Thanks for all the feedback. Just a quick one on the nukes. I think you previously mentioned that ships in a task group would, for the purpose of calculating position, be effectively stacked one on top of the other. If that is the case how is an area effect weapon going to be considered when looking at proximity to ships within a single task group?
Thanks!
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Edit- misleading info removed. :p
@Steve - Are our ships likely to be eaten by a grue in the darkness? :X
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Steve
Thanks for all the feedback. Just a quick one on the nukes. I think you previously mentioned that ships in a task group would, for the purpose of calculating position, be effectively stacked one on top of the other. If that is the case how is an area effect weapon going to be considered when looking at proximity to ships within a single task group?
Thanks!
The nuke will hit all of the ships in the task group
Steve
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So, will it be possible to have ships with a single kilometer distance from each other, in a close formation, but far enough away from nuke danger?
Not that I wouldn't like that, but Auroras task group management isn't quite as intuitive.
Could it be possible to add a "scatter" option for peace time that will just spread ships over a larger dot in space?
So you don't have to manage this when just moving from A to B.
Or maybe allow Sub-Taskgroups, that don't show up in the Task group list until a box is ticked or you order to "disband formation" on the mother-group, or whatever?
I know, senseless ranting, but a bit more control options might slim down the repetition.^^
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Yikes! I can see I will have to start practicing with detaching ships to spread out those task groups - loosing one ship to a single missle will be bad enough, let alone a whole task group.
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More missile testing. The Chinese Jiangzhu managed to generate a miss by accelerating across the path of the first Sabre NASM. That missile (at the top of the screenshot) is now coming around for another try. A second missile has been launched by the Terran Federation ship at the bottom. Note the heading of that missile compared to the actual location of the Chinese ship. The missile is taking into consideration its own speed and acceleration and the heading, observed speed and acceleration of the target ship. Also, that missile actually had to slow down to rest after being launched and then accelerate again because the launching ship was heading away from the target. Manoeuvre is probably going to play a much larger part in Newtonian Aurora than Standard Aurora.
The DVR rating shown next to each missile is the Delta-V it has remaining.
(http://www.pentarch.org/steve/Screenshots/TryAgain.PNG)
Steve
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Steve
Looks great. In terms of helping players work out when to launch a missile or if its possible have you thought about giving an estimated DV usage estimate based on current ship heading, target heading and desired top speed of a missile? Would be good to see ahead of actually hitting the fire button.
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Looking good.
How much control will we have over missiles? Do they just constantly burn to accelerate and correct their vector, or can we order them to coast or accelerate to a certain speed and then save the rest for terminal maneuvers?
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What does the time that the program took to generate have to do with anything? Unless you are arguing that every time a firing solution needs to be calculated the Midshipmen will have to develop the software to calculate the shot from scratch? As far as the data for the models, that does take time to collect, however even on immediate arrival to the system you have a lot of information available to you for reasonable simulations.Guessing asteroids orbits is a fundamentally different problem though. You aren't trying to guess where things will be in an hour, or three hours, or a week, you are trying to guess where things are going to be (in the case of Apophis) 32 years later.
Trust me, it takes longer than you think to come up with the numbers. We have been watching Eris, Sedna, and a number of outer system bodies the size of a small planet and STILL don't have the orbits fixed. In fact Sedna is still a best guess on its path. We could be off by a lot.
You are talking about jumping in from WAY out past these planets and getting accurate data on a body. Gonna take a while....
I am not sure exactly what shooting 'penetrators' at comets and asteroids has to do with this. There are a lot of reason we are not destroying asteroids, and a lack of knowledge of orbital mechanics isn't one of them. We don't have orbital weapons platforms for one, which is in my mind the biggest thing missing from that plan.
If you are claiming the math is that easy, and establishing a platform so stable to shoot elementary, then we could shoot our scientific probes of asteroids from orbit. We can't. Not even close. Even if we could come up with a platform that stable the interplanetary medium is not very condusive.
If we did have huge orbital cannons, however, it would be a lot easier to hit comets with those than what we are doing now. Take the Stardust mission, our piddly little weak modern engines took it out of Earth orbit in the beginning of 1999. It came around Earth again in 2001 for a gravity assist (once again because of our piddly little Earth engines), it didn't get to its comet until 2004, five years after it was launched. So yes, a five year mission does require quite a bit of course correction. If that asteroid interception was made with a slug launched at 40km/s then it would have hit within a few days, long before a problematic amount of uncertainty could accumulate.
Our 'piddly little engines' are the best we have to work with. My apologies for not reaching your expectations. And that slug at 40 km/s would take a launcher that would dwarf anything we currently have. But on that thought, you mention that it would hit in days. This is a lot more of a problem than I believe you understand (at least with current technology).
First problem. Stable platform. Remember Newton's Third Law and action / reaction. That slug just created an enormous amount of recoil. Unless the slug was perfectly formed (not likely), suffered no deformation, and the slug was accelerated in a perfectly duplicatable manner each time, you won't get very reproducable results. We will ignore the fact that the slug won't likely survive launch unless the launcher is hundreds of km long (ok, a dozen km would be doable, but building a 10km object??? in space???). The launcher is going to have to absorb energy imparted on it by that slug. The launcher is going to deform (a lot with this much energy) just as a rifle barrel occilates when firing. The dispertion of the bullet is due to a large part in the inablity of anyone to exactly predict where in the occilation the barrel will be when the bullet exits the barrel. This 40km/s projectile is going to induce SERIOUS occilation on the launcher and whatever it is mounted in.
Next is the fact that space isn't empty. In the planetary area (we aren't sure how far it extends out yet. Still waiting on data from the early probes to come in) densities are on the order of 100,000 particles per cm3. This is considerably less than earth (10 to the 22nd most places at sea level) but you are ramming your projectile through it terribly fast. I will assume it has a very good sectional density and ballistic coeficient but it will still be generating a great deal of drag on those particles. If you should happen to hit an area of higher density you will suffer deflection like a rifle bullet striking water. So if you shoot at a target from beyond the heliopause, you will get a rather pronounced reaction. Just measuring where the heliopause is at would take a great deal of time, and likely require something crossing it while doing constant sampling.
And if this projectile hits a grain of sand on the way in it may as well have hit a nuke. There is a lot of 'dust' out there. Tens of tons of it fall to earth each day. We have a number of satellites collecting it. You will likely hit a grain or two on your weeks long trip in system.
Shooting such a high energy projectile would be a difficult feat over interplanetary distances. Doing it after a few hours or days of observation from such incredible distances would be getting the camel through the eye of the needle.
And thank you byron for speaking in my absence. You summed it up quite nicely.
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Trust me
I make it a habit of not bringing personal identities into internet arguments for a couple reasons, mainly because anyone can claim to be anything on the internet, and also because I don't like appeals to authority. I think that reasoned arguments (and lots of math) are the best way to go about things. However at this point we are really talking about more nebulous claims than can easily be demonstrated, and you've said "trust me" twice, so I suppose I'll return with the "I do this (examination and implementation of force and environment models to accurately propagate space craft and other heavenly bodies) for a living." I'm a software developer for the company I've linked to twice now, and the main developer of one of their propagation products.
it takes longer than you think to come up with the numbers. We have been watching Eris, Sedna, and a number of outer system bodies the size of a small planet and STILL don't have the orbits fixed. In fact Sedna is still a best guess on its path. We could be off by a lot.
You are talking about jumping in from WAY out past these planets and getting accurate data on a body. Gonna take a while....
Calculating Sedna's orbit parameters from Earth is a much harder problem than getting a firing solution on Earth (from, say, Neptune). One of those involves propagating the position of an object 12750 km across a few (say 4) weeks forward in time from measurements taken 4.6E9 km away.
The other involves the propagation of a body 8 times smaller 845 times longer (if you were looking for perihelion position, if you wanted to propagate a whole orbit try 148,200 times longer) from measurements taken almost three times further away.
The longer time is the kicker, as uncertainties in position grow geometrically as you propagate them forward in time.
I'm also not sure how you got that I was trying to shoot at Earth from out past Sedna ("WAY" out past Sedna you said). I have really just been using Neptune because I believe days ago I took an arbitrary firing solution against the Daring that seemed reasonable and extrapolated out where a ship that was that accurate could hit Earth from, and it turned out to be around Neptune. I think that a firing point anywhere in the outer solar system would work equally well as Neptune from a "too far away to do anything about until after the attack" standpoint. And honestly the Neptune case was mostly predicated on speeds the Daring could attain pre-Engine Nerf. When you are attacking something closing at higher speeds the relevant range is smaller. Now that the speeds have been lowered if I reran my numbers I may indeed find a position around Jupiter to be more reasonable, but I think for this discussion that the exact position of the shooter is fairly unimportant.
If you are claiming the math is that easy, and establishing a platform so stable to shoot elementary, then we could shoot our scientific probes of asteroids from orbit. We can't. Not even close. Even if we could come up with a platform that stable the interplanetary medium is not very condusive.
If the math was "normal-speak easy" I wouldn't have a job. What I meant was that it was "easy" in the sense that "it's really hard but we have had thousands of people and millions of computing hours working on it and similar problems in the past 40 years and it's now a solved problem". I also assume that in Aurora their algorithms and computers will be no less effective than ours, and will probably be at least an order of magnitude better.
Our 'piddly little engines' are the best we have to work with. My apologies for not reaching your expectations. And that slug at 40 km/s would take a launcher that would dwarf anything we currently have. But on that thought, you mention that it would hit in days. This is a lot more of a problem than I believe you understand (at least with current technology).
Our 'piddly little engines' are not the best we have to work with in Aurora. According to the schematics we've seen capabilities 100x beyond that of our engines will be commonplace in the early game. Similar to that 40 km/s railgun slug, which is the slowest of the railgun muzzle velocities that Steve has posted. What I have been trying to do is take all of the stated abilities of Aurora tech, and look at what they would accomplish if everything else was similar to modern tech levels.
First problem. Stable platform.
According to NASA fact sites the Hubble telescope has a Pointing Accuracy of 7/1000th of an arcsecond, so platforms in space can align to a target with a great deal of stability. Now granted it's another ball game entirely to maintain stability on an object accelerating on a huge cloud of plasma. I suppose Steve could model accuracy penalties while accelerating, but I think he could also handwave that requirement away. We have a variety of ways already to mitigate instability and jolts for both turrets on naval vessels and more rudimentary science experiments, and it would seem fairly reasonable (to me anyways) to just say, "eh, they have something like that".
Now as far as how long it takes the platform to regain stability after a shot, that depends on the mass of the platform, the offset of the barrel from the center of mass, the abilities of the control system to torque the craft, and a heck of a lot of other things that Steve is not modelling. Seems reasonable to just say that the spaceship is able to damp out it's orientation by the time the next shot is ready.
Remember Newton's Third Law and action / reaction. That slug just created an enormous amount of recoil. Unless the slug was perfectly formed (not likely), suffered no deformation, and the slug was accelerated in a perfectly duplicatable manner each time, you won't get very reproducable results.
You can say literally exactly the same thing about any handgun, rifle, or cannon that has ever existed. It basically amounts to saying “it has to be done carefully” all of the problems you are bringing up are what your millions of scientists are supposed to be figuring out in their cush desk jobs on Terraformed Mars.
We will ignore the fact that the slug won't likely survive launch unless the launcher is hundreds of km long (ok, a dozen km would be doable, but building a 10km object??? in space???). The launcher is going to have to absorb energy imparted on it by that slug. The launcher is going to deform (a lot with this much energy) just as a rifle barrel occilates when firing. The dispertion of the bullet is due to a large part in the inablity of anyone to exactly predict where in the occilation the barrel will be when the bullet exits the barrel. This 40km/s projectile is going to induce SERIOUS occilation on the launcher and whatever it is mounted in.
For a normal unguided kinetic slug going through a coil gun or railgun you don’t have to worry about the G force destroying the slug since the magnetic forces apply to the entire projectile fairly uniformly. It is any fancier components of the slug that are not exactly as magnetic as the rest of the material and accelerating at exactly the same rate as the rest of the slug that will be clobbered, but I agree that for now we’ll have to brush that aside and see how Steve decides to fluff that. As far as the rest of it, you say right there that normal cannons undergo the same flexing, and that is what gives them their inaccuracies. Furthermore I cited earlier that those inaccuracies for a high quality civilian-available hunting rifle were around an arc second. I just make the assumption that with the better materials and technology of the Aurora setting they will be able to maintain and improve on modern accuracy even as the capabilities of their weapons improve. I base this on the entirety of our civilized history, which has shown our weapons becoming longer-ranged, higher powered, and more accurate over time.
Additionally I don’t think that I ever argued that the weapons should be perfectly accurate, on the contrary I think that introducing weapon accuracy in fractions of an arc second or radian as an additional design/research category would be pretty sweet.
I will have to do some more math before I can quantify the sort of effect the interplanetary dust cloud may have on a trajectory, but I would like a citation for that “100,000 particles per cubic centimeter” That is 5 times that of a typical number of gas molecules in a cubic centimeter of atmosphere at 500km above the Earth’s surface.
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I'm also not sure how you got that I was trying to shoot at Earth from out past Sedna ("WAY" out past Sedna you said). I have really just been using Neptune because I believe days ago I took an arbitrary firing solution against the Daring that seemed reasonable and extrapolated out where a ship that was that accurate could hit Earth from, and it turned out to be around Neptune. I think that a firing point anywhere in the outer solar system would work equally well as Neptune from a "too far away to do anything about until after the attack" standpoint. And honestly the Neptune case was mostly predicated on speeds the Daring could attain pre-Engine Nerf. When you are attacking something closing at higher speeds the relevant range is smaller. Now that the speeds have been lowered if I reran my numbers I may indeed find a position around Jupiter to be more reasonable, but I think for this discussion that the exact position of the shooter is fairly unimportant.
I believe you were the one who started with something on the order of half a light-year. I know that was a mistake, but Neptune is closer then usual.
If the math was "normal-speak easy" I wouldn't have a job. What I meant was that it was "easy" in the sense that "it's really hard but we have had thousands of people and millions of computing hours working on it and similar problems in the past 40 years and it's now a solved problem". I also assume that in Aurora their algorithms and computers will be no less effective than ours, and will probably be at least an order of magnitude better.
Again, that's not the problem. If we could do such things, why do we need midcourse corrections on spacecraft? The sort of thing you work on is more then adequate for a spacecraft that can correct its course, but if it can't, there's a problem.
According to NASA fact sites the Hubble telescope has a Pointing Accuracy of 7/1000th of an arcsecond, so platforms in space can align to a target with a great deal of stability. Now granted it's another ball game entirely to maintain stability on an object accelerating on a huge cloud of plasma. I suppose Steve could model accuracy penalties while accelerating, but I think he could also handwave that requirement away. We have a variety of ways already to mitigate instability and jolts for both turrets on naval vessels and more rudimentary science experiments, and it would seem fairly reasonable (to me anyways) to just say, "eh, they have something like that".
That's not as accurate as you think. While it sounds impressive, you'll need much less to be able to hit anything, particularly at the ranges you're proposing. And if you're shooting at earth from Neptune, then I think that someone sneezing will probably be enough to make the shot miss.
You can say literally exactly the same thing about any handgun, rifle, or cannon that has ever existed. It basically amounts to saying “it has to be done carefully” all of the problems you are bringing up are what your millions of scientists are supposed to be figuring out in their cush desk jobs on Terraformed Mars.
For a normal unguided kinetic slug going through a coil gun or railgun you don’t have to worry about the G force destroying the slug since the magnetic forces apply to the entire projectile fairly uniformly. It is any fancier components of the slug that are not exactly as magnetic as the rest of the material and accelerating at exactly the same rate as the rest of the slug that will be clobbered, but I agree that for now we’ll have to brush that aside and see how Steve decides to fluff that. As far as the rest of it, you say right there that normal cannons undergo the same flexing, and that is what gives them their inaccuracies. Furthermore I cited earlier that those inaccuracies for a high quality civilian-available hunting rifle were around an arc second. I just make the assumption that with the better materials and technology of the Aurora setting they will be able to maintain and improve on modern accuracy even as the capabilities of their weapons improve. I base this on the entirety of our civilized history, which has shown our weapons becoming longer-ranged, higher powered, and more accurate over time.
Additionally I don’t think that I ever argued that the weapons should be perfectly accurate, on the contrary I think that introducing weapon accuracy in fractions of an arc second or radian as an additional design/research category would be pretty sweet.
Comparisons to modern weapons are fundamentally flawed. To be able to do what you suggest, you'll need something that is as good if not better then top-of-the-line modern lab equipment. And it has to be military hardware. That's the kicker. It has to be able to work reliably and without handholding from a dozen PhD's.
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There are plenty of people in this thread with more practical knowledge and maths skills than myself so I am not going to get involved in any detailed discussions about shooting Earth from Neptune. However, the Earth is 12,000 kilometers in diameter and Neptune is about 4,500,000,000 km away, so the ratio is about 375,000-1. This may be a simplistic analogy but that is like putting a basketball on top of the Empire State building in New York (or perhaps having it move slowly across the NYC skyline) and trying to shoot it from the Washington Monument (about 435,000-1). Difficult but you could imagine it being possible with modern technology. Whether you could hit one particular spot on the basketball might be trickier but given the probable future state of technology in an Aurora game, I think most people would accept that something like that would be possible without much suspension of disbelief. It's certainly a lot easier than creating the engines in the game :)
My intention is not to create a perfectly accurate simulation but rather a game that has the feel of hard science. Gameplay and fun will always take precedence over physics and even though the game is a lot more 'hard science' than most, it is still going to be far more simplified than reality.
Steve
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There are plenty of people in this thread with more practical knowledge and maths skills than myself so I am not going to get involved in any detailed discussions about shooting Earth from Neptune. However, the Earth is 12,000 kilometers in diameter and Neptune is about 4,500,000,000 km away, so the ratio is about 375,000-1. This may be a simplistic analogy but that is like putting a basketball on top of the Empire State building in New York (or perhaps having it move slowly across the NYC skyline) and trying to shoot it from the Washington Monument (about 435,000-1). Difficult but you could imagine it being possible with modern technology. Whether you could hit one particular spot on the basketball might be trickier but given the probable future state of technology in an Aurora game, I think most people would accept that something like that would be possible without much suspension of disbelief. It's certainly a lot easier than creating the engines in the game :)
I'm not totally sure about that, but it still leaves the question of why you would bother. Unless you're trying for ecocide, there's no reason to throw unguided things at a planet from that sort of range.
My intention is not to create a perfectly accurate simulation but rather a game that has the feel of hard science. Gameplay and fun will always take precedence over physics and even though the game is a lot more 'hard science' than most, it is still going to be far more simplified than reality.
Steve
What? Treason!!
:)
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Again, that's not the problem. If we could do such things, why do we need midcourse corrections on spacecraft? The sort of thing you work on is more then adequate for a spacecraft that can correct its course, but if it can't, there's a problem.
We need mid-course correction for several reasons. The two big ones is that we are generally trying to do way, way harder things than shoot a largish planet. We are hitting specific target sites, or hitting the atmosphere at specific angles so that our fragile craft aren't destroyed, or going for narrow valid orbits on a planetary flyby maneuver. The second issue is one I mentioned earlier, the uncertainty of the position of an orbiting object increases geometrically with time. Many of our missions in the solar system (because of our sadly non-Aurora technology) take many, many months. The more interesting ones take several years, that just gives you enormously higher uncertainty than a shorter mission of a few weeks or a couple of months at most.
less than 7/1000 arc seconds
That's not as accurate as you think. While it sounds impressive, you'll need much less to be able to hit anything, particularly at the ranges you're proposing.
That's just flat out wrong. Borrowing the numbers Steve just used, from Neptune the Earth is approximately .55 arc seconds. 7/1000 arc seconds is enough to Bulls-eye all but the smallest States every time.
Comparisons to modern weapons are fundamentally flawed. To be able to do what you suggest, you'll need something that is as good if not better then top-of-the-line modern lab equipment. And it has to be military hardware. That's the kicker. It has to be able to work reliably and without handholding from a dozen PhD's.
Ok, now I can't even tell if you understand the meaning of science fiction. You don't look at things that barely work in the lab today and say "well I guess that will never work, ever" you are trying to extrapolate (with various degrees of realism, depending on the sort of setting you are aiming for) future capabilities. One of the totally valid ways to do that for near term capabilities is to look at things that barely work in the lab, and try to take those capabilities forward with similar behavior and polish to the modern things the new tech will be replacing.
The other thing that paragraph bugs me about it that I haven't even been doing what you are accusing me of! I have taken a handful of things from Steve's schematics (really just muzzle velocity and ship speed) and applied other traits from modern hardware. Not laboratory "dozen PhDs fussing over it" equipment, but actual, real, equipment, and conservative estimates of that equipment. When I pulled up an Arc Minute as a guide for the accuracy of modern guns (not arc-second like I said in my last post, whoops, the original post I did the math in has the right number though), I did so simply by finding a reference to actual, used in the woods to shoot animals by real people, hunting rifles. And I did that on purpose! I could have tried for a much more detailed measurement of modern military capabilities, say by noting that a torso is around a foot wide, and the longest recorded sniper rifle kill is 2707 yards, and calculating a still conservative accuracy of a modern sniper rifle (since it includes human inaccuracy) of 25 arc seconds. But I was fine with grabbing a quick, easy, and above all conservative number.
Same with that 7/1000 arc seconds number from the Hubble. The Hubble is the most well known orbital telescope, but it's not the newest or the most advanced, but when I wanted a number for stability of a satellite I didn't go trying to look at proposed capabilities for the James Webb, or try to search for the most accurate and stable satellite there was, I just grabbed the conservative number of a satellite's capabilities. The Hubble isn't in a lab somewhere with students nursing it's finicky systems along. It's actually up in space, doing stuff, taking pictures, finding planets, stars, and galaxies, and it has been for 21 years.
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We need mid-course correction for several reasons. The two big ones is that we are generally trying to do way, way harder things than shoot a largish planet. We are hitting specific target sites, or hitting the atmosphere at specific angles so that our fragile craft aren't destroyed, or going for narrow valid orbits on a planetary flyby maneuver. The second issue is one I mentioned earlier, the uncertainty of the position of an orbiting object increases geometrically with time. Many of our missions in the solar system (because of our sadly non-Aurora technology) take many, many months. The more interesting ones take several years, that just gives you enormously higher uncertainty than a shorter mission of a few weeks or a couple of months at most.
Using models of the solar system that we've had years to build, not days. I think it comes out in the wash.
That's just flat out wrong. Borrowing the numbers Steve just used, from Neptune the Earth is approximately .55 arc seconds. 7/1000 arc seconds is enough to Bulls-eye all but the smallest States every time.
True, assuming that is the only uncertainty involved, which it is not.
Ok, now I can't even tell if you understand the meaning of science fiction. You don't look at things that barely work in the lab today and say "well I guess that will never work, ever" you are trying to extrapolate (with various degrees of realism, depending on the sort of setting you are aiming for) future capabilities. One of the totally valid ways to do that for near term capabilities is to look at things that barely work in the lab, and try to take those capabilities forward with similar behavior and polish to the modern things the new tech will be replacing.
No, I'm pointing out that at the level of precision you are proposing, things start to break down. Period. I'm slightly skeptical of the sort of numbers involved for lasers, which are by nature more precise then kinetic weapons. Hubble achieves that sort of accuracy only after taking into account things like thermal expansion from solar heating. It isn't point and shoot. And if it's a manned craft, you'll have things like people walking about, pumps, fans, and all the other stuff of life aboard. Unless you have everyone stop and hold their breath, but then you're getting into my point about laboratories again.
And yes, I have had this debate before.
The other thing that paragraph bugs me about it that I haven't even been doing what you are accusing me of! I have taken a handful of things from Steve's schematics (really just muzzle velocity and ship speed) and applied other traits from modern hardware. Not laboratory "dozen PhDs fussing over it" equipment, but actual, real, equipment, and conservative estimates of that equipment. When I pulled up an Arc Minute as a guide for the accuracy of modern guns (not arc-second like I said in my last post, whoops, the original post I did the math in has the right number though), I did so simply by finding a reference to actual, used in the woods to shoot animals by real people, hunting rifles. And I did that on purpose! I could have tried for a much more detailed measurement of modern military capabilities, say by noting that a torso is around a foot wide, and the longest recorded sniper rifle kill is 2707 yards, and calculating a still conservative accuracy of a modern sniper rifle (since it includes human inaccuracy) of 25 arc seconds. But I was fine with grabbing a quick, easy, and above all conservative number.
Same with that 7/1000 arc seconds number from the Hubble. The Hubble is the most well known orbital telescope, but it's not the newest or the most advanced, but when I wanted a number for stability of a satellite I didn't go trying to look at proposed capabilities for the James Webb, or try to search for the most accurate and stable satellite there was, I just grabbed the conservative number of a satellite's capabilities. The Hubble isn't in a lab somewhere with students nursing it's finicky systems along. It's actually up in space, doing stuff, taking pictures, finding planets, stars, and galaxies, and it has been for 21 years.
No, the Hubble is a piece of lab equipment. It's unmanned, and totally dedicated to astronomy, so it can be totally motionless. When required, virtually nothing is moving erratically. It only operates with light, so you don't have to worry about things like recoil knocking it out of alignment. Oh, and the people tending it are PhDs. They just do it remotely.
The bigger question is why you want to do this. Even granting all of your wishes, we still have the small problem of the fact that you can only hit a state-sized target. Unless you wish to do ecocide, a guided weapon will be easier and cheaper to employ for a given effectiveness, assuming you're firing from somewhere around Jupiter or Neptune. Always. If you took a 1 megaton kinetic impact and distributed it randomly in the US, you would probably kill a few hundred people, and make us mad. If you hit New York, it would be far, far, worse, but New York is too small to hit unless you guide it. As for the cost of guidance, over any reasonable lifespan, you'll get it back in lower startup costs. Not to mention needing less ammo.
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I make it a habit of not bringing personal identities into internet arguments for a couple reasons, mainly because anyone can claim to be anything on the internet, and also because I don't like appeals to authority. I think that reasoned arguments (and lots of math) are the best way to go about things. However at this point we are really talking about more nebulous claims than can easily be demonstrated, and you've said "trust me" twice, so I suppose I'll return with the "I do this (examination and implementation of force and environment models to accurately propagate space craft and other heavenly bodies) for a living." I'm a software developer for the company I've linked to twice now, and the main developer of one of their propagation products.
I don't question your math, so much as the ability to actually implement it. Without the giving of names and creds I worked for the government as a physicist in this field and still colaborate on several projects. I resigned my formal government possition and accepted civilian support status and signed far too many forms to count that made it abundantly clear that if I was to share any of my work that I would get to spend a loooong time in a small cell with a big man named Bubba (my apologies to anyone named Bubba...) who will think I am really cute.
The simple fact that you have argued as intelligently as you have indicates that you also have an abundance of experience in this field. I do not question that. But as you are likely well familiar with, those of us in this field have very different ideas of what is possible when you actually get off this planet.
Calculating Sedna's orbit parameters from Earth is a much harder problem than getting a firing solution on Earth (from, say, Neptune). One of those involves propagating the position of an object 12750 km across a few (say 4) weeks forward in time from measurements taken 4.6E9 km away.
I am not saying that calculating it is that difficult. It would be giving adequate time to collect the necessary data. Collecting the data will take time. How long it would take for a race with this level of tech, I don't know. I do leave that to Steve. I would base a kinetic projectile's maximum range/accuracy on the level you have surveyed a system. (perhaps a mod of some sort? to prevent the jump in and blast the pop from extreme range). The problem is like laying any type of non-guided weapon system. The math is easy. Getting the darned thing to go where the numbers say it will is nearly impossible and has more to do with luck than anything. Ballistic calculators can tell us EXACTLY where a bullet should go with a given sectional density/ballistic coefficient/velocity/air temp and pressure/crossing influences/movement of the earth under it/etc. etc. ad nauseum. Problem is those bullets/shells/ etc always spread out unpredictably. Otherwise we would never miss a target. Like I said, the math can be exact but it never describes reality when it does.
I'm also not sure how you got that I was trying to shoot at Earth from out past Sedna
You implied you were shooting from beyond Neptune, as I understood it. If that was not your intention then I am sorry for the misunderstanding. But even from Neptune, it would require something other than more advanced ways of making a projectile go fast. Somehow you have to keep it from interacting with the interplanetary medium. Jupiter would be considerably easier, but keeping an unguided projectile from deviating to the small degree that is necessary to deflect it would be almost impossible without some form of 'handwavium' that somehow repelled the particles without imparting any deflection.
You also somehow need to keep the launcher and projectile from interacting in any way. Which would be inconducive to firing.
I also assume that in Aurora their algorithms and computers will be no less effective than ours, and will probably be at least an order of magnitude better.
I hope so. Ours are getting better faster than I can keep up. (Ok, I quit trying to over a decade ago. I really haven't moved much past the point when I was happy to program one to generate a number between one and six in school.)
The crux is getting the data. It takes time to measure movements, densities, etc. And I doubt a dedicated warship is going to pack a large number of astrophysics types in its crew just to analyse reams of data so they can figure out how to shoot at a planet. Especially when mass has such a big impact on a ship and its ability to get from point a to b. I know what my superiors would have told me. 'Just get closer.' Which is why when we shoot those asteroids or comets, we get REALLY close. It is a lot easier to do than packing all the gear into a vehicle so that it can do it from a loong ways off.
Which is why I would beleive that most of those distant 'planet killers' would most likely be a missile launched from a long ways out that can follow the planet. The firing solution is so much simpler and chance to hit is immeasurably higher if the vehicle can adjust to its target. By the time it reaches the planet a kinetic kill missile will likely be going a lot faster than the rail gun. This is why we shoot Tomahawks at targets instead of 16" shells. The shells are way cheaper. Just hard to know if you will actually hit anything.
According to NASA fact sites the Hubble telescope has a Pointing Accuracy of 7/1000th of an arcsecond, so platforms in space can align to a target with a great deal of stability. Now granted it's another ball game entirely to maintain stability on an object accelerating on a huge cloud of plasma. I suppose Steve could model accuracy penalties while accelerating, but I think he could also handwave that requirement away. We have a variety of ways already to mitigate instability and jolts for both turrets on naval vessels and more rudimentary science experiments, and it would seem fairly reasonable (to me anyways) to just say, "eh, they have something like that".
Now as far as how long it takes the platform to regain stability after a shot, that depends on the mass of the platform, the offset of the barrel from the center of mass, the abilities of the control system to torque the craft, and a heck of a lot of other things that Steve is not modelling. Seems reasonable to just say that the spaceship is able to damp out it's orientation by the time the next shot is ready.
Pointing something isn't the huge problem. We can aquire a target with a high degree of precision. It is the act of firing that will mess everything up. When Hubble does this it is being held as 'motionless' (I hate that term, sorry) as possible. Firing a projectile will upset this profoundly. I agree that the next shot will not occur until the platform has stabilized, and that could be assumed under the rate of fire. But the platform and launcher are moving and deforming during the shot, and this deviation is impossible to predict within certain levels of certainty. If you are firing a projectile at the limit of what your technology is capable of using (and why wouldn't you on a military weapon) you will only be capable of a certain level of accuracy over distance. The platform will deviate and the environment will then act on it. They accuracy a weapon is capable of - I don't know. But if Steve wished to limit it to much shorter distances than what some people are talking about - it is supportable. Shooting from Earth to Mars - yeah. Might not hit a spacestation/ship/habitat, but the planet would be easy. If you really need to hit the little target either shoot alot (artillery barrage) or firs a missile (tomahawk).
Hitting a Callisto from Earth with an unguided weapon. Better shoot a lot. Hitting Earth from Neptune - hope Steve doesn't track ammo because you will need a lot.
For a normal unguided kinetic slug going through a coil gun or railgun you don’t have to worry about the G force destroying the slug since the magnetic forces apply to the entire projectile fairly uniformly.
Not a good arguement. Gravity applies (as far as we know) perfectly uniformly. Check what happens to a bridge if you exceed its bearing strength. Even or not, exceed what it can take and it comes apart. When you apply a quarter million G's plus to an object - even or not - it will deform unpredictably. You can try to argue that it is being 'pulled' as much as it is being pushed, but that defies Newton's Third Law. In the end, the slug is going to go a direction and the launcher won't be. And they are going to act on one another with the slug absorbing a LOT of energy. It will deform. So will the launcher. And just how much at a given point will be impossible to predict beyond a certain degree.
I base this on the entirety of our civilized history, which has shown our weapons becoming longer-ranged, higher powered, and more accurate over time.
Our weapons have better range and accuracy, but it is due to the type of weapon. Guided munitions are a god send when the bullets start flying. But our accuracy and range with unguided munitions hasn't actually changed much at all since WWII. That is the reason we don't have bigger and better cannons (for the most part). We have the ability to factor in more variables (which is why the Germans considered our use of artillery with TOT fire missions a violation of the rules of war in WWII), but the shell is only so accurate. If they had gotten lots better, the battleships wouldn't be parked, and destroyers that are now the size of WWII cruisers would pack more than a single 5" gun. The M1 fires a shell no bigger than those of the large Soviet Tanks of WWII. We have better first hit percentages, but the range hasn't gotten much longer. That was why when I did my time overseas we used the M1's laser designators to light up our targets for the helos Hellfire's that could find the target farther out than the M1 could reliably engage.
Ok, this will likely be my last post on this. I have stated what I feel to be accurate. What the future holds is going to be a lot different that any of us can see. I mostly have pursued this to give support to the fact that if Steve wishes to give max ranges to unguided projectiles - it is realistic. They don't have to be interplanetary weapons if he doesn't want them to be. If he wants to say that 10+km/s projectiles are only accurate over a few light seconds - so be it. If he wants to shut it off at a light minute - that is very realistic (probably optomistic).
Now guided planet killers ( missiles), those could be a problem.
( I will try to find a public reference to the particle densities in interplanetary space. I don't have any on hand but I know I have read several college papers that stated this fact, so it has to be in the public forum somewhere. I will PM you references that I find if you are truly interested. I suspect that it could be googled to come up with results anymore.)
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There are plenty of people in this thread with more practical knowledge and maths skills than myself so I am not going to get involved in any detailed discussions about shooting Earth from Neptune. However, the Earth is 12,000 kilometers in diameter and Neptune is about 4,500,000,000 km away, so the ratio is about 375,000-1. This may be a simplistic analogy but that is like putting a basketball on top of the Empire State building in New York (or perhaps having it move slowly across the NYC skyline) and trying to shoot it from the Washington Monument (about 435,000-1). Difficult but you could imagine it being possible with modern technology. Whether you could hit one particular spot on the basketball might be trickier but given the probable future state of technology in an Aurora game, I think most people would accept that something like that would be possible without much suspension of disbelief. It's certainly a lot easier than creating the engines in the game :)My intention is not to create a perfectly accurate simulation but rather a game that has the feel of hard science. Gameplay and fun will always take precedence over physics and even though the game is a lot more 'hard science' than most, it is still going to be far more simplified than reality.
Steve
No wish to step on your toes, and my most sincere apologies. I really look forward to this (more than I would have expected for a computer game. I have never found one that compared to playing on a tabletop with my family. :) )
Whatever you decided, that is fine. But when I see something claimed to be possible that is most likely the opposite with our current understanding, I have a nasty habit of speaking up. (My wife hates this at gatherings. I am not always the ideal party guest.)
The fact you have chosen to undertake in your spare time a task that PAID programmers have shied away from as 'to complicated' has earned you my respect. The fact you put up with the rest of us babblers only raises my opinion.
Thank you.
EDIT
I will admit that I am beginning to suffer withdrawl from your fiction though.... ::)
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Furthermore I cited earlier that those inaccuracies for a high quality civilian-available hunting rifle were around an arc second.
I'm sorry, I need to respond to this one. I was also a competitive shooter (used to be on the Army Rifle Team, but now you are probably getting enough on me that you could possibly dig up who I am.) A really good rifle shoots sub MOA. Not sub SOA. That would be wonderful. A 10.47 inch group at 1000 yds is an arc minute. So the difference between shooting (arc minute) and looking (tiny fraction of an arc second) are big. Properly bedded down for a 1000m match, I can easily hold the rifle on a bullseye (probably an arc second give or take). Getting that bullet to do what I wanted was always a pain.
An arc minute is 1/3440 (approx) of the radius. An arc second 1/206,500 (rounding off a bunch). So if Neptune to Earth is 1 to 375,000 it is about 2/3rd of an arc second. That is just really small to shoot. High precision shooting instruments today can only do about one percent of that with a flight time of about a second, and as you point out the longer the flight time the greater the error becomes. Sub MOA is easy at 100m. It is record breaking at 1000m. Range compounds error and introduces new ones.
It just feels wrong to say that not only has the accuracy improved by a factor of 100 times, but it can do it when the flight time has been increased over a half million times for a one week trip. An increase of one half a billion times over what we can do now...Maybe it will happen one day.
Ok, really am done now....
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Absolutely no need to stop posting, informed opinions are of course welcome.
Rather, the issue of flared tempers and confrontation can be reduced, though with professionals it is a common failing to take 'incorrect' comments personally, something I myself have failings with. Arguing on the internet, as aggravating as it may be is fun to be honest, if those you argue with are knowledgeable enough.
As stated, Steve has the final word, not in reality, but rather what will be implemented on Aurora based on a mixture of reality and fun. But our discussions on reality certainly still have an effect. It was the noting that the exhaust of the engines exceed the speed of light that prompted that change. Discussion on this, if it can be modeled and be fun might find its way into Aurora as well.
What I'm thinking is the accuracy of unguided weapons affected by three effects.
First is target lock. Just knowing a ship is there and where it is doesn't mean you know where it is within one meter. There will still be errors in a sensor target lock, possibly off by meters or even kilometers, depending on how close the ship is to the firing ship and the technology of your sensors, affected even more by slight measurement deviations in velocity(even ignoring evasive maneuvers) when it comes to target prediction. Including this as a gameplay mechanic would make missiles more useful due to course corrections and onboard sensors(whether they need a boost is debatable) and require snipers to pack better sensors than shorter range ships. This could in effect be a soft limit on range, requiring longer ranged vessels to have more and better sensors. This might also provide use for the idea of overlapping sensors, such as a ship following 1mil km behind might increase the locking accuracy while not affecting the range of sensors, as with planet based sensors. Downside is micromanagement so this will need to be judged from a fun/realism ratio of course.
Second is pointing accuracy. Realistic based on the Hubble Telescope, the effect might be negligible. But I'm pointing this out to be complete.
Third is deformation and warping during firing. This could be on the projectile or it could be the rails. This can be improved with technology to allow increasingly accurate weapons (compensators or better materials), but is random enough to have a random effect on every shot. The size and speed of the projectile could also have an effect, with larger and slower (but same MJ) projectiles being more accurate than harder hitting smaller projectiles. This is something where it can be safe to step away from reality and pick values tuned to the desired maximum range. Ingame the rails are too short for current modern materials, if I read the comments correctly, so it is already handwavium where gameplay suitable values of deformation can be selected.
Combine all three of these variables and you can have fun soft limits on killing range, giving value to moving close but still keeping longer sniping possible with enough investment. You might still have the issue of attacking planets in general, but hitting a PDC would be difficult. So you can keep bombing planets, eliminating population(less if they take shelter) and infrastructure, having a slight if any effect on industry (kill plenty of civilian industry, but 1000 rare material mines(as opposed to millions of regular material mines) spread over the surface of the planet would be hard to hit, even if every shot destroys a 10km radius(thumb-sucked value). To be able to target these you need MUCH higher accuracy than just hitting a planet. Secondary killing effects such as tidal waves and radiation and climate wrecking smoke clouds is a different story, but potentially manageable with terraforming. Don't get me wrong, MANY people will die, but either a VERY extended random bombardment or a more accurate closer attack would be needed to disable a planet's war ability. In my non-expert opinion.
Well, in closing, I dislike hard limits, even if its actually generous like several light-seconds. I prefer these range limits to be based on practicality and dependent on technology with diminishing returns. That said, intuitive gameplay and fun takes precedence. As for planets, its been noted that hitting them is easy, but I believe that hitting something actually important on the planet(as opposed to just killing people) is much more difficult and cracking a planet in two to kill all of it over extreme range is cost impractical.
EDIT: What's with me and commas?
EDIT2: Actually, more I think about it the more I like it. From the rules post the only difference between the 4800 MJ 1kg and 2kg variations is the energy required. An accuracy penalty for exceeding your race's Railgun vs Maximum projectile maximum would make this parameter tuning more important and possibly lend value to fighters. Short-range harder-hitting rails carried by small faster fighters vs accurate but less powerful (per ton anyway, will be larger so still more powerful in absolute terms) could make fighters practical again in Newtonian Aurora. Or at least FAC ships.
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No wish to step on your toes, and my most sincere apologies. I really look forward to this (more than I would have expected for a computer game. I have never found one that compared to playing on a tabletop with my family. :) )
Don't apologise. That wasn't a request to halt the debate. I was just pointing out the reality isn't the final arbiter of what will end up in the game :). I don't mind debates at all - I only mind if any comments are made that might be construed as personal attacks rather than contributing to the debate.
Whatever you decided, that is fine. But when I see something claimed to be possible that is most likely the opposite with our current understanding, I have a nasty habit of speaking up. (My wife hates this at gatherings. I am not always the ideal party guest.)
I just read this out to my wife who LOL'ed as this is usually me :)
The fact you have chosen to undertake in your spare time a task that PAID programmers have shied away from as 'to complicated' has earned you my respect. The fact you put up with the rest of us babblers only raises my opinion.
I greatly appreciate the community aspect of Aurora. For both Aurora and Starfire Assistant, the majority of the functionality has come from user suggestions.
I will admit that I am beginning to suffer withdrawl from your fiction though.... ::)
Me too! I miss writing it. At the moment I am leaning toward a 2300AD (GDW) flavour for the first Newtonian Aurora campaign. I haven't come up with the exact history yet but I may go for my largest number of starting nations yet :). The thought of the potential for that campaign is keeping me going as I work my way through all the code changes.
Steve
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Me too! I miss writing it. At the moment I am leaning toward a 2300AD (GDW) flavour for the first Newtonian Aurora campaign. I haven't come up with the exact history yet but I may go for my largest number of starting nations yet :). The thought of the potential for that campaign is keeping me going as I work my way through all the code changes.
Steve
Is your NATO vs Soviets campaign still playable after all your changes? I know Newtora (get it? Newtonian Aurora) is the same executable but different to regular Aurora.
It would be nice to get a conclusion to it ... *hint* *hint* ;)
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Is your NATO vs Soviets campaign still playable after all your changes? I know Newtora (get it? Newtonian Aurora) is the same executable but different to regular Aurora.
It would be nice to get a conclusion to it ... *hint* *hint* ;)
No, Newtonian Aurora is a totally different game. It's difficult to convey just how major the changes are but it is a completely new playing experience. However, that doesn't stop me finishing the NATO vs Soviets game. I am now maintaining two different code bases and I can still play that campaign in Standard Aurora.
Steve
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No, Newtonian Aurora is a totally different game. It's difficult to convey just how major the changes are but it is a completely new playing experience. However, that doesn't stop me finishing the NATO vs Soviets game. I am now maintaining two different code bases and I can still play that campaign in Standard Aurora.
Steve
Ah, when you originally started I thought I seen you mention that you were using the same code base which I thought weird at the time but I must have read it wrong.
Anyways, looking forward to Newtora and maybe even a Chinese resurgence - The Long March into Space!
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Don't apologise. That wasn't a request to halt the debate. I was just pointing out the reality isn't the final arbiter of what will end up in the game :). I don't mind debates at all - I only mind if any comments are made that might be construed as personal attacks rather than contributing to the debate.
Oh, I wasn't stopping for that. I had stated what I felt to be accurate. Yonder has a different opinion, which I respect even if I don't agree. In that neither of us has actual knowledge of what will happen - or what another race may develop, I saw no point in continuing. I simply agree to disagree on what would be possible. I leave it to you to decided what will be best for the game.
I greatly appreciate the community aspect of Aurora. For both Aurora and Starfire Assistant, the majority of the functionality has come from user suggestions.
I have been amazed at what I have read so far in this thread, and your responses. That is what got me to throw in my two cents at all. As I said before, you have my respect. Most folks have to be paid rather well to listen constructively to others (counselors and psych make good $). You do it to try and improve what you are doing.
To paraphrase a saying in a book: Don't criticize a fool, as he will only hate you for it. But criticize a wise man and he will thank you.
Me too! I miss writing it. At the moment I am leaning toward a 2300AD (GDW) flavour for the first Newtonian Aurora campaign. I haven't come up with the exact history yet but I may go for my largest number of starting nations yet :). The thought of the potential for that campaign is keeping me going as I work my way through all the code changes.
Oh, now I have to sit patiently waiting on perhaps TWO stories.
How cruel...... ;D
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It seems that to a large degree, research seems to be of the engineering type rather than the classical science fiction Astounding Breakthroughs In Understanding type. You can develop a faster engine or a more accurate laser, but developing teleporters or biological starships or machine intelligence doesn't happen outside of RP.
One thing I'm particularly interested in is stellar-scale construction such as dyson spheres or (more likely) ringworlds/orbitals/halos.
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Even in a 'larger' game like Space Empires, those are absurdly lategame.. they basically never got built except for kicks. 8)
Tho you could build large scale Orbital Habitat and RP them as rings.
And technically you can build a dyson sphere already if you want to. There's just no point because you cant get energy from the sun nor use it for anything.
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On ship structure and acceleration:
Given that we have a rough measure of how resistant TN materials are, would it be possible to enforce a ship size restriction based on weight and acceleration?
Since the acceleration of the ship comes from the engines, the front bits will press onto the back bits and there is a "limit" to how big you can build a ship before the walls crumple under the ever-so-huge nuclear torch drives.
Might be in the hundred thousand tons or so but I have qualms about imagining what goes on in a twenty million ton orbital habitat that's under tow by a fleet of tugs. 1G on that? Your structure might just break if your materials aren't good enough.
EDIT:
basically, I'm suggesting a safe acceleration limit based on (weight of ship / armor tech level), capped to 3x racial gravity tolerances.
And yes, this means that an unladen freighter will have a higher acceleration limit than a fully laden one, which is only expected.
Exceeding the limits might cause equipment to "age" far faster than usual, based again on percentage exceeding the limit. Exceeding racial gravity tolerances might cause crew death.
EDIT EDIT:
Might balance gravity in an interesting way too.
Higher G races make better crews but have less qualifying planets. Low G races can't accelerate as fast but can colonize many moons.
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On ship structure and acceleration:
Given that we have a rough measure of how resistant TN materials are, would it be possible to enforce a ship size restriction based on weight and acceleration?
Since the acceleration of the ship comes from the engines, the front bits will press onto the back bits and there is a "limit" to how big you can build a ship before the walls crumple under the ever-so-huge nuclear torch drives.
Might be in the hundred thousand tons or so but I have qualms about imagining what goes on in a twenty million ton orbital habitat that's under tow by a fleet of tugs. 1G on that? Your structure might just break if your materials aren't good enough.
EDIT:
basically, I'm suggesting a safe acceleration limit based on (weight of ship / armor tech level), capped to 3x racial gravity tolerances.
And yes, this means that an unladen freighter will have a higher acceleration limit than a fully laden one, which is only expected.
Exceeding the limits might cause equipment to "age" far faster than usual, based again on percentage exceeding the limit. Exceeding racial gravity tolerances might cause crew death.
EDIT EDIT:
Might balance gravity in an interesting way too.
Higher G races make better crews but have less qualifying planets. Low G races can't accelerate as fast but can colonize many moons.
I like the suggestion that certain types of things have limits on acceleration. I would add a "space station" switch. You can make the vessel cheaper, but max accel, even under tow, is only about .1G. It's not a big issue for ships unless you get unreasonably large. And by that I mean into the hundreds of thousands if not millions of tons, particularly with TN materials.
The racial acceleration thing is already included.
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On ship structure and acceleration:
Given that we have a rough measure of how resistant TN materials are, would it be possible to enforce a ship size restriction based on weight and acceleration?
Since the acceleration of the ship comes from the engines, the front bits will press onto the back bits and there is a "limit" to how big you can build a ship before the walls crumple under the ever-so-huge nuclear torch drives.
Might be in the hundred thousand tons or so but I have qualms about imagining what goes on in a twenty million ton orbital habitat that's under tow by a fleet of tugs. 1G on that? Your structure might just break if your materials aren't good enough.
EDIT:
basically, I'm suggesting a safe acceleration limit based on (weight of ship / armor tech level), capped to 3x racial gravity tolerances.
And yes, this means that an unladen freighter will have a higher acceleration limit than a fully laden one, which is only expected.
Exceeding the limits might cause equipment to "age" far faster than usual, based again on percentage exceeding the limit. Exceeding racial gravity tolerances might cause crew death.
EDIT EDIT:
Might balance gravity in an interesting way too.
Higher G races make better crews but have less qualifying planets. Low G races can't accelerate as fast but can colonize many moons.
Really good point about racial gravity tolerances. I will definitely add something along those lines at some point. Maybe some type of crew grade penalty at lower levels and chance of crew injury/death at higher levels. I will have to introduce some type of penalty for undermanned ships for that reason, plus I will likely be adding radiation effects on crews as well. The radius of damage from nuclear weapons might be far less in space but the radius of radiation effects is actually greater than in atmosphere.
Some form of structural limitation on large ships is also a good idea. I'll give some thought to the mechanics of that.
Steve
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Isn't it going to be antigravity minerals or somesuch? Doesn't seem to square with racial acceleration limits. Unless it's like, you can counter gravity but not manipulate it.
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Ill bring up a suggestion I made a while back for accelerations;
Up to a certain multiple (say 3x) of maximum gravity tolerance, just suffer penalties (such as crew grade). Beyond this (up to say 5x), disable the ability to actually give orders to ships, beyond perhaps a 'stop accelerating', which will take a while to take effect (like current order changes). Im not sure if weapons should still work at this stage, maybe only totally automated things like PD. Going even further results in the same penalties and crew death.
Live cargoes such as troops and colonists might have their own limits, so while your space crew can handle 4.5g acceleration, the troops might only be able to bear 3g, and the colonists 1.5g, assuming theyre even of the same race.
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Having an acceleration limitation separate from racial tolerances is IMO a good idea. The larger a ship is the less acceleration it should be able to take (assuming it doesn't grow purely in width) for the same reason that a building can only get so tall. Think of the engines as being the base of the building, with the acceleration the strength of the gravity. As the building gets taller for the same amount of gravity more and more force is being placed on it. (Making the building wider, but no taller, brings no change). As a spaceship gets larger it's like making the building larger, the portion of it that corresponds to a wider building doesn't change the force, but the portion that corresponds to the building getting taller requires a stronger building.
This is due to the square-cube law. As the building/spaceship gets larger the force on it diminishes with it's surface area (the square) but increases with the mass (the cube).
The reason that this is necessary from a gameplay standpoint is that it's the only thing that will allow small ships to be faster than large ships. As it is right now (rightfully IMO) the engine techs will be "Thrust per Ton" modified by a thrust modifier and a size modifier. There isn't anything stopping you from designing both your fighter and your battleship engines from being +100% thrust, then putting 20% engine mass on them, and having them each go the same exact speed.
However we don't want an arbitrary size restriction stopping that from happening, we want organic and realistic rules that are the same across the entire spectrum of hull sizes. I can see two ways of doing that, the first similar to what JSeah is talking about.
1a. Maximum acceleration limits for ships based on structural strength and size:
Amax = ArmorStrength / Tonnage1/3
Where ArmorStrength would be a multiplier assigned to each tech level of armor.
For example:
If your ArmorStrength at your tech level was 200 then you'd have some of the following max Accels:
| Tonnage | MaxAccel (m/s2) |
| 250 | 31.7 |
| 1000 | 20 |
| 3000 | 13.9 |
| 15000 | 8.1 |
If you research the next level of armor, your ArmorStrength would go up (say to 300) and your max accelerations for ships with the new armor would go up. You could either put on new engines, or more of the old ones.
1b. Another possibility is to modify the above formula by adding in armor thickness to the mix. On one hand this makes a lot of sense, if you are making a stronger ship then the structure can take more wear and tear, on the other hand how exactly could we calculate that? The armor is just along the outside of the ship, so the larger the ship the less the armor can help the internals at the center of the ship. I would have to dig out my Structure textbooks from college to see how that scales, and I don't want to. It's also ignoring the possibility of internal bulkheads, which you would obviously reinforce if you were going for more acceleration resistance than weapon resistance.
Lets try adding in a multiplier based on the Square Root of the armor thickness, and see what that gives us.
Amax = ArmorStrength * ArmorThickness1/2 / Tonnage1/3
For example:
If your ArmorStrength at your tech level was 200 then you'd have some of the following max Accels:
| Tonnage | Armor Thickness | MaxAccel (m/s2) |
| 250 | 1 | 31.75 |
| 1000 | 2 | 28.28 |
| 3000 | 4 | 27.73 |
| 15000 | 10 | 25.64 |
If we wanted to go this route someone could either try to juryrig up some math to polish it up, or we could decide on the Armor Thickness effect that gives us the feel that we are aiming for. Personally I think that that last equation makes it too easy to make super fast big ships, but that original one that doesn't take into account armor thickness is probably too penalizing.
