Newtonian Aurora

[Rastaman]

As such, we're discussing a possibility for large handwavium shields to prevent planets from being victimized by this.

Or mutually assured destruction.

[Yonder]

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.

[Bremen]

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.

[Vex]

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. 

[Mysterius]

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.   

[UnLimiTeD]

@ 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://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.

[Bremen]

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.

[Yonder]

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.

[Bremen]

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.

[chrislocke2000]

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.

[chrislocke2000]

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.

[Mel Vixen]

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).

[Eseraith]

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

[JimiD]

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 and here 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.

[Dutchling]

I haven't read all the essays in this thread so this might be posted before. But what about mire controls?