Newtonian Aurora

[DatAlien]

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

[UnLimiTeD]

As long as you don't attach a return address, I'd say thats fine. 

[Steve Walmsley (OP)]

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

[Steve Walmsley (OP)]

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

[Steve Walmsley (OP)]

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

[wedgebert]

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.

[Mel Vixen]

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 .

[UnLimiTeD]

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?

[Din182]

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.

[Brian Neumann]

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

[Antagonist]

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.

[PTTG]

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.

[DatAlien]

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

[Gidoran]

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.

[waresky]

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"..