2. I mentioned a second way, also based on the square cube law (as I suppose all realistic size mechanics would be). I'm not going to try to develop any equations for them, but the idea would be that the heat developed by an engine scales linearly with it's thrust (aka the tonnage) but the heat can only escape with respect to the surface area (aka a multiple of tonnage2/3. You could use calculate some sort of maximum thrust ceiling that was more favorable to small engines than big ones. I like the structure-based approach much better for a couple reasons:
1. Steve hasn't modeled thermal effects that much before, so it's an odd mechanical addition to the game.
2. As described you could actually get around the effect with a lot of small engines on your big ship, which wouldn't work IRL because the engines would be bleeding heat into each other, so the ones in the center would overheat, so I guess you'd need to work ship-wide to find the total engine tonnage.
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Another thing I realized about doing this:
If we impose limits onto maximum accelerations of equipment, this nicely leads into railgun-assisted launches. At least, you can tack a number onto it and say "this size railgun can impart total X velocity to launch, capped by max accel and railgun length, or by energy if the railgun is too low powered"
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Not sure if this has been brought up yet, but with regards to railguns and launching things...any chance we might see an EM 'catapult' for launching fighters or gunboats from large carriers?
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Not sure if this has been brought up yet, but with regards to railguns and launching things...any chance we might see an EM 'catapult' for launching fighters or gunboats from large carriers?
Unlikely for physics reasons. If we assume the crew can take 10Gs, a catapult will be about 2.5 km long for a 1 km/s delta-V. I don't think we'll have ships that big.
Yonder:
I'm not so sure that there are such fundamental structural limitations, particularly for warships.
First off, there are two ways that a ship can suffer structural failure (provided we model it as a column). The first is buckling, while the second is simple yielding. The resistance to yielding scales directly with area, or with the square of length scaling, or the 2/3 power of mass scaling, provided we assume that all vessels are of the same proportions. Resistance to buckling scales with the fourth power of radius, and with the 4/3 power of mass scaling.
The point is that bigger vessels will have an advantage in resisting buckling, and a disadvantage in resisting yielding. I'm not sure where the two lines cross, but as I said earlier, I don't see it as being a major problem for reasonably-sized vessels.
On the other hand, if you do use armor as part of the structure (and there's no reason not to) military vessels will most likely be capable of higher accelerations then civilian vessels. Then again, when said cargo ship is empty, he can pretty much go as fast as he wants.
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The point is that bigger vessels will have an advantage in resisting buckling, and a disadvantage in resisting yielding. I'm not sure where the two lines cross, but as I said earlier, I don't see it as being a major problem for reasonably-sized vessels.
But when this is a missile mounted in a railgun, then the question becomes relevant.
True, a crew can't take the accel of a railgun launch. But missiles are unmanned.
True, a missile is small compared to a ship and TN materials are unobtanium-strength. But likewise, this is some massive accelerations here.
I still want that railgun-assisted missile launcher.
And I don't want to see too many engines on a multi-million ton orbital.
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But when this is a missile mounted in a railgun, then the question becomes relevant.
True, a crew can't take the accel of a railgun launch. But missiles are unmanned.
True, a missile is small compared to a ship and TN materials are unobtanium-strength. But likewise, this is some massive accelerations here.
I still want that railgun-assisted missile launcher.
And I don't want to see too many engines on a multi-million ton orbital.
Are you sure you got the right quote? I was talking more about ships during the post on structure.
I can see missiles being launched with some velocity. If the missile can take 100 Gs, the launcher only needs to be 500 meters. Still too long. For 1000 Gs, the launcher is 50 meters. So I would say that it is possible for a few km/s for missiles, but not much more.
And please note that in the absence of artificial gravity, an orbital hab is not a cylinder. It's a disc. I would put an accleration limit on certain components, such as orbital habs and cryo spaces.
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However we don't want an arbitrary size restriction stopping that from happening, we want organic and realistic rules that are the same across the entire spectrum of hull sizes. I can see two ways of doing that, the first similar to what JSeah is talking about.
1a. Maximum acceleration limits for ships based on structural strength and size:
Amax = ArmorStrength / Tonnage1/3
Where ArmorStrength would be a multiplier assigned to each tech level of armor.
For example:
If your ArmorStrength at your tech level was 200 then you'd have some of the following max Accels:
| Tonnage | MaxAccel (m/s2) |
| 250 | 31.7 |
| 1000 | 20 |
| 3000 | 13.9 |
| 15000 | 8.1 |
If you research the next level of armor, your ArmorStrength would go up (say to 300) and your max accelerations for ships with the new armor would go up. You could either put on new engines, or more of the old ones.
I really like the idea in general and the above suggested formula specifically. If we ignore thickness for simplicity but instead use the current armour strength as a measure of 'current materials technology', we can assume that as armour increases in strength, the materials from which the entire structure of the ship is constructed, improve at a similar rate. This idea of using the unspecified material from which the entire structure is constructed avoids the complication of armour thickness as that is just around the exterior of the ship. Armour strengths at each tech level are as follows:
60, 80, 100, 125, 150, 180, 225, 260, 310, 375, 450, 560.
Bearing in mind that engine technology improves as well and that at low tech levels the acceleration rates will be low anyway, the above formula should be fine.
Steve
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I really like the idea in general and the above suggested formula specifically. If we ignore thickness for simplicity but instead use the current armour strength as a measure of 'current materials technology', we can assume that as armour increases in strength, the materials from which the entire structure of the ship is constructed, improve at a similar rate. This idea of using the unspecified material from which the entire structure is constructed avoids the complication of armour thickness as that is just around the exterior of the ship. Armour strengths at each tech level are as follows:
60, 80, 100, 125, 150, 180, 225, 260, 310, 375, 450, 560.
Bearing in mind that engine technology improves as well and that at low tech levels the acceleration rates will be low anyway, the above formula should be fine.
Steve
I'm going to disagree rather strongly with the specific formula. I like the one that includes armor thickness better, as it provides a distinct gap between military and civilian vessels, particularly at larger sizes. For one thing, the armor should be included in the hull structure. For another, it provides a tradeoff between armor and speed, which turns Jackie Fisher's claim that "Speed is armor" on its head. I guess my biggest problem is that instead of being a penalty on bigger ships, it's a sharp limit. If you wish to build something at 60,000 tons (which I have done) it just won't go that fast no matter what.
A couple of other issues. First, how is the limit measured? This actually applies to all formulas. Is it for the full-load mass, the empty mass, or the current mass? For another, at low tech levels, a civilian ship will have absurdly low accelerations. A "standard freighter" (the one outlined in the tutorial, or it's equivalent with 5 bays) is limited to around 1.8 m/s2 at the beginning. That may be normal, or it may be a major headache. However, the same ship at the end is limited to around 17.3 m/s2, which seems a little high for a civilian ship, but low for a military vessel.
Just my opinion, but I would include armor thickness as well, which would allow more flexibility for the player in determining the capabilities of his vessel.
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I'm going to disagree rather strongly with the specific formula. I like the one that includes armor thickness better, as it provides a distinct gap between military and civilian vessels, particularly at larger sizes. For one thing, the armor should be included in the hull structure. For another, it provides a tradeoff between armor and speed, which turns Jackie Fisher's claim that "Speed is armor" on its head. I guess my biggest problem is that instead of being a penalty on bigger ships, it's a sharp limit. If you wish to build something at 60,000 tons (which I have done) it just won't go that fast no matter what.
A couple of other issues. First, how is the limit measured? This actually applies to all formulas. Is it for the full-load mass, the empty mass, or the current mass? For another, at low tech levels, a civilian ship will have absurdly low accelerations. A "standard freighter" (the one outlined in the tutorial, or it's equivalent with 5 bays) is limited to around 1.8 m/s2 at the beginning. That may be normal, or it may be a major headache. However, the same ship at the end is limited to around 17.3 m/s2, which seems a little high for a civilian ship, but low for a military vessel.
Just my opinion, but I would include armor thickness as well, which would allow more flexibility for the player in determining the capabilities of his vessel.
For some reason I was reading the formula as G rather than m/s2 :), which of course makes the limits about 10x higher :)
I'll read the original post bearing that in mind.
Steve
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Hull Reinforcement
next to the existing
Armor
Hull reinforcement could scale off armor tech as well as its own tech?
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I second Byron that there should be some way that the player can design the ship in order to squeeze a little bit of speed out for the same amount of mass. Maybe in addition to "Armor" there could be a second "Internal Bulkhead" category? Multiple levels of this would mass much heavier than Armor though, because Armor is for the surface area, but Bulkheads are for the whole volume of the ship.
Then maybe the ship's number of 'Internal Bulkheads', in addition to increasing the maximum acceleration, adds to the HTK of every component or something like that.
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I second Byron that there should be some way that the player can design the ship in order to squeeze a little bit of speed out for the same amount of mass. Maybe in addition to "Armor" there could be a second "Internal Bulkhead" category? Multiple levels of this would mass much heavier than Armor though, because Armor is for the surface area, but Bulkheads are for the whole volume of the ship.
Then maybe the ship's number of 'Internal Bulkheads', in addition to increasing the maximum acceleration, adds to the HTK of every component or something like that.
Instead of adding to components HTK, why not let it have its own HTKs? So it could soak up hits (and get destroyed) that would otherwise hit components, making an interesting option for meson defence.
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Instead of adding to components HTK, why not let it have its own HTKs? So it could soak up hits (and get destroyed) that would otherwise hit components, making an interesting option for meson defence.
Probably should have a modifier for inverse crew effectiveness as well. . .
By that I mean the more internal bulkheads the more difficult it is for the crew to move about, repair things, reload weapons, etc.
You can see that effect in modern naval vessels. . . it takes training to be able to move through those small corridors effectively.
Just something to think about :)
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It sounds to me that these bulkheads would increase not only the total volume of a ship, but also its density. Now, it seems that right now vessels are assumed to be .1 x density of steel (or whatever) to account for a great deal of any ship being open space or at least somewhat less dense than the primary hull components.
I could definitely see adjusting these values as an interesting way to differentiate commercial/military ships.
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Current vessels are .1x the density of water, which comes out to about .013x the density of steel.
And I'm fairly certain that Steve isn't going to mess with variable density any time soon.
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Well, I'd like an overall coefficient that is raised by a lot of armor or whatever, easy to see for the player;
But I agree it won't happen.
As for Crew tolerances, can you just calculate it as
A Crew before damage taken
B Crew lost by hit
C Crew Max
D Crew Grade Points
E Task Force Training Value
(1-((B/C)*A/C))*D
&
(1-((B/C)*A/C))*E
Example:
Ship: 1000 Crew Max, 2000 Grade Points, 80% TFV
Ship has already lost 100 Crew, 900 Remain; Current Grade Points: 1800, TFV: 72%
The ship loses 90 Personnel on an attack.
(1-((90/1000)*900/1000))*1800 = 1654.2 Crew Grade Points
(1-((90/1000)*900/1000))*72% = 66.17% TFV
Additionally, a modifier of % Crew Lost should apply as a negative to training speed.
This would certainly give a noticeable penalty to losing crew to anything in general.
It would not, however, seriously hamper combat capability if synchronous fire is not required and the crew is green to begin with; Applying the crew lost modifier as a bonus to the maintenance clock speed might achieve that.
Now idea for civilians, though... Apply it to cargo handling multiplier and work speed? ???
Edit; Sorry if numbers are clunky, it's 2am, and I really don't it it much myself.
That simple formula took me a half hour.
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Well i like the idea UnLimiTeD but instead of using the entire crew as basis i would use the Number of crew-members that are needed to operate the ship. For example if i have a survey-ship with a crew of 250 but only 200 crew-members are needed to operate the ship the loss of 50 people (as tragic as it is) wouldnt reduce the TFV.
Now for something different: Steve could you implement a way to recover Missiles? Sometimes when i see those empty Percursor-minefields where only the first-stages of the mines are left i just want to take them apart for study. Sure it would only yield some sensors and maybe Reactor-tech but it would be worth it. Also refuelling a missile would be more cost-effective then building a new one - especially if my salvager is anyway in the system to get the enemys wrecks. Restocking the first stage with fitting Sub-ammunition couldalso be interesting.
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I've added the following paragraph to the missile design section of the Rules thread.
5) Max Speed and Reserve Delta-V
A missile can be designed with a maximum speed and/or a reserve delta-V. If a maximum speed is set, the missile will not accelerate beyond that speed and will retain fuel for course changes or decelerations. If an amount of reserve delta-V is specified, the missile will cease to use fuel for acceleration when its remaining delta-V is equal to or less than that amount. If both are set then a missile will only accelerate if it is currently below max speed and its remaining delta-V is above the reserve amount.
Steve
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Is max speed relative to the launching ship, or absolute in the reference frame?
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Using the posted information about missiles I did some small thought experiments about booster stages and their efficiency. Using the missile design postet under Rules, and the Resolution-class destroyer as orientation, I redesigned the missile a little bit.
here's the original:
Nuclear Anti-ship Missile
Missile Mass: 5 Tons Warhead Strength: 250 Kilotons Guidance: Fire Control
Engine Power: 0.24 MN Fuel Use: 134.40 litres per hour
Launch Acceleration: 48 m/s (4.89G) Per Hour: 172.8 km/s Per Day: 4147.2 km/s
Final Acceleration: 68.6 m/s (6.99G)
Fuel Mass: 1500 litres Delta-V Budget: 2,285 km/s
Full Burn Duration: 11.15 hours Distance Required for Max Velocity: 47m km
Fireball Radius: 1000 MJ/m: 289m 300 MJ/m: 527m 100 MJ/m: 912m
Proximity Detonation Range (PDR): 250m Damage MJ/m: 1331
Cost Per Missile: 2.75
Materials Required: 1.55x Tritanium 0.25x Uridium 0.9x Gallicite Fuel x1500
Development Cost for Project: 275RP
Mostly defining two stages:
1. Booster Stage, transporting a 1. 75 coasting stage, totally 5tons.
Using basically the same engine, only cut to 204kN by reducing the size to 1. 8 and therefore the consumption of fuel to 120. 96l/h. The fuel has been decreased slightly to 1. 45tons, and therefore 1450liter.
The statistics for this stage should be (compared to the original missile):
Delta-V: 2200km/s from 2285km/s
MaxBurnDuration: 11. 98hrs from 11. 15hrs
DistanceToMaxV: 44,7mkm from 47mkm
Therefore it is (slightly) slower, and needs more time to reach final velocity. One reached, however, the second, coasting or steering stage emerges:
2. Coasting Stage, 1. 75 tons
Carrying the warhead of 1. 5 tons and the firecontrol guidance module, this mounts a very, very small engine and only 150liters of fuel.
The used engine is a smaller Fuel Efficient 160 KN Missile Engine, providing a measly 8kN power, and needing only 7l/h fuel. This allows the quite good burn time of 21. 4 hours at an acceleration of something between 4. 57 and 5 m/s², depending on the fuel left. Here, too, the statistics:
Delta-V: 368km/s
MaxBurnDuration: 21. 4h
DistanceToMaxV: 154mkm, assuming the velocity of 2200km/s has been reached, and the missile only makes course corrections.
This gives the missile a theoretical reach of nearly 2000 mkm against an evading Resolution, while still having an end velocity of about 2200km/s, which the previous design couldn't, as it would tap into the acceleration-delta-v-budget for course correction.
This wouldn't be the only improvement, as for everything except the boost-phase, the missile wouldn't be 5tons - it would be 2, pushing it under the minimum detection size, and maybe making interception more difficult.
The statistics, copied together, of the missile would be:
Two-Stage Nuclear Anti-ship Missile
Missile Mass: 5 Tons Warhead Strength: 250 Kilotons Guidance: Fire Control
Engine Power: 0.24 MN/0.008MN Fuel Use: 134.40/7 litres per hour
Launch Acceleration: 43.2 m/s (4.4G)/ 4.57m/s (0.47G) Per Hour: 155.5 km/s / 16.452 km/s Per Day: 3732.4 km/s / 394.8km/s
Final Acceleration: 60.85 m/s (6.2G) / 5m/s (0.51G)
Fuel Mass: 1600 litres Delta-V Budget: 2200 km/s / 368km/s --> 2568km/s
Full Burn Duration: 11.15 hours/21.4hours --> 32.55 Distance Required for Max Velocity: 44.7m km
Fireball Radius: 1000 MJ/m: 289m 300 MJ/m: 527m 100 MJ/m: 912m
Proximity Detonation Range (PDR): 250m Damage MJ/m: 1331
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Copied from the Deep Strike thread. It might apply to the Civ v Mil jump capabilities in an oblique way.
Under current rules, the 'deep strike' would be the way to go. Other than the fact that you won't know where the enemy's main bases are without looking.
Perhaps part of the jump drive tech could be a max duration of the drive to maintain itself in hyperspace. I am not sure I would tie this to fuel use as you could simply build larger fuel reserves to make these deep strikes. Perhaps the drive begins to generate a 'sub-space charge' that will damage the drive after a certain level - forcing the ship out of subspace/hyperspace after a certain amount of time. This would of course increase with research.
So civ ships designed with lower delta V budgets would have lower speeds at jump and would jump shorter distances. Mil ships with higher delta V budgets could afford the high speeds to make longer jumps - but not infinite ones. In this way you would need to operate forward bases to stop - refuel/resupply - reorient on the next system - then jump.
Some ships could be designed to make very long jumps by being very fast, but this would likely require a smaller ship with a large percentage of fuel to reach the required speed for the long jump. A small ship that is mostly fuel probably isn't an ideal warship. A good scout probably, but not a planet killer.
Just a thought. Any opinions?
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+1
Though I'd also like fuel consumption for jumps.
It can be small.
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This wouldn't be the only improvement, as for everything except the boost-phase, the missile wouldn't be 5tons - it would be 2, pushing it under the minimum detection size, and maybe making interception more difficult.
The statistics, copied together, of the missile would be:
i don't think there is a minimum detection size anymore, actually. ~
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Is max speed relative to the launching ship, or absolute in the reference frame?
This is Newtonian Aurora not Einsteinian Aurora :) so it will be absolute speed.
Steve
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This is Newtonian Aurora not Einsteinian Aurora :) so it will be absolute speed.
Steve
Any chance of high tech designs being able to have more than one setting or a range of accepted values, programmable at launch, sort of like torpedoes in WW2 have various settings. This could be extended to detonation distance too. Just feels a little harsh to make it per design only.
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Any chance of high tech designs being able to have more than one setting or a range of accepted values, programmable at launch, sort of like torpedoes in WW2 have various settings. This could be extended to detonation distance too. Just feels a little harsh to make it per design only.
Yes, I will probably add something along those lines once I start working more on fire controls
Steve
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The way missiles can miss and come back around for annuva go gave me an idea. What if missile control range was based on telemetry gadgetry on the missile? So missiles would have a control range as well as a fuel range. This is more complicated, but it would mean ECM would actually work on missiles. The additional tricksiness is that missiles could still seek enemies they have on sensors, even if they're outside control range.
Further thought: Maybe missiles could mount MFC-style 'lock on' sensors of their own, that get the 3x range bonus but need to have acquisition passed to them from the launching ship. I am not sure the numbers would work out on these to ever be effective tho. Hmm...
(Admittedly, I was reviewing my designs recently and realized it was more efficient to mount bigger FCs on missile ships than to mount ECCM. lol.)
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The way missiles can miss and come back around for annuva go gave me an idea.
They really shouldn't. A missile could theoretically turn around and come back, but if we assume that both passes are made at the same velocity, and the target is stationary (both might be incorrect, but not enough to invalidate the argument) then you only spent 1/3rd of your delta-V on the first pass. That is not a good idea. Spend something like 90%, saving the rest for maneuvering.
Edit:
Actually, this could happen if you're firing the missiles at very short range. Given that surprise combat is unlikely, so is this case, but it could happen. I'd recommend nukes, though.
And speaking of missiles, Steve, can you add a self-destruct switch for stages? It's sort of annoying to have to manually clean up mines that have launched their payload.
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They really shouldn't. A missile could theoretically turn around and come back, but if we assume that both passes are made at the same velocity, and the target is stationary (both might be incorrect, but not enough to invalidate the argument) then you only spent 1/3rd of your delta-V on the first pass. That is not a good idea. Spend something like 90%, saving the rest for maneuvering.
Edit:
Actually, this could happen if you're firing the missiles at very short range. Given that surprise combat is unlikely, so is this case, but it could happen. I'd recommend nukes, though.
And speaking of missiles, Steve, can you add a self-destruct switch for stages? It's sort of annoying to have to manually clean up mines that have launched their payload.
It depends on range. You may not be far enough away from the target for a missile to use a large proportion of available deltaV before it arrives at the target, in which case it can turn around. Or the missile may start with a high speed due to the launching ship and cover the distance before using much fuel so again it may reverse course.
Steve
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Just on setting the missile speed I assume this is just the max and not the target speed. Ie if you set top speed at 4000 but your ship is doing 5000 it's not going to immediately decelerate to 4000. (assuming on same bearing to target). Also if you are heading for your target in the above scenario, although the missile has capacity to burn up to 9000 it will stay at 5000 and hence you would have to break your ships to allow the missiles to gain distance.
Given the huge range of possible scenarios on what you want your missile to be doing, being able to set top speed outside of the initial design phase might become somewhat of a necessity.
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True, actually, you could give additional parameters on launch.
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Steve i see how Nebulas and Normal Stars behave in Newtonian aurora but how will Black Holes work out? I guess the speed penalties will not realy work on a newtonian drive.
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Well, it could add a vector to all movement.
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Black holes actually don't have any stronger gravity outside of the diameter of the original star than the original star did. In fact, they usually have lower gravity since the star loses some of it's mass before collapsing. So if you're going for realism they wouldn't really have to do anything unless you got in really close. If you did that, then I imagine it could basically act as if a constant acceleration is being applied in the direction towards the black hole, depending on how close you are. So accelerating at the same speed in the other direction would keep you standing still.
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Steve i see how Nebulas and Normal Stars behave in Newtonian aurora but how will Black Holes work out? I guess the speed penalties will not realy work on a newtonian drive.
For the moment, there are no Black Holes in Newtonian Aurora. In Standard Aurora, a ship can enter a BH system by accident and they can provide a terrain obstacle. Neither of those in true when you can see every system on the map.
Steve
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Just on setting the missile speed I assume this is just the max and not the target speed. Ie if you set top speed at 4000 but your ship is doing 5000 it's not going to immediately decelerate to 4000. (assuming on same bearing to target). Also if you are heading for your target in the above scenario, although the missile has capacity to burn up to 9000 it will stay at 5000 and hence you would have to break your ships to allow the missiles to gain distance.
Given the huge range of possible scenarios on what you want your missile to be doing, being able to set top speed outside of the initial design phase might become somewhat of a necessity.
Yes, it is the max and not the target and yes you would have to decelerate or change course to allow the missile to pull away if you are already exceeding the max speed for the missile.
Steve
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I'd like to see ship designs themselves having to be researched. To me, it just doesn't make sense that while a missile, for example, needs to be designed, a huge warship with complex electronics and interior does not.
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Well, the shipyard has to be tooled for it.
As for BH, I'd like to point back to the suggestion that the star size increases the stability of jumps.
A singularity could have that kind of effect, it's likely an empty system, as such, it won't need to be surveyed.
Quite the opposite of what it does now.
Gravity shouldn't be a problem with the projected accelerations.
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Well, the shipyard has to be tooled for it.
As for BH, I'd like to point back to the suggestion that the star size increases the stability of jumps.
A singularity could have that kind of effect, it's likely an empty system, as such, it won't need to be surveyed.
Quite the opposite of what it does now.
Gravity shouldn't be a problem with the projected accelerations.
Also, btw, black holes are perfectly capable of supporting planetary systems.
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Yeah, but keep in mind that those planets would be damn cold, unless they have a heavy greenhouse atmosphere. Like, very heavy. Way above human tolerance, and if you try to decrease the atmospheric pressure, the planet will soon grow incredibly cold. There is no local star to heat it, remember.
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Yeah, but keep in mind that those planets would be damn cold, unless they have a heavy greenhouse atmosphere. Like, very heavy. Way above human tolerance, and if you try to decrease the atmospheric pressure, the planet will soon grow incredibly cold. There is no local star to heat it, remember.
Yep. Not saying they could be habitable (not sure how the colonising system works in Newt Aurora), but a black hole system would not necessarily need to be empty.
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Just spent 30 minutes going through the movement code looking for bugs as I noticed my two gravitational survey ships had stopped moving. Eventually I remembered that when I revised the engine tech, I deleted the old engines from every class and replaced them with updated versions. Except for the gravitational survey ships which for some reason I left with no engines at all :)
Steve
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You mentioned something about exhaust velocities recently, I don't remember where. Does this mean that engine techs will have progressively higher ev or is there a potential for some engines to have non-linear performance?
For instance, the ion drive could have very good "native" fuel efficiency (that is, even without researching the fuel line) while a nuclear pulse engine could have far greater actual output but worse efficiency.
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You mentioned something about exhaust velocities recently, I don't remember where. Does this mean that engine techs will have progressively higher ev or is there a potential for some engines to have non-linear performance?
For instance, the ion drive could have very good "native" fuel efficiency (that is, even without researching the fuel line) while a nuclear pulse engine could have far greater actual output but worse efficiency.
Exhaust velocities are taken into account by the fuel efficiency tech line. You can design engines with high thrust and low fuel efficiency or vice versa. The reason that exhaust velocities were mentioned is Yonder pointed out that the fuel efficiencies of the original engines were so good that their exhaust velocity exceeded the speed of light :). As this supposed to be a realistic physics game, I dropped the fuel efficiency considerably so that when you converted that to exhaust velocity (which you can do because there is a way to calculate the specific impulse of Aurora engines), it was lower than the speed of light.
Steve
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I think the suggestion would be more that as you research new technologies, sometimes they aren't plain better, they might be worse in one respect and better in two others.
As for BH systems, it can currently be assumed that a stellar black hole is created if a massive star blows up.
Thus, planets are possible, but a lot less likely than in a normal star system.
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XD well it would be funny if a number of BH would stay hidden on the galactic map and you accidently jump into such a system because your ships where on a course that goes through the BH-system (or would pass the BH-system in a reasonable distance).
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It would be interesting if there was a particular NPR associated with black holes, or particular ruins in a rapid orbit. Or you could have unique elements that could only be generated in orbit of black hole. Could _make_ reasons to explore anomalies.
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A thought, will Newtonian Aurora feature Rogue planets?
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A thought, will Newtonian Aurora feature Rogue planets?
Not at the moment but a possibility for the future
Steve
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It occurs to me that we'll have a new problem- ships that run out of fuel on an "escape trajectory"- that is, ships that drift out of system. Will they eventually end up in a distant system? Be presumed lost? When? (any speed above ~42 Km/s will escape solar orbit)
Further, will there be any safety measures to prevent orders that might lead to that? It might be nice to be able to place a standing order on all ships to stop accelerating and break if relative velocity ever reaches remaining Delta-V.
Indeed, ordering a crew to ignore "red lining" might even require a morale roll.
On a related tangent, will ships have to decelerate when approaching planets? Certainly atmospheric breaking and gravitational breaking can do a lot, but if it's late game and a ship with no fuel tries to land at 0.23 C, I get the feeling there should be problems.
Beyond that, if you can stop instantly at a planet, then a ship in an asteroid belt has nearly twice the maneuverability of a similar ship outside of it- instead of decelerating, then accelerating the other way, the ship needs only adjust course to a nearby body, stop at it, then accelerate away.
All that said, gravitational flybys, braking, and slingshotting are an essential part of traditional space travel. It would be interesting to include it, though simplification would be required. Avoiding actually doing a lot of math, you could make a ship leave orbit with a certain percentage of its arrival velocity depending on the mass of the ship, the mass of the body, the arrival velocity, and perhaps pilot skill.
In such a system, a fighter swinging by Jupiter could come to a stop or get 1000% speed, while the death star might only gain or lose 1-2% of velocity swinging past an asteroid.
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Further, will there be any safety measures to prevent orders that might lead to that? It might be nice to be able to place a standing order on all ships to stop accelerating and break if relative velocity ever reaches remaining Delta-V.
I think orders will probably have to have rough fuel consumption estimations similar to current time estimations, with color coded warnings if they exceed 1/4, 1/2 or all remaining fuel. (1/4 = return voyage fuel).
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Keep in mind that in some cases you will be able to mount rescue missions with Tugs and Tankers, though that may take months depending on the relative velocities.
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It occurs to me that we'll have a new problem- ships that run out of fuel on an "escape trajectory"- that is, ships that drift out of system. Will they eventually end up in a distant system? Be presumed lost? When? (any speed above ~42 Km/s will escape solar orbit)
They will remain in the same system on the same course. I might add some sub-light interstellar travel at some point but a ship at 1000 km/s would take well over a thousand years to reach the nearest star and that is assuming it was lucky enough to be on the correct course - which is highly unlikely - so it isn't an urgent need.
Further, will there be any safety measures to prevent orders that might lead to that? It might be nice to be able to place a standing order on all ships to stop accelerating and break if relative velocity ever reaches remaining Delta-V.
You can set a maximum speed for a fleet and it won't accelerate beyond that. That speed can be changed whenever you want. I believe tankers are going to be very common and ships accelerating beyond their ability to slow down without refuelling will not be an unusual situation. There will be special rules for underway replenishment in Newtonian Aurora, including fuel transfer rate, and there is a new tech line for a Fuel Transfer System, which will be useful for speeding up the fuel transfer speed from tankers. This is analagous to the technique used for modern naval underway replenishment. You will no longer be able to instantly transfer fuel between ships.
On a related tangent, will ships have to decelerate when approaching planets? Certainly atmospheric breaking and gravitational breaking can do a lot, but if it's late game and a ship with no fuel tries to land at 0.23 C, I get the feeling there should be problems.
They will absolutely have to slow down. This is a Newtonian game so ships will have to begin slowing a long way out from their destination. The movement code already has this built it so ships will automatically begin decelerating at the appropriate time based on their orders. However, they are allowed to enter orbit as long as they are moving at less than the escape velocity of the planet. So for Earth that would be about 11.2 km/s.
Beyond that, if you can stop instantly at a planet, then a ship in an asteroid belt has nearly twice the maneuverability of a similar ship outside of it- instead of decelerating, then accelerating the other way, the ship needs only adjust course to a nearby body, stop at it, then accelerate away.
There is no instant stopping.
All that said, gravitational flybys, braking, and slingshotting are an essential part of traditional space travel. It would be interesting to include it, though simplification would be required. Avoiding actually doing a lot of math, you could make a ship leave orbit with a certain percentage of its arrival velocity depending on the mass of the ship, the mass of the body, the arrival velocity, and perhaps pilot skill.
I will likely add some form of gravitational slingshot and aerobraking at some point, although in the latter case the ship will have to be designed appropriately.
In such a system, a fighter swinging by Jupiter could come to a stop or get 1000% speed, while the death star might only gain or lose 1-2% of velocity swinging past an asteroid.
The mass of a ship doesn't make any difference to its ability to gain velocity from a planet. Galileo proved this in 1589 :). The only difference is that Jupiter would slow down in its orbit a little more if the Death Star went by than it would due to a fighter.
Steve
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Galileo proved this in 1589 Smiley.
I must have missed that copy of Discovery. I R Dum. Still, in-flight refueling sounds really exciting! I imagine it could be interesting in fighter combat, with them stopping, juicing up, and taking off again in tactically-relevant timespans.
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Speaking of the sort of things fighters will replenish for, it looks like in the current weapon and energy system you'll have a lot of freedom in battery and generator sizes. Would it be possible to design fighters with tiny generators and large batteries?
That way they could fly out, fire several shots, and then return to the carrier ship and recharge?
Will carrier generators see Parasite batteries, and charge them if there is excess power? (Or even if there is not, if the priorities are set to favor parasites).
What about the other way? Can a fighter which is not being used transfer its power to the carrier? Perhaps while doing this the maintenance clock proceeds as normal?
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Are you thinking of ejectable "power cores" which are big generators with basic engines that can be released if damaged?
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Are you thinking of ejectable "power cores" which are big generators with basic engines that can be released if damaged?
No particular plan, although I know that sort of thing may be useful to the people trying to do more and more modular stuff. I was mostly interested in the idea that Carrier's could recharge their fighters, going the other way is more of a brain storm than anything.
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Well, if Fighters will be used at all. Let's not get into that discussion again. 8)
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Well, its equally applicable to other kinds of parasites, and its definately an interesting idea that would add more depth to parasite/fighter operations, both from vessels as well as planetary bases. So I'm all for it.
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On a related tangent, will ships have to decelerate when approaching planets? Certainly atmospheric breaking and gravitational breaking can do a lot, but if it's late game and a ship with no fuel tries to land at 0.23 C, I get the feeling there should be problems.
That absolutely will not work. A rule of thumb for such things is that you can't get breaking more then about escape velocity. That gives a nice rounding error, but will not work with relativistic velocities.
All that said, gravitational flybys, braking, and slingshotting are an essential part of traditional space travel. It would be interesting to include it, though simplification would be required. Avoiding actually doing a lot of math, you could make a ship leave orbit with a certain percentage of its arrival velocity depending on the mass of the ship, the mass of the body, the arrival velocity, and perhaps pilot skill.
In such a system, a fighter swinging by Jupiter could come to a stop or get 1000% speed, while the death star might only gain or lose 1-2% of velocity swinging past an asteroid.
Mass has no effect on such a thing, at least at the scales in question. Yes, you will probably gain less velocity if your ship is 50% of the mass of the swung-by object. However, swing-bys, like aerobreaking, are ineffective when you are traveling much above the object's escape velocity. Considering that NA starts with normal speeds well above that point, I see no reason to add a system.
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Speaking of the sort of things fighters will replenish for, it looks like in the current weapon and energy system you'll have a lot of freedom in battery and generator sizes. Would it be possible to design fighters with tiny generators and large batteries?
That way they could fly out, fire several shots, and then return to the carrier ship and recharge?
Yes, that will be possible.
Will carrier generators see Parasite batteries, and charge them if there is excess power? (Or even if there is not, if the priorities are set to favor parasites).
What about the other way? Can a fighter which is not being used transfer its power to the carrier? Perhaps while doing this the maintenance clock proceeds as normal?
Ships recharge their own batteries first. After that, any spare power from parasites goes into the mothership's batteries and any spare power from the mothership goes into parasite batteries. I guess you could design a parasite ship that is almost all power plant and use it to boost the battery recharge rate of the mothership.
Steve
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Ships recharge their own batteries first. After that, any spare power from parasites goes into the mothership's batteries and any spare power from the mothership goes into parasite batteries. I guess you could design a parasite ship that is almost all power plant and use it to boost the battery recharge rate of the mothership.
Could it work the other way as well, with charges from the batteries of parasites powering batteries of their carriers?
As an example idea, you could have a super large generator on a ship (because those are more efficient), with no room for anything other than some hangars. All of the weapons of the fleet are on other ships. The ships fire, until their parasites are empty, which then fly to the charge ship to charge (passing fully charged parasites which dock at the weapon ships) they then charge at the generator ship, return to the weapon ship, etc etc.
I'm not saying that this is in any way an effective strategy, certainly the micromanagement would be a nightmare, but it may be fun to have the ability to do wacky things like that.
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Actually as "defense-base" this could work. Which makes me wonder how lasers do work in newtonian Aurora. I mean i could imagine a Deathstar-sized Homopolar Generaor (i call them HpG from now on) with a single friging laser attached as planetary defense. I guess it would be impossible to build a single "light"-based laser big enough to vaporize a 500 meter ship on pointblank range but if we get to x-rays ... . The active sensors could be powered by a very small powercore. Hehe reminds me a bit to the xindi-weapon.
Same goes for planetary AMM shields. Instead of just a multistaged "mine" you could use a medicore HpG some Missile-stockpiles and fast mechanized launchers. Just size the HpG so that it runs out of juice at the same time as AMM-base would run out of ammo. If you add a small docking bay (say 2k tons) a small ordonance carrier from the planet could reload the ammo and HpGs.
To bad we dont have a Ai to man those things. i pity the guys who are on guard-duty.
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I've decided to remove the power requirement for active sensors. At the moment sensors are tracked by fleet rather than by ship and not loaded into memory unless they are needed. The power requirement would have meant checking all active sensors each increment prior to the movement/detection phase to find which were on but not damaged. Therefore I decided the extra gameplay of the power requirement wasn't worth the performance hit and the extra coding. The power grid will just apply to shields and weapons.
Steve
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Can't you just have a requirement on ship building, as in, let a sensor function as a negative generator?
On second thought, thats crap. But you could increase the sensors size.
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Can't you just have a requirement on ship building, as in, let a sensor function as a negative generator?
On second thought, thats crap. But you could increase the sensors size.
When I removed the power requirement, I also reduced the active sensor strength per ton, which in effect means you will need a larger sensor for the same capability as before.
Steve
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Due to the slower pace of Newtonian Aurora (for those who find Standard Aurora too fast-paced :)), I have reduced wealth production, construction and mining by about 50%. Shipbuilding and research is reduced by about 60%. Fuel production remains the same as Standard Aurora while the size and cost of the Sorium Harvester module have both been halved, which means you can now produce twice as much fuel for the same ship mass/cost.
In Newtonian Aurora, the chance of a gas giant containing Sorium in the atmosphere will be 50%, compared to 20% for Standard Aurora
Fuel is going to be a vital commodity, which is why despite everything else being slower, fuel production will be the same, fuel harvesting will be twice as fast and Sorium availability in gas giants will be higher. Establishing a fuel harvesting industry to going to be key.
Steve
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Do you have anything planned for diplomacy?
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I'm guessing that this effect would have a negative affect on gameplay, however for completeness sake I want to point out that while passive sensors should diminish in ability based on the second power of the distance, active sensors should actually diminish with the fourth power of the distance.
That is because they emit a signal which degrades with the second power of the distance, and then that signal hits a contact and reflects back, and that reflection also degrades with the second power of the distance, so the total degradation is the fourth power of the distance.
If this change was made in the game the result would be that it would begin to become nearly impossible to scan an enemy with active sensors without him seeing your active sensor signature (right now it's unlikely in most cases, but a moderate tech advantage can give you that scenario for typical ships with small EM sensors).
As an example, if you increased your sensor strength by a factor of 16, you could only see twice as far as you could before, however your enemies can see you 4 times farther out.
I would still model Fire Controls as diminishing with the square of the distance however. Those aren't area sensors, they are only monitoring a single target, so that fixed beam on the way to the target wouldn't lose strength over distance. Once the signal does hit the target, however, the reflection would begin to disperse normally.
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That is because they emit a signal which degrades with the second power of the distance, and then that signal hits a contact and reflects back, and that reflection also degrades with the second power of the distance, so the total degradation is the fourth power of the distance.
Are you sure? I think this would be more the square of twice the distance.
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Think of it as two spheres; one emitted from the source, with power decreasing as a square of distance (inverse-square law). Any 'signal' that hits a target then reflects off that in a second 'sphere' (roughly) which is what we try to detect, and also has power decreasing as a square of distance.
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M1 is the origin of the signal, M2 is where the signal is reflected, the distance between the two is r.
The strength of the signal at M1 going out is x.
The strength of the signal at M2 is x*1/r²=x/r².
The strength of the signal at M1 going in is x/r²*1/r²=x/(r²*r²)=x/r?
Oh. I see.
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The strength of the signal at M1 going in is x/r²*1/r²=x/(r²*r²)=x/r?
=x/r4
;)
Regardless, it dosent matter so much as to if its to 4 or to 2, so long as active and passive maintain a ratio of a square.
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=x/r4
;)
Regardless, it dosent matter so much as to if its to 4 or to 2, so long as active and passive maintain a ratio of a square.
Well, it doesn't matter from a "Can the passive sensor spot the active sensor" standpoint, but from a "how much larger does my sensor need to be to get better range" it matters a great deal. If, for example Actives Shrink with the square and passives shrink linearly, than it's a lot easier to make very very long range tracking stations, you may be able to track an entire system from one location.
If you go by powers of four and powers of two than that may stop being the case, which will make sensor drones and alternative methods of getting data much more important.
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On a different topic, how will sectors be handled?
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I'm guessing that this effect would have a negative affect on gameplay, however for completeness sake I want to point out that while passive sensors should diminish in ability based on the second power of the distance, active sensors should actually diminish with the fourth power of the distance.
That is because they emit a signal which degrades with the second power of the distance, and then that signal hits a contact and reflects back, and that reflection also degrades with the second power of the distance, so the total degradation is the fourth power of the distance.
If this change was made in the game the result would be that it would begin to become nearly impossible to scan an enemy with active sensors without him seeing your active sensor signature (right now it's unlikely in most cases, but a moderate tech advantage can give you that scenario for typical ships with small EM sensors).
As an example, if you increased your sensor strength by a factor of 16, you could only see twice as far as you could before, however your enemies can see you 4 times farther out.
I would still model Fire Controls as diminishing with the square of the distance however. Those aren't area sensors, they are only monitoring a single target, so that fixed beam on the way to the target wouldn't lose strength over distance. Once the signal does hit the target, however, the reflection would begin to disperse normally.
I was contemplating going here (active detection range fall-off as the 4th power, rather than the square of the distance), but didn't because my recollection is that it's more complicated than that. But now that someone's opened the can of worms....
The 4th power thing is for diffuse reflection - if I think of the active emitter as a light bulb, then the reflected radiation from the target is acting as another light bulb, emitting in all directions. The power of the target light bulb goes like 1/r^2 (amount of light falling on it from original emitter), and the travel back gives it another 1/r^2, for a total of 1/r^4.
The problem is that there's also a specular (mirror-like) reflection component. First, imagine the target is a mirror oriented perpendicular to the path from the original bulb to the target. If you trace the rays, then you can see that they keep diverging at the same rate as if no mirror were there. So in the reflective case, the distances add (rather than multiply as in the diffusive case) So for the specular component, the fall-off will be 1/(2*r)^2. This effect is suppressed, however, because the active sensor has to "get lucky" and catch the glint of reflection off the mirror. This is why concave cubic corners are so bad for stealth - they reflect rays back no matter which direction the ray is coming in at. In fact, I remember reading that ocean-going small craft typically mount radar reflectors that are just corner-cube boxes - the idea is that you want a big freighter about to run you over to get 1/(2r)^2 power no matter how your boat is oriented.
Note that ESM will still have a big advantage over active sensors, because even though there's a 1/r^2 component to the active signal, it's still going to be suppressed by geometric factors in the target-emitter geometry. So while I agree that overall it should be MUCH easier to pick up an active signal with ESM than for the active signal to actually see anything, the active range fall-off is much more complicated than one might think.
On the whole fire control question, I don't think it should be any different than actives. Unless the beam is perfectly collimated, it will still have an opening angle, and so its power density should (eventually) still drop off with range like the distance squared. This behavior should kick in when the beam has gone far enough so that it's significantly larger (e.g. 2x) than the original aperture. The question is "how big is the spot size vs. the original beam radius for fire control at typical engagment ranges".
John
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I'm guessing that this effect would have a negative affect on gameplay, however for completeness sake I want to point out that while passive sensors should diminish in ability based on the second power of the distance, active sensors should actually diminish with the fourth power of the distance.
That is because they emit a signal which degrades with the second power of the distance, and then that signal hits a contact and reflects back, and that reflection also degrades with the second power of the distance, so the total degradation is the fourth power of the distance.
If this change was made in the game the result would be that it would begin to become nearly impossible to scan an enemy with active sensors without him seeing your active sensor signature (right now it's unlikely in most cases, but a moderate tech advantage can give you that scenario for typical ships with small EM sensors).
As an example, if you increased your sensor strength by a factor of 16, you could only see twice as far as you could before, however your enemies can see you 4 times farther out.
I would still model Fire Controls as diminishing with the square of the distance however. Those aren't area sensors, they are only monitoring a single target, so that fixed beam on the way to the target wouldn't lose strength over distance. Once the signal does hit the target, however, the reflection would begin to disperse normally.
I considered using the full radar equation but decided against it on the grounds of playability. Newtonian Aurora does use a formula that means the range of active sensors is based on the square root of their power. As passive sensors are still linear, this creates a similar dynamic between the two.
Steve
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Well, it doesn't matter from a "Can the passive sensor spot the active sensor" standpoint, but from a "how much larger does my sensor need to be to get better range" it matters a great deal. If, for example Actives Shrink with the square and passives shrink linearly, than it's a lot easier to make very very long range tracking stations, you may be able to track an entire system from one location.
If you go by powers of four and powers of two than that may stop being the case, which will make sensor drones and alternative methods of getting data much more important.
While that's true, the ranges of sensors in gameplay terms are about what I want them to be. If I changed to a different formula, I would also alter the strength of each level in the sensor tech progressions to end up back where we are now :). So I decided to go with a formula that players would more easily understand while retaining the general feel of active vs passive.
Steve
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On a different topic, how will sectors be handled?
Probably based on distance in LY rather than distance in jumps - although its something I haven't even looked at yet
Steve
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Wouldn't that be a good basic for stealth systems?
The higher the level, the more the range of the sensor moves to an /r^4 drop?
Given that sizes now don't result in a linear increase in TCS, this might make more sense.
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Due to the slower pace of Newtonian Aurora (for those who find Standard Aurora too fast-paced :)), I have reduced wealth production, construction and mining by about 50%. Shipbuilding and research is reduced by about 60%. Fuel production remains the same as Standard Aurora while the size and cost of the Sorium Harvester module have both been halved, which means you can now produce twice as much fuel for the same ship mass/cost.
In Newtonian Aurora, the chance of a gas giant containing Sorium in the atmosphere will be 50%, compared to 20% for Standard Aurora
Fuel is going to be a vital commodity, which is why despite everything else being slower, fuel production will be the same, fuel harvesting will be twice as fast and Sorium availability in gas giants will be higher. Establishing a fuel harvesting industry to going to be key.
I am also halving the population growth rate. The Earth-based pops in my test campaign (all 20 of them!) are growing too fast for the relatively slow rate of industrial growth
Steve
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Now that is something I applaud.
I always found it a little fast even for Auroras economy, given there's no plagues, no overcrowding (Earth is a class 0 world, but it'll be full at some point), no effect of wealth on growth;
Definitely a great improvement. Well, I suppose you're getting tired of it. :P
I'd be nice if a very developed, wealthy population would have a slightly lower growth, maybe reaching 0 at around 5 B?
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Now that is something I applaud.
I always found it a little fast even for Auroras economy, given there's no plagues, no overcrowding (Earth is a class 0 world, but it'll be full at some point), no effect of wealth on growth;
Definitely a great improvement. Well, I suppose you're getting tired of it. :P
I'd be nice if a very developed, wealthy population would have a slightly lower growth, maybe reaching 0 at around 5 B?
Odd that you consider 5 billion the limit a planet can handle with super advanced technology when we have 7 billion IRL now.
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An 10 B till 2100 iirc. But actually the question how many people a planet/moon can support isnt a bad one. Maybe Steve could somehow define a ultimate max based on size and "not submerged" surface of a planet?
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I'm considering 5 B the limit for a wealthy society; given that we got a 2 B fighting starvation and civil wars right now, that's probably valid.
It's ultimately a basis of what causes a stop.
Overcrowding would result in unrest, and require Infrastructure even on a class 0 world, but it probably wouldn't directly stop growth.
Probably make class 0 require Infrastructure based on pop and size?
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I'm considering 5 B the limit for a wealthy society; given that we got a 2 B fighting starvation and civil wars right now, that's probably valid.
It's ultimately a basis of what causes a stop.
Overcrowding would result in unrest, and require Infrastructure even on a class 0 world, but it probably wouldn't directly stop growth.
Probably make class 0 require Infrastructure based on pop and size?
We already produce enough food for every body, we just don't distribute it as well as we should. Also if Africa had the per capita food production of the United States then there would be even more extra food.
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We already produce enough food for every body, we just don't distribute it as well as we should. Also if Africa had the per capita food production of the United States then there would be even more extra food.
Indeed. World food production generates enough food for every single person on the planet to have 4. 5 pounds of food a day, consisting of all food groups.
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An then theres the billion or so people that can't eat wheat, or milk, or...
The main problem here is that the food is not evenly distributed, and it's not only a question of incompetence, but also logistics, of possibility.
Transporting food to the areas where people live, from where it's produced, costs time, excessive amounts of energy, and pollution, while increasing the size of the populous will not only result in more produced greenhouse gas, but also additional pollution, as people will want to do something, and production results in a strain to the environment.
The more land is used for habitation, production, or agrarian use, the less will there be for the biosphere; and where actually damn dependent on that.
Note how in large cities the amount of allergies surges upwards?
Those kind of problems will come up, so at some point, we'll have to spend a large amount of the production on health care, and eventually use special infrastructure to recycle gasses and keep our atmosphere healthy.
And the more people there are in one spot, the more damage will be done by natural disasters, which are more likely the more people there are....
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Wellit depends on how much meat a future civilisation would consume. Right now the USA alone could feed 2 Billion people if the meat-production would go down by 90%.
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Insects.
The food of the future.
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I've been reading a lot about newtonian aurora and I think it's cool. However I'm not sure about space travel. First of all, if I understand correctly (my english is a little bit rusty) there are 3 types of space travel: some kind of "sub-light" travel, hyperspace and jump drives, right?
I've been doing some quick maths about current sub-light acceleration and it seems a little slow to me. Maybe it's just that I have got used to Stargate's space travels, I don't know (Daedalus achieves 200. 000 km/s pretty fast). Another issue I see here is that there is not a speed limit at all. I really think that there should be one, dependant on ship armor or armor type or a combination of both. Even if we take structural stability out of the equation, space debris will hit your ships harder and harder at higher speeds, plus there's the light speed limit of 300. 000km/s. Again, maybe I'm totally biased about speeds because of Stargate, and maybe 200. 000 km/s is way too high speed even at higher tech levels, I don't know. But I really think "high-end" engines should be able to achieve that for a well armored ship.
About hyperspace, there are lots of theories about it, and I don't really like the idea that your speed in hyperspace is dependant on your speed in real space, or improvements being made by switching to other dimensions. Again, maybe Stargate biased, but a single hyperspace dimension and improvements being made by more efficient hyperspace engines (from hyperdrives which let you arrive at near stars at a viable speed to high end hyperdrives that let you reach pretty distant stars and even other galaxies if someday it is implemented. . . who knows!) and those hyperdrives with a fixed speed not dependant on sublight speed.
About Jump Drives I don't have a lot of info right now. If I understand correctly it works similarly to Battlestar Galactica?
Sorry if my thoughts are offensive in any way, just sharing my thoughts with you guys :)
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I've been reading a lot about newtonian aurora and I think it's cool. However I'm not sure about space travel. First of all, if I understand correctly (my english is a little bit rusty) there are 3 types of space travel: some kind of "sub-light" travel, hyperspace and jump drives, right?
I've been doing some quick maths about current sub-light acceleration and it seems a little slow to me. Maybe it's just that I have got used to Stargate's space travels, I don't know (Daedalus achieves 200. 000 km/s pretty fast). Another issue I see here is that there is not a speed limit at all. I really think that there should be one, dependant on ship armor or armor type or a combination of both. Even if we take structural stability out of the equation, space debris will hit your ships harder and harder at higher speeds, plus there's the light speed limit of 300. 000km/s. Again, maybe I'm totally biased about speeds because of Stargate, and maybe 200. 000 km/s is way too high speed even at higher tech levels, I don't know. But I really think "high-end" engines should be able to achieve that for a well armored ship.
About hyperspace, there are lots of theories about it, and I don't really like the idea that your speed in hyperspace is dependant on your speed in real space, or improvements being made by switching to other dimensions. Again, maybe Stargate biased, but a single hyperspace dimension and improvements being made by more efficient hyperspace engines (from hyperdrives which let you arrive at near stars at a viable speed to high end hyperdrives that let you reach pretty distant stars and even other galaxies if someday it is implemented. . . who knows!) and those hyperdrives with a fixed speed not dependant on sublight speed.
About Jump Drives I don't have a lot of info right now. If I understand correctly it works similarly to Battlestar Galactica?
Sorry if my thoughts are offensive in any way, just sharing my thoughts with you guys :)
Catching a plane in two hours but I thought I had better answer this before Byron (no offence Byron :))
There are two types of travel for Newtonian Aurora - sub-light and faster than light (FTL). The jump drive is from standard Aurora although I think its probably been used interchangeably with FTL drive in discussions about Newtonian Aurora. In any event the FTL Drive (AKA Jump Drive) is a way to move from normal space into hyperspace and back again in order to exceed light speed.
Stargate is one of my favourite TV programs but its probably not the ideal model for realistic space travel. Space travel works on the principles of Newton's laws of motion
First law: The velocity of a body remains constant unless the body is acted upon by an external force.
Second law: The acceleration a of a body is parallel and directly proportional to the net force F and inversely proportional to the mass m, i.e., F = ma.
Third law: The mutual forces of action and reaction between two bodies are equal, opposite and collinear.
