Space Combat Techniques Discussion

[Ghostrider]

You can use self-propelled bullets, as I suggested a long time ago in a thread far, far away. It's actually a proven concept, we've had antitank rockets for a while now and the Gyrojet weapons were developed in the '50s.
The main problem with the Gyrojet was the low muzzle velocity (the rocket needed some distance before it accelerated to max speed) but with some reworking you could have the propulsion charge spending itself in the firing chamber. We do have explosives that burn fast enough. This way you solve both the recoil problem and the spent cases, because the whole round is ejected, and you have less moving parts.

 

[RisingFury]

You can use self-propelled bullets, as I suggested a long time ago in a thread far, far away. It's actually a proven concept, we've had antitank rockets for a while now and the Gyrojet weapons were developed in the '50s.
The main problem with the Gyrojet was the low muzzle velocity (the rocket needed some distance before it accelerated to max speed) but with some reworking you could have the propulsion charge spending itself in the firing chamber. We do have explosives that burn fast enough. This way you solve both the recoil problem and the spent cases, because the whole round is ejected, and you have less moving parts.

Actually, if you the ejected propellant from the rocket / RPG round hits the launch vessel, you got rid of instant gun recoil, but the propellant still imparts a linear and possibly angular momentum.

 

[T.Neo]

The problems with firearms are lubricant issues, thermal shock, and dissipation of heat.

Recoil is not a problem if you brace yourself against an object (which you will be doing, because you'll be behind cover). It was worked out that a .45 would give 0.12 m/s of Dv to a 50kg person (and probably less to a heavier person + spacesuit etc).

Vacuumn lubricants, like molybdenum disulfide, can be used with firearms. They tend to get everywhere and leave a big black mess though.

Temperature shock would potentially be a major problem, IMO. Firearms are already designed to withstand a range of temperatures (maybe -30 to 50C), but they're not built to withstand the temperature extremes, and temperature shocks, encountered in space. Potentially this could be mitigated by giving the parts large clearances or perhaps adding insulation and thermal sinks, but you can only do so much.

Getting rid of heat is also a problem in space, because in a vacuum the only method of heat loss is radiation. This would probably make fully automatic weapons like machine guns impractical. It's important to note, though, that lasers produce a lot of waste heat and this would probably make them impractical as well.

The Gyrojet concept mentioned by Ghostrider is pretty cool, and useful as well. If the cartridges could be made to expend their propellant wholly within the barrel, they might become very practical.

a firearm on the Moon would have to deal with that pesky regolith stuff that clings to your moving parts tighter than an umbrella street salesman on a rainy day.

Debris mitigation is already important in firearms. I'd imagine that enclosing the moving parts within the weapon well enough, as well as adding a dust flap or case-catcher to the ejection port (if there is one) would suffice.

At least there isn't any corrosion in a vacuum, for what it's worth...

 

[Ghostrider]

Getting rid of heat is of paramount importance with semiauto and automatic weapons because after some sustained fire, you run the risk of your weapon going auto on its own because the temperature is so high that cartridges cook off by themselves. Modern firearms are air-cooled, and moreover one of the reasons caseless ammo has not caught on despite being experimented on by at least 20 years is that part of the heat generated by the cartridge firing is expelled with the case.
Now, in space this is not enough and probably part of the solution could be going back to the ol' Vickers and cool the weapon with liquid, or gas. This of course means you now have to cool the gas or the fluid, or to dump it into space.

With rocket-propelled bullets part of the problem is solved already, because the "cartridge" is already contained within the projectile and leaves the weapon, and the gas generated by the firing can be vented into space with lateral, forward-canted ports. Now, we can't use the original Gyrojet design because, apart from the rockets using slow-burning propellant, the gun itself has the big problem that, in case one rocket misfires, you have to go through an unholy long process to clear it. With conventional semiautos or automatics, you just cycle the action and it's done but gyrojet-like weapons would have a radically different mechanical design because you don't have a bolt or slide to cycle - essentially because you have no recoil and little gas to make it work.