In very simple terms (and ignoring gravity for the moment) to move in a particular direction, you need to throw something in the opposite direction. If you have a 100 ton spaceship and throw a 1 ton object out of the window at 10 meters a second then the ship will move in the opposite direction at 0.1 meters per second. Force = Mass x Acceleration. So the force is equal to a 1 ton mass at 10 meters per second, that same force will move a 100 ton mass at 0.1 meters per seconds.
That is the basic principle behind the rocket engine, except it is the fuel that is being thrown out of the ship at very high speed. For example, if a 1000 ton rocket uses 1 ton of reaction mass per second and that mass leaves the ship at 10,000 m/s (the exhaust velocity), the force is equal to 10,000 m/s x 1 tons, so the 1000 ton rocket will be pushed forward by 10 m/s. Of course, the rocket now only has a mass of 999 tons, so the second ton of reaction mass pushes it by 10.01 m/s and it is now travelling at 20.01 m/s. This will carry on until the fuel runs out (at which point the rocket cannot slow down). The vast majority of the mass of any modern rocket is fuel - the payload is very small in comparison.
As you might guess, the exhaust velocity is very important because the faster the reaction mass leaves the rocket, the more acceleration the rocket will gain from that fuel. However, the energy required to accelerate the reaction mass has to come from somewhere too. In chemical rocket engines, the fuel itself provides the energy from its own combustion. In more exotic engines the energy may come from a nuclear reactor. In any event, achieving high exhaust velocities is the key to fuel efficiency and high speed space flight. This has a limit thought because the exhaust velocity cannot exceed the speed of light (as Yonder recently pointed out :)).
Newtonian Aurora uses vastly more efficient engines than anything even dreamt of at the moment in real life. The exhaust velocities of the top end engines come very close to the speed of light.
Stargate spacecraft get around these problems by completely ignoring the laws of physics :). I did the same for standard Aurora but for Newtonian Aurora I am trying to create a more realistic feel to the game.
Steve
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Steve: No offense taken. I probably go too technical some times. That said, I think you might have missed a few specific points. Also, I'm not terribly familiar with stargate, so I may be pointing in the wrong direction.
Khalador: There are a number of different models for FTL travel. For physical realism (or at least lack of impossible) stargates are probably closer then the newtonian aurora system. That said, we are talking about FTL, so realism is subjective.
Acceleration is limited by a number of factors. Mostly, the strength of the human body. We don't work terribly well under even 2Gs, which limits sustained accleration. The available engines are another limit, as is the ship's structure, but for most cases, the men are the big issue.
A speed limit is unlikely to be a huge problem. Maybe we could include some armor degradation at certain speeds, but a ship has to be armored against weapons that are more lethal then space debris. That said, it is something to keep in mind.
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As for the argument of speed retention in Hyperspace:
Think: How would Hyperspace work?
It's obviously some sort of dimension, in real space, a ship isn't going to suddenly move that fast, and more over, it would definitely keep it's speed when reaching it's target destination.
So, how does that dimension work?
If it's what we assume it to be, the ship will essentially enter a dimension where everything is somewhat smaller, and moving a certain distance will result in a lot higher distance in real space; the efficiency of the engine is basically a matter of how close you apply the magnifying glass.
If the ship would accelerate in hyperspace on it's own, why does it have to decelerate when it jumps out again?
Not desirable, it would require more technobabble (YAY, technobabble!).
A third, potentially working option would be ships moving in Hyperspace like they do in standard Aurora.
This would allow mid-course changes, and not be influenced by starting speed, but it would result in fuel burn over the entire distance. Including range caps.
Steve has decided against this, and I suppose it's fine to have the most newtonian approach available.
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Hi,
This has a limit thought because the exhaust velocity cannot exceed the speed of light
Beware! As soon as speeds get limited to lightspeed, Einstein steps into the picture, and everything becomes quite complicated once objects (any object in theory, but more importantly manned or remote controlled vehicles) achieve relativistic speeds, ie 10-15% of light speed.
Even in a "purely newtonian" environment, if electromagnetic radiations travel at the speed of light, transmitting information to fast moving objects (ships or missiles) become quite complicated (the signals may take a long while to "catch up"). You could then decide that information can move almost instantaneously through hyperspace, but if so, "hyperspace lasers" could also be built, which would cause problems of their own.
To avoid this, it might be a good idea to create (through the proper use of "dream science") a law which limits all/most practical movement out of hyperspace to non relativisitic speeds. In other words, there would be a theoretical speed limit at 300 000 km/s, but also a practical one (for ships, fighters, and perhaps missiles) around 40 000 km/s, to keep Newtonian Aurora away from Lorenz transforms. . .
The problem, I think, is that, if you consider speed is limited to c, the only way to avoid Einstein is to move very slowly.
Francois
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Beware! Once you limit speeds to lightspeed, Einstein steps into the picture, and all calculations become much more difficult as soon as objects (any object in theory, but more importantly manned or remote controlled vehicles) achieve relativistic speeds, ie 10-15% of light speed.
That's why I think sometimes, in gaming and science fiction (Stargate :P), physical laws must be bent or simply ignored to make the game or the show more enjoyable. Are you traveling at relativistic speeds? Invent something that creates some kind of space-time bubble around your ships to maintain coherence. Are you accelerating at a rate which would kill any human? Put some cool inertial dampener which god knows how it works. Do you need to turn around your ship to counterattack an enemy ship at your back? Just do it like a boss.
Beside, science change a lot every few years. Actual working physical laws can be completely wrong in a decade. Adapting centuries of development and science investigation in our campaings to 21th century physics is like trying to supply water to a growing city through the same pipes. Sure, they will work for the first 200,000 hundred people, but when the city reaches 1 million inhabitants, those pipes are not going to be enough.
However, I think it's pretty interesting that kind of aproach. Personally, I would prefer a little "science fiction" here and there, but trying to build a space empire with today's limitations is. . . challenging at least.
Sorry if I sound like a complete idiot, I'm new here and I don't think I should be arguing about this kind of things. Beside, I really like your work Steve, you have achieved a level of complexity unseen in any other 4X. And again, please, excuse me for my poor english skill.
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Hi,
Beware! As soon as speeds get limited to lightspeed....
The problem, I think, is that, if you consider speed is limited to c, the only way to avoid Einstein is to move very slowly.
I think you may have gotten a little confused between exhaust velocity and ship velocity. Although the exhaust velocity may get very close to c it's very unlikely that any ship will get anywhere near close to relativistic speeds due to the fuel requirements to achieve this. If you look at the rules thread you will see that Steve has created some example ships to demonstrate the effectiveness of the new engines, in these examples you can see ships will a delta v of not much more than 12,000 kms and that is with a ship with a very large proportion of its mass in fuel.
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I think you may have gotten a little confused between exhaust velocity and ship velocity. Although the exhaust velocity may get very close to c it's very unlikely that any ship will get anywhere near close to relativistic speeds due to the fuel requirements to achieve this.
This seems strange to me. . .
From Tsiolkovsky rocket equation,
deltaV= Vexhaust ln(M_initial/M_final)
For delta-V equal to a fifth of exhaust velocity (to accelerate in straight line to relativistic speeds, with exhaust velocity a bit under c), I need a mass ratio equal to exp(1/5), or 1. 22 (double if I slow down). The cost in reaction mass is not prohibitive. That's the gist of the formula : mass ratio only becomes huge when delta v gets higher than exhaust velocity.
The rest belongs to fuel efficiency: how much fuel I need to accelerate reaction masses to close to light speed. There's an approximate equation for the energy on the Tsiolkovsky wiki page, in our case, half of reaction mass times velocity times delta-v, or one tenth of reaction mass times exhaust velocity squared, or the energy in one tenth of the reaction mass (going for a 100% efficient antimatter drive). Again, I see no theoretical limit here. And besides, it is not relevant to ship speed, just to whether such exhaust speeds are feasible.
This brings back my original point: if engines with such exhaust speeds are possible, relativistic ships and missiles will probably have to exist in Aurora.
Francois
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In these examples you can see ships will a delta v of not much more than 12,000 kms and that is with a ship with a very large proportion of its mass in fuel.
That's actually not accurate. While these ships had a large proportion of mass in fuel in comparison to normal Aurora ships (which generally have around half a percentage point of their mass in fuel) they don't actually have a large amount of fuel compared to modern spacecraft. With exhaust velocity at c, then 63% propellant mass will get your spaceship up to the speed of light, and 86% propellant will get it to slow down to a stop again. Those ships may not be good in a fight, but scouts, probes, and missiles could totally reasonably get up to very substantial fractions of c in the late game.
Beside, science change a lot every few years. Actual working physical laws can be completely wrong in a decade.
That's a misleading way of looking at things. Science changes, but the overthrowing comes in the form of the underlying mechanics, not the observed results. You can't look at something that is demonstrably impossible where current theories work well, and hope some new theory will show that it actually can all happen. It's the poorly fitting edges of the old theories that are cleared up in the next generation of advances.
Beware! As soon as speeds get limited to lightspeed, Einstein steps into the picture, and everything becomes quite complicated once objects (any object in theory, but more importantly manned or remote controlled vehicles) achieve relativistic speeds, ie 10-15% of light speed.
Even in a "purely newtonian" environment, if electromagnetic radiations travel at the speed of light, transmitting information to fast moving objects (ships or missiles) become quite complicated (the signals may take a long while to "catch up"). You could then decide that information can move almost instantaneously through hyperspace, but if so, "hyperspace lasers" could also be built, which would cause problems of their own.
To avoid this, it might be a good idea to create (through the proper use of "dream science") a law which limits all/most practical movement out of hyperspace to non relativisitic speeds. In other words, there would be a theoretical speed limit at 300 000 km/s, but also a practical one (for ships, fighters, and perhaps missiles) around 40 000 km/s, to keep Newtonian Aurora away from Lorenz transforms. . .
The problem, I think, is that, if you consider speed is limited to c, the only way to avoid Einstein is to move very slowly.
That's not necessarily true. The only way to smoothly and totally realistically make faster than light movement impossible would be to actually fully model relativity, however you can do several simpler, yet more hacky and discontinuous affects as well. The easiest thing to do would just have full Newtonian motion until c, and then do an arbitrary ful stop so that nothing could go faster than that. Honestly, that's not any different from doing the same thing at .1c, or .15c. The next step (which may be the best choice) would be to do a little bit of relativity modeling, where you do accelerations and delta-v's using relativity math, and nothing else. For example, if you have a ship going .5c, with a railgun that shoots .6c, a completely Newtonian system would create a projectile going 1.1c, a Newtonian system with a hard speed limit at 1c would make a projectile going 1c, but a relativity system would make a projectile going (totally random numbers here, I'm not looking up the math) .85c.
At that point do we have a realistic system? No, there are a lot of weird reference frame shifts and time distortion affects that wouldn't be modeled, but that's perfectly ok, because that lack of modeling keeps you from getting into trouble.
For example, even though we have instantaneous communications, it's impossible to make hyperspace lasers in the game, because those communications are just completely and totally handwaved. The mechanics aren't actually handled in any way, so contradictions like that can't actually come up.
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Hi Yonder,
The next step (which may be the best choice) would be to do a little bit of relativity modeling, where you do accelerations and delta-v's using relativity math, and nothing else. For example, if you have a ship going . 5c, with a railgun that shoots . 6c, a completely Newtonian system would create a projectile going 1. 1c, a Newtonian system with a hard speed limit at 1c would make a projectile going 1c, but a relativity system would make a projectile going (totally random numbers here, I'm not looking up the math) . 85c.
I don't think this is "a bit" of relativity modelling. What you suggest amounts (I think) to calculating everything in Minkowski space and translating it back into one specific frame, the "map frame", the only one the Game understands.
For projectiles (anything without propulsion), you are using special relativity. The calculations are a bit more involved than newtonian kinematics, but it is only kinematics. For ships and missiles, forces and acceleration come into play, and your get a new layer of complexity.
At this point, you have quite a bit of relativity in the model (not all, since gravity, electromagnetism and causality are not in).
But of course you only need to handle this when "propelled objects" move at relativistic speed. This is why I suggest to keep this to a minimum. . .
For example, even though we have instantaneous communications, it's impossible to make hyperspace lasers in the game, because those communications are just completely and totally handwaved.
I understand, and it makes perfect sense so long we talk of general in-game information, player omniscience if you like. I find it less convincing when it comes to tactical information. Aurora models weapon systems with a lot of details, from power supply and ordnance to detection and fire control. Not including comunication delays seems a bit strange to me.
Also, I believe that in long distance space battles, the time needed to communicate with missiles is a very important factor, which adds interesting aspects to the game : the further away you fight, the less control you have. . .
But this is another matter.
Francois
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The next step (which may be the best choice) would be to do a little bit of relativity modeling, where you do accelerations and delta-v's using relativity math, and nothing else. For example, if you have a ship going . 5c, with a railgun that shoots . 6c, a completely Newtonian system would create a projectile going 1. 1c, a Newtonian system with a hard speed limit at 1c would make a projectile going 1c, but a relativity system would make a projectile going (totally random numbers here, I'm not looking up the math) . 85c.
Hi Yonder,
I don't think this is "a bit" of relativity modelling. What you suggest amounts (I think) to calculating everything in Minkowski space and translating it back into one specific frame, the "map frame", the only one the Game understands.
For projectiles (anything without propulsion), you are using special relativity. The calculations are a bit more involved than newtonian kinematics, but it is only kinematics. For ships and missiles, forces and acceleration come into play, and your get a new layer of complexity.
At this point, you have quite a bit of relativity in the model (not all, since gravity, electromagnetism and causality are not in).
But of course you only need to handle this when "propelled objects" move at relativistic speed. This is why I suggest to keep this to a minimum. . .
My hope is for realistic game, not reality. Newtonian is fine for me. I don't expect Steve to come up with a game capable of modeling all the physics we have available. If projectiles cross each other at 1+ c, that is fine with me. The game doesn't need to shift reference for most. Honestly, most people don't know the math, and I doubt those that do want to spend their free game time worrying about it (I sure don't). If it was going to be that complicated, we would be harping on Steve to figure in the change in relative size of an object travelling at high velocities just to see if it affects whether we hit the target or not.
If you really want that level of difficulty it takes 9-12yrs at a good institution or two (and a passable doctoral thesis), and then you can deal with these problems regularly - and get paid for it.
I don't expect this level of detail. Just a good 'realistic feel' with no outright violations (other than FTL travel) of reality. (I'm sorry if guidance systems on projectiles undergoing 1/4 million G accel felt like a violation for me.)
I understand, and it makes perfect sense so long we talk of general in-game information, player omniscience if you like. I find it less convincing when it comes to tactical information. Aurora models weapon systems with a lot of details, from power supply and ordnance to detection and fire control. Not including comunication delays seems a bit strange to me.
To me the comm issue is less of a hurdle. I did a fair amount of time in the military and lack of comm is a common problem. That is what all the training and SOPs are for. To keep everyone on the same sheet of music without having to check in with each other every few seconds.
Also, I believe that in long distance space battles, the time needed to communicate with missiles is a very important factor, which adds interesting aspects to the game : the further away you fight, the less control you have. . .
But this is another matter.
Francois
Lag time for a non self guided munition would be a problem. But I really forsee most of the missiles having some onboard guidance systems. Only time will tell how this game will play out, but I forsee most missile exchanges occuring at very long range with the opponents dropping ordinance and then beginning evasive manuvering to try and run the opposing missile over its delta-v budget so that it will be impossible for it to make intercept. Groups of ships will likely release missiles from vastly different locations and speeds to bracket a target to make it more difficult for a ship to break away from inbound ordinance. In this environment, interplanetary range duels will be quite possible. I forsee the side best able to put missiles on a target from one AU+ to be the winners in this kind of duel.
But as I said, time will see (and I truly can't wait to try it out for myself).
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My hope is for realistic game, not reality. Newtonian is fine for me. I don't expect Steve to come up with a game capable of modeling all the physics we have available. If projectiles cross each other at 1+ c, that is fine with me. The game doesn't need to shift reference for most. Honestly, most people don't know the math, and I doubt those that do want to spend their free game time worrying about it (I sure don't). If it was going to be that complicated, we would be harping on Steve to figure in the change in relative size of an object travelling at high velocities just to see if it affects whether we hit the target or not.
If you really want that level of difficulty it takes 9-12yrs at a good institution or two (and a passable doctoral thesis), and then you can deal with these problems regularly - and get paid for it.
I don't expect this level of detail. Just a good 'realistic feel' with no outright violations (other than FTL travel) of reality. (I'm sorry if guidance systems on projectiles undergoing 1/4 million G accel felt like a violation for me.)
To me the comm issue is less of a hurdle. I did a fair amount of time in the military and lack of comm is a common problem. That is what all the training and SOPs are for. To keep everyone on the same sheet of music without having to check in with each other every few seconds.
Lag time for a non self guided munition would be a problem. But I really forsee most of the missiles having some onboard guidance systems. Only time will tell how this game will play out, but I forsee most missile exchanges occuring at very long range with the opponents dropping ordinance and then beginning evasive manuvering to try and run the opposing missile over its delta-v budget so that it will be impossible for it to make intercept. Groups of ships will likely release missiles from vastly different locations and speeds to bracket a target to make it more difficult for a ship to break away from inbound ordinance. In this environment, interplanetary range duels will be quite possible. I forsee the side best able to put missiles on a target from one AU+ to be the winners in this kind of duel.
But as I said, time will see (and I truly can't wait to try it out for myself).
Well said procyon !
People are taking this waaaay to seriously ... its only a game
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+1, procyon.
I believe most of those issues could be solved with entirely unrealistic, but reasonable soft cap borders, like making ships use more fuel above a certain treshhold, say, 10% and 30% of c, and have kinetic weapon projectiles have less acceleration based on how much % of c, rounded down, the firing ship has.
At 0.6 c, the railgun would only accelerate the projectile with 40% it's speed.
Those should be reasonably graspable, make no difference in early game, which is where most people start out, and it could be pretty consistent over the gameplay as well.
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have kinetic weapon projectiles have less acceleration based on how much % of c, rounded down, the firing ship has.
This would probably work, and would amount to using (special) relativistic formulae for projectiles.
making ships use more fuel above a certain treshhold, say, 10% and 30% of c
This sounds strange. . . The whole point of Newtonian Aurora is that fuel is not spent to move but to accelerate (ie change speed and/or direction of movement). A ship that doesn't accelerate, no matter her speed, will not use fuel.
Francois
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My hope is for realistic game, not reality.
I believe this is the heart of the matter. The problem, to me, is that, if we define "reality" as "what we experience and feel as being real", space movement and combat is highly unreal. We all know that movement uses fuel. For cars, tanks, planes or ships, double the fuel tank and you'll more or less double the range. On contrast, changing course uses only a fraction of the fuel consumed to move.
Unfortunately, this "reality" doesn't work in space, where fuel is spent to change course or speed. This means a lot of concepts we take for granted, in our "blue water navy" vision of space combat (as depicted in Honorverse, and similar works) do not work in "real physical space".
Take range, for instance. In most modern naval wargames (and current Aurora), a sound tactics for missile equipped ships is to close on the enemy, fire missiles and move out of range. In a Newtonian setting, this doesn't work: an enemy missiles, pointed at you (and with some onboard homing system) will probably catch you anyway, so long its speed is greater than yours. To evade pursuit, you should rather close on the missile, change course, and hope that you can outfuel it. To earthbound tacticians, this is is extremely unrealistic.
I think other examples could be produced, notably about dogfights, where high speed, which entails higher fuel cost for course change, might be less decisive than we use to think.
Overall, I think it is less about the game "looking real" (the more science you put in it, the less it will, to us earthbound humans, at least), than about keeping the maths reasonable for the programmer (it won't make a huge difference for the players, anyway).
Francois
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Unfortunately, this "reality" doesn't work in space, where fuel is spent to change course or speed. This means a lot of concepts we take for granted, in our "blue water navy" vision of space combat (as depicted in Honorverse, and similar works) do not work in "real physical space".
Agreed.
Take range, for instance. In most modern naval wargames (and current Aurora), a sound tactics for missile equipped ships is to close on the enemy, fire missiles and move out of range. In a Newtonian setting, this doesn't work: an enemy missiles, pointed at you (and with some onboard homing system) will probably catch you anyway, so long its speed is greater than yours. To evade pursuit, you should rather close on the missile, change course, and hope that you can outfuel it. To earthbound tacticians, this is is extremely unrealistic.
Not necessarily agreed. Hopefully this game will help refine just what tactics work. I personally see turning into an attacker as helping him to bracket you with missiles/projectiles and reducing your manuever options. But I could prove wrong and look forward to finding out.
Overall, I think it is less about the game "looking real" (the more science you put in it, the less it will, to us earthbound humans, at least), than about keeping the maths reasonable for the programmer (it won't make a huge difference for the players, anyway).
Disagee on the first point, agree on the second.
Steve is doing this without pay, and sharing it with us. Whatever makes this easier for him - I see as a good thing.
But on the case of it 'looking real', I disagree.
It would appear to me that Steve and all of the people commenting on this are trying to make it as 'real' in a Newtonian sense as possible, without making Steve generate code that would make NASA envious. There are 48 pages in this thread alone showing that people have a pretty good grasp of what this should be like. The discussions of required fuel per degree for course changes, viability of guidance systems on rail gun projectiles, exhaust velocities and rates of consumption, etc, etc, - prove to me at least - that the group following this and looking forward to it have a very good grasp of what happens outside the Earth's atmosphere.
People don't play Aurora looking for an 'easy' game. They play it for the level of detail and 'reality'.
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like making ships use more fuel above a certain treshhold, say, 10% and 30% of c,
This sounds strange. . . The whole point of Newtonian Aurora is that fuel is not spent to move but to accelerate (ie change speed and/or direction of movement). A ship that doesn't accelerate, no matter her speed, will not use fuel.
I'm not sure I really agree with the % 's he is proposing, but the idea is actually sound.
I don't think UnLimiTeD is suggesting you need fuel to coast, but relative speed will affect fuel use to effect a certain level of delta V.
It has to do with the increasing mass of a body as you increase its kinetic speed, per E=mc2. The energy of movement will increase the apparent mass of the ship, and hence the fuel required to accelerate it. It makes no difference in continuing at a given speed, but changing it will be affected by its current velocity in a given frame of reference.
Hopefully we don't have a lot of objects moving at such high relativistic velocities that it would make a large differece, but I will have to admit that I don't know what a drive in game will be capable of.
EDIT
As a short note, effects below .1c really should be ok without worrying about Lorenz. It only amounts to about 0.5% at this range. If we only fudge half a percent, I am not to worried.
At .5c, it amounts to around 15%. This could be sticky to ignore, but I really don't expect to see many objects passing this limit. Of course, I could be wrong.
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Yup, that's what I meant.
The aim was essentially to discourage those high speeds, even with high tech games, to the point that a hardcap set at, like, 90% lightspeed (as in current Aurora) would not be noticed by anyone that isn't die-hard trying.
I chose 10% as the first threshold because it's a nice, even number, easy to memorize and to calculate with, and a point where not too many distortions should take place.
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I doubt that ships, even given infinite delta-V, would routinely get above about .1 c, anyway. It simply takes too long to accelerate. At 10 m/s2, a ship will put on 864 km/s/day. To get to c, assuming constant acceleration, would take about 347 days. To get to .1 c, then, takes 34.7 days. During that time, a ship will cover 149808 light-seconds, or over 300 AU, which is about 8 times the semi-major axis of pluto's orbit. Very rarely will it make sense to spend that much time and fuel building speed for a jump, and going faster is highly impractical.
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10 m/s2 (around 1G) is a very low acceleration value.
A ship travelling at 1000 km/s (not a crazy speed, at this average, she'd need about 2 months to travel from the Sun to Neptune), with a 10 m/s2 acceleration, would turn arctan(10/1e6), or 5.7e-4 degree, per second. A 45° course change would take almost a full day. Even at 100 km/s, a ship could turn about 20°/hour, and a right angle turn would take 4.5 hours.
At such rates, and unless they move at very low speeds (a few km/s, which means outer planets are hardly reachable, since intra system jumps are not possible), ships become little more than projectiles, and firing a missile in the general direction of something not right ahead becomes a very costly exercise.
So, if you want ships a bit more maneuverable (and space combat possible), you need much higher acceleration rates, which, again, make relativistic speeds feasible.
On the other hand, one could argue that such high speeds are not desirable (for ships and missiles) because of the lack of maneuverability they entail. But you'd still need a lot more acceleration than a few G (more in the hundreds than the tenth, in fact) as soon as you want to travel further than the inner planets and have more maneuverability than a modern day supertanker...
Francois
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10 m/s2 (around 1G) is a very low acceleration value.
A ship travelling at 1000 km/s (not a crazy speed, at this average, she'd need about 2 months to travel from the Sun to Neptune), with a 10 m/s2 acceleration, would turn arctan(10/1e6), or 5.7e-4 degree, per second. A 45° course change would take almost a full day. Even at 100 km/s, a ship could turn about 20°/hour, and a right angle turn would take 4.5 hours.
No arguement there. Now actually turning the ship would be fairly easy. It will rotate on its axis fairly well and this is why I don't mind Steve's decision to ignore facing. Effecting a course change will take time.
I don't know what others forsee, but I expect combats to occur at ranges measured in AU, not km. Weapons will take many hours/days to reach targets, during which a great deal of time will be spent maneuvering to ascertain just what the incoming weapon is capable of (assuming you can see it), while manuevering your own ships and weapons to begin denying your target any movement options that won't put it in danger.
At such rates, and unless they move at very low speeds (a few km/s, which means outer planets are hardly reachable, since intra system jumps are not possible), ships become little more than projectiles, and firing a missile in the general direction of something not right ahead becomes a very costly exercise.
Again, no large arguement. Ship deployment will be critical. The 'Empire State Formation' of old will be a death trap. You won't be able to keep all your eggs in one basket. It will limit your attack options too severely and leave you vulnerable to a single nuke leaking past your defenses and taking out a whole fleet..
So, if you want ships a bit more maneuverable (and space combat possible), you need much higher acceleration rates, which, again, make relativistic speeds feasible.
Not sure I agree. Required fuel will probably make getting much past .1c impractical. Not impossible, but you may not see that ship again as it sails off into the 'long dark'. Weapons may push the limit, but I am willing to overlook the physics violations on 'expedible munitions' to ease the coding burden.
On the other hand, one could argue that such high speeds are not desirable (for ships and missiles) because of the lack of maneuverability they entail. But you'd still need a lot more acceleration than a few G (more in the hundreds than the tenth, in fact) as soon as you want to travel further than the inner planets and have more maneuverability than a modern day supertanker...
High G weapons, ok. High G crewed ships, not so much - unless we posit some huge medical/genetic developments, or an alien race adapted to ultra G environments.
People don't do so well at high G. 10 G for short periods will render most unconcious. More than a few minutes is generally associated with high morbidity/mortality rates.
At 100 Gs most critters we know of get kind of 'squishy' as my 7 y/o says.
As I said, I forsee a lot of combat involving ships jumping in at trans-Neptune orbits, orienting on a target, releasing self guiding ordinance, and then reversing course and jumping out before a return strike occurs. The real battle will involve having a well deployed fleet that can intercept/eliminate incoming weapons, and then be prepared to deal with the 'follow on ships' that come in a week or two later to assess the results.
Out system 'defense bases' or 'patrols' with (probably two stage) missiles that may have a chance to intercept an 'interloper' may become vital designs to prevent a holocaust.
Even extended durations at 2 G will do horrible things to you. The blood vessels in your brain have poor ability to withstand this (hence 'shaken baby syndrome' I get to see far to often) and strokes will occur regularly if you keep up 2 Gs for days on end.
This is why I see most combat occuring at long range. At shorter ranges you simply can't dodge bullets (no matter how cool I think the 'Matrix" is). Ships will start disappearing too quickly. A few railgun armed ships should be able to shred dozens of targets before the opposing weapons even reach them. Of course, the opponents incoming ordinance will doom those ships also. I kind of forsee 'close combat' to be a form of mutually assured destruction. The weapons are just to powerful for a ship to survive.
Which sadly enough, is very 'realistic'......
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Well, at some point midgame, I see 'Cyborg Crews' as relatively realistic. But I obviously agree with you.
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Now actually turning the ship would be fairly easy. It will rotate on its axis fairly well and this is why I don't mind Steve's decision to ignore facing. Effecting a course change will take time.
Yes, unfortunately, for a moving ship, this change of facing would only be useful for energy weapons, and work at very short range.
I don't know what others forsee, but I expect combats to occur at ranges measured in AU, not km.
Only if you can detect your target that far away. I believe this more or less limits this very long range hit and run strategy to attacks on planets and moons. For anything smaller and less predictable, you'll need to close in and detect, then align, then fire. Also, unless you put very long "warp delays", you will always be able to warp out of long range battles.
As I said, I forsee a lot of combat involving ships jumping in at trans-Neptune orbits, orienting on a target, This is why I see most combat occuring at long range. At shorter ranges you simply can't dodge bullets (no matter how cool I think the 'Matrix" is). Ships will start disappearing too quickly. A few railgun armed ships should be able to shred dozens of targets before the opposing weapons even reach them. Of course, the opponents incoming ordinance will doom those ships also. I kind of forsee 'close combat' to be a form of mutually assured destruction. The weapons are just to powerful for a ship to survive.
I think there would be two different styles of battle.
- attacks on planets/moons/orbital installations
Those happen as you suggest. Attacker warps in very far, aligns, shoots, and warps out. Counter fire is pretty much limited to antimissile and point defense. Antimissile tactics is relatively straightforward : move heads on, not necessarily fast, forcing the incoming missile to try to dodge, and use up its delta-v reserve. The further away you detect the enemy, the more delta-v you can force him to use. Point defense are like now, a last ditch attempt.
- ship to ship battles
detection and movement to align would force this to happen at shorter range, but I agree with you, close range is mutually assured destruction. Yet, against incoming missiles, dodging is possible, especially if you are close range (but not too close!), this is because the delta-v cost of a course change is proportional to the angle (its tangent, in fact), and the closer you are, the larger the angle.
This brings back an interesting question about light speed and detection: the cability of a missile to change course and hit an eviding target will depend on its correct evaluation of its future course. Taking information propagation delays into account would probably introduce another interesting twist. The further away you are, the less precise your assessment of future enemy position is, and the faster you move, the less time you have to react. Like a weird OODA loop...
Francois
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......?????
Looking forward to the responses. Most folks don't talk about Minkowski space unless they know something about physics.
I think perhaps the text on your last post got dropped.
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As for high-G acceleration, I thought I had read previously that Trans Newtonian elements would become some sort of "anti-gravity magic dust". Now, if we consider the (very relativistic) idea that acceleration and gravity are two aspects of the same phenomenon (local space time curvature or something), and that TN-elements can offset gravity, we might have a tech-line for high-G acceleration...
Francois
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As for high-G acceleration, I thought I had read previously that Trans Newtonian elements would become some sort of "anti-gravity magic dust". Now, if we consider the (very relativistic) idea that acceleration and gravity are two aspects of the same phenomenon (local space time curvature or something), and that TN-elements can offset gravity, we might have a tech-line for high-G acceleration...
Don't know what place the TN materials will play, but I do expect to see some form of tech to allow high G maneuvers. Whether you call it 'gravatic dampening', 'cyborg crews (ala my Nemesis Camp)', etc, I do expect it to make an appearance to allow for a more 'dynamic' style of play.
Yes, unfortunately, for a moving ship, this change of facing would only be useful for energy weapons, and work at very short range.
It is hard for me to think of a rail gun as an 'energy weapon', - but yes I agree - I expect direct fire weapons at very high velocity will dominate in close.
Only if you can detect your target that far away. I believe this more or less limits this very long range hit and run strategy to attacks on planets and moons. For anything smaller and less predictable, you'll need to close in and detect, then align, then fire. Also, unless you put very long "warp delays", you will always be able to warp out of long range battles.
This is where my lack of familiarity with the prior versions of Aurora will get me for some time. I really have no idea what is possible in the game as it stands. Some may have different ideas on what will be necessary to win. I see only one path, the same as it has been since people figured out how to throw a weapon. He who can strike farthest - wins. With the weapons discussed, nearly any hit will be fatal to a ship. It will all boil down to who can see farthest - ie sensor tech.
A hunter that can't see the deer goes home hungry. A deer that can't see the hunter is DEAD.
EDIT
As a side note, that is why I see the out system attack as the norm. So long as you arrive pointed toward the primary, everything 'in system' will be a viable target - more or less.
I think there would be two different styles of battle.
- attacks on planets/moons/orbital installations
Those happen as you suggest. Attacker warps in very far, aligns, shoots, and warps out. Counter fire is pretty much limited to antimissile and point defense. Antimissile tactics is relatively straightforward : move heads on, not necessarily fast, forcing the incoming missile to try to dodge, and use up its delta-v reserve. The further away you detect the enemy, the more delta-v you can force him to use. Point defense are like now, a last ditch attempt.
To this I would add the one thing I see 'fighters' as useful for. It sounds like they are cheap(er) and fast to produce, requiring less sophisticated facilties. A squadron with rail guns would be able to more rapidly deploy to intercept incoming ordinance, creating multiple interception points. Reusable AAMs as it were.
- ship to ship battles
Yet, against incoming missiles, dodging is possible, especially if you are close range (but not too close!), this is because the delta-v cost of a course change is proportional to the angle (its tangent, in fact), and the closer you are, the larger the angle.
Will wait to see how it works. I forsee bracketing targets with ordinance to reduce maneuver options, but only 'in game' play will see if this is workable.
EDIT
And the bracketing would occur on the approach (which probably took awhile). Intentional 'overshots' just to get inbounds closing from multiple angles should prove devastating if the coding will support it. If you back away from recent launches, you will connect with the earlier ones...
This brings back an interesting question about light speed and detection: the cability of a missile to change course and hit an eviding target will depend on its correct evaluation of its future course. Taking information propagation delays into account would probably introduce another interesting twist. The further away you are, the less precise your assessment of future enemy position is, and the faster you move, the less time you have to react. Like a weird OODA loop...
Steve has had enough headaches trying to just get the missiles to hit a target with the current coding (as I understand). Tracking system delays on targeting data is one hurdle that I don't want to drop on him (or the processor). In reality it is a problem. In the game ????
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One other thing that I wanted to bring up, interestingly completely unrelated to what is currently discussed:
I was thinking about current Size reduced Lasers, and how they apparently sacrifice a part of their "loading mechanism", thus firing more slowly.
Now what I wondered was if it is possible to also try it the other way around:
Have Lasers that have a higher cooldown phase, thus resulting in slower "reload"; possibly due to omitting part of the heat dispension.
They could also have a smaller capacitor that requires a higher incomming energy because they can only hold so much.
That'd allow for interesting ship designs where the generators funnel the energy into a pair of supercapacitors that can load the energy required for a laser shot, and then transmit it to the laser in one second.
They would result in a ship extremely dependent on it's energy system, and more expensive, but with a higher total firepower if one cycles through his "box lasers".
Additionally, will there be a tech to increase radiation efficiency of energy weapons, thus decreasing heat per emitted energy? ;)
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If we are willing to be overt about it, we could say that even auto-tracking missiles need commands from the vessel to properly lock on to a target. Without it, they become dumb, or at least not as smart somehow, and are far more easy to shoot down.
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10 m/s2 (around 1G) is a very low acceleration value.
A ship travelling at 1000 km/s (not a crazy speed, at this average, she'd need about 2 months to travel from the Sun to Neptune), with a 10 m/s2 acceleration, would turn arctan(10/1e6), or 5.7e-4 degree, per second. A 45° course change would take almost a full day. Even at 100 km/s, a ship could turn about 20°/hour, and a right angle turn would take 4.5 hours.
At such rates, and unless they move at very low speeds (a few km/s, which means outer planets are hardly reachable, since intra system jumps are not possible), ships become little more than projectiles, and firing a missile in the general direction of something not right ahead becomes a very costly exercise.
So, if you want ships a bit more maneuverable (and space combat possible), you need much higher acceleration rates, which, again, make relativistic speeds feasible.
On the other hand, one could argue that such high speeds are not desirable (for ships and missiles) because of the lack of maneuverability they entail. But you'd still need a lot more acceleration than a few G (more in the hundreds than the tenth, in fact) as soon as you want to travel further than the inner planets and have more maneuverability than a modern day supertanker...
Francois
This is exactly the case. The fact that you present it as a problem indicates that you don't understand a salient fact about space travel: ships are not maneuverable. In any case with a reasonable delta-V to acceleration ratio (where you are accelerating over the course of days), you will not be capable of serious combat maneuvering. They will spend days building delta-V, and that will prevent them from making quick turns. To see any difference, you need hundreds of Gs, and that is simply not practical, even with drones, for engineering reasons.
Putting a 10G engine on a ship is going to impose enormous penalties for the vessel in question. Not only do you need 10 times the engine of a 1G ship, you also need about 10 times the structure. At that point, there's not much room left for weapons.
Matching vectors with the enemy ship might be the way to go for closer combats. It leaves both sides with more options.
If we are willing to be overt about it, we could say that even auto-tracking missiles need commands from the vessel to properly lock on to a target. Without it, they become dumb, or at least not as smart somehow, and are far more easy to shoot down.
That would help mitigate the drive-by holocaust problem, and even more so if there is a range limit on the tracking commands. You can't control a missile from way, way out-system.
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Couple of thoughts on the drive by shooting piece:
- Upping the travel time variation for longer jumps could make it a lot harder to do this where you need to use several jump ships. If groups of ships are coming out of jump weeks apart that will cause some reasonable logistical issues for you.
- The mechanics of attacks on home planets create more of an issue for NPRs and their generation process as in most cases you will be spawning the NPR and hence will have already found their home system. This gives players a big advantage in knowing where to hit.
- I suspect that planetary defences are going to have to be substantially heftier than they are now.
- Given the big increases in travel time between stars and the loss of communication with ships I'm not sure how practical the whole jump in fire, jump out, jump back and fire again option will be.
On ship to ship combat:
- With the increases in fuel and the resulting reduction in usefull payload and the advent of area effect weapons I can see the number of missiles flying around coming down somewhat compared to current Aurora leaving us to duke it out on the close combat more often.
- For actual ship to ship combat I'm expecting engaging fleets to want to decide to engage each other and then adjust closing speed so it's actually pretty slow. Dog fighting then really just becomes a matter of relative movement - you might both be doing 5000 kms but only a few 100 in relation to one another. Similarly, course corrections will be tiny in the scheme of things but I'm expecting that they will still have a decent impact on relative position when considered against the direct fire weapons being used.
On lasers, I'm eagerly waiting for the rules post on that one. In the mean time it would be great to hear about some more of the initial test game results for combat (hint hint Steve).
Lastly I can see the old precursors as being potentially really nasty - especially if they have ships which mean they can make best of the fact that they have no fleshy bits to worry about for Gs!
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It is hard for me to think of a rail gun as an 'energy weapon', - but yes I agree - I expect direct fire weapons at very high velocity will dominate in close.
I was actually excluding railguns because their projectiles (in a newtonian setting) will be imparted the ship speed. Keeping with the blue navy metaphor, a railgun broadside always shoot a bit forward, whereas a laser broadside would fire sideways. The effect would be negligible if ship speed is much smaller than railgun velocity, of course (but keep in mind we're now in a world where physical limits are not on speed, but on acceleration).
He who can strike farthest - wins. With the weapons discussed, nearly any hit will be fatal to a ship. It will all boil down to who can see farthest - ie sensor tech.
I wonder if this would be the case. In a world where course change is very costly, incoming missiles are very limited in terms of evasive action, and antimissile fire becomes a turkey shoot. So long you can detect incoming missiles (at short range), and have enough ordnance to fire back, you're pretty much safe.
In fact, since you fire your missile at a much shorter range than the enemy fires his, you should enjoy finer targetting. And by the time you see the missiles, it is probably too late to fire yours...
As for "seeing far", I believe we'll see something like forward recon drones, very light ships that can detect and pinpoint enemy ships or missiles. Those might replace most on-board sensors. This matches you idea about fighter, I think.
Tracking system delays on targeting data is one hurdle that I don't want to drop on him (or the processor). In reality it is a problem. In the game ????
I don't know how much it would add to coding problem (in fact, you could perhaps abstract it as some form of "damping" over control, say like a small random element, with variance a function of distance).
But the more I agree with your vision of very long range battles, and projectile-like missiles, the more I believe comm delays should become an important factor. I think they are worth pondering, perhaps just to decide they are unimportant, or can be abstracted. As I said before, all this is very unintuitive (even when you do understand the science behind it).
Francois
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The fact that you present it as a problem indicates that you don't understand a salient fact about space travel: ships are not maneuverable.
This is not specific to space, you have exactly the same situation down here, where acceleration due to course change increase with speed. You can maneuver, in space or on earth, so long velocity and acceleration remains in proportion.
The problem is one of scale. Even with hyperspace allowing moves from system to system, intra-system distances are very large, and call for large speeds (if we want to keep a "human" time scalein the game). And large velocities tend to imply higher accelerations (for speed buildup and course change).
Of course, from a modern technology standpoint, neither high speeds nor high acceleration can be achieved. But in the game, I think both should be technologies, and a player would be well advised to research them in parallel. (In fact, you'd probably have two lines of G resistance : for drones and for crewed vessels)
Francois
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I fully expect a system survey to take a half decade and several billion litres of fuel, and an attack run on an enemy homeworld might very well take a few years as well.
Take current Aurora; a campaign against an enemy might have your fleet in travel for years; now drastically increase the in system travel time and fuel use, but omit 75% of transit systems and their associated times;
It might actually come out pretty similar.
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This is not specific to space, you have exactly the same situation down here, where acceleration due to course change increase with speed. You can maneuver, in space or on earth, so long velocity and acceleration remains in proportion.
The problem is one of scale. Even with hyperspace allowing moves from system to system, intra-system distances are very large, and call for large speeds (if we want to keep a "human" time scalein the game). And large velocities tend to imply higher accelerations (for speed buildup and course change).
Of course, from a modern technology standpoint, neither high speeds nor high acceleration can be achieved. But in the game, I think both should be technologies, and a player would be well advised to research them in parallel. (In fact, you'd probably have two lines of G resistance : for drones and for crewed vessels)
Francois
Not exactly. Yes, your speed does make maneuver harder in a planetary environment. However, my point is that in space, when non-operatic ships fight under the same propulsion the cruise with, they are not capable of serious tactical maneuver. Why? Because a ship will spend days building velocity during cruise, then have minutes to hours to alter it during combat. This is a fact. Increasing acceleration will not change anything. You have a higher base velocity, so the applied acceleration remains roughly proportional. The only solution that provides lots of maneuver is to have a ship fight with a different drive then it cruises with. AV:T did this. Their ships have drives on the order of a G for combat, which run at miligee levels for cruise. We simply can't get around this without adopting that solution, or going for operatic tech like the Honorverse has.
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The only solution that provides lots of maneuver is to have a ship fight with a different drive then it cruises with. AV:T did this. Their ships have drives on the order of a G for combat, which run at miligee levels for cruise. We simply can't get around this without adopting that solution, or going for operatic tech like the Honorverse has.
I guess the other option is to design engines with a fuel efficiency range and then allow the actual efficiency to be set whilst a ship is operational. This allows you to burn your fuel as efficiently as possibly during cruise but then burn fuel heavily to improve performance during combat - basically afterburners. However this is all more coding so I guess until we see how playable current mechanics are we can but ponder!
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That actually makes a lot of sense, though. I know that given the option, I would put combat engines on a ship that were, say, 0.01 times or less the efficiency of the cruise engine in exchange for a 5x thrust, even if it makes the engine or ship itself twice the weight.
Anyway, I remember a discussion somewhere on deep space tactics that expressed that it would basically come down to jousting. I disagree- I think tactics will revolve around simply being at the points of interest first, and holding the planetary high ground.
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I guess the other option is to design engines with a fuel efficiency range and then allow the actual efficiency to be set whilst a ship is operational. This allows you to burn your fuel as efficiently as possibly during cruise but then burn fuel heavily to improve performance during combat - basically afterburners. However this is all more coding so I guess until we see how playable current mechanics are we can but ponder!
That's actually what AV:T did. Either way, the result is the same.
That actually makes a lot of sense, though. I know that given the option, I would put combat engines on a ship that were, say, 0.01 times or less the efficiency of the cruise engine in exchange for a 5x thrust, even if it makes the engine or ship itself twice the weight.
I'm not sure how effective that would be. You're sacrificing cost and mass, and I'm honestly not sure how much even 5x thrust would be helpful.
And as another note, we're dealing with cruising accelerations on the order of 1G. To be useful, a maneuver acceleration has to be sustainable for longish periods of time, which limits it to something on the order of 3Gs for humans.
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That's actually what AV:T did. Either way, the result is the same.
I'm not sure how effective that would be. You're sacrificing cost and mass, and I'm honestly not sure how much even 5x thrust would be helpful.
And as another note, we're dealing with cruising accelerations on the order of 1G. To be useful, a maneuver acceleration has to be sustainable for longish periods of time, which limits it to something on the order of 3Gs for humans.
Which is why I think Newtonian combat will be dominated by fighters, or at least parasite vessels. You could have a mothership with a high efficiency cruise drive, plus all the non-combat components; extra fuel tanks, maintenance storage, etc. Then when combat threatens it launches a bunch of fighters and cruisers, which with their low efficiency drives and less weight spent on secondary systems could massively outmaneuver comparable non-parasite vessels.
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I think that we might still see some kind of bastard ship with neither the speed of fighters nor the staying power of carriers but that might find a good position operating from a planet or base and being strong enough to threaten fighters and fast enough to outmaneuver carriers. For these vessels, having a mixed mode drive could make sense, particularly if you need to get to the edge of the system efficiently, to get to the fight, and then maneuver quickly when you get there. Of course, single-mode drives would be more efficient and faster depending on design.
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If we are willing to be overt about it, we could say that even auto-tracking missiles need commands from the vessel to properly lock on to a target. Without it, they become dumb, or at least not as smart somehow, and are far more easy to shoot down.
Not sure how realistic that would be. I believe even current Aurora has missiles search and home on new targets if the original was lost. Just release and let coast till it finds a target. Fire and forget is a reality today.
Matching vectors with the enemy ship might be the way to go for closer combats. It leaves both sides with more options.
I see that as suicide. Creating nearly uninterceptable trajectories while managing to place ordinance on target will decide battles to me, but only time will tell.
I was actually excluding railguns because their projectiles (in a newtonian setting) will be imparted the ship speed. Keeping with the blue navy metaphor, a railgun broadside always shoot a bit forward, whereas a laser broadside would fire sideways. The effect would be negligible if ship speed is much smaller than railgun velocity, of course (but keep in mind we're now in a world where physical limits are not on speed, but on acceleration).
No arguement. Rail guns will have a momentum issue. You will have to time your fire.
I wonder if this would be the case. In a world where course change is very costly, incoming missiles are very limited in terms of evasive action, and antimissile fire becomes a turkey shoot. So long you can detect incoming missiles (at short range), and have enough ordnance to fire back, you're pretty much safe.
In fact, since you fire your missile at a much shorter range than the enemy fires his, you should enjoy finer targetting. And by the time you see the missiles, it is probably too late to fire yours...
The big question will be on how accurate the AM defenses are. A missile closing at .5c may be a difficult intercept, especially if set to detonate at long range with lase rods. Only game play will prove the effectiveness of various weapon systems.
As for "seeing far", I believe we'll see something like forward recon drones, very light ships that can detect and pinpoint enemy ships or missiles. Those might replace most on-board sensors. This matches you idea about fighter, I think.
Agreed in spades.
And for a comment of the lasers, I am not sure the damage modeling may be correct.
If you can pinpoint a place on the hull of a ship 10s of thousands of km away, moving at thousands of km per second - hitting with any weapon should be a breeze. Even with a pulse measured in ten thousandths of a second your target will have moved one hundred meters if going simply 1000km/s. Most likely your laser painted the side of the ship. The depth it may have scoured the armor could depend on the energy it has, but it is more of a sandpaper effect than a 'boring' one.
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Why? Because a ship will spend days building velocity during cruise, then have minutes to hours to alter it during combat.
I'm not sure I see your point. You seem to imply that velocity building must take days. I would say this would be the case for freighters and early game ships, but warships would have high G engines (with some form of grav/inertial compensator, which would probably be the main feature of TN technology). Such ships would quickly accelerate to cruise speed (fuel cost being the same) and operate, most of the time, in ballistic mode, ie with engines stopped.
Even if high G maneuvers were too risky to be attempted out of battle, you could imagine a high G drive giving a low acceleration. Derivating Tsiolkovski's eq, you get the formula for accelerations (G), as
dV/dt = -v_exhaust/m dm/dt
To reduce acceleration, you could either reduce v_exhaust (which might not be practical in chemical rockets, but is perfectly doable if exhaust are accelerated by a field, as in a ion engine), or reduce mass output. In practice, it just means warships would have much more powerful engines than commercial ships, and probably some kind of anti-grav contraption to allow their crew and frame to sustain the high G delivered by the engine.
For all drives, there would be some speed over which maneuverability drops (because the engine cannot support such accelerations). This max-maneuver velocity would be low for old generation ships, or later day freighters, higher for military vessels, and much higher for fighters (because of the low m in the above eq).
A missile closing at .5c may be a difficult intercept, especially if set to detonate at long range with lase rods.
But those missiles would move in a straight line, bearing on your ship, no? So, if you can align with them (easy task if you are at rest, almost impossible if you are moving fast, but then, the missiles will have a hard time intercepting you...) and if your antimissiles have an area effect (just like enemy missiles), the only thing you need is that your AM "crosses" the enemy missile before it is in range of your ship.
Supposing your AM has the same speed as the missile (but you could adapt the formula), this means you can detect the enemy projectiles at twice their explosion range. But all this only seems to work if you can align your fire with enemy missile path, ie if you are very close to te ship targetted. "sideways" shoots at missiles, on the other hand, would be little more than potshots...
Francois
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For all drives, there would be some speed over which maneuverability drops (because the engine cannot support such accelerations). This max-maneuver velocity would be low for old generation ships, or later day freighters, higher for military vessels, and much higher for fighters (because of the low m in the above eq).
The degree of change in course bearing will relate to relative velocities. But actual displacement over a given time span will always remain a function of your acceleration. Adequate displacement from the incoming weapon (minus it ablility to correct for this) will determine successful intercepts. A half degree course change that moves you two kilometers or a 15 degree course change that moves you two km will all displace you from a weapon path 2km if performed in the same time frame. If Steve models the G forces of inherent in the course change necessary by incoming ordinance the 15 degree change is desirable. If it isn't = displacement will simply be displacement.
But those missiles would move in a straight line, bearing on your ship, no? So, if you can align with them (easy task if you are at rest, almost impossible if you are moving fast, but then, the missiles will have a hard time intercepting you...) and if your antimissile have an area effect (just like enemy missiles), the only thing you need is that your AM "crosses" the enemy missile before it is in range of your ship.
Supposing your AM has the same speed as the missile (but you could adapt the formula), this means you can detect the enemy projectiles at twice their explosion range. But all this only seems to work if you can align your fire with enemy missile path, ie if you are very close to te ship targetted. "sideways" shoots at missiles, on the other hand, would be little more than potshots...
Detection range will be paramount on incoming ordinance. High enough inbound speed may limit counter fire to direct fire weapons as AMM will not have sufficient time to reach a minimum safe distance from the target.
And depending on how the coding works, I only see a few successful 'head on intercept' attempts against mobile opponents with credible defenses.
But a missile at high velocity (or better = several closing on different trajectories) equiped with detonation laser rods on a passing trajectory could be a difficult target (depending on warhead yield, laser output, and accuracy). It won't be coming straight at you. If the coding supports it I would have them veering off on the end of the attack runs. The missile should be able to rotate on its axis even more nimbly than a ship to aquire a target. As you pointed out, it doesn't have to worry about inertia for the lasers and can even detonate after it has passed the target.
Depending on relative velocities, trajectories, and ranges these missiles may give precious little opportunity to stop them.
But again, I will have to wait and see what the game supports.
Of course, you could always have your missiles travel in pairs, with one several kms in the lead. Both with healthy nukes. The first one set to detonate to stop the incoming AMMs....
EDIT
Have I mentioned lately that I really can't wait to see what is possible, and try it out to see what works.... :D
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Yeah, you're already dwelling in possible tactics. ;)
I expect Lasers and particle accelerators to be the weapons of choice for "close" range point defense.
Well, we haven't yet gotten any info on what Lasers will be like.^^
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High enough inbound speed may limit counter fire to direct fire weapons as AMM will not have sufficient time to reach a minimum safe distance from the target.
Yes, it means, AMM efficiency will mostly depend on the acceleration they can provide at launch. An AMM should then be a very light missile (acceleration in inversely proportional to weight), with a very large exhaust speed, that can jump to very high speeds in a very short period. Perhaps they should be a mix between a missile and a railgun projectile...
Note that warhead effective range will most certainly be under 1 million kilometres (it should correspond to laser effective range if laser warheads become the norm). If effective sensor ranges are around 50 million km, then, against an inbound missile at 0.5 c, you have a little more than 300 seconds between detection and interception if you want to intercept out of warhead range. An AMM covering a million km in 300 seconds would have an average speed of 3333 km/s. Under constant acceleration, this would correspond to a final speed of 6 666 km/s, or an acceleration of 22 km/s^2, ie 2.2 G.
Note that the use of laser warheads will make laser less efficient as antimissile weapons : if enemy laser technology is on par with yours, by the time the enemy missiles reaches your effective laser range, it is about to detonate...
Francois (check the above maths before you quote them, I'm running away to a meeting, so the figures might be grossly wrong...)
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Yes, it means, AMM efficiency will mostly depend on the acceleration they can provide at launch. An AMM should then be a very light missile (acceleration in inversely proportional to weight), with a very large exhaust speed, that can jump to very high speeds in a very short period. Perhaps they should be a mix between a missile and a railgun projectile...
AMM drive efficiency will need to be the best you can get, agreed. I could see proactive deployment of AMMs from an escort - before you detect incoming ordinance - to be a possible tactic. Will have to test that one when the time comes. AMMs with internal sensors set to TCS 1 and good drives with a small nuke could make an effective screen.
Note that warhead effective range will most certainly be under 1 million kilometres (it should correspond to laser effective range if laser warheads become the norm). If effective sensor ranges are around 50 million km, then, against an inbound missile at 0.5 c, you have a little more than 300 seconds between detection and interception if you want to intercept out of warhead range. An AMM covering a million km in 300 seconds would have an average speed of 3333 km/s. Under constant acceleration, this would correspond to a final speed of 6 666 km/s, or an acceleration of 22 km/s^2, ie 2.2 G.
Math good to the G point. 22m/s2 is 2.2G. 22km/s2 is 2200 G. A wee bit more than I expect my engines to attain for a while.
As I have said, I look forward to this game. It will put a lot of theories to the test.
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Have to say I can't wait to have a go at this myself. Already started building the brownie points with the wife in the anticipation of some long evenings locked in the study!
Was just having a quick look at the rules again and noticed that the costs in warhead between conventional / nuclear / nuclear laser seem quite small to me and was wondering if these differences should be more pronouced to give players more of a decision to make in the types of ordinance used?
Also, having re-read the rail gun thread I was not sure if Steve was going to be calculating kinetic energy for damage based purely on the exit velocity of the shell or the eventual relative impact velocity when it hits. I'm assuming it's the later with the exit energy just being used to calculate total enegry requirements and cool down requirements.
Just running some numbers I can see that even with a closing speed of just 500kms any shots are going to be lethal: By my calcs that would give an impact energy for a 1 kilo slug of 125k MJ, more than enough to punch through basically any armour and shields and go back out the other side. I'm wondering how that sort of narrow but very high damge will be dealt with for internal systems.
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What we should actually factor in is slug ablation.
If that slug is 1 kg, and it hits the force shilds of the ship, and possibly some sort of wobble shield on the armor ( I know i would mount some), then shouldn't it degrade somewhat?
If it flies though 20 layers of armor, shouldn't the slug take damage as well?
Still, a 1kg chunk of iron shouldn't damage a ship too harsh, it'll just leave two large holes.
And wreck whatever else it passes.
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Math good to the G point. 22m/s2 is 2.2G. 22km/s2 is 2200 G. A wee bit more than I expect my engines to attain for a while.
Sure enough! (and thanks, Procyon!)
The calculation scales linearly with incoming speed, which means a missile moving at 15000 km/s would need 220G-capable AAM to be stopped. This is a lot, but it is not a crazy (current day ABM accelerate to more than 100g, and modern electronic equipment can witstand over a thousand G).
I don't know how plausible 2200 G is? More or less than 0.5c missiles? With 2200 G, you'd need something like 500 million km to accelerate a missile to 0.5c, with accelerations in the hundreds, you'd need several billions.
But then, given that such fast projectiles will not be able to maneuver, maybe a better question is : do we really need missiles? or would railguns with explosive ordnance work better?
We'd be back to older models, as artillery becomes the queen of the space battlefield?
Francois
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Given that as far as we know, Railguns won't have "real" homing projectiles, for now, the accuracy will drop off drastically.
Missiles will be special delivery vehicles, sure you can create an armored one as a kinetic kill vehicle, but it'll mostly be nuke, shrapnell, or laser rod warheads, all with their special uses.
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I'm not sure I see your point. You seem to imply that velocity building must take days. I would say this would be the case for freighters and early game ships, but warships would have high G engines (with some form of grav/inertial compensator, which would probably be the main feature of TN technology). Such ships would quickly accelerate to cruise speed (fuel cost being the same) and operate, most of the time, in ballistic mode, ie with engines stopped.
Yes, I am implying that velocity building must take days, for a simple reason. Steve has not indicated that he's adding any sort of system that would allow tens of Gs of acceleration. As for cruising, that's not the case. If you have the delta-V, it makes sense to burn constantly.
Even if high G maneuvers were too risky to be attempted out of battle, you could imagine a high G drive giving a low acceleration. Derivating Tsiolkovski's eq, you get the formula for accelerations (G), as
dV/dt = -v_exhaust/m dm/dt
To reduce acceleration, you could either reduce v_exhaust (which might not be practical in chemical rockets, but is perfectly doable if exhaust are accelerated by a field, as in a ion engine), or reduce mass output. In practice, it just means warships would have much more powerful engines than commercial ships, and probably some kind of anti-grav contraption to allow their crew and frame to sustain the high G delivered by the engine.
Your formula is technically correct, and I do agree that ships could maneuver harder during battle, but not enough, assuming that we are limited to human tolerances. As for reducing acceleration, you would always reduce mass flow, and, if using something like a Hall Thruster, increase the exhaust velocity.
For all drives, there would be some speed over which maneuverability drops (because the engine cannot support such accelerations). This max-maneuver velocity would be low for old generation ships, or later day freighters, higher for military vessels, and much higher for fighters (because of the low m in the above eq).
But those missiles would move in a straight line, bearing on your ship, no? So, if you can align with them (easy task if you are at rest, almost impossible if you are moving fast, but then, the missiles will have a hard time intercepting you...) and if your antimissiles have an area effect (just like enemy missiles), the only thing you need is that your AM "crosses" the enemy missile before it is in range of your ship.
Supposing your AM has the same speed as the missile (but you could adapt the formula), this means you can detect the enemy projectiles at twice their explosion range. But all this only seems to work if you can align your fire with enemy missile path, ie if you are very close to te ship targetted. "sideways" shoots at missiles, on the other hand, would be little more than potshots...
Francois
You're ignoring part of the above equation, that is the dm/dt, or mass flow. Yes, a smaller ship with the same engine will have better acceleration. This does not mean that fighters are a good idea.
And why is maneuverability so important, anyway? Yes, at higher velocities, it takes longer to make a 90 degree turn. However, nobody will actually look at it that way. If you want to generate a miss with regard to missiles, the only thing going slower does is increase the time it takes for the missile to close with you. You still build the same side vectors, regardless of velocity. A higher velocity will give you less time to build the vectors, but that's all.
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I suppose everytime someone seriously mentions fighters in discussions about engine thrust, they mean unmanned craft?
That might allow for more maneuverability.
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Steve has not indicated that he's adding any sort of system that would allow tens of Gs of acceleration.
Tens of G of acceleration are a fact of modern day technology, an ABM has acceleration over 100G, in fact. Ruling them out from manned ships is possible, but the issue will reappear for drones and missiles.
As for cruising, that's not the case. If you have the delta-V, it makes sense to burn constantly.
Not necessarily. Burning constantly will send you "there" faster, but it will also use more fuel, and might make sudden course changes more expensive. Again, for a cargo ship, on a predefined route, it makes sense, for a military ship on patrol, not necessarily so.
And why is maneuverability so important, anyway?
Can think of many, but in a nutshell, because maneuverability=acceleration
- In a missile vs antimissile dogfight, better acceleration will always win (and if the incoming missile manages to evade the antimissile, it will need to maneuver back towards its target)
- higher accelerations allow an antimissile to reach its target earlier, which is important if warheads are area weapons.
- In a long range ship vs missile situation, a ship with good acceleration can (perhaps) create a situation where the enemy missile runs out of delta-v, lasting longer may matter
- In a more classical (moving) ship vs ship situation, before you fire a missile, you need to align with the target. Better ship maneuverability will allow for an earlier firing solution, better missile maneuverability will allow for a larger set of solutions.
Francois
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Tens of G of acceleration are a fact of modern day technology, an ABM has acceleration over 100G, in fact. Ruling them out from manned ships is possible, but the issue will reappear for drones and missiles.
The statement was meant WRT manned ships. As for drones, I don't see drone ships seriously outperforming manned ships if for no other reason then fleet interoperability. Missiles are an entirely different matter.
Not necessarily. Burning constantly will send you "there" faster, but it will also use more fuel, and might make sudden course changes more expensive. Again, for a cargo ship, on a predefined route, it makes sense, for a military ship on patrol, not necessarily so.
That depends on how much delta-V you have. Modern chemical rockets have low delta-V, but relatively high acceleration, so it makes sense for them to burn quickly. However, there is a limit to how much acceleration a person can handle, and that limit strongly indicates we'll see long term burns to be able to use it. I'm not ruling out coasting at some point, but I don't expect long coasts to be the norm.
Can think of many, but in a nutshell, because maneuverability=acceleration
- In a missile vs antimissile dogfight, better acceleration will always win (and if the incoming missile manages to evade the antimissile, it will need to maneuver back towards its target)
- higher accelerations allow an antimissile to reach its target earlier, which is important if warheads are area weapons.
- In a long range ship vs missile situation, a ship with good acceleration can (perhaps) create a situation where the enemy missile runs out of delta-v, lasting longer may matter
- In a more classical (moving) ship vs ship situation, before you fire a missile, you need to align with the target. Better ship maneuverability will allow for an earlier firing solution, better missile maneuverability will allow for a larger set of solutions.
Francois
All of these are true, but also relative. You stated this argument by claiming that higher accelerations were needed to make space combat possible. A ship with higher acceleration has an advantage, yes. But what that acceleration is is irrelevant.
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Have to say I can't wait to have a go at this myself. Already started building the brownie points with the wife in the anticipation of some long evenings locked in the study!
I wish I could say the same thing. Convincing my wife and kids to put the RPGs and Starfire on hold so I can play is a hurdle I am not looking forward to. :(
Also, having re-read the rail gun thread I was not sure if Steve was going to be calculating kinetic energy for damage based purely on the exit velocity of the shell or the eventual relative impact velocity when it hits. I'm assuming it's the later with the exit energy just being used to calculate total enegry requirements and cool down requirements.
Just running some numbers I can see that even with a closing speed of just 500kms any shots are going to be lethal: By my calcs that would give an impact energy for a 1 kilo slug of 125k MJ, more than enough to punch through basically any armour and shields and go back out the other side. I'm wondering how that sort of narrow but very high damge will be dealt with for internal systems.
I am fairly sure he intends to use actually impact speeds, not launch speeds. I wouldn't think it would be hard to code for, but I am not a programmer.
The damage modeling for slugs could really use some attention. My reasons....
At those velocities, unless this slug is made of some incredibly resilient material it won't survive impact intact. If it could, we need to be using whatever it is made of for armor. The energy generated will create an enormous amount of heat (depending on velocity at impact) - likely vaporizing the slug and turning it into a violently expanding mass of superheated gas and particles. It is going to become a bomb.
The slugs fired from the 120mm on our tanks only hits targets at < 3 km/s. Often less than 2 km/s. They turn into molten slag on the way through the armor and essentially detonate in the target. Check the records. I saw a fair number of enemy vehicles hit by our tanks - the only exit holes were on soft vehicles.
The railgun slugs will likely be hitting at higher than single digit km/s. The penetrator (if it overcomes the armor) won't be intact. It will be a 'fireball'.
EDIT
On the thought of a slug hitting a shield, I really don't have any idea what would happen. I don't really know what the shields are. If they are some distance from the ship, they may yaw the slug. This would ruin its sectional density as it struck and profoundly limit its penetration. If the shields are nearly flush with the ship, then I doubt it makes much difference.
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All of these are true, but also relative. You stated this argument by claiming that higher accelerations were needed to make space combat possible. A ship with higher acceleration has an advantage, yes. But what that acceleration is is irrelevant.
Ok, couldn't resist.
You don't need ANY acceleration for space combat....
You just can't expect to live very long though... ::)
I apologize. I'm better now.
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So, will we get a new tech line called "Slug integrity", that starts at maybe 5000, and goes up from there? ;)
The question would be, how do we treat it afterwards?
Degrading penetration if it goes any further?
After all, an armor square is a meter², so shell expansion wouldn't factor into the system much.
And a slug of molten metal, radiation and plasma is probably still as lethal as one from solid metal, given the speeds that are required to reach that state anyways.
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So, will we get a new tech line called "Slug integrity", that starts at maybe 5000, and goes up from there? ;)
The question would be, how do we treat it afterwards?
Not to worried about slug integrity. If it could survive the hit - use that stuff as armor because it can survive the hit.
Degrading penetration if it goes any further?
After all, an armor square is a meter², so shell expansion wouldn't factor into the system much.
And a slug of molten metal, radiation and plasma is probably still as lethal as one from solid metal, given the speeds that are required to reach that state anyways.
After a quick thought, and check with a wee bit of math... I came to a conclusion. (Very possibly incorrect, which won't be a first. Comments expected.)
With the velocities we are expecting to see from the ships, the ship is likely to hit the slug - more than the slug hitting the ship as it were. You can't guarantee that it will hit 'nose first'. We shoot at relatively slow moving objects here on Earth. That won't apply.
So my guess is with a fair chance that a ship will hit it from any vector (heck, it might come in from behind and slam into it a hundreds of km/s) - our slugs are going to look more like cylinders, or maybe even old time cannon balls.
The energy of the collision should be enough with even a 1kg projectile (assuming >50km/s) of penetrating a large amount of armor. Lots more than most ships will likely pack on. Didn't check the MJ level for armor, but with most measured in cm's - penetration should be assured for a spherical projectile.
Once your blob of molten/vaporized stuff gets through the armor, it is going to expand like a bomb. Don't worry about it going out the back. It will look more like a bundle of TNT going off. I'm not worried about whether it will do damage. It just shouldn't be limited to a few systems (unless you have internal armoring/bulkheads), it should take out anything it can expend energy on. Any atmosphere in the ship is just going to propogate this massive shockwave. If it has enough energy - it should gut a ship. Not put out a few systems and then go on its merry way.
That was my point. It wouldn't do limited damage to the inside of a ship. If it was going fast enough into a ship filled with atmosphere - it could blow it up as completely as a bomb placed inside the vessel.
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Hi Procyon,
I very much agree with your analysis. Unless slugs are extremely small (and I don't understand why they should be), and relative speed is very low (ie the ship overtakes the slug), the amount of kinetic energy will be such that armour will make very little difference. With respect to projectiles, a hit is a kill.
On the other hand, long distances and large speeds would make 'aiming' extremely difficult. Even with perfect control on the firing vector (and there are physical limits on this), you can't expect slug and target speed to be absolutely constant, nor can you expect their trajectory to be perfectly straight (due to gravity, at least). And volleys of slugs shot at long distance would probably scatter a lot.
In my opinion, projectile weapons will make short distance combat impossible (which is why, I believe, missiles, and maybe some projectiles, must be area weapons), but at longer ranges they will become a form of "lottery weapon", with a small probability of sudden kill. And volleys of projectiles would only improve the hit probability at short range (as range increases, so does scatter).
Apart from luck, the only defense against slugs I can think of would be some yet to be handwaved "grav/mag/whatever shield" that could deflect incoming trajectories. This would work against slugs arriving on low angle trajectories, but probably not for direct hits.
Now, this raises an interesting question about missiles, and "explosive rounds" (if such things exist). Should they be fragmentation or "pure energy" weapons? (or maybe a combination of both)?
Francois
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On the other hand, long distances and large speeds would make 'aiming' extremely difficult. Even with perfect control on the firing vector (and there are physical limits on this), you can't expect slug and target speed to be absolutely constant, nor can you expect their trajectory to be perfectly straight (due to gravity, at least). And volleys of slugs shot at long distance would probably scatter a lot.
Yes, we had a very long discussion earlier in this thread of the viability of long distance accuracy on rail guns. I will defer (as will everyone else) to Steve's decision, but long range fire will be problematic.
In my opinion, projectile weapons will make short distance combat impossible (which is why, I believe, missiles, and maybe some projectiles, must be area weapons), but at longer ranges they will become a form of "lottery weapon", with a small probability of sudden kill. And volleys of projectiles would only improve the hit probability at short range (as range increases, so does scatter).
I expect Steve to set some maximum range for the rail gun projectiles. How he figures it is up to him. But having the processor track hundreds or thousands of rail gun slugs as they drift deep out system will really put a strain on the computer (I think).
Apart from luck, the only defense against slugs I can think of would be some yet to be handwaved "grav/mag/whatever shield" that could deflect incoming trajectories. This would work against slugs arriving on low angle trajectories, but probably not for direct hits.
Not sure if Steve will allow the detection of incoming slugs. Hitting 'bullets with bullets' will be difficult. I suppose some form of 'sand caster (ala traveller)' could deflect/disrupt them. If you could see them long enough and could paint one with a high enough energy laser you may also be able to deflect (by vaporizing part of the surface)/ disrupt (by creating shock wave through rapid heating/expansion) it. But it would take a lot of energy as you aren't likely to hold it in the beam for long.
Now, this raises an interesting question about missiles, and "explosive rounds" (if such things exist). Should they be fragmentation or "pure energy" weapons? (or maybe a combination of both)?
Personnally I think all missiles should have a 'kinetic' setting. Just don't arm the warhead. Shrapnel will likely look like a railgun when it hits, unless the fragments are very large. But a missile with a 4 ton warhead releasing 4000 - 1kg chunks of metal could be a real terror as it approached a group of ships. Will make 'dodging' difficult.
There could probably be a distinction for a pure kinetic kill weapon. A 1kg projectile hitting a target at km/s will vaporize into a bomb like weapon. A 1000kg chunk of metal probably won't. Might fragment.
But with the energy it will contain the shockwave it should create will make the issue of 'will there be a hole in the back' more of a 'will there be a big enough piece left to identify the exit hole'.
As I said before. I see this game happening at very long ranges if you plan to go home. Up close the energy and accuracy makes it fairly suicidal. If you are close enough to get a firing solution with your rail guns/lasers, you probably have a bunch of incoming ordinance heading toward you.
Long range sniping, perhaps survivable. At close range it will be like fighting in a closet with hand grenades.
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And we all know what bloody fun that can be! :D
So, if we have force fields at a distance to the projectile, or wobble shields through reactive armor, wouldn't that effect the effect on the target?
Could we use turreted pulse lasers in a last ditch attempt to deflect incomming rounds?
Could we mount shotguns that blanket an area of space with hundreds of small pebbles, thus making the rounds fragment before they hit the armor?
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I expect Steve to set some maximum range for the rail gun projectiles. How he figures it is up to him. But having the processor track hundreds or thousands of rail gun slugs as they drift deep out system will really put a strain on the computer (I think).
The way I see it (and this would apply to fragmentation missiles as well) is that you stop tracking a slug (or volley) once its chance of a random hit falls under a certain value. It is akin to rounding probabilities to a certain precision: below a certain value, everything ceases to exist.
Here are the maths behind the idea... Every railgun (or similar) has an "angular precision" (a), expressed in fractions of a degree. This factors everything in : launch bearing imprecision, fulctuations in course and speed of the projectile, imprecision is target determination. The best approach is probably to imagine a as a gaussian random variable, but I think a constant probability would work just as fine, and keep the calculations simple.
- Over a certain distance, this angular precision translates into a positional imprecision, as a times d (in fact tan(a).d, but a=tan(a) holds for such low values), so the probability to hit (in the case of a constant probability) is ratio between the surface of the target (PI r^2, where r is some average dimension) to the surface of the "drift cap" (PI (ad)^2 is a good approximation at a distance). In other words (r/ad)^2. You can use this formula to determine practical range from some angular precision, or the reverse, and correlate range to target size (it is obviously easier to hit a shipyard than a ship).
- Now, and this is, I think, the interesting part of the calculation, you could apply this calculation to a volley of slugs. Probability to hit would then be 1- (1-(r/ad)^2)^n, you'd then get a relation between range, rate of fire and size of target (and you can readily approximate it as n(r/ad)^2...)
To summarize, instead of tracking individual slugs, the processor would track volleys, and handle them as a probability of hitting over a certain range (decreasing as the inverse square of distance). This would not (I think) add unreasonable burden on the processor, but would account for the fact that railgun range depends on target size.
Francois
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As far as i remember a past discussion about this, steve will have them be deleted if they miss their target and theres currently nothing in the future path.
But if the target is in front of a planet, that planet will be hit.
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As it stands it seems to me that there will actually be very little point in adding armour to your ships, better to spend the weight on increasing your acceleration or Delta V reserves so you can get out of the way as there is a good chance that any hit is going to be lethal irrespective of the armour you have.
Just looking at Steve's example of each armour block having 125MJ damage resistance, if we say a pretty well armoured ship has ten layers that does not give much protection on point hits at all compared to the numbers being tossed around.
On the shrapnel missile side of things I would expect 100gram ball bearings to cause enough damage, let alone 1 kilo slugs.
I like the idea of making shields particularly effective against kinetics and armour effective against energy weapons as a possible rock-paper-scissors approach. I also like the idea of some very close range laser defences that can track and shoot down slugs - potentially something limited to say a 10k range to enable enough energy to be applied to the slug.
On a totally different note I was thinking that perhaps my empire was going to need to invest in some slightly more effective escape pods - with the new mechanics I can see 14 days to be too short a time for rescue even when you have other ships in the system and judging my the weapon mechanics I'm going to be using a lot of them!
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With the velocities we are expecting to see from the ships, the ship is likely to hit the slug - more than the slug hitting the ship as it were. You can't guarantee that it will hit 'nose first'. We shoot at relatively slow moving objects here on Earth. That won't apply.
The projectile doesn't care, but I can see this happening. Cannonballs might be a good idea. And I have some formulas for penetration I should dig up and test.
Here are the maths behind the idea... Every railgun (or similar) has an "angular precision" (a), expressed in fractions of a degree. This factors everything in : launch bearing imprecision, fulctuations in course and speed of the projectile, imprecision is target determination. The best approach is probably to imagine a as a gaussian random variable, but I think a constant probability would work just as fine, and keep the calculations simple.
- Over a certain distance, this angular precision translates into a positional imprecision, as a times d (in fact tan(a).d, but a=tan(a) holds for such low values), so the probability to hit (in the case of a constant probability) is ratio between the surface of the target (PI r^2, where r is some average dimension) to the surface of the "drift cap" (PI (ad)^2 is a good approximation at a distance). In other words (r/ad)^2. You can use this formula to determine practical range from some angular precision, or the reverse, and correlate range to target size (it is obviously easier to hit a shipyard than a ship).
- Now, and this is, I think, the interesting part of the calculation, you could apply this calculation to a volley of slugs. Probability to hit would then be 1- (1-(r/ad)^2)^n, you'd then get a relation between range, rate of fire and size of target (and you can readily approximate it as n(r/ad)^2...)
I haven't checked the math too closely, but it looks good. One thing, though, is that you should be using radians instead of degrees.
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You wouldn't want to go without armor against nuclear explosions though, and especially lasers.
I've been thinking about what happens when a slug hits a ship, and I think one way to try to model the amount of dissipation on the slug directly.
Maybe have a ratio of the hardness of the armor and the slug, and from that you get the sideways acceleration on the cloud/molten ball of matter that was once the projectile after it hits the ship. Spread out the kinetic energy of the of the round at all the armor pieces hit at that level. If there is enough kinetic energy to destroy them then knock that amount off, calculate the new speed of the projectile mass, and widen the cone again. Continue until you either run out of kinetic energy or run out the back of the ship.
So a projectile hitting relatively slowly may have a damage pattern like this:
oooxooo
ooxxxoo
xxxxxxx
ooooooo
While the same projectile hitting the same ship at a much higher speed would be something like this:
ooxooo
ooxooo
ooxxoo
oxxxoo
oxxxxo
xxxxxx
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You are aware that the armor thickness per level is one centimeter and the size of one square is a square meter?
I don't quite think that a projectile the size of a tennis ball would spread out that fast.
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but not enough, assuming that we are limited to human tolerances.
I mentioned a while back that this was potentially a method to balance high and low G races.
High G races can withstand higher maximum accelerations, giving their ships a boost in tactical combat.
Low G races get to colonize damn near everything, giving them more ships in general.
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How comes you guys combine Gravity with G tolerances? Some animals survive Gs better then Humans, iirc peregrin falcons can survive some higher Gs for a short time. I see that Gravity and g-force-tolerances are linked but there has to be some variance in it.
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Uh, gravity tolerance is the same as g-force. Gravity is acceleration.
A species that is adapted to life on a large earth-like world with 7g gravity can build ships that go at 7g accelerations without meeting any biological limit.
No species would have any trouble on a ship accelerating at less than it's homeworld gravity.
It's the question of how much *higher* than homeworld gravity can a species survive that can have variance.
Although it is obvious that higher-G races would cope better with higher accelerations. I dunno, guess it might be proportional? 1G races might have an average tolerance maximum of say 1.6Gs for long periods and 10G races might have an average tolerance max of 16Gs for long periods.
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You are aware that the armor thickness per level is one centimeter and the size of one square is a square meter?
I don't quite think that a projectile the size of a tennis ball would spread out that fast.
At these velocities the projectile will very violently explode, I think that it will have a decent spread rate. It can also be handwaved as not only the area of the ship that is physically touched by the projectile, but also that is destroyed by the shockwave of the armor being pushed out away from the projectile to make room for it.
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How comes you guys combine Gravity with G tolerances? Some animals survive Gs better then Humans, iirc peregrin falcons can survive some higher Gs for a short time. I see that Gravity and g-force-tolerances are linked but there has to be some variance in it.
There are several reasons for this. One is that the creature in question is smaller then a human, and the square-cube law works in its favor. For example, if you threw a mouse out of an airplane, it would land totally unharmed. A rat wouldn't. Partially, it's the lower terminal velocity of the mouse, and partially, the mouse's size.
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Uh, gravity tolerance is the same as g-force. Gravity is acceleration.
A species that is adapted to life on a large earth-like world with 7g gravity can build ships that go at 7g accelerations without meeting any biological limit.
No species would have any trouble on a ship accelerating at less than it's homeworld gravity.
It's the question of how much *higher* than homeworld gravity can a species survive that can have variance.
Although it is obvious that higher-G races would cope better with higher accelerations. I dunno, guess it might be proportional? 1G races might have an average tolerance maximum of say 1.6Gs for long periods and 10G races might have an average tolerance max of 16Gs for long periods.
But a worlds gravity does necesserely mean that a species is able to survive its own homeworlds gravity respective a certain acceleration. Take a whale, out of the water most bigger whales crush themselves say if they are stranded. Then there are trees, most wouldnt withstand a accelartion of 1G in any direction except "down".
What i try to say is that we shouldnt think that a planets g-force determines strictly what kind accelerations a Alien species can withstand altough it might be a factor. I mean there could be even 0G species especially if a world has a thick supportive medium like water or Atmospheres with high pressures.
@byron: Wouldnt the mouse survive because its acceleration plus its weight wouldnt create a impact-force that is big enough to harm it? The terminal velocity of the mouse wouldnt exceed its actual acceleration tolerance.
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At these velocities the projectile will very violently explode, I think that it will have a decent spread rate. It can also be handwaved as not only the area of the ship that is physically touched by the projectile, but also that is destroyed by the shockwave of the armor being pushed out away from the projectile to make room for it.
However, at this speed, say, an impact speed of "just" 1000 km/s, the projectile would also take just one tenth of a millisecond to pass the entire ship.
As far as i know, and I openly admit that I really don't, the detonation velocity of a strong nuke is at best half that.
So, if you hit the target with a metal ball large enough to penetrate both sides of armor if it would not disintegrate, the lowest speed that still achieves that would have the most devastating effects, destroying the ship.
Go too fast, and the shell exits the other way before expanding enough.
For example, if we calculate shell expansion at 750 km/s in an airlike atmosphere, which I think is pretty generous, then if the impact speed is above 2000 km/s, the effect would diminish.
Interesting, more power might not always be better.
As for the G question, that would mainly mean that if a whale was to jump into space, it would require a heavier ship to contain water, and have a lower max acceleration?
Isn't that also a question of size, as with the mouse?
Currently Aurora only models beings of roughly humanoid shape....
Also, it should be mentioned that the ideal gravity for a being isn't necessarily the one you get on your homeplanet.
Humans would probably function better at 0.95 g.
The problem so many people get back problems while aging is that our spinal column, more precisely our intervertebral discs, aren't made for this kind of strain, especially not over the life span we experience.
However, one could use a very slow acceleration during cruise as means of artificial gravity.^^
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Whales and aquatic life would of course require their supportive mediums. In their natural environment, it should be obvious that life would survive at accelerations equal or below its homeworld gravity.
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So, if you hit the target with a metal ball large enough to penetrate both sides of armor if it would not disintegrate, the lowest speed that still achieves that would have the most devastating effects, destroying the ship.
Go too fast, and the shell exits the other way before expanding enough.
My method actually does capture that affect.
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However, in that case we need to calculate the energy that the shell actually has at those levels, instead of just assuming everything it touches is destroyed.
Also, taking this reaction to shields would result in smaller rounds "harmlessly" exploding on the armor even though half their energy might actually penetrate.
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However, at this speed, say, an impact speed of "just" 1000 km/s, the projectile would also take just one tenth of a millisecond to pass the entire ship.
As far as i know, and I openly admit that I really don't, the detonation velocity of a strong nuke is at best half that.
So, if you hit the target with a metal ball large enough to penetrate both sides of armor if it would not disintegrate, the lowest speed that still achieves that would have the most devastating effects, destroying the ship.
Go too fast, and the shell exits the other way before expanding enough.
For example, if we calculate shell expansion at 750 km/s in an airlike atmosphere, which I think is pretty generous, then if the impact speed is above 2000 km/s, the effect would diminish.
Interesting, more power might not always be better.
I doubt we would actually see any projectile survive. In fact, I would tend to design the projectiles just so they didn't. No one designs bullets/shells/etc to pass through the target and waste the energy.
Copper works just fine punching through several inches of armor on the M1 when used in an IED. The detonation of the 'bomb' turns it into a molten fragment/EFP that simply cuts/burns its way through the armor. Once inside the tank the (now even hotter after punching through the armor at a few km/s) penetrator and armor both violently expand and essentially sets the atmosphere in the vehicle on fire. Its not pretty - but unfortunately very effective. This happens at about 3km/s.
We are talking about things moving (on the slow end) in the tens of km/s. Remember when Steve gave his little equation on rail guns that said energy of the projectile is proportional to the square of the velocity...
Even at 10km/s, perhaps three time what the IEDs in the Middle East manage - we have nine time the energy. And I have been to sites and seen where those chucks of copper have cut through over 4 inches of the most advanced armor we can field today.
At 100km/s - we are talking about 900 times the energy. If three km/s liquified copper, 100 will turn it and the armor to vapor.
These projectiles - as they strike the vessel - just created an amount of energy that rivals a small nuke. The projectile didn't survive. Neither did the armor it hit (assuming penetration). Both have now been heated to temps that I am sure (haven't done the math, but don't think it is really necessary on this one) turned them into a gaseous state. If the structure/atmosphere in the vessel is at all reactive/combustible - it just became a bomb along with the violently expanding material of the penetrator and armor. The shock wave of the expansion should tear apart the inside of the structure - just like a bomb. And if it turns into a gas - the rate of expansion won't make much difference on penetration. It won't go out the other side (ok, some will as it tears the ship apart), it will impart this energy to the structures/air around it. Kind of like shooting a milk jug with a fragmenting bullet from a rifle. The bullet doesn't just pass through - the milk jug explodes from the shockwave. It is called hydrostatic shock. With the energies we are assuming the remains of the projectile and armor will do just fine to carry the shockwave - with any air in the ship adding insult to injury.
Any ship expecting combat should be evacutating all the atmosphere early to limit this. It would lessen the medium for the shock wave. Probably wouldn't save the ship - the energy it will be absorbing is just going to be too much. But might help. Maybe.
And as for the 'impact' spreading on armor - maybe if the armor stopped it. Everything I have ever seen looks like a hole cut right through.
And on the thought of skipping armor on designs, I agree. Every bit of weight is that much less acceleration/delta-v I will have. Even today - mobility is survivability. The best advice I ever got was,
"Best way to survive, just don't get shot." Easy to say - hard to do - but it works. I see being unpredictable to be the best defense. Don't be where the enemy thinks you will end up. Don't group ships together. Don't have them going the same directions. Change course often. And try to line up your ordinance so it surrounds the enemy and closes on them before they can do the same to you. If you keep your ships together, they will be able to bracket all of them at once. Force them to expend ordinance and fuel hunting each one.
And those life pods, if it looks bad you probably want to eject before the enemy ordinance gets to you. If the other guy misses they can always pick up your ship when they pick up you. If they hit, sending your life pod out into the nuclear blast probably didn't help you much....
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And on the thought of shields, I still don't know what would happen to a projectile. Thinking out loud here.
If there was a gap of perhaps half a meter give or take, it might make a difference. Not really sure.
The slug may vaporize before impact if the shield can impart enough energy to the slug. In that case it might act as a whipple shield and help to disipate the blast. But a whipple shield works on the principle of dispersing the energy of a small projectile and distributing it over a larger area that can survive that level of energy. That won't likely apply. If you have really thick armor and the slug didn't have huge amounts of energy - maybe you could survive. But the ship is still going to have to absorb an amount of energy that will likely be enormous. Too much most likely.
Maybe you could spread it out over a wider patch of the surface, but I am just afraid that the level of energy involved is still going to tear the target apart. It just won't matter if the slug turns into a vapor or not. Even if it is a gas - the energy has to go somewhere. Air is a gas, and does a fine job transmitting energy from explosions to the target. If the slug becomes a gas, it will just become the atmosphere transmitting the shockwave to the ship. If the shockwave contains too much energy, the structure it strikes will still suffer the effects.
No, I just don't see the shield saving the ship unless it can really soak a lot of the energy. May change how the ship was destroyed, but that is all.
But I really have no idea how the 'shields' work, so this is all open to wide interpretation.
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Well, there is a section in Steves thread showing the mechanics, even though assuming much slower impact speeds.
Appearently, the Shields radius is 10% larger than the ships, so size could actually protect you, as with a ship 100m in diameter, you shields will bring 10m distance between you and the slug.
As for armor;
You'll want some, or the enemy will just flay you to death with heavy pulse lasers.
Or fire a few shrapnel warheads, at a fleet speed difference of 500 kps, having a few hundred cubic meters filled with 50 gram metal pellets could prove devastating to unarmored targets, and as a screen might actually disintegrate the shells fired at you.
So maybe, combat including projectile weapons would start by "deploying your armor" in the form of more projectiles.
And what will happen to the particle beams we have in Aurora?
Are they essentially projectiles with limit range, but undeflectable?^^
Crap, there's so many potential possibilities.
edit, fixed a typo
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Good point; armor won't protect you from big things, but it will prevent an Ewok victory. (Sticks and rocks beating lasers and force fields.)
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Yeah, if your armor doesn't have the ability to block the spread out energy, then Whipple shielding (physical or otherwise) will just hurt you more, spreading out the path of destruction that a projectile weaves through your ship.
If the projectile has the energy to pierce through your ship, then you want it to do so while leaving the smallest possible hole.
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It will explode inside the ship, that's the entire point.
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It will explode inside the ship, that's the entire point.
I'm assuming that was directed at me?
Yeah, but the explosive cloud doesn't magically fix itself to the position of the ship. The explosive cloud will continue to move through the ship at tens of kilometers a second, passing through the other side, and taking all of that extra kinetic energy with it.
The same thing will happen with a whipple shield, but the projectile will start exploding 10 meters (or whatever the specific number is) outside the ship, so when it impacts the ship proper it will be traveling through a (slightly) larger cross-section of the ship, and as it passes through and out of the ship it will continue to affect a (slightly) larger cross section of the ship.
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What we have to keep in mind is that the shield also takes a bit energy off, but while it's currently a fixed amount, I'd advocate it to be a smaller fixed amount of point strength, and a small %, so it's the same effect when the projectile is exactly point strength.
Because, if the projectile disintegrates, it will expand, and thats not only sideways.
A small part will go faster, but a more noticeable part will go slower ("backwards" doesn't really fit if it's still going at speeds in the 100's of kps), and with 10m difference, if expect it to expand 1/3 of the projectile speed for now, that'd be an area of nearly 7 squares that the shell is spread over, with probably a fourth of it's kinetic energy already scattered away.
Nonetheless, I agree it would obliterate the ship it hits, the Energy is just too high.
Then, we must model several other things:
1. The integrity of the slug dictates the maximum acceleration it can take, go to fast, it'll break in the launcher, limiting range.
2. The expansion speed of the projectile doesn't scale with the impact speed, but is influenced by it, and by the object it hits.
--> This might create the odd situation where moving so fast you'd be oblitered can be counted by moving faster, as the projectile would then detonate behind the ship.
If your Impact speed is 5000kps, and the ship is not heavily armored, but contains internal bulkheads, the shockwave would be small compared to the actual projectiles energy.
Main question: If attacked by kinetic energy projectiles, should we have shields on or off? Does it depend on the speed (I think so)?
Ultimately, deploying a pebble screen seems like the best option to me.
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Copper works just fine punching through several inches of armor on the M1 when used in an IED. The detonation of the 'bomb' turns it into a molten fragment/EFP that simply cuts/burns its way through the armor. Once inside the tank the (now even hotter after punching through the armor at a few km/s) penetrator and armor both violently expand and essentially sets the atmosphere in the vehicle on fire. Its not pretty - but unfortunately very effective. This happens at about 3km/s.
We are talking about things moving (on the slow end) in the tens of km/s. Remember when Steve gave his little equation on rail guns that said energy of the projectile is proportional to the square of the velocity...
Even at 10km/s, perhaps three time what the IEDs in the Middle East manage - we have nine time the energy. And I have been to sites and seen where those chucks of copper have cut through over 4 inches of the most advanced armor we can field today.
At 100km/s - we are talking about 900 times the energy. If three km/s liquified copper, 100 will turn it and the armor to vapor.
This is not right at all. First, IEDs are generally not shaped charges. They're bombs. An RPG-7 can't penetrate the frontal armor on an M1, and it's going to have a much better warhead. Second, the speed of a shaped charge jet tip is on the order of 7 to 14 km/s, not 3 km/s.
And just so we're clear, energy is always proportional to the square of velocity.
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Nonetheless, I agree it would obliterate the ship it hits, the Energy is just too high.
We can't just say that it will obliterate a ship it hits, because many hits won't do that, depending on relative velocities we could have slugs 'gently' tapping ships at a few handfuls of km/s. We need to do our best to come up with a damage model that will handle this scaling up.
I also argue that once we start implementing this damage model we may very well find that ships don't get obliterated for really fast slugs, because so much of the kinetic energy will escape out the back. I'm not saying that it will be pleasant for the ship, after all there will be a small hole at the front, a medium hole on the inside, and a large hole on the opposite end of the armor, but if it's a large ship it may just be crippled, not killed.
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Well, the figure I used there was expecting a speed of roughly 100 kps.
Sure, on other speeds we really have no idea.^^
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Once you have a kinetic weapon going through the ship and exiting the other side, some of the kinetic energy will be deposited on the ship and the rest carried out by the exiting round.
As you increase the kinetic energy of the weapon (and thus increase proportionally sqrt impact speed), surely more kinetic energy is deposited on the ship?
The ratio of energy on the ship to initial weapon energy may decrease, but I would expect the absolute amount of energy placed on the ship increase.
Of course, by the time you have this, the damage is usually pretty severe anyway.
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Thats what we've been discussing those last few pages. ;)
We expect that at a certain level, likely a few 100 kps tops, the projectile is going to completely disintegrate, thus spreading out.
It might have an effect like detonating a small nuke inside the ship.
If, however, the projectile goes too fast, it'll exit out the other side before that can happen, thus decreasing the effect.
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Oh yes, the transition from projectile not exiting to projectile shooting through may mean that increasing the energy over that threshold would decrease damage.
- And I'm not entirely certain that this would actually reduce damage at all. As you increase projectile energy, its going to get closer to the other edge of the ship. As you approach the "shoot through" energy level, you get spallation on the other side of the armour, carrying energy away. Around the "shoot through" energy level, armour plating on the other side is going to flake off or simply be blasted right out of the hull by the shockwave.
Either way, there could simply be a reducing damage to energy ratio as you approach the shoot through limit without actually reducing absolute damage at any point.
I don't know enough to say either way.
But from there, further increasing projectile energy will only increase damage.
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I doubt that.
At an impact of 1000 kps, the projectile will disintegrate, which means turning into very hot gas and dust, the blast traveling through the ships atmosphere.
The expansion of this cloud of death can only go so fast, so if the projectile is so fast it only measureably expands when reaching the other end of the ship, the harm done is noticeably smaller than if it detonates inside the ship.
So decreasing the projectile speed by 100 might increase the effective damage, while increasing it will make it harmless at some point.
Increasing the projectiles size will do more, if it's at all measurable when the ship's gone, but more speed will not always make a difference.
In fact, whether shields should be used or not depends on speed as well, if the energy of the projectile can be stopped by the armor if spread out, a shield to break the shot before it hits the armor is useful, if it can't, a shield will actually increase the internal damage.
Unless you're exactly at the point where the projectile would reach the inside and scatter, but not fully fly out again, in which case the shield would slightly reduce internal damage at the cost of armor.
I'm slowly reaching the point where I'm just willing to wait until I can test it. ???
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This is not right at all. First, IEDs are generally not shaped charges. They're bombs.
No arguement. Lots were/are just old Soviet WWII era 152mm shells. Buried in roads. Stuck in a pile of trash or junked car on the roadside. Those aren't too dangerous to an M1. Usually blows a tread, tears up a road wheel or two, screws up torsion bars, etc. Hard on softer targets, but that is to be expected.
What the tankers fear are the old shells with about 1-3kg of copper strapped to the side and lined up with the road.
An RPG-7 can't penetrate the frontal armor on an M1, and it's going to have a much better warhead. Second, the speed of a shaped charge jet tip is on the order of 7 to 14 km/s, not 3 km/s.
RPGs don't do well against the frontal armor. Usually don't make it past the side either. Can't go into the configuration of Chobham as it is still classified (getting the tankers and infantry to sign papers to not disclose what they saw when the armor was penetrated was a pain) but it works pretty well disipating the energy of the shaped charges. But a solid chunk of copper hitting it just cuts right through. Too much energy. And most of the copper blocks were/are going a couple km/s.
Same physics that allow our penetrators to cut through vast amounts of armor, just far more primitive. But as one of my instructors in basic pointed out, an old obsolete rifle will kill you just as dead as the latest in technology.
And just so we're clear, energy is always proportional to the square of velocity.
Energy yes. Momentum no. Just being a little facetious. Sorry.
If you got to deal with the number of sites I did, you tend to develop some 'coping strategies' when talking about IEDs.
And in reply to the many posts positing that the projectile will exit the target in some localized area - I will simply have to disagree. It will turn into a gaseous cloud of immense energy. The original projectile will have a certain amount of momentum that will try to drive it out the back end of the ship. Unless you just barely grazed the target you have hit a fair amount of mass (the armor/hull) that was part of the ship. This material has the same momentum as the ship does/did - and just absorbed a bunch of energy. It will not be moving to exit the ship in some organized manner. It will just be moving to deposit the energy it has as randomly as it can (per the 2nd L. Therm.). As will every structure in the ship that is 'hit' by this gaseous cloud of energy. The 'particles' of the projectile will still have momentum trying to drive them through the ship, but individually the particles will have considerably less momentum than the objects they are likely to strike. They are likely to be 'stopped/captured' by the structures they impact inside the target. They will still be carrying a large amount of energy that will then be transferred to the structures - which will also begin depositing this energy to the rest of the target. Add in the thermal wave of IR radiation going in every direction this whole cascade is generating and it just gets worse. Unless the ship is very small and made of tinfoil - it is going to absorb a large percentage of the energy from the projectile to its structure - and not just in the path of the projectile.
If you feel that the projectile exits the back, then there isn't much experimental data on what happens to contradict you. I don't know of any organized attempts to shoot 'space vehicles' with 10's of km/s slugs to see just what happens.
I believe that is will look like you placed a large amount of explosives inside the hull. A big flash and detonation, with an expanding cloud of debris after. But to each their own.
Whatever Steve codes for, I will happily work with. ;D
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As said, it depends on speed.
While yes, the projectile will scatter, if it is too fast, it will punch straight through because the expansion of material is physically limited.
Until the point where the matter hits so fast we see nuclear fusion as a result, which in late game could happen.
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While yes, the projectile will scatter, if it is too fast, it will punch straight through because the expansion of material is physically limited.
Of the projectile, if the structure doesn't capture the energetic particles of the gas it becomes.
But the structures of the target that absorb the energy won't have this problem. They will release the energy they absorb fairly uniformly. Whatever the 'gas/projectile' hits will become the next detonation.
EDIT
If your target is in single digit meters and the projectile hits nothing but hull (no intervening structures - but you apparently don't mind wasting space in your vehicle if this is the case), maybe it would just leave a pair of holes and a lot of very hot material exposed to the impact sites. This necessitates that the projectile also hit nothing with an atmosphere. The gas will propogate the shockwave.
But if your ship is measured in 10s of meters with large structures inside it that intersect the projectile's course, it really should make nice fireworks.
EDIT 2
I suppose the easiest way to illustrate this is that the projectile is likely going faster than the speed of 'sound' in the material it hits. This means that any material struck will tend to displace to the side, as in any shockwave propagating in a stationary medium per Cherenkov. I really don't like to dredge up the math as it is not the most refined area of science at the moment. But most (not all) everything this projectile hits will be displaced sideways expanding into the target. This will be bad on the target if the gas of the projectile is captured by the target.
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No arguement. Lots were/are just old Soviet WWII era 152mm shells. Buried in roads. Stuck in a pile of trash or junked car on the roadside. Those aren't too dangerous to an M1. Usually blows a tread, tears up a road wheel or two, screws up torsion bars, etc. Hard on softer targets, but that is to be expected.
What the tankers fear are the old shells with about 1-3kg of copper strapped to the side and lined up with the road.
RPGs don't do well against the frontal armor. Usually don't make it past the side either. Can't go into the configuration of Chobham as it is still classified (getting the tankers and infantry to sign papers to not disclose what they saw when the armor was penetrated was a pain) but it works pretty well disipating the energy of the shaped charges. But a solid chunk of copper hitting it just cuts right through. Too much energy. And most of the copper blocks were/are going a couple km/s.
Same physics that allow our penetrators to cut through vast amounts of armor, just far more primitive. But as one of my instructors in basic pointed out, an old obsolete rifle will kill you just as dead as the latest in technology.
If you feel that the projectile exits the back, then there isn't much experimental data on what happens to contradict you. I don't know of any organized attempts to shoot 'space vehicles' with 10's of km/s slugs to see just what happens.
I believe that is will look like you placed a large amount of explosives inside the hull. A big flash and detonation, with an expanding cloud of debris after. But to each their own.
Whatever Steve codes for, I will happily work with. ;D
I'm a tiny bit skeptical about this. No offense, but anyone can say anything on the internet, and I find it hard to believe that a couple kilograms of copper is some sort of wonder penetrator.
As for penetration, there's a professor at my school who studies armor penetration and space debris. I'm meeting him on the 26th, and will try to get some answers.
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Damage to the spaceships could be limited if we posited extremely effective crumple zones in the structure and armor that limited the energy dissipation perpendicular to the path of the round.
In fact that could be an explanation for our very discrete armor "spaces". Maybe each armor space is separated from the next by one of these great crumple zones.
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That's why I think sometimes, in gaming and science fiction (Stargate :P), physical laws must be bent or simply ignored to make the game or the show more enjoyable. Are you traveling at relativistic speeds? Invent something that creates some kind of space-time bubble around your ships to maintain coherence. Are you accelerating at a rate which would kill any human? Put some cool inertial dampener which god knows how it works. Do you need to turn around your ship to counterattack an enemy ship at your back? Just do it like a boss.
Beside, science change a lot every few years. Actual working physical laws can be completely wrong in a decade. Adapting centuries of development and science investigation in our campaings to 21th century physics is like trying to supply water to a growing city through the same pipes. Sure, they will work for the first 200,000 hundred people, but when the city reaches 1 million inhabitants, those pipes are not going to be enough.
However, I think it's pretty interesting that kind of aproach. Personally, I would prefer a little "science fiction" here and there, but trying to build a space empire with today's limitations is. . . challenging at least.
I agree that bending or ignoring the laws of physics where necessary is a reasonable idea to make a game playable and enjoyable. That is the approach I took with Aurora. The whole point of Newtonian Aurora though is to try to implement realistic physics as much as possible and see what happens. I am not convinced it will turn out to be playable so the whole game is really an experiment :)
Steve
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And in reply to the many posts positing that the projectile will exit the target in some localized area - I will simply have to disagree. It will turn into a gaseous cloud of immense energy.
A few figures to support this...
Suppose the slug is metallic, its specific heat will be in the 100 - 1000 J / kg K (depending on its density), and its boiling point will be in the range of 1000 - 6000 K. Thus, the energy needed to heat a 1kg slug to melting point would therefore be on the order of 100 KJ - 6 MJ, say around a megajoule. (Note : correct calculation is more complicated as you'd need to add latent heat, take care of pressure, etc, but the order of magnitude should be fine...)
A 1kg slug (for instance, the calculation is independent of mass) travelling at 100 km/s will have a kinetic energy of 5 gigajoules (0.5 x 1 x 100 000^2), and 500 GJ at 1000 km/s. Thats 5000 to 500 000 more than the energy needed to vaporize the slug.
Now, the slug could explode out of the ship if the time it takes to vaporize is longer than its travel time through the hull. Assuming a 100 metres cross section, that would be 1/1000th of a second at 100 km/s, and 1/10000th at 1000 km/s. Not sure how you calculate the "heat speed", though...
Francois
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Not sure how you calculate the "heat speed", though...
I have no idea either. Perhaps the speed of sound of the gas would be a suitable approximation? Of course that requires the knowledge of the temperature of the material, which would also have to be approximated somehow.
Maybe say that some arbitrary fraction of the impact energy (1/100th, 1/1000th?) goes into instantly heating the projectile, calculate the heat of the projectile, then the speed of sound, then use that.
That's two layers of completely arbitrary assumptions, but it may look reasonable. I think that's what we are going to have to do. List out a bunch of wacky and arbitrary methodologies, pick a bunch of those that sound most reasonable to us, then go with the one out of those that sounds like the best for gameplay.
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This is exactly the case. The fact that you present it as a problem indicates that you don't understand a salient fact about space travel: ships are not maneuverable. In any case with a reasonable delta-V to acceleration ratio (where you are accelerating over the course of days), you will not be capable of serious combat maneuvering. They will spend days building delta-V, and that will prevent them from making quick turns. To see any difference, you need hundreds of Gs, and that is simply not practical, even with drones, for engineering reasons.
Putting a 10G engine on a ship is going to impose enormous penalties for the vessel in question. Not only do you need 10 times the engine of a 1G ship, you also need about 10 times the structure. At that point, there's not much room left for weapons.
Matching vectors with the enemy ship might be the way to go for closer combats. It leaves both sides with more options.
That would help mitigate the drive-by holocaust problem, and even more so if there is a range limit on the tracking commands. You can't control a missile from way, way out-system.
I agree. Ships will definitely not be able to manoeuvre significantly in any short-time frame. It will be about positioning pre-engagment and making manoeuvres that could take several hours or days to complete. On the other hand, my experience with the limited missile engagements I have tried so far indicate that missile flight times could be on the order of days for some battles rather than minutes or hours.
Steve
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I was actually excluding railguns because their projectiles (in a newtonian setting) will be imparted the ship speed.
This is true. Railgun projectiles start with the ship speed. I am slowly forming an opinion that railguns will probably have high damage but low accuracy. They have low muzzle velocity (relative to likely ship speeds), which means they will be relatively easy to avoid. They will have potentially high impact velocity when launched from a fast ship because the ship speed is added but even then they will be difficult to aim because you will have limited control over the directions in which you can fire them as a large part of their post-launch vector is preset by the ship's vector.
Lasers will be much more accurate because of their high muzzle velocity but the beam widens with range so they will have less of a concentrated impact. In fact, depending on range the beam could be wider than the target ship so a lot of energy will be lost in that case.
Steve
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Which is why I think Newtonian combat will be dominated by fighters, or at least parasite vessels. You could have a mothership with a high efficiency cruise drive, plus all the non-combat components; extra fuel tanks, maintenance storage, etc. Then when combat threatens it launches a bunch of fighters and cruisers, which with their low efficiency drives and less weight spent on secondary systems could massively outmaneuver comparable non-parasite vessels.
I think is a real possibility. The other reasons I think fighters or small parasites will be common are cost and weapon effects. Firstly, it is possible that in a battle you may have to commit to a course toward the enemy in order to close the range and once on that course you will have a limited ability to pull away again. In that case, an 'expendable' launch platform would constitute a more acceptable level of risk than a major warship that would be hard to replace. Secondly, in an environment where a single nuke can take out a capital ship, you would probably want the enemy to expand high yield weapons on relatively low-cost and harder to hit targets.
Steve
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Have to say I can't wait to have a go at this myself. Already started building the brownie points with the wife in the anticipation of some long evenings locked in the study!
Was just having a quick look at the rules again and noticed that the costs in warhead between conventional / nuclear / nuclear laser seem quite small to me and was wondering if these differences should be more pronouced to give players more of a decision to make in the types of ordinance used?
Also, having re-read the rail gun thread I was not sure if Steve was going to be calculating kinetic energy for damage based purely on the exit velocity of the shell or the eventual relative impact velocity when it hits. I'm assuming it's the later with the exit energy just being used to calculate total enegry requirements and cool down requirements.
Just running some numbers I can see that even with a closing speed of just 500kms any shots are going to be lethal: By my calcs that would give an impact energy for a 1 kilo slug of 125k MJ, more than enough to punch through basically any armour and shields and go back out the other side. I'm wondering how that sort of narrow but very high damge will be dealt with for internal systems.
Laser warheads are larger as well as more expensive, which means the missile will have less acceleration. That will be a factor as well as cost. Conventional warheads will be mainly for RP situations in a multi-Earth start.
At the moment a railgun round penetrates armour and then expends all its remaining energy inside the target. I haven't definitely decided if this final yet so its possible I might have an exit hole as well and not have all the energy expended inside the target. I really don't know enough about the subject yet so I'll finalise this once I find some relevant materials to study.
Steve
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I wish I could say the same thing. Convincing my wife and kids to put the RPGs and Starfire on hold so I can play is a hurdle I am not looking forward to. :(
I am fairly sure he intends to use actually impact speeds, not launch speeds. I wouldn't think it would be hard to code for, but I am not a programmer.
The damage modeling for slugs could really use some attention. My reasons....
At those velocities, unless this slug is made of some incredibly resilient material it won't survive impact intact. If it could, we need to be using whatever it is made of for armor. The energy generated will create an enormous amount of heat (depending on velocity at impact) - likely vaporizing the slug and turning it into a violently expanding mass of superheated gas and particles. It is going to become a bomb.
The slugs fired from the 120mm on our tanks only hits targets at < 3 km/s. Often less than 2 km/s. They turn into molten slag on the way through the armor and essentially detonate in the target. Check the records. I saw a fair number of enemy vehicles hit by our tanks - the only exit holes were on soft vehicles.
The railgun slugs will likely be hitting at higher than single digit km/s. The penetrator (if it overcomes the armor) won't be intact. It will be a 'fireball'.
EDIT
On the thought of a slug hitting a shield, I really don't have any idea what would happen. I don't really know what the shields are. If they are some distance from the ship, they may yaw the slug. This would ruin its sectional density as it struck and profoundly limit its penetration. If the shields are nearly flush with the ship, then I doubt it makes much difference.
I will use impact speeds - not launch speeds - so moving very fast when someone is firing railguns is only a good idea if you don't get hit :)
Useful information about current anti-tank rounds. That is how the kinetic strike code works at the moment.
Shields are very close to the ship (unlike my earlier assumptions). At the moment, they are modelled simply as removing 'energy' from the lasers and railgun projectiles. In the latter case that effectively means slowing them down before they hit.
Steve
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Now, this raises an interesting question about missiles, and "explosive rounds" (if such things exist). Should they be fragmentation or "pure energy" weapons? (or maybe a combination of both)?
At the moment I have coded conventional warheads, which are impact only, plus bomb-pumped lasers and standard nukes, which are area effect. I plan on a solid warhead - in effect the same as a railgun round but with a mass in tons rather than kilograms - and you really wouldn't want to run head-on into one of those at speed, plus a fragmentation warhead that splits into perhaps a thousand one kilogram chunks. Also not a very pleasant prospect. You will likely be able to set a dispersion rate for the latter (I am assuming a small explosive charge to provide 'sideways' momentum), so while the forward motion of the projectiles will be the same as the original missile, the rate at which the 'width' of the projectile cloud increases over time will be preset during missile design. Obviously the speed at which the 'width' increases will be far less than the forward momentum.
I have upped the ship armour strength a little so it ranges from 100 MJ per 'box' at level 1 tech up to 1500 MJ per box at level 12 tech. Even so, battles in Newtonian Aurora are likely to be extremely brutal and seeing the enemy first is going to be vital.
Steve
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Personnally I think all missiles should have a 'kinetic' setting. Just don't arm the warhead. Shrapnel will likely look like a railgun when it hits, unless the fragments are very large. But a missile with a 4 ton warhead releasing 4000 - 1kg chunks of metal could be a real terror as it approached a group of ships. Will make 'dodging' difficult.
There could probably be a distinction for a pure kinetic kill weapon. A 1kg projectile hitting a target at km/s will vaporize into a bomb like weapon. A 1000kg chunk of metal probably won't. Might fragment.
But with the energy it will contain the shockwave it should create will make the issue of 'will there be a hole in the back' more of a 'will there be a big enough piece left to identify the exit hole'.
I wrote the previous reply before reading this post :)
Either of the above is going to make life extremely difficult for the target
Steve
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As far as i remember a past discussion about this, steve will have them be deleted if they miss their target and theres currently nothing in the future path.
But if the target is in front of a planet, that planet will be hit.
That is the plan at the moment. I'll clean up projectiles and out of fuel missiles when there is nothing for them to hit.
Steve
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As it stands it seems to me that there will actually be very little point in adding armour to your ships, better to spend the weight on increasing your acceleration or Delta V reserves so you can get out of the way as there is a good chance that any hit is going to be lethal irrespective of the armour you have.
Just looking at Steve's example of each armour block having 125MJ damage resistance, if we say a pretty well armoured ship has ten layers that does not give much protection on point hits at all compared to the numbers being tossed around.
I do think that is a valid design choice. Although in Newtonian Aurora you will get about twice the armour thickness for the same tonnage as you do in Standard Aurora, so ships will be able to carry a significant amount of armour.
Steve
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I have no idea either. Perhaps the speed of sound of the gas would be a suitable approximation?
Of course that requires the knowledge of the temperature of the material, which would also have to be approximated somehow.
Speed of sound would be too slow (a few hundred metres per second, most explosives have detonation velocities of several km/s).
I've been thinking about it, not very efficiently, school was a long time ago...
Normally, apart from thermal radiation (which is electromagnetic and therefore propagates at the speed of light), the "heat wave" would move according to Fourier law. That is to say, heat transfer over time would be proportional to surface, times temperature gradient, divided by distance.
If you imagine heat exchange between two concentric spheres (the "slug" and some reference radius in the ship), you have something like
dQ/dt = 4 PI k r1 r2 (T2-T1)/(r1-r2), where k is medium conductivity, ri the radii of the spheres, and Ti the temperatures.
You could derive the temperature by assuming a fraction of kinetic energy gets converted into heat (and an average specific heat), but if the projectile vaporizes, we're talking of a gradient of several thousand degrees, which should result in a very brutal heating of its surroundings.
Yet, I doubt this is the relevant factor. No matter how fast the heatwave, the ship is pretty much dead if the projectile vaporizes inside, and probably safe if it does outside. The matter, then, would be how long it takes for the slug to heat, melt and vaporize...
Francois
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On the other hand, my experience with the limited missile engagements I have tried so far indicate that missile flight times could be on the order of days for some battles rather than minutes or hours.
Is there any plan to reduce the number of forced 5sec increment over those many-days engagements?
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Speed of sound would be too slow (a few hundred metres per second, most explosives have detonation velocities of several km/s).
Not speed of sound in air at sea level, speed of sound of the substance involved (in this case superheated duranium, or tungsten, or lead, or something).
I believe that the definition of an explosion (as opposed to just a fast burn) is that the expansion is faster than the speed of sound in the medium it is exploding in, but I also thought that that detonation velocity was directly based on the speed of sound of the explosive as it burned. As in the speed of sound of the super heated gases the explosive formed immediately after firing.
Unfortunately while there are a lot of examples of exhaust velocity, but far fewer for explosion temperature, so I can't put that assumption to the test. There would be an additional complication because there is a coefficient (the ratio of specific heats) that is (mainly) determined by the form of the gas, ie Monatomic, Diatomic, etc. While there are many tables available for this coefficient for common gases, I am sure that finding coefficients for the more complicated molecules often formed by an explosion, for example the (CH2-N-NO2)3 + 3CH2(ONO2)2 + NH4NO3 + 3H2O created by C4, would be more difficult. It would still be possible to do in principle though, in simpler explosives that yielded smaller molecules.
If that method was used for modelling the expansion of a slug that last part wouldn't be a concern for solid elemental metal projectiles, as they would sublimate as Monatomic Gases.
As an example for this method, lets say that a 1kg slug of tungsten hits a ship at 100km/s. This collision has 5GJ of energy. We'll posit that a thousandth of this goes into heating the slug at the instant of impact. If the projectile started at perfect zero then after heating it would be turned into a cloud of tungsten gas with a temperature of 37.83 million Kelvin (around twice that of the center of the sun). If I have done my rusty thermodynamics math right that comes out to a speed of sound of 53.3 km/s!
The last step is to check and see whether the assumption that gaseous cloud would actually disperse at it's speed of sound, and given the incredibly high speed of sound we just got I'm guessing it won't. In fact you can see this with a very cursory look, we got a speed half that of our starting speed (a quarter of the starting energy), by pulling out one thousandth of the energy at the start.
Ah, there is an even more direct way to get the average molecular speed from the temperature, which is actually directly defined from average molecular speed, I'm silly.
If you go that route you find that the average molecular speed of our tungsten gas is 2.27km/s.
Of course the problem with this whole method is that top choice: One thousandth of the energy goes into heating the projectile, it was completely arbitrary. I'm not really sure how we could choose an "accurate" number.
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I agree. Ships will definitely not be able to manoeuvre significantly in any short-time frame. It will be about positioning pre-engagment and making manoeuvres that could take several hours or days to complete. On the other hand, my experience with the limited missile engagements I have tried so far indicate that missile flight times could be on the order of days for some battles rather than minutes or hours.
Steve
If anyone's read the "Lost Fleet" series of novels (which I highly recommend), it features combat that resembles this. The basic strategy fleets employ is to maneuver in such a way that they "glance" past an enemy, making it so they can concentrate fire on a group of enemy ships can return fire is spread throughout their fleet; the better lead fleet then sails past and has several hours to recharge their shields/repair damage while the other fleet.. well, you can't fix ships that got blown up.
So this kind of combat might be a major advantage for shields. On the other hand, its starting to sound like railguns might be so lethal armor or shields wont help much against them.
Also, in response to the test campaign post, even with a million liters of fuel that's not a lot of delta-v (as is realistic). Surveying asteroid belts will be expensive early on.
I know there's going to be an option for maximum speed, but would you consider a "minimum travel time" option? Something to make sure a ship wouldn't burn full thrust to travel to a moon in 6 hours instead of a day. Might be useful for surveying those planets with a dozen moons.
Actually, did some quick math. At full load (for simplicity of math) leaving Earth and coming to rest at the moon would take 5.81 hours and burn 3,661 liters of fuel. The rest of the math is trickier and I'm not particularly knowledgeable, but using a quarter the fuel (915 liters) results in a flight time of only, by my sloppy math that would probably make a physicist scream, 13.74 hours.
Upon thinking about it, maybe instead of "minimum travel time" a "maximum proportion of journey spent accelerating" would be better. Spending the whole trip accelerating is fastest, but not by much, and very inefficient.
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Hi Yonder,
Very interesting comments. I believe you're right on explosion speeds.
As an example for this method, lets say that a 1kg slug of tungsten hits a ship at 100km/s. This collision has 5GJ of energy. We'll posit that a thousandth of this goes into heating the slug at the instant of impact. If the projectile started at perfect zero then after heating it would be turned into a cloud of tungsten gas with a temperature of 37.83 million Kelvin (around twice that of the center of the sun). If I have done my rusty thermodynamics math right that comes out to a speed of sound of 53.3 km/s!
Not sure how you get that 38 million kelvin. To me, a thousandth of 5GJ means 5MJ, tungsten has a specific heat of 170 joules per kg.K, so you'd get an increase of about 29 000 K, no? The millions would be if all the kinetic energy is turned into heat. This said 1/1000th is probably a very low value, and a few percent of kinetic energy turned into heat would heat the slug to a million degrees...
But even with this lower temperature gradient, I suspect that most of the damage would result from the electromagnetic energy and heat freed by this brutal increase in temperature, which would "roast" the ship before the gas had the time to explode.
And then, this temperature increase might make the fact the slug explodes into the ship or comes out of it irrelevant. I don't think a ship can survive the temperature increase caused by the collision (a million degrees even a few hundred km away is a lot of temperature).
But then, if the railgun was shot at close range, this would be true for the firing ship as well...
Francois
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For reference, the detonation velocity of nuke is ~400 km/s for gas expansion, and 550 km/s for implosion, based on earth like atmospheres.
These numbers should be sort of the upper limit for expansion, short of nuclear fusion taking place; keep in mind a nuke actually creates matter, as in, atoms split into more atoms that want to get away from each other.
So while we need to have a formula as laid out, we need slightly diminishing returns once to get to high 3 digit speeds, and if the ship is going at the shell with 5000 km/s, and it's structure can handle the shock, the shell would blaze right through, only leaving a part of it's energy within the ship.
There is no doubt that that part would still destroy the ship, but it might not utterly disintegrate it.
@ Steve, if you have energy Shields essentially as a form of Electric Armor, only against energy instead of kinetic, wouldn't it be interesting to have multiple shield types?
Like, having a force shield 50m away from the ship, but requiring enormous amounts of energy to keep up; One could have a battery ship to activate it for seconds before the next railgun barrage comes in.
Also, I'm starting to think that people will forgo small caliber, high muzzle velocity railguns, and just go for larger slugs, given that 50% of the speed in an average combat situation will come from the ship itself.
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But then, if the railgun was shot at close range, this would be true for the firing ship as well...
Yes, I have wondered when throwing around nukes and high energy shells if a 'minimum safe distance' isn't something you would want to look at. And having your own nuke chase down a ship closing on you could also turn out embarassingly.
(I am so looking forward to dealing with this. I do hope it works out.)
I have said more than enough on what I feel will happen if you shoot a ship. On the heat of the slug, when you compress mass it heats also, and it occured to me some time back (shortly after composing the thought that slugs probably look like cannonballs) that it is probably going to be molten when it leaves the railgun, or shortly there after. If not molten, at least fairly close (depending on the material). As I said, I would want a material that best deposited all of the energy into the target.
On the speed of expansion, this is one that I have argued with colleuges before. The current formulas for shockwave propagation are less than ideal. The don't always confirm experimental observation, so it truly is open to debate in some areas. The rate that a wave can propagate through material can actually exceed the speed of light in certain mediums (which is why reactors glow, the electrons are exceeding the speed of light in water). With the levels of energy and velocities we are talking about, we could get a large number of people arguing, but all should agree it would be fairly energetic.
Whatever is easiest for Steve, is fine with me.
I'm a tiny bit skeptical about this. No offense, but anyone can say anything on the internet, and I find it hard to believe that a couple kilograms of copper is some sort of wonder penetrator.
As for penetration, there's a professor at my school who studies armor penetration and space debris. I'm meeting him on the 26th, and will try to get some answers.
I tend to be skeptical by nature also, so this is not a problem for me. Do all the research you want. I can only talk from what I have seen and worked on. I don't know how much data is available on some of the EFPs from the IEDs in Iraq, as the military was pretty good on confiscating any cameras or notes that were on the soldiers around if it involved penetration of the armor on an M1. But data on the APDS penetrators the M1 (ok, most any NATO 120mm smoothbore) fires is fairly easy to get ahold of. It would do just as well as an example of what happens to a chunk of material striking armor at a few km/s. Turns molten as it punches through and then 'detonates'. Easier to find and just as much a proof of concept.
EDIT
The example with copper was just to show that even a material that common can make a good kinetic kill penetrator. (Actually, it is looking to become the material of choice in some EFPs).
You will likely be able to set a dispersion rate for the latter (I am assuming a small explosive charge to provide 'sideways' momentum), so while the forward motion of the projectiles will be the same as the original missile, the rate at which the 'width' of the projectile cloud increases over time will be preset during missile design. Obviously the speed at which the 'width' increases will be far less than the forward momentum.
Steve
You really don't need an explosive charge, and could control the dispertion rate fairly accurately with modern tech. Just have the 'shrapnel' be 'sleeves' of cylinder like slugs. Then have the missile begin to 'spin' as it releases the slugs. It would be able to control the dispertion and density without the random accelerations of an explosive. When done you could have a small explosive charge (a bit of left over propellent) shatter the remaining hull of the missile to add extra fragments to the center of the pattern.
If you had a ship nearby that could communicate with the missile, controlling the rate of dispertion might not be difficult 'on the fly'. (Ok, sorry about the pun...)
If the missile was still accel/decel ' ing while releasing the slugs it could even create a 'cloud' with considerable length as well as width, in case you are intercepting a crossing target and having 'ordinance' in the target's flight path for a duration of time was important.
But this isn't a big issue for me. You do this for free. Whatever suits your fancy will work.
As long as I get to try and blow up the 'bad guy' !! ;D
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Steve
Nice to see the armour ratings going up and am eagerly looking forward to more instalments on your test campaign, a couple of other random thoughts:
- Are you thinking of tracking rail gun ordnance now? Was wondering what sort of usage of ammo there would be in long slow approaches where you might be firing continuously and if this may now be enough to start worrying about magazine and weight requirements. This might also have more of an impact on fighters.
- Any more thoughts on maximum effective speeds for ships due to the dangers of impact from space debris? I could see this as being more of an issue when it comes to moving around asteroid belts.
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I tend to be skeptical by nature also, so this is not a problem for me. Do all the research you want. I can only talk from what I have seen and worked on. I don't know how much data is available on some of the EFPs from the IEDs in Iraq, as the military was pretty good on confiscating any cameras or notes that were on the soldiers around if it involved penetration of the armor on an M1. But data on the APDS penetrators the M1 (ok, most any NATO 120mm smoothbore) fires is fairly easy to get ahold of. It would do just as well as an example of what happens to a chunk of material striking armor at a few km/s. Turns molten as it punches through and then 'detonates'. Easier to find and just as much a proof of concept.
That's not what I was skeptical about. I'm skeptical that copper on an artillery shell behaves at all like an APDS. I'd think it gets torn to pieces by the blast, and just adds some shrapnel.
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I would just like to add on the copper shaped charge. It is very dangerous, after enough tours in Iraq and afghan it is one of the most feared ieds and we have had plenty of lectures/training videos on them. As for findinding info on the public side I remember future weapons on the discovery channel doing a few things that used cone shaped copper to punch through metal...should be easy enough to find.
-Five
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Not sure how you get that 38 million kelvin. To me, a thousandth of 5GJ means 5MJ, tungsten has a specific heat of 170 joules per kg.K, so you'd get an increase of about 29 000 K, no? The millions would be if all the kinetic energy is turned into heat. This said 1/1000th is probably a very low value, and a few percent of kinetic energy turned into heat would heat the slug to a million degrees...
Yeah my thermodynamics is rusty, let me go through step by step.
Molar heat capacity is 24.27 J/mol/K, There are 183.84 kg in a mol of Tungsten, so the specific heat is .132 J/kg (this seems to be where we differ, where did you get 170 from?)
Heat of fusion is 35.3 kJ/mol, so 192 J/kg, and heat of vaporization is 806.7 kJ/mol, so 4388 J/kg. We know everything will be vaporized, so first we take out the heats of fusion and vaporization, which leaves us with 4,995,420J left (so honestly the heats of fusion and vaporization didn't matter, but I had to check first, and now that we've done the math we may as well use it). That remaining energy heats the projectile to 37.84 million Kelvin.
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I would just like to add on the copper shaped charge. It is very dangerous, after enough tours in Iraq and afghan it is one of the most feared ieds and we have had plenty of lectures/training videos on them. As for findinding info on the public side I remember future weapons on the discovery channel doing a few things that used cone shaped copper to punch through metal...should be easy enough to find.
-Five
I am familiar with the concept of a shaped charge, and that of the EFP. I'm not questioning that either exists, or that EFPs were used in IEDs. I'm skeptical of Procyon's statement that a piece of copper on an artillery shell makes a good penetrator.
Yeah my thermodynamics is rusty, let me go through step by step.
Molar heat capacity is 24.27 J/mol/K, There are 183.84 kg in a mol of Tungsten, so the specific heat is .132 J/kg (this seems to be where we differ, where did you get 170 from?)
Heat of fusion is 35.3 kJ/mol, so 192 J/kg, and heat of vaporization is 806.7 kJ/mol, so 4388 J/kg. We know everything will be vaporized, so first we take out the heats of fusion and vaporization, which leaves us with 4,995,420J left (so honestly the heats of fusion and vaporization didn't matter, but I had to check first, and now that we've done the math we may as well use it). That remaining energy heats the projectile to 37.84 million Kelvin.
You have a three orders of magnitude here. The molar mass of Tungsten is in fact 183.84 grams per mole, not kilograms. The projectile only reaches about 37,000 kelvin.
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It's pretty certain the copper makes a good penetrator, but why does it not fragment on acceleration?. I suppose this is what byron is asking.
If we expect it to melt and spread when hitting the tank, decelerating from X->0, then shouldn't it already do that when accelerating from 0->X?
We can expect the projectile in the railgun be come close to the point of melting already.
It will have to be a rather durable material, though, as it MUST not spread in the launcher.
Might damage the ship, and terrible for accuracy.
Like using a Flamethrower as Artillery.
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It's pretty certain the copper makes a good penetrator, but why does it not fragment on acceleration?. I suppose this is what byron is asking.
If we expect it to melt and spread when hitting the tank, decelerating from X->0, then shouldn't it already do that when accelerating from 0->X?
Because the acceleration from X->0 is orders of magnitude higher than 0->X? Also the acceleration from 0->X is applied on the entire rear of the projectile (and maybe even along the sides if the sabot is very tight) while the acceleration from stopping will all be on the contact point, so until the round is already greatly deformed the pressure on the round will be even more orders of magnitude higher on impact.
We can expect the projectile in the railgun be come close to the point of melting already.
It will have to be a rather durable material, though, as it MUST not spread in the launcher.
A railgun (but not a coilgun) may indeed be shooting a molten or close to molten projectile. For very long shots it may cool down before firing, but I'm guessing most shots will be against targets less than 10 seconds out, so it will indeed still be very hot.
The railgun projectile really won't spread in the launcher, this isn't a gun, it accelerates the round through magnetic forces that apply nearly equally for all parts of the slug. It won't be as uniform as the Coil Gun, because a Railgun projectile will have friction along the sides, but the railgun will obviously be designed to minimize that friction, and if you toss that force then all molecules of the slug will accelerate uniformly.
Now if you are trying to do tricky things like fire a non-conductive round via a conductive sabot, or launch a non-uniform material that doesn't have uniform conductance and hence magnetism (like something with control mechanisms) then you will have enormous forces involved, but for a simple slug you won't have many internal forces.
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Molar heat capacity is 24.27 J/mol/K, There are 183.84 kg in a mol of Tungsten, so the specific heat is .132 J/kg (this seems to be where we differ, where did you get 170 from?)
Got the 170 here http://www.engineeringtoolbox.com/specific-heat-solids-d_154.html . I believe it explains the difference between my 29 and you 38. The magnitude difference is as Byron said: molar mass is in grams not kilograms, so you get a specific heat of 0.132 J / kg K, whereas it should be 132 J/kg K.
Welcome to the 1e3 club, Yonder, got myself there too a couple of posts above !
Francois
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I am familiar with the concept of a shaped charge, and that of the EFP. I'm not questioning that either exists, or that EFPs were used in IEDs. I'm skeptical of Procyon's statement that a piece of copper on an artillery shell makes a good penetrator.
It's pretty certain the copper makes a good penetrator, but why does it not fragment on acceleration?. I suppose this is what byron is asking.
Ummm....
I guess if the question is why doesn't the copper turn into a bunch of shrapnel... I don't know.
I was always looking at what it did. The fact it hit as a mass was a given. I didn't worry about that, just what the effects on the vehicles were and what could be done. There may have been sites where it fragmented and failed to penetrate, but I didn't look into our sucessful stops, just the failures.
I know that the copper wire in our fragmentation grenades has to be pre-serated to achieve uniform fragmentation. But why it works so well strapped to 70 year old artillery shells...? I honestly don't know.
But why copper makes a good IED EFP really doesn't have anything to do with Aurora, so I am going to let those interested follow this one up on their own if they are curious.
EDIT
I don't normally use Wikipedia as a reference, but there seems to be decent info there with a fair number of sources listed that should be easy enough to check on EFPs. Here is the link if anyone wants to do the actual homework. I didn't read it through, but hope it is helpful. At least it is easy to reach.
http://en.wikipedia.org/wiki/Explosively_formed_penetrator
EDIT 2
And from the picture, it looks like the copper is actually on the end of the artillery/mortar shell (probably the base?). My apologies on that. When I got to the sites they could tell what the explosive charge was by the remaining fragments, but the shell itself was long gone so I never actually saw it intact. WWII artillery shell plus couple kgs of copper always seemed to = a ruined vehicle and dead crew.
The question wasn't so much how they did it, as they already knew how and it worked. The question was what could we do about it.
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But why copper makes a good IED EFP really doesn't have anything to do with Aurora, so I am going to let those interested follow this one up on their own if they are curious.
I suspect that it actually comes from the other side of the equation as an EFP it works and that's good enough rather than it being particularly good v other materials, as a material that is readily available, relatively easy to shape and is forgiving on impurities I would see it as a winner in an environment where the logistics for the user have a lot of challenges.
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So it's an EFP based off of an old artillery shell. That makes so much more sense. From you initial statement, it sounded like artillery shell plus copper chunk plus duct tape equals dead tank.
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So it's an EFP based off of an old artillery shell. That makes so much more sense. From you initial statement, it sounded like artillery shell plus copper chunk plus duct tape equals dead tank.
I never needed to worry about the fine details of how the IED was made, and each was generally different so it wouldn't have helped much. It is pretty much an old artillery shell with clips or tape holding a chunk of copper water pipe someone hammered out to shape. You can work copper with a blow torch, and it isn't terribly hard, so it doesn't take much to make any old piece of copper into a plate. It seemed that so long as they could get the stupid thing secured to a chunk of explosives the d@*ned things would cut through whatever was in the way and then turn into a fireball on the far side.
But this has wandered a bunch. All I was hoping to show was that a chunk of metal moving at 'slow' velocities for the game we expect is very good at tearing through substantial protection and destroying a target - as opposed to punching through. If I was going to spend the money to send my shells into space, I would make sure they didn't just pass on through the target.
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Is there any plan to reduce the number of forced 5sec increment over those many-days engagements?
As in Standard Aurora, there are only forced increment lengths when missiles are being launched or about to hit their targets. There are no forced increments when they are in flight.
Steve
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Upon thinking about it, maybe instead of "minimum travel time" a "maximum proportion of journey spent accelerating" would be better. Spending the whole trip accelerating is fastest, but not by much, and very inefficient.
I am coming to a similar conclusion based on testing. I keep changing max fleet speeds for a geosurvey fleet, depending on whether it is moving from Jupiter to Saturn, or operating within Saturn's moons, or moving within the inner planets. So far this has varied from 100 km/s to 2000 km/s for the same ship. To reduce micromanagement, what I need is a more intelligent way to set max deltaV used for a particular journey, especially when the ship is operating mainly on default orders, such as for geological survey.
Perhaps a combination of the portion of journey under acceleration and max speed, with the lowest speed taking precedence. Or maybe base it on distance rather than portion of journey so I can set a max speed at the start of the journey and won't need to track time passed.
Steve
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Steve
Nice to see the armour ratings going up and am eagerly looking forward to more instalments on your test campaign, a couple of other random thoughts:
- Are you thinking of tracking rail gun ordnance now? Was wondering what sort of usage of ammo there would be in long slow approaches where you might be firing continuously and if this may now be enough to start worrying about magazine and weight requirements. This might also have more of an impact on fighters.
- Any more thoughts on maximum effective speeds for ships due to the dangers of impact from space debris? I could see this as being more of an issue when it comes to moving around asteroid belts.
The jury is still out on rail gun ordnance. Maybe to prevent continual firing, an easier option may be some type of failure chance for a weapon.
I have been looking at cosmic dust and the speeds that would be required for significant damage. Based on the size and mass of cosmic dust particles, the speed required to damage armour is a lot higher than I would have expected. It probably wouldn't be worth it for the early to middle game, except in Nebula systems. On the other hand, there isn't a huge amount of material available on this subject so if someone has knowledge in this area please speak up.
Steve
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I've added some extra TG conditions in the format: "Fuel less than 20% + Required Decel". This will trigger the condition as True when the ship has an amount of fuel that is less than 20% of its maximum fuel capacity plus enough fuel to decelerate to rest from its current speed. There are similiar conditions for 10%, 30% and 40%.
A new Conditional Order of: "Create Fuel Warning Event" has also been created. This condition just generates an event message but takes no further action.
With the complexities involved in Newtonian Aurora, a simple "Move to the Nearest Colony for Refuelling" conditional order may no longer be appropriate (although it is still available) so this new event generation alerts the player to a potential issue and the player can then decide what action to take.
Steve
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On the other hand, there isn't a huge amount of material available on this subject so if someone has knowledge in this area please speak up.
Steve
I personally am not an expert in this area, but on the 26th, I'm meeting Dr. Schonberg (http://civil.mst.edu/facultyandstaff/directoryschonberg.html), and I intend to ask him about this.
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I personally am not an expert in this area, but on the 26th, I'm meeting Dr. Schonberg (http://civil.mst.edu/facultyandstaff/directoryschonberg.html), and I intend to ask him about this.
Great! Looking at his background he certainly would be an excellent source of information. If I can get hold of the appropriate data, my intention is to have a chance of impact based on distance travelled in a sub-pulse and the particle density in the system. The energy of the impact(s) would be based on particle mass and closing velocity. I haven't decided yet whether to simply average out a chance of impact across a system or have areas of greater particle density, such as within asteroid belts or in the tail of comets. The latter would be more complex but would add an extra terrain element.
The type of information that would be extremely useful would include particle densities and particle mass ranges within the Sol System, as well as the likely vectors of such particles. Are they generally orbiting the sun or are they passing through the system? How would those figures changes for other star systems or for systems within a nebula and what is the density range for different nebulae. I know this is reducing a very complex subject to a few numbers but any advice or guidance would be appreciated.
Steve
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Conventional warheads will be mainly for RP situations in a multi-Earth start.
Will conventional warheads have any use for planetary bombardment to minimize ecological damage?
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Will conventional warheads have any use for planetary bombardment to minimize ecological damage?
Interesting question. Conventional warheads are more like an anti-ship warhead on a modern day tomahawk missile so they are tactically useful but you would need a lot to equal the destructive power of a nuke. Although perhaps some equivalent of the MOAB might be possible. The obvious advantage would be no radiation effects. I guess dust wouldn't be a major factor either. I'll have to look at this when I tackle planetary bombardment.
Steve
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I am coming to a similar conclusion based on testing. I keep changing max fleet speeds for a geosurvey fleet, depending on whether it is moving from Jupiter to Saturn, or operating within Saturn's moons, or moving within the inner planets. So far this has varied from 100 km/s to 2000 km/s for the same ship. To reduce micromanagement, what I need is a more intelligent way to set max deltaV used for a particular journey, especially when the ship is operating mainly on default orders, such as for geological survey.
Perhaps a combination of the portion of journey under acceleration and max speed, with the lowest speed taking precedence. Or maybe base it on distance rather than portion of journey so I can set a max speed at the start of the journey and won't need to track time passed.
Steve
I've been giving it some thought as well. The most useful setting would probably be something like "Only accelerate when one liter of fuel will reduce journey by x seconds", and possibly also a maximum speed setting. At least for civilian ships, what really matters is the amount of time involved, regardless of the length of the trip. At a guess the calculations might be pretty cpu expensive though, and it's also something tough for new players to understand.
More practical is probably your idea, and have a "only accelerate for x% of distance" setting alongside maximum speed. Not only is it easier to calculate, but without doing the calculations I suspect it probably scales fairly linearly with fuel efficiency. After all you're still accelerating at the same rate, what matters is how long you'll be moving faster before you have to slow back down. Expect plenty of newbie questions about why they can't set it over 50% though :P
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Interesting question. Conventional warheads are more like an anti-ship warhead on a modern day tomahawk missile so they are tactically useful but you would need a lot to equal the destructive power of a nuke. Although perhaps some equivalent of the MOAB might be possible. The obvious advantage would be no radiation effects. I guess dust wouldn't be a major factor either. I'll have to look at this when I tackle planetary bombardment.
Steve
Even a smallish size 4 anti-ship missile launcher is still spitting out 10-ton missiles, isn't it? A planetary bombardment missile design could be mostly warhead (planets being notoriously sluggish at the helm), which puts it right in the neighborhood of the MOAB. (Wikipedia says it's about 11 tons) And that's assuming you're wanting to fire one of them out of a light anti-ship launcher. I could see specialized planetary bombardment missiles being far, far larger than that, (for instance, one designed to be fired out a drone/probe/mine tube) and I'd think they could wreak havoc on any ground units which get caught outside of PDBs.
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More practical is probably your idea, and have a "only accelerate for x% of distance" setting alongside maximum speed. Not only is it easier to calculate, but without doing the calculations I suspect it probably scales fairly linearly with fuel efficiency. After all you're still accelerating at the same rate, what matters is how long you'll be moving faster before you have to slow back down. Expect plenty of newbie questions about why they can't set it over 50% though :P
Might be more intuitive if labeled as "minimum %costing, maximum speed"
For continual acceleration/deceleration between points at relative rest Vmax = ?(distance * acceleration)*. So, if a survey ship with 4 m/s2 set at (60% minimum costing, 2,000 km/s maximum speed) might hit max speed on trips to the outer system, but for a short 380,000 km trip to the moon would hit ?(380k km * 0.4 * 4 m/s2) = 24.7 km/s relative on the acceleration leg.
Fuel efficiency (deltV) by %distance looks to be quadratic, not linear. To get a linear fuel efficiency correlation, it would need to be tied directly to either peak velocity or time accelerating. Either ought to be easily calculated, but I can't think of any concise, accurate wording for labeling that wouldn't lead to confusion.
Further thought: since earth has an orbital velocity of nearly 30 km/s, mistakenly using '24.7 km/s' maximum absolute velocity relative to the solar reference point could be Bad. I'd guess any maximum velocity checks should take into account relative motion of the destination.
* d = 0.5*a*t^2 for continual linear acceleration, so d = a*t^2 for total acceleration/deceleration where t is time spent both accelerating and decelerating. So t = ?(d/a), Vmax = t*a=?(d*a). This calculates 'max relative speed'
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This is a bit of a tangent, but I was thinking about the multi-mode-motors from earlier and how future strategy may revolve around the use of low-acceleration high-duration carriers fielding high-acceleration low-duration fighters.
How about the addition of a proper docking system? What I'm thinking of is that we would be able to design, say, a cruising engine module consisting of, for instance, an engine, fuel tanks, crew quarters, and engineering sections, but no bridge, active defenses, or anything else. When alone, it would be unable to function. When docked to a ship with a bridge, it becomes a fully-functional part of the ship, increasing the mass of the vessel and everything. The only thing that remains is the ability to tell the command vessel to disable the inefficient engines.
Also, it'd be nice to be able to have a way to connect ships without using tractor beams.
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Interesting question. Conventional warheads are more like an anti-ship warhead on a modern day tomahawk missile so they are tactically useful but you would need a lot to equal the destructive power of a nuke. Although perhaps some equivalent of the MOAB might be possible. The obvious advantage would be no radiation effects. I guess dust wouldn't be a major factor either. I'll have to look at this when I tackle planetary bombardment.
Steve
Im not sure what the request is. I think its for weapons that don't hurt industry much, which is why we have the high-yield radiation weapons now to target population more directly.
For low radiation yield, Normal research lines to decrease radiation yield would probably do the trick. Nuclear weapons can be made to be quite dirty-- produce heavy, long lasting fallout, or astonishingly clean, in which there is an intense pulse of gamma radiation (blistering those in the vicinity) but little residual fallout. Additionally, targeting plays as important a role as the weapon technology-- the altitude at which the weapon is set off makes a big deal.
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Well if we get a proper planetary invasion with a map, conventional weapons could be nice to take out enemy units and pdcs without harming the population or the environment. Also iirc the Russians demonstrated a fuel-air bomb that was as destructive as little boy.
Now something different, we have Nuclear-laser warheads but what about single use chemical-pumped lasers? Iirc there were some Flour-hydrogen lasers that worked that way.
edit:
Ok wikipedia has a lengthy article here (http://"http://en.wikipedia.org/wiki/Chemical_laser"). And there is even a patent for a explosive-chemical laser that does not need radioactive compounds. The patent is found here (http://"http://www.freepatentsonline.com/4099142.pdf")
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Now something different, we have Nuclear-laser warheads but what about single use chemical-pumped lasers? Iirc there were some Flour-hydrogen lasers that worked that way.
edit:
Ok wikipedia has a lengthy article here (http://"http://en.wikipedia.org/wiki/Chemical_laser"). And there is even a patent for a explosive-chemical laser that does not need radioactive compounds. The patent is found here (http://"http://www.freepatentsonline.com/4099142.pdf")
Chemical lasers actually aren't necessarily single use, you can keep using them until you run out of fuel. The YAL-1 was planned to carry enough fuel for 20+ shots before it landed to be refueled.
I mentioned the possibility that we could design a fighter with all batteries and no generators to mimic such a system, but unless batteries are naturally very tiny in NA that won't really work well unless there is some way to make the mechanics mimic the fact that we are using something with a much higher energy density. (Or at least Power Density). One way to handle this would be to apply the current "Reduced Size/ Increased Charge Time" technologies to the batteries (or PTGs, or whatever they are called). This could culminate with something like Box Launchers that can't be recharged outside of a hangar, or even--to fully replicate Chemical Lasers--actually had to be refilled from special magazines, or from the fuel tanks, or something else like that.
I'm sure it wouldn't be easy to implement something that went: slower fire rate, slower fire rate, slower fire rate, all the sudden needs 'ammo' though.
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Frankly I think that box launchers need to be a separate tree from regular ones. I don't see why I need to spend most of a decade removing the reloading system piece by piece before I can figure out how to make a hollow tube.
As for lasers, I would love to see a tech tree about energy density per ton and recharge rate per ton, ultimately enabling a fighter that specializes in laser weapons but needs to land to recharge.
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Well, I asked about the function of lasers a while ago, either a few pages past, or in another thread, and how "charges slower" would be only one way to do it, and not make much sense.
Ultimately, in NA, Lasers will be very high range weapons compared to everything but missiles, and very accurate at that.
Sure they have falloff, but they'll hit.
So having lasers that charge slowly is one way, having lasers that directly feed from the batteries, thus being small without direct drawback as long as the ship has enough supercapacitors to actually supply the energy is another, and I think having Lasers that require Ammunition isn't that far off.
One could also go the other direction, with lasers that contain a small backup powersource and extra cooling system.
Looking forward to what we'll find there.
Will we be able to set ship speed on a single move order, like "Move to jupiter at 1500 km/s"?
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I was actually thinking that the explosive-chemical pumped variant could be part of a missile-warhead thus the low power variant of the nuclearpumped laser. That YAL was canceled is new to me :( it was promising. Having "laser-shots" as ammo is a interesting concept ... i wonder if you could get that down to the size of a riffle.
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Well if we get a proper planetary invasion with a map, conventional weapons could be nice to take out enemy units and pdcs without harming the population or the environment. Also iirc the Russians demonstrated a fuel-air bomb that was as destructive as little boy.
Two things:
First, the yield of the weapon in question was 44 tons according to Wikipedia. Nowhere near little boy. Secondly, I doubt that an FAE would work well at supersonic velocity.
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So i was misinformed no big deal for me 8) , still 44tons TnT equivalent arent bad and i doubt you need supersonic speeds in planetary warfare althought having supersonic stuff is still neat.
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My point was that I highly doubt you can drop one from orbit and have it work unless you slow it way down.
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Given inheritance, dropping bombs should be easy even without working gravity. Creating pure bombs should be a possibility.
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Steve any chance of a quick update on how things are going with the test campaign?
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Steve any chance of a quick update on how things are going with the test campaign?
I've been away for a week and haven't touched it in about 10 days overall. I'll probably be doing some programming and playtesting over the weekend.
Steve
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The jury is still out on rail gun ordnance. Maybe to prevent continual firing, an easier option may be some type of failure chance for a weapon.
I have been looking at cosmic dust and the speeds that would be required for significant damage. Based on the size and mass of cosmic dust particles, the speed required to damage armour is a lot higher than I would have expected. It probably wouldn't be worth it for the early to middle game, except in Nebula systems. On the other hand, there isn't a huge amount of material available on this subject so if someone has knowledge in this area please speak up.
Steve
Couldnt Cosmic dust be heated together to form larger particles of matter?
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I was wondering why the implied results of newtonian railguns were so devastating. 1kg railgun shell enough to blow apart a ship?
So I got to thinking about where the energy came from.
Scenario: (note: newtonian calculations only, if scaling to high tech levels, might need correction for relativistic effects)
Magneto-plasma Drive
Thrust: 12.5 MN Base Fuel Consumption per MN: 188.1 litres per hour
Fuel Use at Full Burn: 2351 litres per hour
(Source: Vanguard, test campaign setup) 1 million litres of fuel = 1kton; 1litre of fuel = 1kg (sorium fuel has the density of water?)
Fuel use at Full Burn: 2351kg per hour = 0.653kg per second (3sf) = 0.000653 tons per second
Force on fuel (action/reaction): 12.5MN
"One Meganewton (MN) is equal to the amount of net force required to accelerate a mass of one ton at a rate of one kilometre per second squared. "
Exhaust velocity (engine's frame of reference): 19100 km/s (3sf)
Exhaust energy (and hence energy yield of fuel): 1.20E14 J (3sf)
Energy Density of Sorium Fuel: 1.83E14 J per kg (3sf)
Seems a bit high to me...
For comparision, energy density of antimatter is 8.99E16 J per kg (source: wikipedia (http://en.wikipedia.org/wiki/Orders_of_magnitude_(specific_energy_density)))
And nuclear fusion is 5.76E14 J per kg...
And to think I wondered why railguns are so insanely powerful. Why, we're using nuclear fusion energy densities to propel the 1kg chunk (railgun drones), does it really so surprise us that the impact energies are within an order of magnitude or two from nuclear fusion weapons?
EDIT:
If you already thought of this, then do pardon me for not having thought of doing this before. Just correcting some of my misconceptions.
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Its true, but I think people are getting so caught up in math and realism that they forget this is a game.
Sure, one way to deal with the power of railguns would be to severely restrict the speed of ships, but that would make for a very slow and boring game. I think it's better to keep the speeds the same and handwave the physics to avoid fights being all 1 shot kills.
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For that matter, since sorium fuel is going to be so much more plentiful now (relative to other things), we could have a cheap version of a nuclear missile that uses sorium reactions instead of nuclear warheads.
An order of magnitude less powerful per ton, but able to convert all remaining fuel to explosive yield, plus cheaper.
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I think it's better to keep the speeds the same and handwave the physics to avoid fights being all 1 shot kills.
Actually, I don't think that's necessary. True, when having great differences in speed, the railgun hits will probably be one hit kills. But that's it, "one hit kills". If it doesn't hit you, it doesn't kill you. The "time to displace ship once" (tds) is probably quite important here. That means the time needed to accelerate in such a way, that the ship has not a single meter at the position it would be when not having accelerated. For example, for the geosurvey ship in the test campaign this would be about 19 seconds. But let's take the warship on page 4 of the newtonian fighter thread. It has a neat 22. 5 second tds. That means when accelerating constantly and randomly, even when closing in at let's say 40,000km/s (quite a high figure), that still means that, even when your gun is hitting perfect in the center of a target at no matter what range, you'll still have an 100%-hit range of only 900,000km. Therefore the game will probably be about probability. Shoot enough, and you're bound to hit at least something.
In fact, I think I can more or less see how combat will turn out:
Long Range:
about 50mkm and more:
Missiles rule the vacuum. They can correct for course changes of the enemies, and they can accelerate to high speeds. Two alternatives exist for their armament: Kinetic (including probably shrapnel) and nuclear (including beams).
Kinetic warheads will have the advantage of depending on the speed difference. A 1ton warhead hitting you with 10m/s will probably just ruin your paint job, but the same warhead crashing into you at 4,000km/s as you try to reach the enemy will pretty much ruin your day, a. k. a. pulverizing the ship (although the jury's still out on how much exactly you're screwed). Their disadvantage? They depend on the speed difference.
Nuclear warheads on the other hand always deal the same damage, independent of movement. And laser warheads will make point defence more difficult. More to that, later.
Mid Range:
Long live the railguns! And someday lasers. This is where the aforementioned spraying will occur. Here, again, the same rules apply as above: Railguns are great when you and the enemy are flying head-on. When however you're on a parallel course, they will not do much damage. And if he's flying away? Forget it.
Lasers on the other hand (when implemented as I'm thinking they will) will hit with always the same damage, no matter who's moving where. And should have a higher effective range than railguns. That cruiser I mentioned above? You have a range against that of about 22. 5 lightseconds, not considering jitter and such. That are 6. 75mkm!
Point Defence:
Now it's getting interesting. What is stopping these kinetic missiles to fly through your ship? In short, you of course ;-). There have been different ideas to deal with those missiles:
Dust: Simply use their speed against them, by shooting dust (or small spheres or whatever) in the path of enemy missiles, they will use their kinetic energy to kill them. Is of course dependent on different factors, all of which are discussed at Impact Physics.
Nuclear Antimissiles:
Shoot one, kill dozens. In theory. Has, of course, to be shot quite some time before the enemies missiles reach you, or you will destroy that armor yourself. And, the enemy could send nuclear antinuclear anti missiles with theirs.
Missiles with shrapnel: Basically the dust above, but at a range.
And my favourite, although not yet implemented: Lasers. Why? Because they should be able to kill missiles at quite a big range. Using the nuclear anti-ship missile as an example, estimating their length to about 4 metres, one can see that a laser without jitter should be able to hit it at 100% certainty at a distance of 25kkm. While, without knowing the strength of lasers one cannot certainly say that this will one-hit-kill such a missile, even trading the warhead for armor it would need less than 800MJ at ceramic composite armor to at least punch a hole through. Looking at the railguns that seems possible.
And even if there is debris, at 25kkm even a slight deviation will carry it far, far away from the attacked ship.
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Its true, but I think people are getting so caught up in math and realism that they forget this is a game.
Of course its a game! That's why some of us are playing fast and loose with extrapolated math. Playing with the applied math is almost as much fun as actually playing the game using the math. ;D
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That is precisely the point.
For once, a game that models space combat more or less correctly, is an exiting project.
How playable it turns out is another thing.
I have no problem with one hit kills.
I would certainly build my ships with shotguns, though.
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but the same warhead crashing into you at 4,000km/s as you try to reach the enemy will pretty much ruin your day, a. k. a. pulverizing the ship (although the jury's still out on how much exactly you're screwed)
Ahem, no. You're screwed.
I don't think anyone is arguing whether you can live from a 1ton missile hitting you at relative 4kkm/s. It's the 1kg shell that we're arguing about.
1kg shell: 8 TJ (just under 2 kilotons)
1ton missile: 8 PJ (around 2 megatons)
That's equivalent to a really big nuclear warhead.
You don't mess around with the petajoules. If that thing so much as glances off, bye bye ship.
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Don't know if this is the proper thread to ask this question, but...
Given the great impact that fuel and delta-v will have on this game, has the idea of including Light-Sails been considered? They would take some time to build up any signifigant velocity, but the "fuel" is free, giving them a better payload-to-gross-tonage ratio and effectively unlimited range. Possibly useful for commercial ships, and a potential way of recovering out-of-fuel powered ships.
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What actually excites me about this is that Newtonian Aurora has a chance at really changing how we think of space combat. With the energy delivery that your talking about in the weapons department, its effectively eggshells armed with sledgehammers groping for each other in the dark.... except their is no darkness to sensors!
I am really interested in seeing how the sensors come into play. Since this is combustion based thrust, and hard science based, your pretty much NOT having any issue detecting anything out there. Ships are HOT compared to space, even if they are not at full thrust. So, the question then becomes when you go active to lock the target. Passives will have you spotted long before your in effective shooting range, even longer if their is a high intensity burn. On top of that, if the FTL drive generates a flash at exit, its pretty much a given that everyone is going to know when your in the neighborhood.
So, if everyone knows that there are bad guys in system, and everyone knows roughly where the bad guys are via passives, the only real issue is going to be acquisition via actives for a firing solution (especially for railguns/lasers) OR deploying remotes that are self seeking.
Now the rub is going to be, deploying missiles in and off itself is going to be blatantly obvious if they are combustion driven. As soon as a missile launches, the thermal is going to give bird away. So, the bad guys know its coming.
Since the thermal signature and power is easily read for very long distances with passive sensors, its going to be very easy to spot ships vs. missiles.
So, what this boils down to is, since everyone can see you, the only thing that's going to matter is throwing off the other guys math long enough to make sure he misses while you get an accurate shot in.
So, basically combat is going to be a giant game of chicken played with slide rules... and that should keep the pucker factor fairly high when you think about it!
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.... except their is no darkness to sensors!
I am really interested in seeing how the sensors come into play. Since this is combustion based thrust, and hard science based, your pretty much NOT having any issue detecting anything out there. Ships are HOT compared to space, even if they are not at full thrust.
Is this confirmed?
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A quick update on how things are progressing. I have had a frustrating few days with moving ships towards planets. The basic issue is that with Aurora-style orbital movement planets make sudden jumps every few days. This is a far more significant issue when ships are expending fuel to make course change and decelerations. In fact, so much of an issue that I came to the reluctant conclusion that orbital movement is going to have to take place a LOT more often. After trying a few different options, I have settled on the start of every increment that is longer than an hour. While this means that a planet might take slightly longer than its normal year to make an orbit if you use a lot of short increments during that year, the negligible gameplay effect is acceptable compared to orbiting planets even during 5 second increments.
This introduces a new issue though. Ships are slowing down to reach a planet and then the planet is moving slightly at the start of every increment, which leads to the comical sight of ships chasing planets around the map, with the planet keeping slightly ahead of the ship. Well, comical at first - now frustrating :)
I have tried a few quick fixes but I think that for movement purposes I am going to have predict the future positions of planets in the same way that missiles predict the future locations of ships. This doesn't sound too bad until you consider that a moon could be orbiting a planet that is orbiting a star that is orbiting another star that is orbiting a third star. Some coding required.
Shipyards are now working as discussed, with a few small changes. You have shipyard hub modules, capacity modules and slipway modules. They are separated for commercial and military so you have six in total and they are built only by construction factories not shipyards. A hub includes one slipway and 1000 capacity. Assembling and disassembling shipyards requires time and a small amount of wealth but no supporting infrastructure. This means you can create very large shipyards more easily than before and also you can dissemble several shipyards, move the modules in freighters and then reassemble them in a different configuration. Commercial and military cost the same and take the same time to assemble. However, commercial are 3x larger to move and have 10x capacity. I'll post more details when I have time in the rules thread.
Beam fire controls are now created using the same design process and background tech as active sensors and missile fire controls, except that missile fire controls have 3x active sensor range and beam fire controls have 1/3 active sensor range (technobabble being that MFC just paint the target for a missile that can change course en route whereas BFC need very precise information on exact location, heading, speed and acceleration)
And here is a quick shot of the unfinished battle overview window. As you can see, you will have far more detailed control when you set up firing solutions and you will able to modify the parameters for targets while missiles are in flight. This is because unlike standard Aurora, missiles will be heading for a predicted intercept point, not the target's current location. I haven't decided whether fire controls should be able to pass on a change of target though.
(http://www.pentarch.org/steve/Screenshots/BattleTab3.PNG)
Steve
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Level 2 Epic.
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Level 2 Epic.
Level 2 brain ache more like :)
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Level 2 brain ache more like :)
Probably! But I'm expecting it to be a very enjoyable one :) I'm looking forward to doing plenty of AARs on my various disasters.
Steve, on the moving to planet issue is this arising because you have ships slowing down to 0 rather than slowing down to the speed of the planet? I assume when ships leave a planet they start at zero rather than a speed relative to the sun(s)? If thats the case, when ordering a move to planet could you take the planet orbital speed, multiply by say 1.25 and then use this as the stop speed. Once the ship "hits" the planet it then just switches to a zero speed state. I'm not sure how fast some of the planets can orbit but would have thought this would not have too much of an impact on fuel saving issues.
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I have tried a few quick fixes but I think that for movement purposes I am going to have predict the future positions of planets in the same way that missiles predict the future locations of ships. This doesn't sound too bad until you consider that a moon could be orbiting a planet that is orbiting a star that is orbiting another star that is orbiting a third star. Some coding required.
I actually ran into this about 6 months ago when I was fooling around with SA/Aurora-style (i.e. max velocity, instant acceleration) intercepts. It (the orbits of orbits of orbits) is a REALLY nasty problem. A couple of suggestions:
1) Hierarchically throw away detail. By this I mean you want to predict the intercept to the outermost orbit (i.e. the 2nd star) 1st. That will give you an intercept time. If the intercept time is long compared to the next period, stop there and pretend you're aiming for the central body. If it's not recursively go to the next body. As an example in the Earth/Luna system, first you'd calculate an intercept to Sol. If the time was more than a year, you'd stop and simply aim at Sol. If the time was less than a year but more than a month, you'd calculate the intercept to Earth and ignore Luna. If less than a month, you'd simplify the orbit of Earth (see below) and intercept Luna. Note that this assumes that an orbiter has a significantly shorter period than an orbitee - if that's not the case you've got a big problem :)
2) Use a "constant acceleration" approximation (i.e. a Taylor expansion) to approximate orbits whose period is much longer than the intercept time. In the example below (assuming Sol is not moving), when aiming at Luna you would not model Earth's motion as a circle. Instead you'd calculate Earth's velocity and acceleration. (I would calculate them relative to Sol, then add in Sol's velocity and accel to get a total. This is because, relative to Sol, they'll always have the same magnitude and simply have different directions.) You'd then approximate Luna's motion as a circle orbiting a object moving along a parabola. The reason for doing this is that a) it makes the math easier and b) it's recursive - no matter how many nestings you've got, you're still always solving the same problem. This is simply a more sophisticated version of what you're doing right now, i.e. simply using the 0'th derivative (position) to approximate the correct course. When you get really close to the target (say an intercept time of less than Period/4), then you can approximate the targets motion too, at which point you're calculating an intercept to something with a simple parabolic path (i.e. intercepting a constant acceleration body).
3) Looking at the above, if the "circle around a parabola" problem is too hard, then you could just ignore the orbiting body until intercept time was less than Period/4, then pop over directly to approximating its motion with constant acceleration. So at that point the two changes to your existing algorithm would be a) ignore nested orbits until the intercept time drops to some fraction of a period and b) approximate all orbital motion as constant velocity (no accel) or constant accel, which allows you to use the same intercept code you'd use for ships.
4) Another thing I just thought of: when calculating the intercept time to see if you should igore a sub-orbit, I really meant "intercept time to the closest point on the orbital circle". In other words, you should use the motion of the central body, but subtract off the orbital radius from the distance to the central body (you should probably use this as the course target as well). This will keep you from getting falsely small time values if you happen to be inside the orbit of whatever you're chasing. So the real suggestion when ignoring inner orbits is to calculate the intercept to the motion (due to central body motion) of the closest point on the orbital circle to your current position.
Hope that helps....
John
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You could calculate the Hill sphere for various bodies in the solar system, then apply gravitational acceleration to ships within them? Then ships can do parking maneuvers.
Outside those Hill spheres, ships accelerate wrt. the sun (binary or more systems default to primary star unless ship is inside the Hill sphere of secondary star)
In this case, you don't have to worry about "catching up" with planets that run away. Since your ship would ideally want to retain orbital velocity (assume circular orbit), you will be moving with respect to the planet.
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Level 2 brain ache more like :)
You've obviously never played Attack Vector: Tactical.
The intercept problem is a tricky one. However, due to the hill sphere, I'm fairly certain that you can't have a level three body with a period approaching that of the level 2 body. Unless it's tidally locked.
Speaking of which, will we be able to stick stuff at the lagrange points? Not like they are now, but for real? Also, probably only for planets, for simplicity reasons.
You could calculate the Hill sphere for various bodies in the solar system, then apply gravitational acceleration to ships within them? Then ships can do parking maneuvers.
Outside those Hill spheres, ships accelerate wrt. the sun (binary or more systems default to primary star unless ship is inside the Hill sphere of secondary star)
In this case, you don't have to worry about "catching up" with planets that run away. Since your ship would ideally want to retain orbital velocity (assume circular orbit), you will be moving with respect to the planet.
That's a really good idea. While aiming where the planet will be is a good solution, adding the Hill sphere can reduce issues in that regard.
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Ladies and Gentlemen, our ships are moving too fast.
When a rail gun does more damage than a nuclear warhead kg per kg, something is quite possibly wrong.
At starting tech, a nuclear warhead does 100 kTon per ton, or 418 GJ/kg.
If the sample campaign ship dropped a 1kg rock out the window after using 1/10th the available deltaV (2,474 km/s), then the rock would do 3,063 GJ/kg.
I'll give the nod to jseah for being the first to comment on the reason and implications last page, and admit it took a few days for the implications to sink in.
For that matter, since sorium fuel is going to be so much more plentiful now (relative to other things), we could have a cheap version of a nuclear missile that uses sorium reactions instead of nuclear warheads.
An order of magnitude less powerful per ton, but able to convert all remaining fuel to explosive yield, plus cheaper.
Only, a Sorium bomb is likely to be more powerful, not less powerful, than the nukes. At maxium engine size and the most favorable Thrust / Fuel Consumption Modifiers (but neglecting the base fuel efficiency tech) leaves Sorium derived fuel at 7.8E15 J/Kg energy density. A 0.01% energy efficient sorium bomb would have double the output of the starting nuclear warhead.
So what can be done?
Two solutions come to mind:
Option A: Increase fuel consumption. A 40x increase in fuel consumption would give Sorium equal recoverable energy density to nuclear warheads when they are both at the starting fuel efficiency/warhead size tech levels. For simplicity, call it 60x increase and replace 'liters per hour' with 'liters per minute' The sample campaign Vanguard now has a hair more than 412 km/s delta V to work with. That really isn't that bad compared to the current human probe speed record. Since this will be painfully slow by the old Aurora standards, the old hyperdrive would probably need to return for in-system transit outside of planetary gravity zones, with the old hyper-limit applying just to system jumps. Maybe 10x movement while under hyper, leave big bright signature even while coasting, can't fire weapons or use sensors while under hyper. I guess we can let them be assumed to have their base speed when calculating railgun collision damage, and of course return to normal base speed when exiting hyper.
Option B: Grand Handwavian. Replace 'TransNewtonian' with 'PostEinsteinian' or 'dimensionally resonate.' Ships are still zooming around the map as fast as before thanks to their anti-gravity sorium-infused repulso-thrusters. Further, if we go this way and accept that this is the same fantastic Aurora space fiction just using newtonian motion, we shouldn't stop the scale-up with propulsion. Are the titanium hulls tin-foil pathetic? Well then: thanks to dimensionally-locked Duranium lamination, the armor is 10x tougher than ever! (I'm assuming current armor is already 4x better than theoretical real world, so 10x more might bring it closer to the sorium fuel.) Maybe the hull spaces are twice as tough, and are now 5 layers per cm thickness, and only added in cm groupings.
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More like 1000x tougher. You need armour to start in the gigajoule range for it to be worth anything.
EDIT:
Does result in the very interesting scenario of enemy ships decelerating wrt to you in order to survive railgun shells.
Nukes will need to contact to actually do damage. Although if they do acheive a contact hit, it's still probably bye bye ship.
EDIT2:
Whuffie get! =P
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Definitely in favor of option A. Actually, reduce both exhaust velocity, and acceleration.
Actually, even better idea (courtesy of AV:T):
The standard drive is in the .01-.1 G range, and has a max delta-V equal to maybe 1/10th that we currently have. However, military drives, and only military drives, have a boosted thrust mode, which increases thrust by a factor of about 20, but increases fuel consumption the same amount. This way, we get lower kinetic death quotient, and maneuverability becomes a factor again.
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Well, essentially, for in-system Hyperdrives. we'd have to have a new hyperlimit system.
Suggestion:
Have one from the Star, 1 Au per solar mass (based on our home system), and maybe a million kilometers per [planet size (how ever we define that)]^1.1.
The ^1.1 is meant to result in low values on small planets, so that we can cut off and abstract away; A large Jupiter-like body with two dozen moons would only have one hyperlimit assigned to it.
Thus, movement would be relatively slow near planets, but one could cruise faster in between; The inter system would be more secure due to the stars hyperlimit.
Maybe, a ^0.95 on the stars limit would result in bigger stars with huge systems not having an equally huge limit.
But that would have to be done drastically different from Aurora is the actual hyper-system.
Either, we require ships to have a jump engine, then it could just be a modified engine that allows a speed boost for low, ongoing fuel consumption, only in system outside of the "inner" hyperlimits.
The speed boost shouldn't be a flat x10, it should maybe start at x2 and then increase by 0.5 or 1 with every advancement of Hyper-Jump technology.
We could also go the way of having special thrusters, this would allow us to specify a minimum size and maximum size efficiency, where ships get a speedbost based on how large they are compared to their thruster array.
I can see a combination of both, where small defensive ships get a small hyper-thruster and thus have no need for a larger jump engine.
As for the fuel efficiency, I think it's ok to start higher than what we have today, because in this case, with a bit of handwavium in place, we can go for gameplay concerns as well.
Once it takes a month of acceleration to reach the projected lethal speeds we try to avoid, we don't need to ramp up the fuel consumption any further, even if that still means a silly high fuel efficiency; as much as I love logistics, that might be a bit much.
Maybe, higher level engines should give less extra output, and more bonus to efficiency, with less cost ramp up than we are used to by Aurora.
/rant ;D
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The higher fuel consumption + hyperdrive theory is to limit the true speed and thus the incredibly rail gun power, while allowing system transit to be carried out in a reasonable time. Where before a military ship might accelerate to 2,000 km/s for an attack run, with a 60x fuel consumption jump the same ship burning twice the fuel will only hit 67 km/s for the run. That works out to about a 3x energy increase for the rail gun round compared to the currently troublesome 440x energy increase. Kinetic kill overpowerdness largely solved. The hyperdrive then makes in-system transit acceptable again. Now, how slow is acceptable? If a starting-tech ship only does 50km/s acceleration runs, and we want 200 km/s interplanetary speed seen in the early game, then having a 4x hyperdrive would need to be the starting tech.
Suggestions if increased fuel and added hyperdrive
First, no solar hyper-limit. Use the Planetary Hill Zones already suggested for simplifying planet intercepts as local hyper-limits instead. Technobable says hyperdrive are unable to function when influenced by multiple bodies. Ships/objects within a planet's hill zone get moved to keep relative position with the planet, and can't hyper. Ships outside move independently and can hyper. This would make the system ship movement start to mirror the Galactic ship movement on a smaller scale.
In Transnewtonian Aurora the hyper is a fixed 10x, with tech reducing added mass. In Newtonian Aurora I'd suggest making the hyperdrive a fixed mass increase (+50%?) with tech increasing the hyper speed. Hyper speed might starts at 4x and increases by +1x with each tech advancement. (I think starting at 2x will be too slow) Ships lacking hyperdrives become the dedicated planetary-defense craft.
Astroid Belts are reefs. With all the interception issues astroid movement gets disabled. Instead of individual astroids having Hill Zones, the entire astorid belt becomes a hyper-blocking hill-zone barrier. This could create inner defensive zones against interstellar foes jumping in-system.
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I must admit I'm not too keen on the idea of having three propulsion methods in the game still and I think hyper drives could cause even more issues-
- If it's an instant transit from normal drive to hyper drive you are going to have a non Newtonion change in speed which means ships will be able to pretty much dodge any incoming missiles or other ordnance which are stuck under Newtonion rules.
- If it's a non instant transit then you go right back to the original issue of ships travelling too fast for big periods of time when they can be one shot killed and may be particularly prone when they leave hyper transit and are effectively unable to make course corrections until they slow down enough for the engines to have a reasonable relative effect again.
- Having ships both unable to fire and immune to attacks in hyper just compounds my first point. If ships are vulnerable in hyper then they are at an even bigger risk of one shot kills - especially if they are heading towards an enemy.
Therefore I think that, all in all, hyper would cause more issues then it solves.
As it stands the balance on speed of exploration and development seems OK. If ships were slowed even further you may have to increase ship production capabilities to allow players to have enough ships to continue to achieve anything in a reasonable time scale.
I quite like the idea of having to seriously hit the brakes if I want to fight and the damage potential if I fail to do so. I do think defensive armaments need to be beefed up a bit though to help make those hits less often. I think there could also be some very interesting interplays between better lasers that could be effective at longer ranges v rails that will be pretty devastating at close range.
One other thought, would the energy wave of a nuke be one hell of a great Whipple shield. You probably only need to get the new 5-10k away from the ship so I guess you would have reaction time to do this?
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That... is a good point on the hyper dodging. A very good point. Having a large warm up might help there: if engaging a hyper drive took an hour, then a hyper ship could realistically only dodge once in an engagement by exiting hyper space.
Currently speed and development seem balanced. The issue is combat damage. Currently Newtonian Aurora looks to be balloon-tack-tag. Only active defenses and dodging will work. It might be fun to play a game like that, but the after-action fiction reports do sound better if damaged survivors exist.
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The alternative is simply to fudge the impact physics a little bit for the sake of gameplay and go with kinetics punching holes in things rather than making like a fusion bomb; this would make large ships in particular more survivable. This doesnt mean reducing their impact energy, rather just limiting the amount of energy theyre capable of depositing on a target.
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But that would mean that bigger is automatically better, which.... sucks.
Ultimately, an in-system Hyperdrive is the same as an extra-solar hyperdrive, just without disappearing from the 'physical' world.
Tech development and warmup and all that jazz already exist.
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But that would mean that bigger is automatically better, which.... sucks.
Ultimately, an in-system Hyperdrive is the same as an extra-solar hyperdrive, just without disappearing from the 'physical' world.
Tech development and warmup and all that jazz already exist.
Its just an option, and its not like it cannot be offset (or isnt already) through numerous other factors; most relevant to this case being larger cross section = easier to hit.
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Must admit I like the idea of just punching holes in things, maybe with an inverse proportion of energy getting transferred to the ship so whilst overall energy goes up hugely then actual energy as a percentage of total drops dramatically as well.
Actually it could be very interesting if this created a bell shape curve on energy transfer so there was effectively a sweet spot on maximising the damage from a shell. Now you have an interesting conundrum - speed up or slow down to reduce damage!
Having ships survive and limp home or with crews madly rushing to get systems back up and running is going to make engagements a lot more enjoyable.
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The revised impact damage is OK with me. It may not be totally realistic, but it's far better then introducing in-system hyperdrives back in. Steve, please don't do that.
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The revised impact damage is OK with me. It may not be totally realistic, but it's far better then introducing in-system hyperdrives back in. Steve, please don't do that.
Agreed, I'd rather something else (handwavium shields, dodgy impact physics) to fix any issues rather than hyperdrives or some other movement tweak; the only place for those might be a way to fast travel between components in a multi-star system, and even then it would probably be just a variant of the intersystem hyperdrive.
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I really don't see the difference between "in-system" and "out of system".
If it's fine to take two months from one planet to another, I have no problem waiting 10 years for my ships either. And no, I'm kidding.
it should be consistent.
Just increasing the fuel cost by another factor, and be it just another x2, is a step in the right direction.
Having shells just "penetrate" is fine with me as well, though.
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If it's fine to take two months from one planet to another, I have no problem waiting 10 years for my ships either. And no, I'm kidding.
Imagine the course plotting for that, lol. I think the game will process far too slow to have low-energy travel. It would take real hours to process enough time to get anything done at all. Also, the relationship between industrial productivity and travel times would get all wonky. Unless you drastically slow down construction of all sorts (see above problem) then you'd end up with whole fleets being constructed by the time you got to an enemy world.
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Which brings us to the sad truth.
Space Combat probably ain't happening. ::) :P
So yeah, compromises will have to be had.
While assuming a good part of the energy will just pass through, probably a % dependent on the size of the ship, increasing the fuel consumption by another bit doesn't seem harmful to me.
Could be a tech line "fuel compression" that increases fuel/tank while slightly decreasing weight/fuel.
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Must admit I like the idea of just punching holes in things, maybe with an inverse proportion of energy getting transferred to the ship so whilst overall energy goes up hugely then actual energy as a percentage of total drops dramatically as well.
If you pick this, can I recommend that energy (damage) deposited on target ship increases by the square root of the energy on the shell?
Then it becomes linear with respect to speed (and less than linear with respect to fuel).
EDIT:
I can also support an in-system hyperdrive. Except that I want it to be the same as the inter-system hyperdrive.
Just remove hyper-limit and require a spooling-up time. Jump from anywhere to anywhere, limited to Hill Sphere of bodies (which means no hyper to inside the orbit of the innermost planet) as long as the Hill Sphere itself is bigger than some minimum size.
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Current physics would say that the shell can't just punch a hole.... :(
But current physics don't have any way for the slug to survive the quarter million plus Gs of acceleration it would take for the current railgun velocities we plan to implement.... ???
So to be honest, I see no reason not to fudge the whole thing if it serves the greater good. :)
I would say that some 'handwavium' be involved though in the ammo if it can survive mega Gs. The ammo should probably be something that is 'out of this world' and ammo 'built' and tracked. Otherwise the mass firing of slugs could still become a killer. But I would defer on this to whatever Steve's feels like dealing with.
Don't like the in system hyper drive. I would love to abuse it, but it would get abused badly and would likely make combat impossible. Even an hour long warm up time, if we slow down accelerations, is way longer than what you will need to jump away from incoming ordinance.
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Energy Density of Sorium Fuel: 1.83E14 J per kg (3sf)
Quite apart from the fact that Sorium Fuel has the density of water (which no one commented on =( ), this also means that the Vanguard survey vessel is carrying 43.7 gigatons of TNT equivalent in its fuel tanks.
The handwavium of sorium engines might be needed to get the energy out, but this means kinetic kill missiles can replace nukes.
Gigatons of TNT... I'm not familiar with impact physics, and no asteroid impact estimates include anything traveling faster than 100km/s or so. And certainly not with pure iron projectiles less than a meter across.
Drive-by nuclear holocaust is more like fragmentation missiles now. Using a single interceptable drone for your random bombardment is not wise. If the drone fragments into a thousand pieces, each with the power of a Hiroshima nuke... now THAT is a real nightmare to deal with.
And this problem only gets worse as the tech increases. Accelerations increase, max feasible delta-v increases, fuel efficiency increases. Hence, the energy density of sorium fuel increases as well as the delta-v on a planetary iron bombing run. Energy of proposed kinetic planet-killers will increase quadratically.
If it's not feasible at starting tech, it'll be feasible by mid-game.
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I might like to note that whatever you do, whether it be leaving the one-shot-one-kill on the table or in-system hyper or making railgun shells punch through or something crazier, I will still be playing Newtonian Aurora.
There is just about no way I *won't* be playing Newtonian Aurora unless it stops being newtonian (although moving to einsteinian might get me back =P)
EDIT:
I dislike moving away from realism. I do, really.
Leaving the one-shot-one-kill in would be what I would want to happen.
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But current physics don't have any way for the slug to survive the quarter million plus Gs of acceleration it would take for the current railgun velocities we plan to implement.... ???
In a theoretical optimally designed rail gun a solid slug is effectively in free fall and could survive any amount of acceleration. The electromagnetic acceleration is distributed evenly throughout a conductive round as a body force, accelerating every atom in about the same direction at about the same rate. Any compressive/shear forces in the object would be small, sort of similar to how satellites in orbit are constantly accelerating but practically weightless. In Newtonian Aurora rail guns appear to be much closer to their theoretical potential than the modern prototypes of today.
The usual reason high Gs are fatal is that they are resulting from contact forces. The atoms in back are getting pushed into the atoms in front to propagate the force. As a result the inertial forces from the atoms in front trying to stay at rest (or the ones in back trying to stay in motion) generate internal forces compressing/pulling/shearing the object.
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The problem with one shot one kill is that it makes building larger ships foolhardy, and it messes up the balance between offense and defense.
I did have one idea, though it may be a bit late; make shields into deflection shields (IE, divert kinetic projectiles). This would mean that armor would be useful against lasers, and shields against kinetics.
The basic idea in my mind for deflection shields is they effectively reduce your target cross section while active, by diverting projectiles around the ship. Since shield strength scales by volume but target cross section just by area, this would have the interesting effect of giving a battleship a smaller TCS than a fighter. A hit would still be a kill, but would be even less likely on large ships.
Alternately, if people prefer shields that can be beaten down over just a reduced chance of catastrophic damage, the shield could drain energy to deflect each projectile until it ran out, then the ship dies. One is reduced chance of death and the other is x hits to kill, in the long run it works out to mostly the same results.
Before anyone claims this would make big ships too powerful, consider that the battleship would still be vulnerable if hit, and you could afford a lot of fighters for one battleship (and fighters would probably still be faster, making them hard to hit as well). I just think a game where smaller = always better would be pretty boring.
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Reducing target cross section means the fighters just get closer. >.>
Maybe if it got reduced enough, lasers could get an intercept. Then fighter is expanding cloud of gas.
Kinetic kill missiles will still hit a vast majority of the time.
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I like the deflection shield idea. Maybe something that gave each kinetic a percent chance to miss based its mass. With a 1 g projectile, it would be something like 99.9%, 1 kg 99%, 10 kg 95%, and 100 kg 50%. This would prevent the kitty litter of doom from being quite as effective. Not sure how it works. Magnetic field, particle beams, something like that.
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I was thinking about a similar concept. Afterall the TN minerals are going to become Antigravity minerals or somesuch. An anti-kinetics shield (that deflects the vast majority of energy) is at least vaguely plausible. I say reduces energy rather than cross section because that provides an application for armor.
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One idea is to calculate the deflection needed based on momentum; those hits that barely 'hit' (ie on the outer edge (radius if this was 3d) of the TCS) take little energy to deflect, while those that are bullseyes are much harder/impossible. Since were using momentum, this would favour larger projectiles, giving them a reason compared to the 1g fragment spam. As in the other cases, shields will loose power even from the 'easy' deflections, until eventually the opponent either gets lucky (say lands a hit on the center 5% of the TCS) or the shields weaken enough that hits outside that stop being deflectable.
This presents an interesting trade off; larger ships will be easier to hit (larger TCS), but on the other hand have more capable shields, and probably be more survivable overall. On the other hand, since you want to make sure any hits arent right in the middle of your ship, ships with higher accelerations will likely be better off, especially as ranges close and reaction time decreases.
While I dont think 1 hit kills as a concept are bad for gameplay, uninterceptable/detectable 1 hit kills that reduce it to purely a game of chance might be. Contrast the nuclear missile exploding on contact with the hull (very much a case of can be detected, defended against, and mitigated) vs the invisible 1kg kinetic killer slug.
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I actually ran into this about 6 months ago when I was fooling around with SA/Aurora-style (i.e. max velocity, instant acceleration) intercepts. It (the orbits of orbits of orbits) is a REALLY nasty problem. A couple of suggestions:
1) Hierarchically throw away detail. By this I mean you want to predict the intercept to the outermost orbit (i.e. the 2nd star) 1st. That will give you an intercept time. If the intercept time is long compared to the next period, stop there and pretend you're aiming for the central body. If it's not recursively go to the next body. As an example in the Earth/Luna system, first you'd calculate an intercept to Sol. If the time was more than a year, you'd stop and simply aim at Sol. If the time was less than a year but more than a month, you'd calculate the intercept to Earth and ignore Luna. If less than a month, you'd simplify the orbit of Earth (see below) and intercept Luna. Note that this assumes that an orbiter has a significantly shorter period than an orbitee - if that's not the case you've got a big problem :)
2) Use a "constant acceleration" approximation (i.e. a Taylor expansion) to approximate orbits whose period is much longer than the intercept time. In the example below (assuming Sol is not moving), when aiming at Luna you would not model Earth's motion as a circle. Instead you'd calculate Earth's velocity and acceleration. (I would calculate them relative to Sol, then add in Sol's velocity and accel to get a total. This is because, relative to Sol, they'll always have the same magnitude and simply have different directions.) You'd then approximate Luna's motion as a circle orbiting a object moving along a parabola. The reason for doing this is that a) it makes the math easier and b) it's recursive - no matter how many nestings you've got, you're still always solving the same problem. This is simply a more sophisticated version of what you're doing right now, i.e. simply using the 0'th derivative (position) to approximate the correct course. When you get really close to the target (say an intercept time of less than Period/4), then you can approximate the targets motion too, at which point you're calculating an intercept to something with a simple parabolic path (i.e. intercepting a constant acceleration body).
3) Looking at the above, if the "circle around a parabola" problem is too hard, then you could just ignore the orbiting body until intercept time was less than Period/4, then pop over directly to approximating its motion with constant acceleration. So at that point the two changes to your existing algorithm would be a) ignore nested orbits until the intercept time drops to some fraction of a period and b) approximate all orbital motion as constant velocity (no accel) or constant accel, which allows you to use the same intercept code you'd use for ships.
4) Another thing I just thought of: when calculating the intercept time to see if you should igore a sub-orbit, I really meant "intercept time to the closest point on the orbital circle". In other words, you should use the motion of the central body, but subtract off the orbital radius from the distance to the central body (you should probably use this as the course target as well). This will keep you from getting falsely small time values if you happen to be inside the orbit of whatever you're chasing. So the real suggestion when ignoring inner orbits is to calculate the intercept to the motion (due to central body motion) of the closest point on the orbital circle to your current position.
The orbit calculations in Aurora are fairly easy as I cheat slightly :). Rather than work out objects moving in parabolas, I store the current bearing of each body from its parent body. Then, based on how much time has passed since the last orbital movement phase, I work out how far around its orbit the planet has moved (time since last move in seconds / orbital period in seconds). I multiply that result by 360 so I know the new bearing then just calculate the position of the body based on a line the length of the orbital radius drawn from the location of the parent body on the new bearing. Using this method, it is very fast to work out exactly where a moon orbiting a planet orbiting a star orbiting another star will be in a specified period of time (assuming you do all the bodies in the right order :))
I am now loading all system bodies into memory and orbital movement takes place during every sub-pulse. It's faster than I expected, much more accurate and looks cooler too :). A body won't move if the length of the time period means that its orbit changes by less than 1/10,000th of a degree.
For fleets, I now estimate the time taken to reach the target body, based on time required for acceleration from current speed to max fleet speed (if one is set), the time required for deceleration from there to the escape velocity of the planet and any time at top speed (which is sometimes zero because max speed cannot be achieved before deceleration must start). Then I work out where the planet will be after that amount of time and recalculate the fleet time of arrival using that new estimated planetary position as the destination. I run that cycle 10x and by the tenth time the estimated destination is changing by a very small amount.
However, a new problem arose despite the above. In some cases, the fleet was still chasing the planet and for the life of me I couldn't figure out why. After a few days of frustration it finally occured to me to check the speed at which the target planet (Earth in this case) was moving along its orbital path. It turns out to be 30 km/s. As the fleet was slowing to Earth's escape velocity of 11.2 km/s, Earth was moving away from it. The fleet would then speed up to catch Earth and repeat the cycle.
Which creates an entirely new problem, especially as the fleet could be approaching a body on a orbital path from any direction. The fleet would therefore be closing on the planet at different velocities depending on direction and that closing velocity would change during the approach as the planet moved on its curved path. Not to mention that a moon, its parent planet and the parent star could all be moving in different relative directions to the approaching fleet, which severely complicates any calculations regarding suitable approach speeds. Aaagh!
Therefore, instead of using a planet's escape velocity as the maximum speed at which a fleet can successfully enter close orbit, I think I will use the maximum speed of the planet through space plus its escape velocity. For example, that means that if you reach Earth at a speed of less than 41.2 km/s, you can enter orbit. In this case of approaching from behind the planet, this is perfectly reasonable in reality. In the case of approaching from ahead then I am breaking the laws of physics a little :). Of course, for moons this means including both the orbital speed of the moon and its parent planet, because for part of the moon's orbit its motion through space (from the perspective of a stationary observer - well stationary relative to the system anyway) it would be moving at a combined velocity of its own orbital speed and that of the parent planet. As you can imagine, this is more complicated for planets and moons orbiting the outer stars in a multiple system. Even given all that, I still think this is still a reasonable compromise given the horrendous maths involved in the alternative.
Because of this solution, I will compensate by also adding the motion of a moon/planet to the momentum of a ship that leaves orbit. This will require me to optionally display the current bearing and speed of all system bodies (including any motion from parent planets/stars) so that the player can see the tactical implications of leaving orbit at any given time. A combination of entering and leaving orbit could be used for slingshot maneuvers, which while unrealistic in some circumstances will at least provide the flavour of such manoeuvers and create an extra tactical dimension.
Steve
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Regarding discussions as to whether ships should be slower or new propulsion systems should be used, or kinetic weapons should work differently, etc.
For the first version of Newtonian Aurora, I am going to try and make things feel as realistic as possible, unless the math problems are just too horrible. This means the possibility of one shot kills. I don't want to start compromising this design goal of realism due to concerns of what will happen in the game. I can honestly say that I don't know how things will work out because there are just too many factors involved to make accurate assumptions. However, some points to consider.
From a stationary ship railguns are going to be fired at probably a max of 100 km/s for early tech levels. Assuming a stationary target as well, that impact damage could be withstood for strong shiels/armour. As kinetic strikes are calculated on closing speed rather than launch speed, you will do even less damage to a target moving away from you. Stern chases won't work out well for the railguns on the chasing ship. If you move fast to try to generate higher impact damage, the limited launch speed of the railgun projectiles means that you won't be able to generate much sideways delta-V. In other words, you will only be able to shoot at targets ahead of you. The limited muzzle velocities also means accuracy is a real issue at any significant range.
In other words, kinetic warfare is going to have a host of tactical problems before you can even hit anything. Lets see how it works out in practice before changing things to prevent a problem that might not turn out to be a problem. I believe tactics that we haven't even thought of yet will evolve to match the available weapons.
Steve
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The Steve has spoken. XD
A very good point of course is the accuracy. More powerful engines reduce the time taken to displace one ship length from current path (assuming no acceleration), which reduces effective railgun range and increases railgun damage. Which gives time for missiles to intercept approaching railgun ships.
Notes that in Transnewtonian Aurora, missile ships already get slaughtered by beams in beam range.
The only one I can think of being a problem is the fragmentation missile being dominating compared to nukes. Nukes could be better at planetary bombardment, but the fragment missile has standoff range as well as lower cost.
Fragment missiles (and suicide fighters) dodge the missile intercept problem since you don't plan to get it back and are cheap enough to launch in significant numbers.
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I don't remember seeing these questions before so if they have been asked sorry :-[
1. will their be weapon facings the reason I ask is because of the statement that the railgin will have a limited fire arch that will get smaller the faster the ship goes and that fact that ships have to turn to accelerate it would make this the logical progression in realism even if not implemented right now
2. can you target railgun shots if yes oneshot kills might not be so bad as you would end up with the same relationship as missile-AMM/pointdefence or in this case both sides using their railguns to shoot down or more likely deflect their opponents shots, after all any impact (unless it hits perfectly dead on) will generate some lateral velocity and knocking a shell a few millimeters to the left far enough away will generate a miss
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I think its been said that there wont be facings; the limited arc arises as a result of vector addition.
If your ship is doing 1000km/s on a bearing of 000 degrees (North), and your railgun has a launch velocity of 100km/s, then your arc of fire is 5.7 degrees to both sides of that (ie 11.4 degrees wide). This deviation would occur when 'firing' perpendicular to the line of travel, ie a bearing of 090 degrees. Anything beyond 090 would result in a smaller deviation, and a slower projectile relative to the ship (the perpendicular shot would keep pace with the ship northwards).
If youre only going at 200km/s, your arc of fire is now 26.6 degrees to both sides of your line of travel (total of 53.2 degrees). And so on. Its easy to calculate by finding the inverse tangent of the maximum railgun velocity divided by the ships speed.
An answer to your second question would be interesting.
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I don't remember seeing these questions before so if they have been asked sorry :-[
1. will their be weapon facings the reason I ask is because of the statement that the railgin will have a limited fire arch that will get smaller the faster the ship goes and that fact that ships have to turn to accelerate it would make this the logical progression in realism even if not implemented right now
2. can you target railgun shots if yes oneshot kills might not be so bad as you would end up with the same relationship as missile-AMM/pointdefence or in this case both sides using their railguns to shoot down or more likely deflect their opponents shots, after all any impact (unless it hits perfectly dead on) will generate some lateral velocity and knocking a shell a few millimeters to the left far enough away will generate a miss
There won't be weapon facings in the same way as SFB, so you won't have a forward facing weapon or a weapon that can fire to port, etc.. One thing I am considering is whether a ship should be able to accelerate and fire beam weapons in the same increment, or at least only accelerate for part of an increment. I might add a ship 'rotation rate', which is how fast it can bring weapons to bear on different bearings, or to switch back to the necessary bearing for main engine burn. There are no turrets at the moment in Newtonian Aurora. Adding them would allow a ship to ignore its rotation rate and to fire weapons and accelerate during the same increment. The main reason for not doing this is that unless rotation rates are significantly slower than weapon recharge rates, they wouldn't have much impact.
One major decision I need to take is whether you can detect 1 kg railgun projectiles. Given their potential lethality I think navies would find a way to track them. I believe modern counter-battery radar can track shells in flight and predict their source so it is certainly possible. It's just whether it is possible at sufficient range to be useful.
Steve
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Its easy to calculate by finding the inverse tangent of the maximum railgun velocity divided by the ships speed.
And this statement tells you all you need to know about the Aurora demographic :)
Steve
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You know how many people who play regular games like World of Warcraft of Final Fantasy are called nerds?
Aurora fans appear to be some ascended super variety that is able to harness the power of showing your work combined with reasoned intellectual debate to turn into something I am not sure English actually has a word for.
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OK on the facing i just had a vision of a stoped ship firing it's broadside at an accelerating ship and the damage getting progressively greater as the moving ship got faster. ;D
for the shells, grav sensors can find a ship with a relatively low speed and grav signature so even tho the shell is smaller it's greater speed would probably generate a bigger signature, faster the shells the further their seen, this would also allow players to deflect drive by shooting of planets with def platforms/ ships (or every planet targeted would die in the first fight)
edit: this would make for an intresting choice between firing faster/ more damaging but easier to detect shells over slower/ harder to see shells that are less likely to be intercepted
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Easier to detect also means they are faster on the target, so if that detection is simplified, you'll essentially have a tech line with "detection X seconds before impact" as an improving constant, no matter how fast the projectile.
It should be limited to a certain range, though.
I think Turrets are a good idea for countering projectiles, but in direct ship-ship combat, they will have little use.
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I'm not sure that detecting incoming projectiles, even small ones, would be that difficult. Any projectile that is a danger to the ship will be on a constant-bearing, decreasing-range course. That means you only have to worry about objects that stay at one bearing, or move slowly. I'd imagine that a filter for those parameters could increase detection range significantly. Or to put it another way, there is a physical explanation for any special treatment given to projectile defense as opposed to general detection.
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And from a purely defensive posture, beam weapons would be ideal for defense against the "killer kinetic". A laser will be operating at speed of light, so hitting something on a closing bearing is computationally possible. And it would not need to "kill" the projectile, even a glancing hit would cause the projectile to heat and lose mass in reaction. Obviously the further away you engage, the better, but at the speeds your talking about, a few degrees of adjustment to the path of the projectile will generate a miss.
Combat in Newtonian Aurora is a LOT like WW II sub warfare, and it doesn't take much in terms of speed or course adjustment to screw up a shot. :)
A perfect shot IS a one shot kill. But torpedo spreads were fired to allow for changes in course and bearing from the target.
Similarly, constant speed and bearing in Newtonian is going to make it much easier to hit with unguided munitions (or missiles for that matter). Throw in some constant course changes and speed changes, and your targeting solutions get MUCH more complicated. Downside is your burning reaction mass to do so.
If your going for realism, I think it would be very likely that warships would be entering a potential battlespace with exactly that in mind. They would be burning reaction mass to do constant speed and course changes to make it that much more difficult to put together and accurate intercept.
With the initial speeds Steve is talking about for kinetic weapons, your pretty assured that they are going to be fairly short ranged due to those variables. Beam weapons operating closer to the speed of light are going to be more effective at range from a hitting perspective, but they aren't going to be carrying the kind of energy potential that the kinetics will.
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Similarly, constant speed and bearing in Newtonian is going to make it much easier to hit with unguided munitions (or missiles for that matter). Throw in some constant course changes and speed changes, and your targeting solutions get MUCH more complicated. Downside is your burning reaction mass to do so.
I'll almost certainly be adding some type of optional automated random course and speed change, where you can specify how often and to what extent they take place. The cost will be fuel and added travel time. I can't overestimate how important fuel is going to be in this game.
Steve
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Given the expected lethality of kinetic weapons it does seem to me that we need a better way of defending ships. As already mentioned the US have deployed a land based version of their CIWS system to shoot down incoming rockets, mortars and artillery in high risk areas in Afghanistan. Given the need to deal with atmospherics I could happily see an evolution of this tech to shoot down incoming ordnance. It's really then a matter of how far they will need to be able to see to react and engage.
From a bit of an internet trawl I've seen contact to kill times of 5.5 seconds for a goalkeeper system which is a pretty old piece of kit. Maybe a reaction time of 2 seconds dropping to 1 with increased tech would therefore be reasonable for Aurora. Assuming a worse case closing speed of say 12k kms that gives a required detection range of say 25k km. That does not feel too bad to me for a 1kg slug.
One other thing I noticed with the CIWS was that the heaviest in operation today is about 10 tons. Admitidly it still needs some power but I would think that anti kinetic CIWS could be substantially smaller than those in the game at the moment, allowing all ships to field several each. This makes it harder to get a munition through but once you do it counts.
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Just been thinking about turrets and how they could benefit a ship.
As I understand it, at the moment guns have a targetting error due to an assumed mix of errors in sensor and the accuracy of the gun itself / lens jitter. I would think that these errors would be compounded by the effects of being under thrust and the need to aim by moving the whole ship.
Turrets can address these issues by creating more stable platforms from which to shoot. For lasers especially this could have a significant impact on effective range of the weapons. You could therefore have a turret tech that increasingly reduced the impact of thrust and movement on overall accuracy.
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re projectile defence:
You are forgetting the fragmentation missile. Railguns on ships slugging it out like in TN Aurora aren't what I would expect to see.
It's the missiles that close at 4x ship standard velocity and turn into a cloud of a few thousand 1kg pellets. It has the same effective ranges as a railgun but the ability to salvo missiles and the payload of each missile will result in sheer saturation overwhelming any anti-pellet point defence.
Of course, you can always use antimissiles. But the same applies to closing ships. Anti-antimissiles are easily possible (as are PD dedicated suicide fighters as missile escorts)
And this statement tells you all you need to know about the Aurora demographic :)
What? It IS easy. Anyone who can't do geometry might as well not play. =P
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I think that the defense and lethality envelops SHOULD be a bit more "iffy" and not so black and white. Starfire did an excellent job of showing how combat, tactics, and designs changed as the technology shifted (yes it got silly twoards the end, so did SFB).
To that point, anti-missile work, and anti-kinetic work are NOT the same thing.
Missiles are much easier to detect, since they are burning reaction mass and generating heat. Missiles are also relatively fragile constructs. Any beam/missile/kinetic hit is likely to cause significant damage to a unarmored missile. Blinding the missiles tracking or sensors, penatrating the skin and damaging the explosive payload, or causing catastrophic heating will all give a mission kill on a missile.
Kinetic weapons are tougher kills. They are much smaller, much harder to detect, and much tougher. Kinetics are inert bricks, so destroying/deflecting them is much tougher. It would take a lot more energy (kinetic/beam/handwavium ect) to get a mission kill on a lump of metal.
Frag missiles give the shotgun approach like the old torpedo spreads used in WW II. They wont all hit buy something MIGHT hit. Even with that, since Steve has already said that closure speeds will dictate impact damage, turning away from ANY missile shot is going to be a good idea.
For that matter, just to touch on geometry. SHIP geometry would be an interesting issue as well. Realistically, a ship would want to present the smallest possible cross section to a hostile ship to minimize is potential to be hit. For a traditional "rocket ship" this would be the nose and stern of the ship. Both of which are actually bad places to get hit. Bow shots mean your closing, and increased closure rates equals increased lethality. It also means that your presenting more of the ship internals to a penetrating hit, since a bow hit would punch through the length of the ship.
Presenting the stern is the same issue. Shots striking the stern have a lessend closure rate, but increased likelyhood of a maneuver kill on the ship. Penetrating shots will almost certainly wreck the propulsion systems, and also get the plunging fire through the decks of a bow shot.
A flattened wedge or something similar might actually work better, from a broadside perspective, since it would minimize penetration through the decks.
Might be harder to code, but I think realistically, you would see exactly that kind of thing in those ship designs. Presenting minimized cross sections to the enemy would be the rule of thumb when your talking the kind of hitting power these weapons would have.
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In a theoretical optimally designed rail gun a solid slug is effectively in free fall and could survive any amount of acceleration. The electromagnetic acceleration is distributed evenly throughout a conductive round as a body force, accelerating every atom in about the same direction at about the same rate. Any compressive/shear forces in the object would be small, sort of similar to how satellites in orbit are constantly accelerating but practically weightless. In Newtonian Aurora rail guns appear to be much closer to their theoretical potential than the modern prototypes of today.
The usual reason high Gs are fatal is that they are resulting from contact forces. The atoms in back are getting pushed into the atoms in front to propagate the force. As a result the inertial forces from the atoms in front trying to stay at rest (or the ones in back trying to stay in motion) generate internal forces compressing/pulling/shearing the object.
Touched on this a few (ok, maybe 30ish...) pages back. Action/reaction. You are sending the slug out at a substantial velocity. Doesn't matter whether it is pushed, pulled, slid, slipped, etc. It is aquiring a large amount of momentum in a very short period of time. This is acceleration.
As for it being applied in equal amounts to all the atoms, gravity is the most even force we have. It will be far more uniform than any railgun acceleration (that I can forsee). Place a material under a G load in excess of its bearing strength and it will fail. Check out what happens to bridges that are poorly engineered.
And at the accelerations we may posit for the high end railguns - if you were to mount them in a smaller ship (ie small time of acceleration to acheive velocity), and you may be approaching G levels capable of generating degenerate matter.
And on the matter of the NA demographic, I see that as a compliment.
The fact that my wife thinks that a popular TV show about overly intellectual individuals is based on the people in this thread is completely beside the point... ;)
And on kinetic kill defense...
I and some associates have actually been discussing this one at length.
Modern radar can track lots of objects that don't ever make it onto a screen. It won't display all the returns from birds, etc, as they don't pass certain parameters. The displays only show objects moving with velocities exceeding certain speeds/return signatures/etc. I am not an expert on radar, but I expect the dopler shift on an incoming projectile moving at hundreds or thousands of km/s would give it a rather distinct signature. How far out you can detect it is beyond me, but it should be obvious if you have an object closing at that velocity.
Problem is stopping something with the kinetic energy of a small nuke. So far the best solution we have come up with sounds more like a karate proverb about using your opponent's strength against them. The laser hitting a slug would have an easy time striking, but a hard time deflecting enough in the short time needed to stop a hit. But even a grain of sand far enough from the ship could cause the slug to turn into a ball of plasma - and could stop it.
Missiles would be poor for this as the time to accelerate would be inadequate to reach adequate standoff distance (I think, it depends on detection time). But a mass driver projectile could be hundreds of meters from the ship firing it. That would be adequate to disperse the 'energy/blast'. If a mass driver was to fire - instead of a solid slug - a 'packet' of tiny projectiles of even perhaps a hundredth or less of a gram, it could disrupt the incoming weapon. Your railgun could also act as its own defense.
The chance of intercepting an incoming slug could be based on the mass of the slug fired by the railgun. Small slug (fewer projectiles) equals lower intercept chance. Heavy slug gives a higher chance of successful intercept due to saturation of the target area. Might not help against a thousand inbounds that will hit your ship, but if the shrapnel has that tight a spread it will be easier to avoid. If they spread the shrapnel out to better cover a target area, it will be easier to intercept the few inbound projectiles.
It would also make larger payload railguns more useful (perhaps, or at least more versatile) than smaller slug, higher velocity railguns.
Thoughts.....
So far this is just a concept in the initial stages, and could undoubtedly use some outside thoughts/improvements. But it is the best we have come up with to stop the one shot kill railgun.
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Place a material under a G load in excess of its bearing strength and it will fail.
Only happens to objects not in free fall. A uniformly accelerated railgun slug (source doesn't matter) is in free fall while in the tube.
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Free fall is not a free ride.
Check out what the Rouche Limit is. If free fall was without hazard, then this wouldn't exist.
Acceleration beyond bearing strength will cause failure.
And it isn't free fall. The slug is being accelerated by the ship. How that acceleration is applied is not at issue. It is undergoing acceleration. Whether the ship is pushing/pulling the projectile or both, it is applying force to the object to impart momentum. The projectile will have to deal with this load.
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But I am willing to 'suspend disbelief' in this case as I love the concept. Of course if we can make materials with load bearing strengths a million times their own mass, orbital elevators would be easy.
The material would also make some INCREDIBLE armor as the tensile strength would make the armor Steve has listed look puny.
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Ultimately, both armor and slugs might be forcefields containing pure energy.^^
Somewhere, not to many billion years in the future, in a galaxy not far from here...
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Ultimately, both armor and slugs might be forcefields containing pure energy.^^
Somewhere, not to many billion years in the future, in a galaxy not far from here...
I looked at this and kind of chuckled.
And then I sat and thought about it. Hmmm....
And decided I really kind of like the idea. Maybe a bunch.
In that the whole physics of force fields is kind of poorly defined (perhaps not a bad thing...), it could solve a lot of problems with the railgun as it stands. It wouldn't have to contain energy, as the energy could just be the field used to hit a target.
1. Having a field based projectile would allow unlimited ammo.
2. Would alleviate the 'looking the other way' that the ammo would have to survive launch. If it has no actual material component, it won't have to worry about tensile strength.
3. Would not have to detonate on impact. Could maintain integrity as passing through a ship (or not, however you want it...)
4. Could be given an arbitrary max range as the field disipates after a set amount of time.
5. May not have to hit with the force of a nuke. If it only contains so much energy and is a field/wave phenomena - it will only deliver so much energy regardless of relative velocities.
6. Would be more easily detectable as an active emmission source.
The more I look at this, the better I like it. Alot.
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It won't solve the problem of a shrapnel missile, but those missile will take time to get up to speed, should be more easily detected, and more readily destroyed/evaded. A shrapnel missile won't be a whole lot more dangerous than a nuke. It pretty much boils down to the fact that if you let a missile through your defense - its game over for that ship...
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Call me stupid but i can only find the "Roche limit" online and it applys to the destruction of planetary bodys by tidalforces from another massive body overcoming the first bodys internal gravity. I dont see how that applies to a Projectile if we assume it would be accelerated evenly where tidalforces (due to the involved object sizes and the nature of gravity) are uneven.
If there is a "Rouche Limit" i would like to have a link to it. I mean i can be wrong too.
You can assume that a railgunslug desintegrates if its accelerates to fast against its own inerta either by overcomming the tensile (drawing) or Bulk (pushing) limits maybe shearing too -this would only happen if you apply the accelerating force in a way that the railgunslug is accelerated unevenly, say by applying the force only to one surface/side/part of the slug. This effect is know from highpower x-bows where the string hitting the arrow/bolts shattered the projectile - because of this people changed to bullets from metal stone and ceramics.
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Free fall is not a free ride.
Check out what the Rouche Limit is. If free fall was without hazard, then this wouldn't exist.
Acceleration beyond bearing strength will cause failure.
And it isn't free fall. The slug is being accelerated by the ship. How that acceleration is applied is not at issue. It is undergoing acceleration. Whether the ship is pushing/pulling the projectile or both, it is applying force to the object to impart momentum. The projectile will have to deal with this load.
I find Roche limit has little in common with a railgun slug. The propelling of that slug is analogous to freefall in that we can suppose the force applied is uniform, and not a contact pressure. A bridge is subject to gravitational acceleration, yet is not itself accelerated, since its supports resist the weight of the whole structure (and can fail/break). That's not freefall. In the slug, there's no part that supports the applied acceleration of the rest, so the whole is accelerated without tensile, buckling or shear involved, assuming the railgun is well designed and propel the slug straight out of the muzzle.
With a gun, the bullet is propelled by an explosion applying a pressure to its base surface. If your charge was too big, the bullet could crush itself, not from the acceleration, but from the internal stress applied to its base. Same with a human body in a rocket accelerating too much, the body is pushed by direct contact from the seat and internal organs could be crushed together, since they're not held very well inside the body. That is not the case for a railgun, thanks to uniform force.
Of course, one could argue that the force applied by a railgun to its slug isn't exactly uniform. Then is it significantly localized? And can very high technology improve the uniformity?
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Of course, one could argue that the force applied by a railgun to its slug isn't exactly uniform. Then is it significantly localized? And can very high technology improve the uniformity?
I think this was the point. Is the EM force that accellerates a railgun slug applied at the surface, or uniformly throughout the body. For example, I was surprised to learn the other day that inductive heating depends critically on the skin depth of the material to be heated (not just conductivity/resistivity) - apparently the power absorbtion rate goes like the inverse square of the penetration depth of the radiation. It makes sense that the same effect would happen in a railgun, since both effects should be due to eddy currents. So in addition to the physical limit procyon talks about, there might also be a "how hard can I accellerate the slug before the skin vaporizes from the eddy currents" effect too (which is actually almost the same thing).
That being said, I don't think it really matters - I think the physical properties of what exactly is getting accellerated how are the sort of thing to abstract away in the game design - as long as the game mechanics are internally consistent I think this falls into the category of "TN materials have better properties".
John
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The skin evaporating into plasma wouldnt be a problem, the plasma itself would act as conductor and accelrate the (now slighly smaller) slug along the path. Iirc you can have a noncuductive not sabboted slug if you add a piece of cooperwire to its rearend. The wire would naturally evaporate but the projectile would ride on the plasma-arc. Take it with a grain of salt that i cant find the article where i did read that.
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And on kinetic kill defense...
I and some associates have actually been discussing this one at length.
Modern radar can track lots of objects that don't ever make it onto a screen. It won't display all the returns from birds, etc, as they don't pass certain parameters. The displays only show objects moving with velocities exceeding certain speeds/return signatures/etc. I am not an expert on radar, but I expect the dopler shift on an incoming projectile moving at hundreds or thousands of km/s would give it a rather distinct signature. How far out you can detect it is beyond me, but it should be obvious if you have an object closing at that velocity.
Problem is stopping something with the kinetic energy of a small nuke. So far the best solution we have come up with sounds more like a karate proverb about using your opponent's strength against them. The laser hitting a slug would have an easy time striking, but a hard time deflecting enough in the short time needed to stop a hit. But even a grain of sand far enough from the ship could cause the slug to turn into a ball of plasma - and could stop it.
Missiles would be poor for this as the time to accelerate would be inadequate to reach adequate standoff distance (I think, it depends on detection time). But a mass driver projectile could be hundreds of meters from the ship firing it. That would be adequate to disperse the 'energy/blast'. If a mass driver was to fire - instead of a solid slug - a 'packet' of tiny projectiles of even perhaps a hundredth or less of a gram, it could disrupt the incoming weapon. Your railgun could also act as its own defense.
The chance of intercepting an incoming slug could be based on the mass of the slug fired by the railgun. Small slug (fewer projectiles) equals lower intercept chance. Heavy slug gives a higher chance of successful intercept due to saturation of the target area. Might not help against a thousand inbounds that will hit your ship, but if the shrapnel has that tight a spread it will be easier to avoid. If they spread the shrapnel out to better cover a target area, it will be easier to intercept the few inbound projectiles.
It would also make larger payload railguns more useful (perhaps, or at least more versatile) than smaller slug, higher velocity railguns.
Thoughts.....
So far this is just a concept in the initial stages, and could undoubtedly use some outside thoughts/improvements. But it is the best we have come up with to stop the one shot kill railgun.
How about sandcasters? Originally a defensive weapons system from Traveller, the original concept was a low velocity weapon throwing out a canister of common sand. A bursting charge destroyed the canister and dispersed the sand. In that system, it was to defend against lasers, but when you consider the velocities that are being discussed here, it would work fairly well against any high velocity system.
At sufficient speeds, running into sand particles is just like running into a brick wall.
For that matter, if you had a good aggregate of powder sand up to small stones, it would work pretty well against any of the weapon systems discussed. You would still have stuff penetrating, but their would be an effect. Small stones in the path of a missile running 30,000 km/s is going to play hell with that missile.
Dispersion from the bursting charge is going to eventually spread the screen out, and the velocity of the firing ship is going to carry it past the screen rapidly. BUT if you dropped them along the bearing of the enemy firing at you, where you GOING to be, they could be fairly effective.
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How about sandcasters? Originally a defensive weapons system from Traveller, the original concept was a low velocity weapon throwing out a canister of common sand. A bursting charge destroyed the canister and dispersed the sand. In that system, it was to defend against lasers, but when you consider the velocities that are being discussed here, it would work fairly well against any high velocity system.
At sufficient speeds, running into sand particles is just like running into a brick wall.
For that matter, if you had a good aggregate of powder sand up to small stones, it would work pretty well against any of the weapon systems discussed. You would still have stuff penetrating, but their would be an effect. Small stones in the path of a missile running 30,000 km/s is going to play hell with that missile.
Dispersion from the bursting charge is going to eventually spread the screen out, and the velocity of the firing ship is going to carry it past the screen rapidly. BUT if you dropped them along the bearing of the enemy firing at you, where you GOING to be, they could be fairly effective.
I've thought about similar things, both for this application, and for destroying laser mirrors. The laser mirror application turned out to be quite practical, but I'll have to do the math on the anti-kinetic use.
As to the viability of railguns, both sides are correct. If the projectile could be accelerated entirely uniformly, then it would be possible for the projectile to undergo arbitrary accelerations. However, something like the Roche Limit (which only applies to orbital bodies, due to tidal forces) will apply if "tidal forces" are present for whatever reason, either due to non-uniform force application, or due to non-uniform fields. I'm not sure how assumptions like uniform charge distribution will hold up in these cases. It could be that the electrons are physically ripped out of the material. I also think that non-uniform fields will be a problem. Normally, one can assume that, for example, the field inside a solenoid is uniform, but I'm not sure about it in this case.
The above comments can be taken about any for of kinetic launcher, be it railgun, coilgun, gravdriver, ram cannon, or what have you.
As for the specific case of railguns, I'm really skeptical. They generally rely on physical contact with the rails, and good luck with that at 100 km/s.
And please, no force fields. I do like the doppler radar idea, though.
Edit:
I've done some very rough math on the sandcaster thing. I could be entirely out to lunch on how I went about it, but it should at least be a starting point.
Assume a grain of sand (Silica) impacts a tungsten projectile at 200 km/s. The grain has a diameter of .5 mm, and a mass of 1.73e-7 kg.
It should produce a total impulse of about 24 N*s, and a force of about 57 MN.
Please take these numbers with a very large grain of salt. However, I do believe that they should be indicative of the order of magnitude that we're dealing with.
My conclusion is that it while a grain this size should be able to shatter or deflect the target projectile, I'm not sure if it is possible to achieve the required particle density. To cover an area against a projectile that has a diameter of 2 cm will take 3183 particles/m^2 (assuming perfect distribution) and will take about .55 grams/m^2. However, I'm not sure you could accurately disperse that many particles, and then, how do you get them to stop dispersing?
Also, remember that the fragments of the projectile in question are still out there, and heading for your ship. The main advantage to this is that the projectile is neither a long rod, nor guided anymore.
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I've thought about similar things, both for this application, and for destroying laser mirrors. The laser mirror application turned out to be quite practical, but I'll have to do the math on the anti-kinetic use.
As to the viability of railguns, both sides are correct. If the projectile could be accelerated entirely uniformly, then it would be possible for the projectile to undergo arbitrary accelerations. However, something like the Roche Limit (which only applies to orbital bodies, due to tidal forces) will apply if "tidal forces" are present for whatever reason, either due to non-uniform force application, or due to non-uniform fields. I'm not sure how assumptions like uniform charge distribution will hold up in these cases. It could be that the electrons are physically ripped out of the material. I also think that non-uniform fields will be a problem. Normally, one can assume that, for example, the field inside a solenoid is uniform, but I'm not sure about it in this case.
The above comments can be taken about any for of kinetic launcher, be it railgun, coilgun, gravdriver, ram cannon, or what have you.
As for the specific case of railguns, I'm really skeptical. They generally rely on physical contact with the rails, and good luck with that at 100 km/s.
And please, no force fields. I do like the doppler radar idea, though.
Edit:
I've done some very rough math on the sandcaster thing. I could be entirely out to lunch on how I went about it, but it should at least be a starting point.
Assume a grain of sand (Silica) impacts a tungsten projectile at 200 km/s. The grain has a diameter of .5 mm, and a mass of 1.73e-7 kg.
It should produce a total impulse of about 24 N*s, and a force of about 57 MN.
Please take these numbers with a very large grain of salt. However, I do believe that they should be indicative of the order of magnitude that we're dealing with.
My conclusion is that it while a grain this size should be able to shatter or deflect the target projectile, I'm not sure if it is possible to achieve the required particle density. To cover an area against a projectile that has a diameter of 2 cm will take 3183 particles/m^2 (assuming perfect distribution) and will take about .55 grams/m^2. However, I'm not sure you could accurately disperse that many particles, and then, how do you get them to stop dispersing?
Also, remember that the fragments of the projectile in question are still out there, and heading for your ship. The main advantage to this is that the projectile is neither a long rod, nor guided anymore.
Ok, I cheated a bit and Googled this since I am at lunch. The number I found were running around 8,000 grains per cm3. So, from a particle density perspective, you have the requisite number of particles and in a reasonably sized packaged (1xcm3). So, the issue is going to be dispersion. Any bursting charge is going to scatter the particles quickly, even a low powered charge. So the question is really, how fast the charge disperses the particles to fill a m^2 and how long the density is high enough in that m^2 to provide an effective defense. I would thing seconds at best, unless the size of the sand charge is larger.
Assuming a cubic centimeter weighs about 3 grams, you could pack a much large volume of sand per canister, plus the bursting charge. So, say 10 grams of sand + bursting charge per canister? That would be fairly compact from a delivery perspective. The question would be area of coverage and duration before dispersion renders it useless.
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If you wanted to go that route, an alternative to explosive bursting would be mechanical dispersion, along the lines of certain submunition weapons which disperse through centrifugal forces. This would probably rule out these being launched through railguns; they would probably require their own launcher system, but delivery would be much more uniform/even/predictable (although more limited in terms of range, due to the slower launch speed).
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I think speed of delivery would be an issue, hence the bursting charge idea. But your right, it wouldn't have to be particularly fast or large. Ideally though, the farther out you can push the screen, the better the chance of causing a miss.
Even if the screen doesn't destroying an incoming, if it causes just a few degrees of deflection, than the longer the distance traveled from the interception, the better the chance the projectile will miss.
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Made redundant by other replies I did not read.
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Ok, I cheated a bit and Googled this since I am at lunch. The number I found were running around 8,000 grains per cm3. So, from a particle density perspective, you have the requisite number of particles and in a reasonably sized packaged (1xcm3). So, the issue is going to be dispersion. Any bursting charge is going to scatter the particles quickly, even a low powered charge. So the question is really, how fast the charge disperses the particles to fill a m^2 and how long the density is high enough in that m^2 to provide an effective defense. I would thing seconds at best, unless the size of the sand charge is larger.
Assuming a cubic centimeter weighs about 3 grams, you could pack a much large volume of sand per canister, plus the bursting charge. So, say 10 grams of sand + bursting charge per canister? That would be fairly compact from a delivery perspective. The question would be area of coverage and duration before dispersion renders it useless.
The density would be about half that, unless you're using something like iron for the payload. And my impression of this was that you'd want enough particles to cover the entire ship, at minimum, so a few grams isn't going to be enough, unless you can launch a bunch of canisters.
Mechanical dispersion would work well. Release the sand as the projectile spins up to get a nice velocity gradient.
I think speed of delivery would be an issue, hence the bursting charge idea. But your right, it wouldn't have to be particularly fast or large. Ideally though, the farther out you can push the screen, the better the chance of causing a miss.
Even if the screen doesn't destroying an incoming, if it causes just a few degrees of deflection, than the longer the distance traveled from the interception, the better the chance the projectile will miss.
Even if the projectile still hits, its effectiveness as a penetrator has been destroyed.
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As to the viability of railguns, both sides are correct. If the projectile could be accelerated entirely uniformly, then it would be possible for the projectile to undergo arbitrary accelerations. However, something like the Roche Limit (which only applies to orbital bodies, due to tidal forces) will apply if "tidal forces" are present for whatever reason, either due to non-uniform force application, or due to non-uniform fields. I'm not sure how assumptions like uniform charge distribution will hold up in these cases. It could be that the electrons are physically ripped out of the material. I also think that non-uniform fields will be a problem. Normally, one can assume that, for example, the field inside a solenoid is uniform, but I'm not sure about it in this case.
The above comments can be taken about any for of kinetic launcher, be it railgun, coilgun, gravdriver, ram cannon, or what have you.
As for the specific case of railguns, I'm really skeptical. They generally rely on physical contact with the rails, and good luck with that at 100 km/s.
And please, no force fields. I do like the doppler radar idea, though.
Thanks, Byron. You touch on one of the two points I would make
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No 'force/information' can be transmitted faster than c. This means that the impulse from a railgun will have a tidal effect as it begins acceleration. As the rails begin the impulse to launch the slug the wave of force will travel in a wavefront as it imparts its momentum to the slug. This force will create a sheer of around a quarter million Gs to the material. Try and find one that will survive and you will be rich.
Number two, even if you could somehow cheat Einstien and create an 'instant' effect on the projectile, you would need a launcher will 0% error in distribution of force. If the launcher has even a tiny fraction of a percent mal-distribution of its force you will see an immense load on the projectile. In that no known material does not deform under a load, the launcher will have an associated yaw/pitch/occilation associated with the launch. The finest weapons available today under lesser loads will occilate within a minute of arc under stress. That will be more than enough with the Gs we are talking about to disintegrate any known material. If your railgun is a few kms long this could be overcome as you lessen the Gs required.
EDIT
And as number three, it doesn't matter how you look at from the push/pull/whatever point of view, or how even this energy is distributed, you are moving this material in one direction. Ie - you are applying a FORCE to it to accomplish work. As in work/force/distance. This force is beyond immense and will overcome this objects binding strength/tensile strength/etc/ad nauseum. It will be destroyed.
EDIT
On the thought of sandcasters, I remember them from Traveller. A mechanical distribution would be ideal, but it all depends on how you intend to launch the 'barrel of sand' and how far out it will be able to interdict an incoming projectile.
Another issue is how accurate your 'interceptor' will be. If a high level of accuracy is possible, then you wouldn't have to disperse the 'sand/particles' until you were relatively close to the target and a high saturation would be possible.
How viable any method will be and how it will need to be delivered is probably going to be determined by how far out you can detect the incoming slug. Long lead times will give you a wide variety of options. Short reaction time will require that you use a fairly high velocity interceptor.
EDIT
Of course it occurs to me that if you have a long lead time and can see it coming a long ways out, you could just move out of the way... ::)
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And as number three, it doesn't matter how you look at from the push/pull/whatever point of view, or how even this energy is distributed, you are moving this material in one direction. Ie - you are applying a FORCE to it to accomplish work. As in work/force/distance. This force is beyond immense and will overcome this objects binding strength/tensile strength/etc/ad nauseum. It will be destroyed.
Ok, I suppose a somewhat better illustration would be appropriate. After a short chat with a colleauge he pointed out perhaps that some may not understand what I am seeing.
You can accelerate this slug evenly -that is not at issue. It won't matter.
Assuming perfect distribution (not possible), you will be accelerating every particle in this slug. EVERY PARTICLE. Not just a solid object - but every last proton/neutron/electron. Your acceleration is going to exceed the binding strength of the atoms in the material. It won't behave as a solid, but as a mass of individual elementary particles being blasted along under incredible levels of energy. You will rip electrons from atoms, quite possibly pressing nuclei into contact with one another. Quantum Mech will not allow you to accelerate every particle in the exact same path. It will behave more as a gas/plasma under this level of energy. The only place you see this kind of energy is deep in stars or on collapsed remenants of them. What comes out the end of the rail gun is anyones guess.
But it probably won't look like what you put in it to fire....
EDIT
Sorry for this rant. As I said, I really like the idea of these guns and am willing to ignore physics on this one as it looks really cool. But it is also why I like the idea of the force field projectiles. If we include shields, they look to be the only 'projectile' that could survive being fired by one.
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Can you provide some numbers Procyon (and slides since i am more a visual type) i see now from where you are coming but cant comprehend the implications.
Anyway from a engineering point of view wouldnt it be sufficient to keep the charge/accelerating force just under the Roche limit and still get our fast shells by lengthening the rails? (or have rails that consist of "segments") . Or maybe just increasing the acceleration lineary so that the stresses stay low enought?
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End of shift (thank goodness, busy night. Five deliveries with three needing intervention in the NICU) so maybe tomorrow night I can dredge up the numbers. I am also trying to retype out my copy of part 27 for my fiction so I can get it posted between other things at work.
The biggest problem is the size of the ships. If treated as spheres then you limit the length of the rails to the diameter. This is much easier for Steve I am sure than trying to code for custom sized ships, etc. etc.
You have only so far of a distance to achieve a certain speed from a standing start, which requires a certain amount of energy. In this case it is a bunch.
In that Steve does this for free, I don't want to make this something he doesn't want to do, as I doubt anyone else will. If I have to deal with a spherical ship that should really be a fairly long skinny thing to house the rails, I am willing to deal with it. A ship with a rail gun capable of the energy we are talking about should probably be a whole lot larger/longer with any materials we know.
But I am also accepting that we will make >c movement so this detail is not a 'war stopper' as far as I am concerned. If it requires some intervention from the 'handwavium' in the weapon to 'suspend inertia' or some such that is fine with me.
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Even if the projectile still hits, its effectiveness as a penetrator has been destroyed.
With gigajoule energy ranges, I don't think penetration is the idea... In fact, I don't think I would even bother to make long rods for railgun shells. More like sandcasters set to detonate near the target. (what? If sandcasters can be launched from railguns, they can be used offensively)
Or a flat disk with the flat side perpendicular to movement.
We have the proposed problem of penetration and I certainly wouldn't want to risk wasting precious shot-energy. The penalty of hitting more armour squares isn't really a penalty, since we can easily afford to burn through more armour.
I mean, if the fragments hit and all the energy goes into the ship, it'll be more or less like a contact nuke.
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EDIT
On the thought of sandcasters, I remember them from Traveller. A mechanical distribution would be ideal, but it all depends on how you intend to launch the 'barrel of sand' and how far out it will be able to interdict an incoming projectile.
Another issue is how accurate your 'interceptor' will be. If a high level of accuracy is possible, then you wouldn't have to disperse the 'sand/particles' until you were relatively close to the target and a high saturation would be possible.
How viable any method will be and how it will need to be delivered is probably going to be determined by how far out you can detect the incoming slug. Long lead times will give you a wide variety of options. Short reaction time will require that you use a fairly high velocity interceptor.
A lot of that depends on how sophisticated the interceptor is. I see this as a minimum-tech method of shooting things down. A small launcher (railgun/coilgun) that fires it out at a couple km/s, an electronic fuze, and a spinner rocket system. Probably fire enough to lay a screen between you and the enemy.
EDIT
Of course it occurs to me that if you have a long lead time and can see it coming a long ways out, you could just move out of the way... ::)
Assuming the projectile in question isn't guided, of course. The sand cloud would remove any chance of a projectile being guided, which is its own advantage.
With gigajoule energy ranges, I don't think penetration is the idea... In fact, I don't think I would even bother to make long rods for railgun shells. More like sandcasters set to detonate near the target. (what? If sandcasters can be launched from railguns, they can be used offensively)
Or a flat disk with the flat side perpendicular to movement.
We have the proposed problem of penetration and I certainly wouldn't want to risk wasting precious shot-energy. The penalty of hitting more armour squares isn't really a penalty, since we can easily afford to burn through more armour.
I mean, if the fragments hit and all the energy goes into the ship, it'll be more or less like a contact nuke.
The fact that a projectile is a long rod has a very significant effect on penetration. A non-long-rod projectile will be disrupted by the whipple shield, and hit the main armor in a spray of fragments and plasma. Dangerous, yes, but with the sort of armor we're looking at, not terribly effective. A long rod will hopefully still have an intact section that can cleanly penetrate said armor.
Offensive sandcasters make good anti-laser warheads, but they'll just splat on the armor. At 200 km/s, the sand grain I used above dug about 5 mm into tungsten. (If my math is good. If not, it could vary quite a bit). The same goes for disks, though to a lesser degree.
And remember that a contact nuke is less efficient then a focused blast. You're intentionally making it more difficult to penetrate.
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The ships are only considered spherical for calculating active sensor cross sections and armor mass. Looking at the sample ships seems to indicate the descriptive length is 3.5x the spherical radius. For realistic railguns, it doesn't help.
When I pointed out that a theoretically optimal railgun shell is under uniform field acceleration, I first calculated how long the rails would have to be if the force was concentrated at one end. I guessed aluminum would be a good material since it is a good conductor with a high strength/weight ratio. Say, 400 MPa strength and 3000 kg/m3 density for a short, squat, 1kg cylindrical shell 50% longer than it is wide. If accelerated by a uniform pressure force on one end (one of the worst case situations) this round should withstand 138,000 Gs. However, even at that acceleration to reach 69 km/s the shell would need 50 ms and 1,760m long rails.
I spent maybe 10 seconds worrying at this length, before remembering that the sorium fuel has 10,000x the energy output of our nuclear missile warheads. Then I shrugged, tossed the math figuratively out the window, and declared that the Newtonian Aurora rail-guns appeared to be nearly theoretically optimal in design. Maybe the railguns are nearly optimal, maybe the shells use T-N materials themselves for better performance. It doesn't really matter either way. Newtonian aurora is operating a half step beyond what is theoretical possible. So what if a 100x acceleration increase is needed to make the rails fit inside a ship: compared to other game aspects a 100x improvement in material choice and/or field distribution over a suboptimal design with modern materials isn't much of a stretch.
No 'force/information' can be transmitted faster than c. This means that the impulse from a railgun will have a tidal effect as it begins acceleration. As the rails begin the impulse to launch the slug the wave of force will travel in a wavefront as it imparts its momentum to the slug.
It doesn't have to be an instantaneous change in acceleration. A ramp-up time to full acceleration is going to be essential to limit jerk and at least partial intrinsic to overcoming rail inductance. Ideally the ramp up time ought to be small compared to time spent accelerating, but a 1% ramp-up time (say 5e-6s) should be sufficiently small to avoid impacting final velocity. By comparison, the time required for light to cross the rail width is 2.2e-10s. I don't think light-speed tidal lag will be an issue.
Ok, I suppose a somewhat better illustration would be appropriate. After a short chat with a colleauge he pointed out perhaps that some may not understand what I am seeing.
You can accelerate this slug evenly -that is not at issue. It won't matter.
Assuming perfect distribution (not possible), you will be accelerating every particle in this slug. EVERY PARTICLE. Not just a solid object - but every last proton/neutron/electron. Your acceleration is going to exceed the binding strength of the atoms in the material. It won't behave as a solid, but as a mass of individual elementary particles being blasted along under incredible levels of energy. You will rip electrons from atoms, quite possibly pressing nuclei into contact with one another. Quantum Mech will not allow you to accelerate every particle in the exact same path. It will behave more as a gas/plasma under this level of energy. The only place you see this kind of energy is deep in stars or on collapsed remenants of them. What comes out the end of the rail gun is anyones guess.
Ok... quantum mechanics and sub-atomic physics is beyond me, but this doesn't seem quite right. Railguns are applied electromagnetics, so it should only be the electrons, and maybe protons, that get accelerated. Binding forces then allow us to assume it the individual charged atoms getting accelerated. This seems similar to ion thrusters, which accelerate individual charged attoms to nearly the same speeds over much shorter distances. I guess particle stripping might be a concern at realy high accelerations, but I'm uncertain if even newtonian aurora railguns are accelerating that fast.
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<...> The fact that a projectile is a long rod has a very significant effect on penetration. A non-long-rod projectile will be disrupted by the whipple shield, and hit the main armor in a spray of fragments and plasma. Dangerous, yes, but with the sort of armor we're looking at, not terribly effective.
Are you forgetting that ship speeds are on the order of a thousand km per second or so?
Even plasma is not particularly healthy, with armour at 100s of MJ and shells starting at GJ all the way up to TJ ranges.
A projectile vapourizing on your whipple shield is like a nuke going off right next to you. And we all know what happens when one does that.
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Another quick update:
When you leave planetary orbit (or if you launch missiles), your ships (missiles) will have the same momentum as the planet or moon from which they are departing. If their destination lies in the opposite direction they will have to overcome that starting momentum first. To aid in decision making, you can optionally display information about each system body on the system map. The four values are:
OS: Orbital Speed. This is the speed at which a body moves along its orbit, relative to its parent body, and this value will never change during the game.
MS: Maximum Speed. This is the maximum speed a body will move through space, based on its own orbital speed plus the combined speeds of its hierachy of parent bodies. For example, if a moon moving at 30 km/s is orbiting a planet moving at 10 km/s, which in turn is orbiting a star that is moving at 6 km/s, at one point in its orbit the moon will be moving through space (relative to the system primary) at 46 km/s. The maximum possible speed of the body will remain constant during the game
HD: Heading. The current heading of the system body relative to the system primary. If this is a planet orbiting the primary, its heading will always be equal to its bearing from the star + 90 degrees. However, a moon orbiting that planet will have a heading that combines the vectors of its own movement and that of the parent body. The heading will change as a planet or moon orbits.
AS: Actual Speed. The actual speed of the body through space on its current heading, relative to the system primary. For a planet orbiting the primary, this will not change. For a moon orbiting that planet, its speed will increase as its moves in the same general direction as the planet and then decrease as its moves in the opposite direction. For a moon orbiting a planet, orbiting a star that is orbiting another star, the actual speed will vary considerably during the game.
These factors are affected by whether orbital movement in general is turned on and also if asteroid orbital movement is turned on. Even if asteroid orbital movement is turned off and the orbital speed of an asteroid is therefore zero, an asteroid may have a non-zero max speed if orbiting a non-primary star. In that case, heading will change during the game and potentially actual speed as well (if the parent star is orbiting a second star that is in turn orbiting the primary.
Below is a screenshot of the inner moons of a gas giant. The gas giant is orbiting the primary star and is currently on a heading of 181 at an orbital speed of 5.4 km/s. Those moons on the left are moving in the opposite direction to their parent so their actual speeds are lower than their orbital speeds. Moons on the right are overtaking their parent as therefore have actual speeds greater than their orbital speeds. The current heading and actual speeds of system bodies could have significant impacts on play, especially in multiple-star systems.
(http://www.pentarch.org/steve/Screenshots/OrbitSpeeds.PNG)
Steve
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Cripes Steve, I thought learning to fly was a reasonably challenging past time for me but I can see now taking on NA is going to be far more of strain for the old grey cells!
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Are you forgetting that ship speeds are on the order of a thousand km per second or so?
Even plasma is not particularly healthy, with armour at 100s of MJ and shells starting at GJ all the way up to TJ ranges.
A projectile vapourizing on your whipple shield is like a nuke going off right next to you. And we all know what happens when one does that.
No, I'm not. I'm assuming that armor has a role at all, because if it doesn't, then we're into one-shot, and I thought it was agreed that that was not fun.
Steve really should bump the armor or lower ship velocity. Either way, the physical shape of the projectile will be important.
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Cripes Steve, I thought learning to fly was a reasonably challenging past time for me but I can see now taking on NA is going to be far more of strain for the old grey cells!
Yeah, I don't see this as a game for the faint of heart. You won't turn it on and be ruling the galaxy in an hour or so. I'm guessing I'll be lucky to figure out how to do anything at all in the first hours/day/week....
The ships are only considered spherical for calculating active sensor cross sections and armor mass. Looking at the sample ships seems to indicate the descriptive length is 3.5x the spherical radius. For realistic railguns, it doesn't help.
When I pointed out that a theoretically optimal railgun shell is under uniform field acceleration, I first calculated how long the rails would have to be if the force was concentrated at one end. I guessed aluminum would be a good material since it is a good conductor with a high strength/weight ratio. Say, 400 MPa strength and 3000 kg/m3 density for a short, squat, 1kg cylindrical shell 50% longer than it is wide. If accelerated by a uniform pressure force on one end (one of the worst case situations) this round should withstand 138,000 Gs. However, even at that acceleration to reach 69 km/s the shell would need 50 ms and 1,760m long rails.
I spent maybe 10 seconds worrying at this length, before remembering that the sorium fuel has 10,000x the energy output of our nuclear missile warheads. Then I shrugged, tossed the math figuratively out the window, and declared that the Newtonian Aurora rail-guns appeared to be nearly theoretically optimal in design. Maybe the railguns are nearly optimal, maybe the shells use T-N materials themselves for better performance. It doesn't really matter either way. Newtonian aurora is operating a half step beyond what is theoretical possible. So what if a 100x acceleration increase is needed to make the rails fit inside a ship: compared to other game aspects a 100x improvement in material choice and/or field distribution over a suboptimal design with modern materials isn't much of a stretch.
It doesn't have to be an instantaneous change in acceleration. A ramp-up time to full acceleration is going to be essential to limit jerk and at least partial intrinsic to overcoming rail inductance. Ideally the ramp up time ought to be small compared to time spent accelerating, but a 1% ramp-up time (say 5e-6s) should be sufficiently small to avoid impacting final velocity. By comparison, the time required for light to cross the rail width is 2.2e-10s. I don't think light-speed tidal lag will be an issue.
Ok... quantum mechanics and sub-atomic physics is beyond me, but this doesn't seem quite right. Railguns are applied electromagnetics, so it should only be the electrons, and maybe protons, that get accelerated. Binding forces then allow us to assume it the individual charged atoms getting accelerated. This seems similar to ion thrusters, which accelerate individual charged attoms to nearly the same speeds over much shorter distances. I guess particle stripping might be a concern at realy high accelerations, but I'm uncertain if even newtonian aurora railguns are accelerating that fast.
I pretty much decided the same thing on the math. If folks try to point out something patently false I have a bad habit of trying to correct their view. But for this game, it really shouldn't make so much difference. So long as we don't blatantly violate reality I am ok with it.
On the thought of railgun slugs, getting a rod to hit with the proper orientation is pretty remote - but shouldn't matter. If your close enough to guarantee orientation, you are dead too. But on how the damage is applied, I will accept whatever Steve codes. With the energy we will see, it won't make much difference unless it can pass through without a detonation. Otherwise the energy will just be too much. A rod hitting the whipple shield sideways just means that the ball of plasma that destroys your ship occurred a meter of so earlier than it would have if it had hit the hull.
Same with defenses and such.
The slug might be a solid object that is somehow engineered to survive launch. It might be a pure field that has an associated mass that is what the launcher is firing. It might be a field to contain the plasma created by launching the slug. Regardless, it will be a projectile moving at a certain velocity that will impart its energy to the target if it connects. If you see it as a solid slug, that is ok. If I see it as a field, not a problem. The effect in the game will be the same for all intents and purposes. Discussing how it works is fun, but not Steve's issue. In the end it just needs to be a projectile that is tracked and damages a target.
Same with the sandcaster. Tungsten dust, silica sand, table salt spilled in the galley, doesn't actually matter to the game. Fun to discuss the details, but for Steve it should just boil down to how fast it can intercept an inbound and how effective it will be. As your tech increases, it should get more effective. Whether better saturation, better interception accuracy, whatever it is wouldn't actually matter - just that it stops inbounds more effectively.
I love the discussions, but I don't want this to slow Steve down.
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No, I'm not. I'm assuming that armor has a role at all, because if it doesn't, then we're into one-shot, and I thought it was agreed that that was not fun.
Steve really should bump the armor or lower ship velocity. Either way, the physical shape of the projectile will be important.
Regarding discussions as to whether ships should be slower or new propulsion systems should be used, or kinetic weapons should work differently, etc.
For the first version of Newtonian Aurora, I am going to try and make things feel as realistic as possible, unless the math problems are just too horrible. This means the possibility of one shot kills.
Looks like it's going to be that way for first version at least.
Although I feel the need to mention that railgun damage depends on closing velocity and hence sometimes it will be useless (stern chase) and sometimes one-shot-kill (head-to-head fly by).
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Looks like it's going to be that way for first version at least.
Although I feel the need to mention that railgun damage depends on closing velocity and hence sometimes it will be useless (stern chase) and sometimes one-shot-kill (head-to-head fly by).
I can't speak for anyone else, but I'd far rather be hit by something blunt that explodes on the outside, then by something pointy that goes in. At the very least, the energy is spread over more armor area.
On the thought of railgun slugs, getting a rod to hit with the proper orientation is pretty remote - but shouldn't matter.
It's called a guidance system.
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I quite honestly don't care how several hundred gigajoule are spread over a spaceship, there won't by one left afterwards no matter what.
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I quite honestly don't care how several hundred gigajoule are spread over a spaceship, there won't by one left afterwards no matter what.
That depends on several things. For one thing (and this is poorly simulated by current Aurora, btw) hits will often pour on a lot of overkill. It may only take 100 MJ functionally destroy a system, but in death, the system might well absorb another 900. Another is that we're assuming a lot of advances, including materials science. With good enough armor, you could survive that sort of pounding.
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It may only take 100 MJ functionally destroy a system, but in death, the system might well absorb another 900.
This is a pretty good point. Since most systems are TN materials, we could increase the damage absorption of components to gigajoule range.
Would mean that systems need a way of tracking damage received and have a "disabled" threshold and a "destroyed" threshold. Destroyed systems would probably need a shipyard to fix while disabled could be fixed with maintenance supplies.
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Will there be any automatic logic to say "Hey, if you wait 5 days to launch, you can get there faster and/or expend less fuel?"
I know I'm looking forward to scheduling low-deltaV launch windows for cargo runs on the Earth-Mars route.
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If nothing else, it'd be nice to have a "delay until forecasted fuel consumption for next order is below 50% capacity"
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I dunno, I think it'll be interesting how peoples howitzers-at-ten-paces warship designs evolve. We might see ridiculous thrust ratios for generating misses. I don't know if that discussion about having structural ratings on ships wrt acceleration went anywhere in terms of Steve's design- it might be where all the design tonnage you used to put into armor goes :)
Let's not forget the RP possibilities. A multi-faction Earth game imposes many political limitations on warship design and objectives. Heavily armored orbital stations or warships designed to win orbital control in WW3, since it might start at a hair trigger. Ships designed to sit in the outer system and commit relativistic strikes on signal - solar MAD. RP'd treaties which prohibit same relativistic strikes.
I wonder... If railgun projectiles are actually tracked, as it were, could you put a parasite warship in between you and the cloud to eat the impact? Perhaps hangar space = armor :]
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I wonder... If railgun projectiles are actually tracked, as it were, could you put a parasite warship in between you and the cloud to eat the impact? Perhaps hangar space = armor :]
That is my plan for defenses for planets/facilities.
A small crowd of fighters with railguns/light nukes.
Disperse to destroy interceptible munitions.
Have interpose to stop leakers/uninterceptable.
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I must admit I didn't think of that. Then its a race to see whether interceptors are more expensive than munitions + fuel needed to get it there.
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Or, see if you can get interceptors moving fast enough directly away from the railgun munitions to reduce the damage to nothing.
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Wow, guys, dont you think this new Aurora goes far to difficult to play? I mean im already using windows calculator for sensors, but tanking railgun munition with fighters its just crazy you know
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There are two types of individuals in this world.
Those that rise to a challenge, and those that run from them.....
But this one will be a really big hurdle.... ;)
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Maybe I'm just a masochist, but when it comes to games like Aurora, the steeper the learning cliff, the better...
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To be honest I like it a lot in theory, and the discussions are fun to follow, but in practice i think I might find myself overwhelmed as well. We'll see.
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i can get a learning curve if some basic concepts are included
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Wow, guys, dont you think this new Aurora goes far to difficult to play? I mean im already using windows calculator for sensors, but tanking railgun munition with fighters its just crazy you know
That's just a crazy idea. Not at all complex, might not even be feasible.
Games aren't too complex until you have to solve three body problems. =) After that, ok, I might be willing to admit its too hard for me.
(You want your moon sized battlestation? Well, have fun predicting the impact of your parking orbit around the gas giant on the nearby moon or you'll be dealing with a moon-sized impact)
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(You want your moon sized battlestation? Well, have fun predicting the impact of your parking orbit around the gas giant on the nearby moon or you'll be dealing with a moon-sized impact)
How soon do you think Steve can include this in NA?
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Gravity is so far not included.
Neither will anyone realistically be building such a huge ship.
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is there anywhere to download newtrowinan aurora ?
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Once it's done, there probably will.
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and its not done yet so its not downloadable and given steves apparent time constraints im guessing end of year at least ah well ill keep putting ideas and comments on as he posts his dev blogs
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Extending the energy calculation a bit more:
Steve has said that the highest exhaust velocity will be just under c. For simplicity's sake, I will assume the highest is exactly c and calculate it from that.
1MN = accel 1ton at 1km/s/s
Minimum thrust modifier (0.1) = (4 ^ 0.1) / 4 = 0.287 fuel consumption modifier
2500ton engine = 2500/50 = 50% fuel consumption
At c exhaust velocity: 1litre (1kg) of fuel will require 300MN to reach c in 1 second (newtonian calculations)
300MN per litre per second = 1/300 litres per MN per second = 1/5 litres per MN per hour
Baseline tech: 1.39 litres per MN per hour (3s.f.)
1 litre of fuel moving at c = 45E15 J
Obviously, we're not about to stick a 2.5kton engine on a missile so fuel efficiency and thus exhaust velocity is going to be alot lower, but it looks like 0.8 c missiles might be possible end-game and if you really really want to do it, ships past the speed of light could be doable but inefficient.
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Given the calculations in exhaust velocity and energy values of fuel, I would like to resurrect the idea of relativistic missiles.
Please don't say that they are inefficient compared with nukes.
Relativistic missiles are faster: less reaction time
Cheaper: fuel is more plentiful compared to other things
More deadly: with 20% speed of light achievable by early-mid game and near-light at end, relativistic missiles make nukes obsolete past the first three or four tech levels.
They're also simpler, having no warhead at all. Engine and fuel, that's it.
You could even have one all-purpose missile. Fragmentation for anti-ship and anti-missile work. Disable detonation charge for anti-planet.
Won't be as efficient as it could be (anti-missile needs high accel, which has lower delta-v), but eh, logistics savings might be worth it.
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relatistivic missiles ofr the reasons u have outlined are reasonable well have to see if they make their way into game
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The biggest issue with flitting about at high fractions of c is acceleration. For tactical combat, I highly doubt that missiles will be used at long enough ranges to make those sort of velocities. Yes, I know they can pull much higher accelerations then humans can, but how much higher? Even at 1000 m/s, it will take a missile 83 hours to reach c, during which it will cover about 41 light-hours. That's an extreme case, but there is a limit to how much acceleration an object can take, particularly when supported not by a more-or-less uniform field, but by an engine. For strategic combat, this is less of an issue, as you can launch from whatever range you choose.
There are two ways to limit the use of relativistic missiles. The first is to apply the relativistic rocket equation (http://en.wikipedia.org/wiki/Relativistic_rocket) to objects near c. A good point to start applying that might be at exhaust velocities around .4c, with mass ratios above 1.5. This prevents the object in question from ever achieving lightspeed, or even cheaply getting to a good fraction thereof. For example, take an object with a mass ratio of e and an exhaust velocity of c. Conventional rocket science suggests that it will have a delta-V of c, but in actuality, it will only reach about .76c.
The second is to apply an accuracy penalty to missiles at high velocity relative to the target. This is to simulate that the missile simply doesn't have time to respond when closing at high fractions of the speed of light.
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I have some question :
*Are planetary bodies will have any influence in "short range " combat ex: Will planets could be used as "shield" againt direct firing or sensor detection. What about collateral damage in low orbit battle?
*When ships are taking off from planets or landing on it, will dense atmospheres and gravity have influence on possible components failure or even explosion, and on fuel consumption. What about the atmospheric decceleration over time. this feature might encourage construicting space station , or base onthe moon and asteroide.
*It would be nice if we could automate the officer order ex: telling a task group or a ship to patrol a system without telling him to refuel, resuply fire ect. . . The higher the military grade the higher they are autonomous. it would be great even for roleplaying , seeing a commodore trying a risky and unexpected maneuver, or a coward fleeing depending on the officer character or experience the caseulties and the opponent forces. some orders might be denied , delayed or not fully understood , depending again on the officers. :)
*and very important : Does all thoses orbital calculation slow down very much the game? I guess after 20 years of playing it going to be Very very very slow, if so , how will you remedy this?
*I guess orbital inclinaison isnt taken in account , considering that map are in 2d , or is it calculated virtually?
* whate about eccentricity? is eccentricity will be taken in account for bodies?
With the newtonian feature, its going to looks like Orbiter simulation plus the political and econommical feature. ;D
Hope my english is undertandable.
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At first, I wasn't all too excited about NA for some reason. After reading half of the Rules thread, however, I have changed my mind. Even though a good bit of that made my physics knowledge lacking brain almost kill itself, it was a very interesting read. Can't wait. :)
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It's sometimes a bit above my head as well.
I just do too much calculation at work already, I guess.^^
I suppose the discussions here are already half the fun in the game. ;)
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Some of the abstract numbers Aurora I had are being turned into real world figures now, that's pretty cool. Think of the kind of discussions we can have with something like that...
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Some of the abstract numbers Aurora I had are being turned into real world figures now, that's pretty cool. Think of the kind of discussions we can have with something like that...
What do you mean by that? Most of Aurora I is completely impossible as far as we know.
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I'm wondering how much of an expectation there is that some aspects of NA will filter back into regular Aurora, or eventually A2. You say it's an "Experiment" that might not even work, but regardless of whether or not it comes out as a successful spin-off, it'd be a shame if some of the things being looked at here didn't eventually make their way into the core game. I'm thinking specifically about the non-missile weapons being made more complex and detailed, longer-ranged and generally more versatile. I also like the idea of having more control over the intricacies of engine design, so every civilization in the entire galaxy doesn't have the same super-generic Ion E7s and Inertial Confinement E5s.
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I have been thinking about newtonian tactics and the more I think about it, the more I am convinced that small craft swarms are actually the way to go.
Yes, I know all the arguments about fighters. I am talking about FACs here. Independently operating ships, made to be as tiny as possible while carrying capital-level armament. Probably 1 to 2ktons. Whether the engines are up-engineered is optional, probably not however.
Essentially, each ship would carry a few missile tubes, a couple of salvoes ammo and one firecon. Minimum armour and everything else. PD ships are the same but with PD tubes. Any railgun ships are likewise similar, just one firecon (which likely to be the biggest thing) attached to whatever ratio of weapons:firecon you use.
If ships are sufficiently cheap compared to missiles, you could go suicide fighters carrying railguns.
With the incredible damage kinetic weapons have, likely to mission kill a ship on a good hit, it appears best to simply divide your force into as many small chunks as possible since a 10kton ship costs only slightly less than 5x of a 2kton ship. (and the 10kton jump ship for the 10kton fleet costs more than 5x of 2kton jumpships)
In fact, I could see a carrier doctrine actually winning over a Deathstar builder (ie. concentration of production into few extremely huge ships); and putting up a good fight against standard battleships + escorts doctrine (where ships range from 5ktons to ~20ktons)
Simply put, the fighters don't really have to come back if they cost less than a fleet and they can kill one.
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On the other hand, a small group of battelships with extreme range and a very large number of weapons might be effective at engaging a fleet with small firecons and lower weapon velocities.
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The tactics to use are essentially to either
A) Evade and build cheap, or
B) Mass so much firepower in one spot that the wall of counterfire will prevent anything physical from reaching you.
C) Would be to outrange them, but the sole option to reliably do that is to outtech them, and everyone can potentially do that.
The small, low armored ships droctrine will work extremely well as long as you're in long range fight with significant momentum.
Then i 100% agree.
However, if anything gets close, and that thing is armed with lasers, that tactic may backfire.
Keep in mind that if you're moving away from a target, your kinectics will barely deal any damage, and I expect Laser batteries to be quite efficient at swatting missiles.
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Well, using the tactics of WW1-2, and modern navies and comparing them to Newtonian Aurora, you have:
1) Fleet-in-being: The fact that there is a fleet somewhere out there, even if in orbit around a planet, means you must also place a fleet in proximity, in case they move for something important. They don't ever have to move away from their planet, but just being there forces you to commit a fleet to counter their fleet.
NA: Because ships are so easily detectable with planetary sensors, and it would take the enemy quite a while to reach your planet, this doctrine is valid. It's actually more valid in space than it ever was in navy warfare. You would want a fleet of heavy cruisers, as you could build more, spreading them out and bog down the enemy over multiple systems.
2) Battle Fleet Concentration: You create fleets so massive in firepower and numbers that a single fleet could wipe out any fleet of the opposing navy. For this you would need massive battleships, escorts and pickets. By applying the fleet against the enemies most valued planet, you would be able to disrupt their operations.
NA: Because fleets are going to be so slow (in comparison to aurora), this might not work as planned. You just won't be able to build enough ships to control an area. Plus, any ships you do manage to build will be used to support your fleets in operation. It does have the benefit of destroying any gunboat navies you encounter. A battle fleet would be the most capable of penetrating an enemy held system.
3) Wolfpacks: Small ships, using the best stealth technology available, will attack weaker enemies in overwhelming numbers. The small size allows them to evade most active detection methods, while reducing their costs and increasing the number you can field at once.
NA: This one is probably the best. While they are less effective because of the square-cube law, their main target would be civilian traffic and support ships. Their weapons are smaller, therefor exponentially lower range and damage, but 30+ could easily take down a lone battlecruiser. Their high speed would also allow them to dictate range and engagement, choosing instead to run from large fleets. This would of course mean that another form of doctrine is required to protect against fleet concentrations. You would also be able to spread them across a solar system, allowing for rapid response to incursion.
4) Carrier Fleet: A large ship housing a bunch of small, independently powered vehicles for use well outside the motherships area of operations. The carrier would carry multiple types of craft, each specialized for it's intended purpose. These craft can be swapped out to allow for different configurations.
NA: The primary benefit is acceleration, with a fighter being able to change it's speed and vector with much less fuel than a capital ship. The disadvantage is that the guns that a fighter would carry would have lower damage and range than any capital ship weapon. The advantage of missile carrying fighters would depend on if fire control ranges were capped, if enemies could jam missiles in flight, or if ECM became exponentially stronger then farther away the target is.
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The fact that single hits cripple entire ships, regardless of size (within practical limits), under certain not-so-rare circumstances of an intercept, strongly strongly discourages building big ships.
Because big ships are costly to maneuver, and are a big expensive target, you tempt enemies to try a suicidal intercept to take it out.
And due to how acceleration compares with velocity, taking days to change your relative speed simply worsens the situation.
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Well, using the tactics of WW1-2, and modern navies and comparing them to Newtonian Aurora, you have:
1) Fleet-in-being: The fact that there is a fleet somewhere out there, even if in orbit around a planet, means you must also place a fleet in proximity, in case they move for something important. They don't ever have to move away from their planet, but just being there forces you to commit a fleet to counter their fleet.
NA: Because ships are so easily detectable with planetary sensors, and it would take the enemy quite a while to reach your planet, this doctrine is valid. It's actually more valid in space than it ever was in navy warfare. You would want a fleet of heavy cruisers, as you could build more, spreading them out and bog down the enemy over multiple systems.
Disagree in theory. If you concentrate a fleet to protect a point, you limits its engagement ability. Counter manuevers/fire will be effective against the entire fleet. Weapons the fleet can't stop will leave them with little abiltiy to deal with a threat without risking destruction of the fleet.
2) Battle Fleet Concentration: You create fleets so massive in firepower and numbers that a single fleet could wipe out any fleet of the opposing navy. For this you would need massive battleships, escorts and pickets. By applying the fleet against the enemies most valued planet, you would be able to disrupt their operations.
NA: Because fleets are going to be so slow (in comparison to aurora), this might not work as planned. You just won't be able to build enough ships to control an area. Plus, any ships you do manage to build will be used to support your fleets in operation. It does have the benefit of destroying any gunboat navies you encounter. A battle fleet would be the most capable of penetrating an enemy held system.
Tentatively agree. I think at least with what you are saying.
You will still need strength in numbers. But most likely dispersed. A single concentration will limit your options/abilities. A single big ship could be taken out by a single hit. Multiple small and cheap ships will be better able to control area and respond to/bracket enemies.
3) Wolfpacks: Small ships, using the best stealth technology available, will attack weaker enemies in overwhelming numbers. The small size allows them to evade most active detection methods, while reducing their costs and increasing the number you can field at once.
NA: This one is probably the best. While they are less effective because of the square-cube law, their main target would be civilian traffic and support ships. Their weapons are smaller, therefor exponentially lower range and damage, but 30+ could easily take down a lone battlecruiser. Their high speed would also allow them to dictate range and engagement, choosing instead to run from large fleets. This would of course mean that another form of doctrine is required to protect against fleet concentrations. You would also be able to spread them across a solar system, allowing for rapid response to incursion.
Don't have a clue how stealth will work in NA, so no idea.
I don't expect that hiding in space will be very effective. Now, firing/launching from far enough out that they can't do anything about it before you are gone - that is a different issue.
But with the high fuel needs for a battle of manuever, a ship capable of multiple turns at anything but slow speeds will have almost no room for weapons. As for 30+ to take down a battlecruiser, I would see that as overkill or poor tactical position.
But only time will tell on this.
4) Carrier Fleet: A large ship housing a bunch of small, independently powered vehicles for use well outside the motherships area of operations. The carrier would carry multiple types of craft, each specialized for it's intended purpose. These craft can be swapped out to allow for different configurations.
NA: The primary benefit is acceleration, with a fighter being able to change it's speed and vector with much less fuel than a capital ship. The disadvantage is that the guns that a fighter would carry would have lower damage and range than any capital ship weapon. The advantage of missile carrying fighters would depend on if fire control ranges were capped, if enemies could jam missiles in flight, or if ECM became exponentially stronger then farther away the target is.
The problem with a manueverable fighter is the same for a ship. If it can actually manuever much, it is almost all fuel. What it will need is parasites with endurance. They will need to be capable of reaching distant points on widely differing vectors and still rendevous for pick up (or not if you are a little more ruthless...).
Small weapons won't necessarily be a big problem if you can bracket a target. If it runs from some to reduce their damage, it will be closing with other turning them into one hit one kill wonders. Either that or it must hold still or to very low velocities to minimize damage. But I forsee stationary (or nearly so) targets to be tanamount to suicide in NA combat.
Bracketing a target with several vessels on widely divergent and random vectors/courses will be the best defense/offense as manuevering against one will make them vulnerable to the others.
I really forsee the most dangerous and difficult of the NA combats to resemble zero G furballs of WWII. Formations will just get you killed.
But I do agree with the smaller craft in multiples to be the way to go, at least when opposed to single or few larger vessels. At least in combat circumstances. Mostly fuel, a weapon (or better if possible, two differing weapon types - one guided and one unguided), and something to detect/engage targets. For a combat vessel where one railgun projectile/nuke will possibly destroy even the most massive ship - anything else is just money thrown away when your craft takes a hit. If you don't need it for a fight, put it on something that won't get in one.
My plan for any ship not designed as a combatant will be to always make sure it is capable to jump away at any given time. If in a system, try to make it so it can warm up and jump before a weapon could reach it. If it jumps into a system, land so far out that it will be able to reset before any weapon can respond. In NA, landing way out will take no more fuel to reach the inner system than landing closer. Coasting is just coasting, and distance will equal safety. If it takes me a while to reach the inner system, big deal. I would expect an exploration ship to be designed for extended ops. And if it will take me a month to get there, it will take a while for a weapon to reach me....
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Somehow managed to miss these posts. Obviously caffeine deficient here tonight.... ;)
I have been thinking about newtonian tactics and the more I think about it, the more I am convinced that small craft swarms are actually the way to go.
Yes, I know all the arguments about fighters. I am talking about FACs here. Independently operating ships, made to be as tiny as possible while carrying capital-level armament. Probably 1 to 2ktons. Whether the engines are up-engineered is optional, probably not however.
......
In fact, I could see a carrier doctrine actually winning over a Deathstar builder (ie. concentration of production into few extremely huge ships); and putting up a good fight against standard battleships + escorts doctrine (where ships range from 5ktons to ~20ktons)
Simply put, the fighters don't really have to come back if they cost less than a fleet and they can kill one.
Sounds like we are on the same page. Of course the game may prove us wrong.
On the other hand, a small group of battelships with extreme range and a very large number of weapons might be effective at engaging a fleet with small firecons and lower weapon velocities.
If you could achieve near parity in numbers, and had an advantage in achieving intercepts, you could win. But you may still lose economically. You will likely have to destroy far more of their vessels to equal the loss of just one or two of your battleships. They will likely be able to replace their losses faster than you also. If it is a battle for their homeworld, it wouldn't matter. If this turns into a battle over several systems, battleships might bankrupt you.
The tactics to use are essentially to either
A) Evade and build cheap, or
This will be my first strategy if this comes to fruition. Hope it works.
B) Mass so much firepower in one spot that the wall of counterfire will prevent anything physical from reaching you.
This is going to depend on how well kinetic rounds can be targetted/saturate an area. And if they can be stopped. If they are nearly impossible to detect/stop a bunch of ships just becomes more objects in the 'beaten zone'.
C) Would be to outrange them, but the sole option to reliably do that is to outtech them, and everyone can potentially do that.
Wars have almost always been decided by who can shoot the farthest and hit what they are aiming at. May that always be in your favor...
The small, low armored ships droctrine will work extremely well as long as you're in long range fight with significant momentum.
Then i 100% agree.
Hence a doctorine of many ships firing from different points and with different course/velocities. This will rob an opponent of opportunities to manuever that will not be creating high momentum impacts.
However, if anything gets close, and that thing is armed with lasers, that tactic may backfire.
Keep in mind that if you're moving away from a target, your kinectics will barely deal any damage, and I expect Laser batteries to be quite efficient at swatting missiles.
I do see laser and rail guns being assured kills in close. Lasers will likely have a slight edge, but it will be more of a 'I got to see my weapon destroy my target before his kinetic rounds vaporized me...' sort of edge. If both sides have them, it will likely be MAD. Particularly with railguns as both may be able to effectively target all of an opponents ships before their ordinance reaches you. Hence the doctorine of not putting all your eggs in one basket. I have a feeling in NA that combat in space will be a lonely thing. You will be a long ways from anyone friendly as you trade death across the long dark....
Only actual play will tell though.
Have I mentioned I am really hoping this happens...
;D
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Have I mentioned I am really hoping this happens...
;D
Me too :)
The break to work on normal Aurora has taken a lot longer than I planned but I will get back to Newtonian eventually :)
Steve
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Well, you improved a lot that may come back here, didn't you.
I only fear that NA might turn out to be totally unplayable, what with setting dozen of waypoints to spread out a force of small ship.
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Well, you improved a lot that may come back here, didn't you.
I only fear that NA might turn out to be totally unplayable, what with setting dozen of waypoints to spread out a force of small ship.
Agree this could be a lot of additional management but one that could be quite well managed through a revist of the TG detachments process. Having pre-set formations and spreads could help an awful lot on this.
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Well, you improved a lot that may come back here, didn't you.
I only fear that NA might turn out to be totally unplayable, what with setting dozen of waypoints to spread out a force of small ship.
You won't need dozens of waypoints. You can just use the existing escort function. One of the reasons btw that NA uses FTL rather than jump travel is so you don't have to compress formations to enter JPs.
Steve
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If you could achieve near parity in numbers, and had an advantage in achieving intercepts, you could win. But you may still lose economically. You will likely have to destroy far more of their vessels to equal the loss of just one or two of your battleships. They will likely be able to replace their losses faster than you also. If it is a battle for their homeworld, it wouldn't matter. If this turns into a battle over several systems, battleships might bankrupt you.
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Not really. A battleship would save you money over time with maintenance (larger ships are historically and intrinsically easier to maintain), and would have a large amount of shields protecting it.
Wars have almost always been decided by who can shoot the farthest and hit what they are aiming at. May that always be in your favor...
Hence a doctorine of many ships firing from different points and with different course/velocities. This will rob an opponent of opportunities to manuever that will not be creating high momentum impacts.
Not really. The amount of vectors you would need to be firing from would be prohibitive. Since your trying to hit the target, they would all cross near the target anyways. Plus, a 45-90 degree flank attack would require a lot of fuel. Unless of course you used fighters as the flank attack.
I do see laser and rail guns being assured kills in close. Lasers will likely have a slight edge, but it will be more of a 'I got to see my weapon destroy my target before his kinetic rounds vaporized me...' sort of edge. If both sides have them, it will likely be MAD. Particularly with railguns as both may be able to effectively target all of an opponents ships before their ordinance reaches you. Hence the doctorine of not putting all your eggs in one basket. I have a feeling in NA that combat in space will be a lonely thing. You will be a long ways from anyone friendly as you trade death across the long dark....
While this may be possible in NA, there are many practical reasons why this would never happen. First, the energy required to move an object exponentially increases at relativistic speeds, meaning you would need a more powerful gun. Second, the material's strength determines the maximum pressure you can place upon it from acceleration, capping acceleration. You can of course bypass this by creating larger guns, but then you'll run into the problem of having large capital ships with kilometres of internal spinal mounts. Smaller ships would not be able to have these larger guns and would therefor always be outgunned and outranged. Finally, if you could design a weapon capable of withstanding the extreme heat of a laser, or the pressures involved with railguns, you could make armour out of that same material and get relatively good protection.
According to the Harvard Study On Hypervelocity Impacts From Space Debris, the amount of energy required for catastrophic failure (on a satellite) is about 10,000 Mt Joules, with Mt being mass of target in kilograms. A 2.8 ton satellite requires 28 MJ of energy for catastrophic failure (this is dependent on impact angle, with anything over ~30% drastically spreading the damage out. While this only deals with small objects like satellites, it basically means that MAD outcomes will be doubtful, unless the math is simplified to k=1/2mv^2. An armoured battleship would be able to shrug off anything lower than battleship sized weapons, and probably 6-10 rounds of railguns.
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According to the Harvard Study On Hypervelocity Impacts From Space Debris, the amount of energy required for catastrophic failure (on a satellite) is about 10,000 Mt Joules, with Mt being mass of target in kilograms. A 2.8 ton satellite requires 28 MJ of energy for catastrophic failure (this is dependent on impact angle, with anything over ~30% drastically spreading the damage out. While this only deals with small objects like satellites, it basically means that MAD outcomes will be doubtful, unless the math is simplified to k=1/2mv^2. An armoured battleship would be able to shrug off anything lower than battleship sized weapons, and probably 6-10 rounds of railguns.
Some time earlier...
Are you forgetting that ship speeds are on the order of a thousand km per second or so?
Even plasma is not particularly healthy, with armour at 100s of MJ and shells starting at GJ all the way up to TJ ranges.
A projectile vapourizing on your whipple shield is like a nuke going off right next to you. And we all know what happens when one does that.
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Not really. A battleship would save you money over time with maintenance (larger ships are historically and intrinsically easier to maintain), and would have a large amount of shields protecting it.
Problem is, your battleships with a lot of expensive systems/munitions/fuel can still be destroyed by a single nuke from a cheap 'figher/FAC'. You will have to destroy many of the attackers, where as only one of them has to get lucky.
Not really. The amount of vectors you would need to be firing from would be prohibitive. Since your trying to hit the target, they would all cross near the target anyways. Plus, a 45-90 degree flank attack would require a lot of fuel. Unless of course you used fighters as the flank attack.
I don't think you are grasping the concept.
You won't be facing a fleet all coming from a single point with a single vector that then tries to break up and manuever.
You will be facing a group that starts in a wide variety of locations. As an example deployment in Sol - A couple around Earth's orbit. More stationed in the Jovian/Trojans. More from Neptune/trans Neptune. All set on differing points in the orbits/vectors. The shots/missiles coming at you will be originating from a large number of angles. Manuevering in any direction to avoid some will increase your closing speed with others. Unless you are coming in from way out system you will not be able to keep them from closing off your available vectors of manuever. And if I can limit your manuever options, you are going to end up becoming a simpler target to fix/destroy.
While this may be possible in NA, there are many practical reasons why this would never happen. First, the energy required to move an object exponentially increases at relativistic speeds, meaning you would need a more powerful gun. Second, the material's strength determines the maximum pressure you can place upon it from acceleration, capping acceleration. You can of course bypass this by creating larger guns, but then you'll run into the problem of having large capital ships with kilometres of internal spinal mounts. Smaller ships would not be able to have these larger guns and would therefor always be outgunned and outranged. Finally, if you could design a weapon capable of withstanding the extreme heat of a laser, or the pressures involved with railguns, you could make armour out of that same material and get relatively good protection.
We have already discussed at length the issues with what it will take for a material to survive the posited rail guns. I was/am a big opponent of any guided rail munitions due to the stress involved in firing. I'm not going to rehash that.
And for the 'if it can survive launch, it makes great armor' thought, this can be true - to a point. But modern materials used in cannons, etc can withstand firing and when used as armor tend to fail against a weapon made with the same materials given sufficient energy. In fact they fail against materials of lesser integrety with adequate energy involved. Copper penetrators do a fine job punching through our tanks overseas...
According to the Harvard Study On Hypervelocity Impacts From Space Debris, the amount of energy required for catastrophic failure (on a satellite) is about 10,000 Mt Joules, with Mt being mass of target in kilograms. A 2.8 ton satellite requires 28 MJ of energy for catastrophic failure (this is dependent on impact angle, with anything over ~30% drastically spreading the damage out. While this only deals with small objects like satellites, it basically means that MAD outcomes will be doubtful, unless the math is simplified to k=1/2mv^2. An armoured battleship would be able to shrug off anything lower than battleship sized weapons, and probably 6-10 rounds of railguns.
jseah already adequately dispelled this issue...
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PART ONE: SHIPS' WEAPON SYSTEMS IN THE TERAJOULES RANGE
Well let's figure this out. A 30.0 kg projectile will be fired at a velocity of 570,000m/s, giving a muzzle energy of (Ek=0.5mv^2) Ek=0.5(30.0)(570000)^2=4.8735E12 Joules, or 4.87 TJ. This I figure is a nice TJ number for this thought exercise. First off, we need to figure out the maximum acceleration of the round, the distance of the barrel, the power requirements and the rate of fire.
We need to figure out how fast a round may be fired out of a railgun. If the initial velocity is 0 m/s and the final velocity is 5.7E5 m/s, then we can find the length of the barrel. Distance round must travel is equal to (final velocity minus initial velocity divided by 2) times the duration of acceleration. Now we need the time in the barrel.
Time in barrel is equal to final velocity divided by acceleration. Now we require acceleration. We shall use F=mass*acceleration. F=30kg*m/s-2. Using the pressure formula (Pressure=Force/Area) and the force formula, we get (Pressure=(mass * metres)/(Area * seconds^2)). Steve says that 10m^3 = 1 ton, so 0.03kg * 10 = 0.3m^3. Cube root that and you get 0.66943295 metres. Assuming a square round, the area of one side is 0.448140475m^2. Now we have area and mass, but require pressure to get the final acceleration. For this I will use adamantine (5GPa) and assume that the gun will fire the round at maximum pressure. (5E9 Pa * ~0.45 m^2) / 30.0 Kg = 74,690,000 m/s-2. With final velocity (570,000m/s) divided by acceleration (~75,000 km/s^2), we get 0.007631536 seconds in the barrel.
With the final velocity (570,000m/s) averaged against the initial velocity (0 m/s), we get (285000m/s) times the time in the barrel, we get a 2,175 metre long barrel. The length of the barrel seems reasonable, as does the time in barrel and acceleration. A spinal mount can be mounted inside a ship the size of a star destroyer fairly easily, and most spinal mounts in different universes can take up 40-85% of the ships length. With tempered steel today reaching ~2GPa with special treatment, I think this is reasonable as well.
Now this is where things start to go bad for Terajoule weapons. Steve's rules show a MJ to ton constant for weapons, with what I think is TL4 being 12 MJ/Ton. This would make the 4.87 TJ gun have a mass of 406,125 Tonnes at TL4 [1]. The power requirement would be 4.87 TJ / Efficiency. With Steve's listed 35% (which I'm guessing is TL2), the gun would require 13.9 TJ of energy to fire.
The rate of fire is dependant upon the radius of the gun compared to it's mass, and the heat dissipation rate (we shall assume TL5? 0.6 MJ/s per m^2 of surface area. If the gun has a mass of 4.06E5 Tonnes, then the volume is [2] 40,613 metres cubed. If this is a circle, then the radius would be (3*40613/(4*pi))^(1/3)=21.323516207 metres. The surface area would be area = 4 * pi * 21.32^2 = 5714 metres squared. The gun may radiate 5714 * 0.6 = 3428 MJ of heat a second. This gives a fire rate of 4870000 MJ/ 3428 MJ/s = 1420.65 seconds, or ~23 minutes. [3]
For smegs and giggles, if the gun were counted as a cylinder instead of a circle, with the gun length being 2175 metres long. We already calculated the bore to be 0.67 metres in diameter, so we can estimate the size and mass of the gun itself (and not the power capacitors, wiring, etc) as 3067 metres cubed and 30,673 tonnes respectively (lol, 7.5% gun). The surface area is 9159 metres squared, giving a heat lose and fire rate of 5495.4 MJ and 886.20 seconds, respectively. This could be further enhanced by the volume to surface area ratio, taking into effect the conduction of heat through the material being faster. The sphere is ~0.14 surface/volume, while the cylinder is ~2.99 surface/volume. You of course then have to worry about the mass ratio getting out of control as you try to increase surface area (length) while decreasing volume (bore). I just find the ~15 minute firing time to be more reasonable, so ignore this whole section if you want.
Power requirements to power a gun in 1420.65 or 886.20 seconds will require a reactor capable of producing 9.8 GW or 15.7 GW of power for the entire recharge cycle. As I don't know how much energy sorium has, I'm not sure if this is a good number to go by or not. If you compare the total power when dealing with heat radiating(IE factor in efficiency for recharge time), then you get a recharge time of 4059.01 seconds.[3]
CONCLUSION:
-That weapons in the TJ range will be useless except for late game, and will always be more inefficient than a bunch of smaller guns.
-That the range you gain will limit your ability to fight multiple attackers, and make misses more deadly for you.
-That larger ships will be the only ones capable of fielding GJ weapons until far later in the game.
-That Steve's designs hint at high MJ to low GJ range for basic ship armaments.
-That efficiency will make or break your design.
-That DPS through high rate of fire may be more useful than fielding large, ship killing weapons.
-That a person with no social life will find errors in anything.
Also, since all the shield tech seem to line up with weapon tech, a ship capable of fielding a 400,000 ton railgun will certainly be able to equipped a large amount of shields to go with it, as well as smaller cannons around itself.
[1] Does the initial tech level count as TL1 or TL0?
[2] Hull section says 10 tonnes per cubic metre, weapons section says 1 ton per cubic metre???
[3] Shouldn't fire rate use the total power required instead of muzzle energy? Doesn't the inefficiency of the gun count as HEAT?!?
Yes, I kind of just proved my point on no instant kill weapons while at the same time disproving the use of battleships in space combat.
#I understand that if I worked backwards from the volume and mass to get pressure and gun length that I would have gotten a more accurate answer. I also apologize in advanced to errors, as it is 11:00pm local time on a weekday. I also understand I choose a rather poor level in efficiency, but that was the only example I could find in the same section.
Part two, attacks from multiple vectors and the myth of envelopment in space, even if space is 2D. I'm doing this one tomorrow though as I am very tired.
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It has nothing to do with the speed of the launch and everything to do with the speed of the ship.
Again, I quote:
Are you forgetting that ship speeds are on the order of a thousand km per second or so?
Emphasis mine.
The idea was to mount a railgun with 10-100km/s muzzle velocity (MJ range), onto a ship with ~30 000km/s total delta-v. With some leftover for maneuvering and depending on tactical situation, ship closing speeds could vary from nearly 0 to over 10 000km/s.
I'm sure you could do the equations for a 1kg ball of metal flying at 5kkm/s?
And this sort of delta-v is around the tech level of the example ships posted. Aka. quite early indeed.
With widely spaced attack and defence groups, ala the situation described by Procyon, it will be impossible to be "at rest" relative to all groups. You will have high relative velocity to some groups, and that is enough to kill you.
Fragmentation missles are the same, but worse. Missiles have 4x the delta-v of ships for the same fuel since they aren't going to slow down (although they are less efficient, so it's not quite 4x). Their speed and accel will always be higher than any ship can feasibly acheive, given roughly similar tech levels, and even standard overtaking speeds will be on the order of thousands of km/s relative.
You don't need to have a big ass railgun to dump rocks out the hatch. And yes, yes, rocks WILL kill you when they are going that fast.
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Let us consider two ships of the same design. 2000 tons total, 6 layers of armour, using the example weapon and engines. For this we shall consider the ship to have unlimited range against static or predictable opponents and will always hit.
The ship will look like:
Example ship
2,214 tons
Acceleration: 6.78 m*s-2 (0.69g)
Armor 6cm/70 (125 MJ per cm)
Maximum Shield Strength: 24,000 MJ
Point Shield Strength: 1,144 MJ
Magneto-plasma Drive
Thrust: 12.5 MN Base Fuel Consumption per MN: 188.1 litres per hour
Base Acceleration: 50 mp/s (5.1G)
Fuel Use at Full Burn: 2351 litres per hour
Engine Size: 250 Tons Engine HTK: 2
Thermal Signature: 125 Exp Chance: 12
Cost: 62.5 Crew: 8
Materials Required: 15.625x Duranium 46.875x Gallicite
Development Cost for Project: 625RP
2x 2400 MJ Railgun
Muzzle Energy: 2400 MJ Muzzle Velocity 69,282 m/s Cooldown Period: 24 seconds
Power Requirement per shot: 6,857 MJ Energy Efficiency: 35%
Mass Ratio: 200k Energy Efficiency Penalty: 0%
Railgun Size: 200 tons Surface Area: 165.4 Projectile Mass: 1 kg
Cost: 24 Crew: 20 HTK: 2
Materials Required: 24x Vendarite
Development Cost for Project: 240RP
Shield Generator
Size: 200 tons HTK:2 <-I just guessed with that.
MJ/T: 100 MJ/T (20,000MJ) +20% (24,000 MJ)
Recharge Rate per ton: 0.25 MJ/s per ton (50MJ/s) [1]
Point strength: (200/4194)*24,000=1144 MJ/200m^2
We shall also assume 40% fuel, 10% crew, bridge, etc and 150 tons of fire control and reactors. HTK 31 in total, if fuel is armoured. Otherwise, 15.
We shall also assume there are four types of damage being inflicted: No damage, light damage, mission destruction and total destruction. Total destruction only occurs when an explosion happens, or if all crew members were killed.
Damage: 2400 MJ - 1140 MJ = 1260 MJ - 750 MJ = 510 MJ. Since the diameter of the ship before armour is 34m and the armour section has a size of 10m^2, I shall consider the area damaged as 340m^3 out of a total of 20,000m^3 before armour. A total area of 1.7% of the ship is damaged. My guess is that the round would find nothing powerful enough to fully stop it, and would continue out the other side of the ship. Since I have no idea how Steve is handling internal damage, I shall give my own idea.
First idea, mass provides the chance that a component will be hit. Since the engine takes up 12.5% of internal mass, and it's the only component that can explode#1#, I'll look at that first. Each m^3 of damage has a power of 1.5 MJ. Since the lowest sized component on this ship is 50 tons, that means that each component has a minimum size of 500m^3. The largest size, the fuel tanks has 800 tons (8,000m^3). The engine is 2,500m^3, so only 13.6% of the engine room would be effected.
The chances of the engines being hit is 12.5%, the chance of hitting something vital (HTK) I shall assume has something to do with how much area is effected. There is a 13.6% chance for one of the HTK being hit, and a 1.8% chance of both being hit. Each HTK gives a 12% chance to explode (which I assume would be a critical death), so both being hit results in 24% chance of total death. Both exploding gives a 1.4% chance. In total, the chance of an instant death is 0.2%, per hit. This does not include chance to hit.
This is also assuming the round would remain intact and continue through the ship. If the round detonated into plasma, then you could simply keep the armour layers a few centimetres apart to reduce the damage sustained over a large amount of empty space.
This is not even considering evasion, interception or retaliation. The amount of damage possible against a ship will be dependent upon the amount of energy that can be transfered to it's surroundings. A penetrator will be best at moving through defences, but will also penetrate the area it must damage as well. An explosive or round designed to fragment into shrapnel or plasma will do great against internal sections, but would spread it's damage out over a larger shield/armour section. You would also have to take into account plasma cooling over the layers of armour, and heat conduction through the metal of the ship, which would both reduce the final energy that reaches the ship systems.
[1] Would the size efficiency help shield recharge rates as well?
Edit:
#1#Yes, I noticed I have a reactor in there that may explode as well, but since I don't have a reactor example in NA:Rules, I have left that out. There would be 2 reactors with a total of 100 tons in this design, with an Explosion chance of 5% each (I would guess), if anyone wants to figure it out.
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Take your example ship.
2214 tons dry weight
40% fuel = 3690 full load = 1476 tons fuel = 1 476 000 litres
Total burn time assuming 1 engine: 7847 (0d.p.) hours = 28 248 803 s (0d.p.)
Max delta-v assuming pushing full load (I'm lazy and it errs on the low side, consider the excess lost to evasive maneuvers): 95 693 (0d.p.) km / s
Take 1/20th delta-v as standard combat velocity: 4784 km / s (0d.p.) combat speed
Railgun muzzle velocity as portion of combat velocity: 1.4%
Assuming our enthusiastic Kapitan decides to do a demonstration strike on the moon, we can expect a railgun round to travel at 4784 km / s.
Projectile mass: 1kg
Projectile kinetic energy: 11 TJ (2s.f.)
- Wikipedia tells me this is about 1/6th the yield of the hiroshima nuke
The moon gains a new crater that astronomical enthusiasts can spot with a telescope.
In other news, an unwary patrol frigate is caught by a swashbuckling pirate who decides to fire a "shot across his bow". The gunner misaims and hits the ship instead.
Shields - 20GJ
Armour - 70 x 6 x 125 MJ = 52.5 GJ
The "warning shot" blows down all the shields, all the armour, and is still has 11 TJ left to go (decimals absorbed the rest...)
The shell will almost certainly vapourize upon contacting the shield or armour. The expanding ball of plasma blows a hole in the armour and proceeds to knock a hole all the way out the other side of the ship. Assuming the projectile leaves only 1% of it's energy on the ship, that's still enough to vapourize everyone on board.
EDIT:
In practice, the pirate or Kapitan won't be getting perfect delta-v shots. The actual damage will swing widely from twice the speed (4x the power) to something like your scenario, depending on the geometry of the combat.
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The easiest way to remedy that situation is to create a cage armour around the ship, which would therefor make the round expand into a spray of plasma early. Or, you could fire a small round at the round. If the round is turned to plasma far enough away, then the shields can absorb most of the damage. After all, the plasma will lose energy exponentially the farther away it is. My guess is a CIWS that shoots at targets 1-10km away would work perfectly. Another problem is that, because the round is exploding instead of penetrating, the explosion would radiate in all directions, not only against the ship. A shield would more than likely reflect most of the damage away from the ship, if that were simulated. After all, a nuclear resistant armour is not new. The Orion drive was designed to survive multiple nuclear blasts near it.
While yes, the velocity of the railgun is only a small part of the velocity you can achieve, there is the small problem of not being able to fire, except for a very limited arc. The round maintains the momentum and velocity it was traveling, +/- the railgun's launch velocity. If you needed to shoot behind you or to the side, you would not be able to hit anything.
While a railgun shot at high speed is great, it wont work against a moving target. A target that sees you can simply veer lazily at an AOB of 90 or 270. At high speed the attacking ship would not be able to change the momentum of the ship fast enough. Not only that, but now the defending ship can fire a round or two in the direction of the attacker, and that round will have the same amount of damage as the attacker's.
Finally, I have my doubts that the round would continue going if it detonated into plasma. Either it penetrates or detonates, it can't do both without major changes to physics.
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My guess is a CIWS that shoots at targets 1-10km away would work perfectly.
This would work. The others... not. Anything that makes the projectile explode closer than one to two hundred meters or so will not work, the dispersed plasma still all hits your ship and your ship still explodes. At higher tech levels, this can maybe go to a full km.
The problem with CIWS comes with fragmentation missiles which split into hundreds of projectiles, each with higher relative velocity and higher weight than a standard railgun round. Can't get them all.
The question of whether the round goes through the ship or not is academic. It has TJ range energy. Your ship is dead.
While a railgun shot at high speed is great, it wont work against a moving target. A target that sees you can simply veer lazily at an AOB of 90 or 270. At high speed the attacking ship would not be able to change the momentum of the ship fast enough.
It will work. Assuming the approaching ship has already achieved a lethal velocity, all it has to do is match the fleeing ship's accelerations and then net change to relative velocity is zero. If your target is in your firing arc... well then!
A missile will have necessarily higher accel than a ship. In which case, a ship can never escape a fragmentation missile's cone of debris, plus the missile still gets to evade and still gets to gain delta-v.
Of course, accelerating on a closing vector at any distance will be treated as hostile act, for this very reason.
EDIT: obviously, I don't mean that all the time. Good reasons exist for closing vectors. But meeting an unknown ship out in the darkness? If it turns to chase you, it's probably hostile.
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This would work. The others... not. Anything that makes the projectile explode closer than one to two hundred meters or so will not work, the dispersed plasma still all hits your ship and your ship still explodes. At higher tech levels, this can maybe go to a full km.
The problem with CIWS comes with fragmentation missiles which split into hundreds of projectiles, each with higher relative velocity and higher weight than a standard railgun round. Can't get them all.
If the projectiles can be considered like shrapnel or space caltrops, then we can view the missile as a dispersion machine. At these speeds your talking about, the dispersion would have to be from far away or very fast. If fast, then explosives must be used to separate the missile and fragments apart, thus reducing some of the mass (and kinetic energy) before even reaching the target. If done from far away, then the fragments will be spread out more and will be like micrometeorite impacts, which I'm sure something like a spaceship would be able to defend itself against. There is always some cost and con to every weapon system.
The question of whether the round goes through the ship or not is academic. It has TJ range energy. Your ship is dead.
It will work. Assuming the approaching ship has already achieved a lethal velocity, all it has to do is match the fleeing ship's accelerations and then net change to relative velocity is zero. If your target is in your firing arc... well then!
Would it be effective against armour? Yes. Would it destroy the ship? Probably. Would it be cool? Yep. Would the ship exploded into fiery bits? The universe loves to disappoint people. And your firing arc in your example is +/- 0.83 degrees.
I suppose the question to ask is what happens at contact to the round? Will it: remain intact, break into fragments, turn into molten shards, turn into plasma or vaporize. In that order, the density of the energy decreases to the point of you being able to resist it with ablative armour. If it remains intact, unlikely at 5000k km/s, then the round would make a big hole in the armour, go in a straight line through the ship and come out the other side. I doubt it would pass any more energy to the ship besides the energy required to get through the armour, although the molten bits of armour would continue with the round and exit out the other side.
Again, not as awesome as the round leaving a trail of space debris into the next ship, but the universe does have rules in place that prevent ever increasing energy. Eventually you'll reach a point where more energy and more velocity is a bad thing.
A missile will have necessarily higher accel than a ship. In which case, a ship can never escape a fragmentation missile's cone of debris, plus the missile still gets to evade and still gets to gain delta-v.
Of course, accelerating on a closing vector at any distance will be treated as hostile act, for this very reason.
EDIT: obviously, I don't mean that all the time. Good reasons exist for closing vectors. But meeting an unknown ship out in the darkness? If it turns to chase you, it's probably hostile.
Well you don't start evading when the missile has exploded, you start evading the instant the guy fires. If you can make him miss, you just have to turn opposite his movement and start speeding up. He'll overshoot you before he gets a chance to fire another shot and will take him hours to days to change direction and follow.
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That is interestingly enough the point.
Kinetic rounds will be fatal, but extremely hard to hit with.
Maximum accuracy at long ranges is probably up to missiles, preferable fragmentation mirvs and Laser Rod Warheads.
I recommend this (http://aurora2.pentarch.org/index.php/topic,4585.0.html) thread for more info, especially the Article about the ravioli.
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If the projectiles can be considered like shrapnel or space caltrops, then we can view the missile as a dispersion machine. At these speeds your talking about, the dispersion would have to be from far away or very fast. If fast, then explosives must be used to separate the missile and fragments apart, thus reducing some of the mass (and kinetic energy) before even reaching the target. If done from far away, then the fragments will be spread out more and will be like micrometeorite impacts, which I'm sure something like a spaceship would be able to defend itself against. There is always some cost and con to every weapon system.
I was thinking something like a 5 ton missile (same tech level as your proposed ship), max accel 10 times of the ship, max delta-v around 1/10th to 1/20th of the ship's. It's about 70% fuel (technically, for best energy, the fuel fraction should be 2.71 times of the warhead).
Plus, the missile STILL gets the firing ships' velocity (ala railgun), and still gets to accelerate even more.
The 1.5 ton warhead then separates into 500 chunks ranging from 1 to 5 kg each. Say 20% is in the separation charge.
That's not micrometeorite impacts. A 1 gram chunk at 10kkm/s? Ok, your ship can survive that. 1 kg? No way.
Even if the chunk plasmarizes on your shield, the plasma ball contains the same momentum it originally did. If it doesn't get to spread out enough, and a hundred meters isn't enough at the speed its going at, your ship is dead.
Sure, every panel of armour takes less damage, the density of the energy decreases. But when 1% of the chunk has enough energy to vapourize ALL your armour, that doesn't help at all. Those armour columns are going to receive a hundred GJ in plasma, each.
Furthermore, whether you can generate a miss from a missile fired within it's powered envelope (the max distance the missile can travel at full burn) can be calculated. In the standard case of a ship firing a missile at a target somewhere in front of it (front being the direction the ship is moving in), the target ship cannot make it miss.
The missile has higher accel than ships, thus it matches the ship's accel and uses the excess to build delta-v or course correct. This makes missiles have ridiculous firing arcs compared to railguns, especially since a 2.71 fuel ratio missile will have a long burn and massive powered envelope.
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I like the discussion.
This is why I love NA. People actually have to think in real term. Not just rule lawyering to try and come up with a good design in a game.
If the projectiles can be considered like shrapnel or space caltrops, then we can view the missile as a dispersion machine. At these speeds your talking about, the dispersion would have to be from far away or very fast. If fast, then explosives must be used to separate the missile and fragments apart,
Nope, no explosives. Bad idea. Poor ability to get even predictable dispertion.
If it is designed as a 'shrapnel missile', it has some lateral thrusters able to induce a degree of spin. It can build this up and then release the preformed fragments to disperse at an easily calculated rate to acheive a set level of saturation on target. This is already done in several current weapon designs.
Would it be effective against armour? Yes. Would it destroy the ship? Probably. Would it be cool? Yep. Would the ship exploded into fiery bits?
I don't care what victory looks like, smells like, tastes like.
It is victory.
Well you don't start evading when the missile has exploded, you start evading the instant the guy fires. If you can make him miss, you just have to turn opposite his movement and start speeding up. He'll overshoot you before he gets a chance to fire another shot and will take him hours to days to change direction and follow.
Furthermore, whether you can generate a miss from a missile fired within it's powered envelope (the max distance the missile can travel at full burn) can be calculated. In the standard case of a ship firing a missile at a target somewhere in front of it (front being the direction the ship is moving in), the target ship cannot make it miss.
This pretty much is drifting in the direction I did months ago.
Kinetic kill. Needs saturation and predictable target trajectory.
Guided kill. Needs target defense saturation or fractional engagement times.
Hence why I think a small ship (your huge cage or shields out a long distance from a ship just provides more area to catch bad things...) with a kinetic kill weapon (rail gun or like) with fair ROF and high ordinance carried paired with a few guided weapons (missile with nuke/lase/shrapnel payloads) in dispersed formations.
Those railguns may have a hard time tagging you with individual shots, but several closing from differing vectors may give you little room to manuever. Depending on how well you can resolve the slugs on your sensors, you may not be able to see them until it is too late. If your CIWS only has an engagement range of 10km, on a slug closing at 4000km/s, well - you have .0025 seconds to stop it. Hope there isn't more than one at a time....
Add in missiles and your manuever options may get worse. A number closing on you that you are manuevering against may chase you right into the railgun rounds you can't see coming. I also expect single ships to make multiple vector missile courses simply by manueuvering. No 'launch all at once'.
Launch one with excessive velocity that will overshoot on a wide course and then come back from the far side of a target. A second with a course to more directly approach a target. A third targetted to make a particular vector hazardous should the target decide to manuever that direction.
Saturate escape vectors with rail gun rounds.
Now put this all coming in from three or four (or more) different sources, each with several missiles closing on different trajectories, with a minefield of rail gun rounds dispersed within it.
I forsee the player best able to master this as the winner.
I have also stated, and believe, that if the tech allows you to track target ships at interplanetary distances, and the game will track the projectiles over that range, that this is the range these battles will be fought at. With ships firing from Earth, Jupiter, and Saturn on a target near Mars as an example. And manuevering against the same problem.
I anticipate lots of caffeine, incredible headaches, terrible frustration with a computer that seems to crawl towards a resolution - and amazing fun !
But until the game actually comes out, it is all just a guess.
But with ships moving at 1000s of km/s speeds, a 1kg chunk of anything is death.
The best defense will be the same as it is now in a gun fight.
DON'T GET HIT.
;D
EDIT
I also love seeing people go through the math you did Sw Sad. Reaffirms my belief that not all folks out there have been swallowed up by video games.
I did the same thing (in a different vein) many pages back in this thread, but came at it from the G's induced by firing and the bearing strength of materials to show that a rail gun slug would become anything but a lump (at best). Guided railgun rounds even at MJ ranges without ships at least half a klick in length just aren't going to be anything but a crushed molten mass.
I also debated induced occilation/maximum achievable accuracy in the barrel of a rail gun when the possibility of firing 'planetkillers' at Earth from Neptune or past orbits. Your huge rail gun would be worthless as a ship to ship weapon. But if you jump in far enough out that hostile weapons may need days to reach you, that 23 minutes (or even an hour) per shot will still give your massive ship a LOT of time to dump death on a world before it turns and jumps out.
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Come to think of it, how about this.
Fuel is expensive. Ships in NA guzzle fuel incessantly and massive amounts of it are needed. Fuel fractions dominate designs.
Engines also cost alot.
A space station that doesn't use fuel will be incredibly cheap in comparison. It will be half the size or smaller than the equivalent ship.
So, to augment system defence fleets, colonies could build giant railguns in orbit. Need it to be three km long to shoot missiles? So be it. Stationary objects are dead anyway, so target profile doesn't matter so much.
The railguns will take time to die however, possibly even days. During which time, they could chuck an obscene amount of guided ordnance at things. A few of those guns could even be on interception duty, shooting sandcasters to interdict potential lines of fire. After all, you are not moving, so enemy ships shooting at you have their stuff travelling in straight lines. So chuck a ton of sand a million km out in the direction of a target and watch the fireworks.
Plus, while enemy missiles and rounds are targeting your cheap railguns (after all, they don't use fuel), those ammunition aren't targeting your expensive ships and your shots are forcing them to burn delta-v to evade. Evade all the way in-system until the railguns disappear in the flash of a TJ hit.
All while you wonder if they still have enough delta-v to get home.
Best of all, since target braketing will be very useful, this is a cheap option to providing another vector of attack.
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Come to think of it, how about this.
I like it.
Only one thought.
We all know that the stationary station is a goner. But a deadly goner. Its weakness may be long range strikes from a ship that jumps in at great distance, releases a payload, and then jumps out before return fire can engage/destroy it.
Then the next ship shows up in a month and cleans up the rest/starts the mobile battle.
Instead of big orbital bases - how about a half dozen small one that might be built in a short timeframe.
More ability to put mulitple slugs on a target to overwhelm defenses/ bracket manuevers/ etc. Or the ability to fire them at multiple ships that jumped in from widespread locations.
And if they jump out (having now burned a bunch of fuel...) and your stations bite the dust - you can rebuild the small/cheap platform in time for the follow on party (hopefully...).
But I like it. I intend to ruthlessly steal this.
;D
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But as an idle question -
Are there many (any?) other posts here that have nearly a thousand replies...???
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But as an idle question -
Are there many (any?) other posts here that have nearly a thousand replies...???
The official 5.2 suggestion thread has about 50 less replies than this one.
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We all know that the stationary station is a goner. But a deadly goner. Its weakness may be long range strikes from a ship that jumps in at great distance, releases a payload, and then jumps out before return fire can engage/destroy it.
Not too sure about that one.
Non-guided projectiles must necessarily be on a "constant bearing, reducing range" course, as a certain someone mentioned multiple times upthread. You know where the enemy ships were, so you know the axis along which any mass driver rounds must go through. And you have days to do it in. That's alot of interception shots.
Interdict it with multiple layers of sandcasters (your huge railgun length is precisely so your payload survives the launch), and hope you can blow up the incoming shots. They'll still be highly energetic plasma, but over a million km, it'll spread out enough.
Well, 1 million km ought to be enough until you get into the high relativistic speeds, but then that's a whole different kettle of fish.
Guided projectiles in the form of missiles can be shot at and intercepted with anti-missiles. With days in flight time, hopefully you have enough railgun launched AMMs to kill his incoming fragmentation missiles before they reach separation range.
For the record, I am not advocating humongous expensive railguns; I am saying we should build huge cheap railguns. It should be a low power railgun for the size, just that the acceleration is deliberately kept down so you can shoot a missile out the barrel. With much lower accels and power densities, you may not need much TN materials (after all, even a TN missile will be put through the wringer if they got fired out a hypothetical missile-launch railgun we could build today), bringing the cost way way down.
Capacitors and heatsinks are likely to be TN, but the barrel might not need to be.
Another nasty trick you can use is to hide the railguns on the surface of the planet, with short range planet-to-orbit tugs ready to move them out. Your enemy jumps into the system, he can't find anything. When he is well and truly committed to the mobile phase of the battle, bam! The railguns go into space and begin spewing shots, hopefully they will do something useful in their brief but exciting life.
Note that you can tell he is committed before the missiles start to fly, getting up to a good speed heading insystem or towards one of your system ship TGs is just as committed as being in the thick of it.
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Actually, NA combat is going to prove alot more interesting than TNA.
Single hits are devastating. Every incoming missile is a potential ship killer. Every railgun shot, even sandcasters, can be used to bleed shields or even sandpaper away at armour. (1g chunk won't kill your ship , but it sure can blow off a plate of armour)
This means that even single ships or PDCs can do disproportionately large amounts of damage for their cost.
Furthermore, the difficulty of generating intercepts and possibility of evasion means that additional angles of attack increase your chance to hit and damage of every other angle.
This means having the ability to strike from widely spaced areas with weak forces is going to be dominant over single concentrated fleets.
Taking the railgun station further, it would be prudent to have missile and railgun PDCs hiding on some asteroids and outer moons. Built to be small and hard to detect, with the intention of ambushing enemies en-masse. Cloaking tech also became a lot more powerful, as you can sit TGs some distance outside the hyperlimit under cloak and engines off.
Imagine your enemy's surprise when he heads in-system with his battleships against your feeble system defence destroyer squadron when the colony and an asteroid begin shooting missiles. And a light cruiser TG from outside the hyperlimit lights up and begins shooting missiles down the path he is going to retreat across.
For that matter, the way that NA warp drives split up warping fleets into individual squadrons across the system is an advantage. It spreads out the attacking TGs, giving them an advantage in generating favourable geometry.
EDIT: a way of storing the railgun stations on the planet would be a PDC hangar built for this purpose. Can dual role as strike craft base as well.
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Honestly, I'm still uncomfortable with the energy density that sorium seems to possess, just as the artificial hyper limit.
But embracing that mechanic, the mentioned tactics need not be suicidal.
A railgun station will require at least a small maneuvering drive, which would discourage an enemy from just jumping in, firing at them, and leaving; they'd need to bracket at least a few kilometers with fire to be sure;
If you tow them from the surface, once the enemy leaves, you can tow them back; Even a trace atmosphere will protect reliably against railgun rounds.
In a PDC, you could also store interception fighters, each equipped with a ship scale standard railgun and a small sandcaster, or alternatively a middleground of the two if such will ever be available.
Just start a few hundred of them, form a screen in front of the planet and fire in the general direction of an attacker, while your regular fleet keeps him endangered.
They'd be a great compliment to a railgun station, and their drives need to only contain enough fuel to break into orbit and get back, with acceleration to match. Should be cheap.
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Suggestion RE the hyperlimit:
Instead of having a strict hyperlimit, have a scaling risk of failure based on distance from stars.
At the traditional hyperlimit, the failure rate is 0%. This increases linearly to 100% across 10% of the limit distance.
The failure rate can be reduced by the crew grade (say, just a direct failure rate - crew grade = new failure chance, min 0%) so that more experienced crews can jump in/out closer and stay safe.
Perhaps have the size of the hyperlimit vary based on the grav survey.
Obviously, the failure rate for a particular command will need to appear somewhere, possibly in the Jump To Star command. (slider scale of desired failure rate and distance. Moving one causes the other to move appropriately)
As for what happens when it fails (whether the ship explodes or the jump just fails), that can be something suitably detrimental that it is a risk.
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Newtonian Aurora is going to need some form of vertical positioning. The 2-D abstraction worked pretty well with Standard Aurora. All the interesting stuff is on the orbital plane, and with 10,000 km considered point-blank weapons distance ignoring the implied vertical didn't hurt any. I sort of figured ship within a task-force were 10-100km apart justifingy both the single-ship CIWS protection and full squadron shared PD coverage. However, in Newtonian Aurora mere meters will matter with the introduction of area-of-effect nuclear explosions, debris shrapnel clouds, and more.
So, I'd like to propose Newtonian Aurora add a vertical dimension for task force stacking. For simplicity, the 3rd dimension could be ignored entirely for ship movement and only consulted as a final check for physical collisions and nuclear proximity.
As mentioned earlier, 10,000 km is/was point blank weapons range. Point blank range in Newtonian might be a lot shorter, perhaps 1,000 km. Going much smaller than that, and ships could easily have +/- 100 km wiggle room around the orbital plane and still have the vertical axis neglected. For task forces with less than 100 ships, the ships could easily all be 1km apart from their closest neighbor. When flying at speeds of over 1,000 km/s, a 1km separation would a rather tight formation, but would still save the fleet if one ship takes a nuclear missile.
So. Task force ships flying 1km apart. Room for 200 ships in a task force. The actual position doesn't matter much: we can assume any commander is going to fly at a random altitude to try to prevent an iron ball bearing from getting dropped in a predictable location. Anything non-targeted (like a rail gun fired at a passive contact) that happens to intersect the fleet could be assigned a random position between +100 km and -100km, and then check to see if it matches any unlucky ship hull. The chance of a random shot hitting a 20m wide object somewhere within a 200 km range isn't very good (0.01%). The odds of hitting one of 10 100m freighters is better (5%) but still requires a lot of spaying and praying. (Space is big.)
All objects fired at an active target might be assumed to have the same elevation as their target. So, a nuclear anti-missile missile could easily knock out all missiles fired from the same opposing taskforce against the same target, but might not take out missiles several km apart targeted at a different ships. This makes missile defense still much easier than Standard Aurora, but not so one-sided as it was currently looking.
Also, a 3rd dimension allows limited automatic dodging against active unguided projectiles. With 1-hit kills not getting hit is a priority. Adding a +/- 500m wiggle against actively targeted unguided projectiles would take a bit less than 500 m/s deltaV per day to dodge projectiles at least 10 minutes distant. The same protection against projectiles at least 30 minutes distant would cost a more affordable 53 m/s deltaV per day. The 95% dodge chance given a 50m wide craft isn't a substitute for proper 2-D zig-zags and won't apply against close range shots: yet such a feature might save a few lives among AI and inexperienced commander crews.
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On Speed: I'm with UnLimiTeD. I'm in the 'Sorium fuel consumption rate should be increased' camp. Probably won't happen since that would either slow the game down or require retaining an even more complicated hyperdrive. Oh well.
On the Hyper(Jump?)Limit. I'd suggest leaving it a hard line. Possibly adjust for commander survey bonus, but don't put a catastrophic failure chance in. Our ships will be fragile enough without them spontaneously detonating by mistake.
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Not too sure about that one.
I didn't say it would be an easy kill. But I am afraid the writing would be on the wall eventually.
I see the bases as powerful. But I just don't anticipate them surviving if someone was serious about taking them out.
Cheap and fast to build would be my main goals. If it could lay down a thick defense that would be great. I think sand casters would be perfect, but haven't heard Steve say anything about them - so I haven't put a lot of thought into the old Traveller standby.
The problem will be one of percentages.
Even supposing Steve puts a limit on rail gun ammo, and I need to dedicate a ton to get my 1000 1kg slugs, I'm ok with that.
And my jump carrier has three parasites - each with a rail gun or two. And I bring a couple carriers to make sure that I end up dispersed around the outer part of the system so that I can set up brackets.
Now the percentages come in.
If I can detect stationary targets, those will be a priority for a first jump in. Say at least one parasite from each group would be tasked to engage. And say that my rail gun needs 30 seconds between shots. It will unload its 1000 shots over about 8 1/2 hours. Then it will return to momma for the trip home. The odds of a weapon reaching the outer system in that time frame would be small. (Distant patrols will be vital I believe. Those PDC on distant asteroids, etc could be lifesavers.)
Now, the base has a string of deadly 1 kg chunks coming at it. Possibly from 2-3 directions. For a base I probably won't worry about coordinating TOT, just looking for volume.
The base will need to be able to detect the slugs (which I have no idea of how successful it will be. I have no idea how the NA sensors are going to work...), and then put up a defense that can stop them for a solid 8 hours plus. It will need to be able to see a 1kg slug moving at 4000km/s from 4000km just to have one second to react. That isn't much time for the sandcaster to deploy. And you will have to be able to detect them at amazing ranges, otherwise you will have a terrible time predicting the exact time they will arive so your sandcaster isn't excessively dispersed.
And it needs to be 100% effective.
Because at 99.9% - one of those slugs got through...
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Depending on how thick the atmosphere of your colony is, it might not cost all that much to bring the station back down into a PDC hangar.
Secondly, you do know where the slugs are coming from if you see the enemy ships (and if your colony can't see them, then why are you building these guns?). Your planet and station aren't going to move, so necessarily their incoming rounds are going to be limited in firing arc. Very limited.
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Depending on how thick the atmosphere of your colony is, it might not cost all that much to bring the station back down into a PDC hangar.
I am completely unfamiliar with any previous version, so taking an orbital station down into a PDC is new to me. Could be very useful in this instance. I don't know what this entails so I will be going on faith here. It ought to take a healthy amount of fuel to keep moving between orbit and the surface though. I don't know what the mechanics are for this at all.
Secondly, you do know where the slugs are coming from if you see the enemy ships (and if your colony can't see them, then why are you building these guns?). Your planet and station aren't going to move, so necessarily their incoming rounds are going to be limited in firing arc. Very limited.
I didn't say you wouldn't have a pretty good idea where they would be coming from. Again, I have no familiarity with Aurora and how good the sensors are. I am assuming they are far enough away you can't detect the gun firing. If you can detect the firing from interplanetary distances then you will have a very good fix on the origin - if not just which target.
The trick is unless you know the ship design that is firing at you - you will have no clue when they are going to show up. You can take a guess, but when talking about the distances I envision an error of a hundred km/s could make the first slugs showing up anywhere in a couple of hour timeframe.
And if you don't know exactly when they are going to show up, and can't see them very far out, it may be difficult to stop them effectively. Again, my lack of any familiarity with aurora means I have absolutely no idea what is possible in this area.
The defense will have to be very effective though if you have strings of slugs coming at you over a span of eight or so hours. Again, one screw up shooting them down and it could be over.
The game will be the best place to find out.
And I expect to have a lot of fun finding out... ;D
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The game will be the best place to find out.
And I expect to have a lot of fun finding out... ;D
XD Post a small projectile detection sensor along the expected angle. You won't know the time they come, but if the enemy ships just leave, your system defence frigates near your colony (you have some there right? right?) can go hang around on the correct bearing a couple of million km out.
Since we assume your DSTS can see enemy ships jumping in and out, you know the bearing the slugs are coming by to incredible accuracy. Compared with interplanetary distances, a couple of million km gives you a comparatively large error tolerance (you can miss the angle by half a degree and it probably won't matter) thus you have alot of wiggle room to put your ships.
You'll have a few minutes warning.
As for landing your stations in PDC hangars, depending on how the game mechanics bear out, it could be instant deploy. >.> Which uh, would be hax.
A TN Aurora version of this scheme (with long range drones) could land the railgun base instantly. Obviously, in NA, you'll probably have tractor beams or tugs or some suitably cheap low-powered thing to move it on/off the planet.
Lol, if we could land ships in PDCs instantly, energy weapon battles against enemy bases became pointless. The bases could recharge on the surface where railguns and lasers can't reach them, then pop up to fire.
<Needs fixing.
Mini-fiction EDIT:
The battle destroys a few PDCs and the retreating enemy ships fired a barrage of rounds (or at least they appeared to). A few bases cannot land due to lack of space and a desperate defence is mounted. Round after round detonates on the thick cloud of dust placed in the way, escort ships spotting a seemingly endless shower.
Ten grueling hours, desperate hours, later, one freakishly lucky metal pellet misses enough sand and a railgun base disappears in a brilliant flash of light, thousands of men and a fine officer didn't even know they were hit before the entire base vapourizes. At the speeds the rounds travel, a hit explodes like a thermonuclear device, even though nothing in the target or round is explosive. It is the only one to make it through, the huge clouds of sand are already dispersing, but for the next decade, ships approaching the colony are restricted to sub 1000 km/s speeds or require shields due to the orbiting dust.
Alternatively:
The system commander (aka. you) could decide that defending the bases isn't worth risking the lives of crew and officers. Abandon the bases to their fate and evacuate!
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Post a small projectile detection sensor along the expected angle....
Since we assume your DSTS can see enemy ships jumping in and out, you know the bearing the slugs are coming by to incredible accuracy....
You'll have a few minutes warning.
Ok, this is where my familiarity of Aurora is going to crimp my ability in the first few games. I just don't know how far out I will be able to see the slugs. I expect to see the ships a long ways off. It looks like you don't see missile (much smaller) until they are considerably closer. I just don't know how far off you will be able to see the slugs.
If sensors designed to see missiles (something measured in meters) are a fair factor less efficient than those used to see ships (which is what it looks like) - how effecient are they going to be when used to spot a (assuming just a 1kg ball of copper) slug about 5-6 cm/2" across closing at what may be 10K km/s? If you have minutes, you can spot that little pup a long ways out (over half a million km's?).
If that little ball of metal is even harder to see than the missiles - I am afraid your response time will be measured in seconds.
But I don't know how far out in standard Aurora you can see a rail gun slug (if there are any...).
Obviously, in NA, you'll probably have tractor beams or tugs or some suitably cheap low-powered thing to move it on/off the planet.
Sounds good. And if it works for the stations - will it keep me from using fuel to take my ships off from a planet?
Mini-fiction EDIT:
The battle destroys a few PDCs and the retreating enemy ships fired a barrage of rounds (or at least they appeared to). A few bases cannot land due to lack of space and a desperate defence is mounted. Round after round detonates on the thick cloud of dust placed in the way, escort ships spotting a seemingly endless shower.
Ten grueling hours, desperate hours, later, one freakishly lucky metal pellet misses enough sand and a railgun base disappears in a brilliant flash of light, thousands of men and a fine officer didn't even know they were hit before the entire base vapourizes. At the speeds the rounds travel, a hit explodes like a thermonuclear device, even though nothing in the target or round is explosive. It is the only one to make it through, the huge clouds of sand are already dispersing, but for the next decade, ships approaching the colony are restricted to sub 1000 km/s speeds or require shields due to the orbiting dust.
Alternatively:
The system commander (aka. you) could decide that defending the bases isn't worth risking the lives of crew and officers. Abandon the bases to their fate and evacuate!
I like your story. Very nice.
As long as I have ammo left or a population in danger - I would mount the defense.
If the base is empty, I may decided to devote my attention and effort elsewhere.
(My apologies to the fine crew. 'The needs of the many... and such.') :'(
;D
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Ok, this is where my familiarity of Aurora is going to crimp my ability in the first few games. I just don't know how far out I will be able to see the slugs. I expect to see the ships a long ways off. It looks like you don't see missile (much smaller) until they are considerably closer. I just don't know how far off you will be able to see the slugs.
If sensors designed to see missiles (something measured in meters) are a fair factor less efficient than those used to see ships (which is what it looks like) - how effecient are they going to be when used to spot a (assuming just a 1kg ball of copper) slug about 5-6 cm/2" across closing at what may be 10K km/s? If you have minutes, you can spot that little pup a long ways out (over half a million km's?).
If that little ball of metal is even harder to see than the missiles - I am afraid your response time will be measured in seconds.
I think jseah is talking about passive thermal sensors. If you know where all the enemy ships are, you know any projectiles the fire will have to be roughly on the intercept line from their possition to your projected position at a speed no greater than the enemy vessel's closing speed + 100km/s. If the thermal energy spike generated from firing is vissible (no clue if it would be) then you also know when they fire. For all of this actualy seeing the projectile isn't required.
For active detection no Standard Aurora knowledge is needed: the sensor system is being redone for Newtonian.
Using the new rules, the sample 150 ton resolution-1 missile detection sensor can spot a 4-ton missile 2.2m km out. If our 1kg projectile has the same density as a missile, then it has 1/4000th the mass and volume, 1/16th the radius, and 1/252 the cross sectional area. This gives a detection range of... 35km. Even at a standard firing velocity of 60 km/s, you have less than 1s reaction time. With 5s increments odds are the projectile would pass an advance scout without ever getting noticed. You may as well assume projectiles are undetectable and not waste processor time checking.
There is no indication that a resolution smaller than 1 is possible, but lets see what things would look like if there was a projectile sensor. Say, a 0.01 resolution sensor, sized to optimally detect 4 kg objects. This would have a maximum detection range of 220k km for a 150 ton sensor. A 1kg projectile would be seen at 35k km for a 1,000x improvement. Even a projectile accelerated to 3.5k km/s would still leave a 10s detection window.
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The point was that you know the angle the projectile must approach and so you can camp your ships along that line to spot the incomings. And likely, NA will force very large missile sensors, due to the range you need to react properly. (AMMs take forever to get to decent speeds)
Eg. in my proposed defense tactics, I do mention having multiple groups carrying their own size 25 sensor (1250tons) for missile detection.
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The point was that you know the angle the projectile must approach and so you can camp your ships along that line to spot the incomings. And likely, NA will force very large missile sensors, due to the range you need to react properly. (AMMs take forever to get to decent speeds)
If we are talking a pure newtonian setting, then time to accelerate your AMMs shouldn't have any (well, much anyway) bearing if you are on or relatively close to the line of flight of the missiles you are intercepting. Absolute speed has no impact on maneuverability (a newtonian missile in a vacuum doesn't care at all about its "absolute velocity" or velocity relative to its launcher as far as maneuvering goes), so all you have to consider is closing velocity and "sideways speed," i.e. relative velocity normal to the intercept velocity, which becomes zero if you are on an intercept path. Launching AMMs early gets you standoff distance at intercept (which in practical "real" terms can mean that you have time for followup intercepts or that you are far enough from the resulting explosion to not have to worry about blast, shrapnel, or radiation effects), but kinetically there should be no improved capability to intercept. It can even be argued that intercepting farther out and at higher velocities decreases the likelihood of a successful intercept- timing becomes trickier for a warhead which must detonate within a certain distance of the target, and distance and delta v from the launcher results in less signal strength from the launcher's active sensor, and more doppler shift to deal with.
Mike
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Yes, but follow up intercepts for leakers is rather important. Assuming interception rates are roughly the same as in TN Aurora, you're going to want many interception chances.
In fact, given that missiles tend towards one-hit-one-kill, AMM defense is pretty much compulsory. Beam only defense gets one shot on the final approach, and a full salvo of ASMs will very likely leak at least one. (remember that ASMs can do evasive maneuvers too, and they have a tiny cross-section to displace)
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On the other hand, they likely won't come in salvos as a single nuke can blast them all.
After all, they need to hit more of less the same target.
A sandblaster should be an option there.
The most dangerous ASMs in my book as Laser Rod Warheads and Shrapnell, set off at a distance of a few kilometers.
Lower hit/Kill rate, but way harder to intercept as well.
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^When I said salvoes, I meant something more like 10+ ASMs travelling from the same firing ship on slightly divergent initial vectors. They could essentially travel together, yet be far enough apart that you can't nuke them all. 100km separation is nothing in Aurora.
Also, ASM + Escort AMMs in attack groups ala the ones I posted about in the Tactics thread would also be a massive headache to deal with without multiple interception chances. There will probably be less groups than a pure ASM bumrush that we see now in TN Aurora, but the saturation of TN Aurora-style salvoes will mean you will need multiple interceptions anyway.
NA's missiles being able to change accelerations and generally act more intelligently would radically change missile warfare. But some things stay the same. Like saturation. ToT salvoes are even easier, with missiles being able to make minor course correction burns (the ahead ones slow down a bit and the behind ones speed up), don't even need the TN Aurora hack of multiple slightly slower designs.
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On the other hand, the defender might just fire high power lasers in the direction of any potential target, all the time.
With no limit in range, they are bound to hit something.
Damn, combat's gonna get complicated.
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On the other hand, the defender might just fire high power lasers in the direction of any potential target, all the time.
With no limit in range, they are bound to hit something.
Damn, combat's gonna get complicated.
Unlike railguns, though, lasers do have a range limit (when their damage drops below 100 MJ/m²). Inside that limit they'll be far more accurate, though, so I suspect lasers will be the premier anti-missile/anti-fighter weapon, with railguns being the weapon of choice for taking out large, well protected ships.
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Any chance NA would be continued? =D
Would play it even if there was only railguns, lasers and missiles. That's more or less good enough to do everything.
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Any chance NA would be continued? =D
Would play it even if there was only railguns, lasers and missiles. That's more or less good enough to do everything.
There is a chance. Just had a lot less free time since I stopped playing cards and got a real job again :)
Steve
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real jobs pay the bills ;D
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real jobs pay the bills ;D
Playing poker also pays the bills but now my wife and I are both awake at the same time :). Anyway I am still in poker, just working for the house now :)