I'm a semiauto person myself but I think going back to the revolver design could have its advantages: you have very little in the way of moving parts, compared to a semiauto, and if you have a misfire you just pull the trigger again. Reloading could be an issue because using a speedloader with spacesuit gloves feels a little awkward, but what about having the whole cylinder as a magazine? It's already done in the Amsel Striker shotgun, after all...

 

[Ark]

I can think of one possible problem with ballistic weapons: Wouldn't spraying bullets (self-propelled or otherwise) all over the place completely foul the area you're trying to take over with space debris? Bullets are slow compared to orbital speed, so they're just going to settle into a slightly different orbit than the thing you're shooting at. It doesn't do much good to knock the enemy out of, say, a piece of geostationary orbit you want to take over if the installations you build there get shredded by bullets you fired weeks ago.

Heck, I can't think of an event that creates more debris than combat.

 

[Kevon Daye]

Another problem with Lasers (at least as an offensive weapon) is that, aside from their range being limited to "knife fight" distances, they can be spoofed by diffraction. For example if a vessel were to disperse vapor around itself, if it were thick enough, it could essentially dissipate the beam to the point of uselessness. Although, they could be used quite well in a defensive role against projectile weapons (this idea is actually used in Mass Effect, the GARDIAN laser)

http://masseffect.wikia.com/wiki/GARDIAN

 

[Ghostrider]

Heck, I can't think of an event that creates more debris than combat.

Kindergarten kids at play: they redefine the term "mass destruction".

 

[Hartmann]

I always considered the point of Orbiter was whatever you want it to be. While I'm not interested in combat myself, the collision detection, Autopilots/AI, and scripting elements are VERY interesting.

A lot of technical advances and discoverys come from military investigation, so it could be interesting for orbiter too :lol:

In space the better weapons are high energy lasers and missiles despite it can cause huge problems of space debris when they hit the target. And more with conventional weapons, for example a single 12 shotgun shell fired in a retrogade orbit hundred of miles away can cause extensive damage in any spacecraft

Lasers can be deflected by shielding or reflective materials
http://www.wired.com/dangerroom/2008/07/spray-on-laser/

 

[Kevon Daye]

A few ideas for some weapons (and defense systems)

"Thor" Orbital Bombardment System: Releases(in orbit) hundreds of solid metal projectiles (no larger than baseballs) carried in racks. The projectiles would be shaped in such a way that they lose as little kinetic energy as possible during descent. On impact, they would be travelling at such speed as to give them the explosive force of a (rather large) artillery shell. The projectiles would also be semi-molten at the time of impact.To be used in support of ground operations in place of (or complimentary to) terrestrial artillery.

Vapor Diffraction Laser Defense System: Releases a cloud of water (or other liquid) vapor around the ship, diffracting (and therefore neutralizing) the beams of directed energy weapons.

Independently Controlled Rocket Propelled Projectile Launch System(Try saying that in one breath):Essentially a rocket launcher with RCS thrusters, independently controlled from within the spacecraft. Alleviates the problems of Recoil generally encountered with firing projectile weapons in zero-g.

 

[T.Neo]

As to whether bullets pose a debris risk, they're not going to be in the vicinity of the target/firer for long. You'd be surprised at how far away you can get from something, at 200-300 m/s.

The problem of debris sticking around in orbit for months or years is a valid one, but one that cannot really be avoided, if you are destroying a target (the target will become debris).

"Thor" Orbital Bombardment System: Releases(in orbit) hundreds of solid metal projectiles (no larger than baseballs) carried in racks.

AFAIK Project Thor used tungsten rods, ranging in size from crowbars to telephone poles, not spheres.

Vapor Diffraction Laser Defense System: Releases a cloud of water (or other liquid) vapor around the ship, diffracting (and therefore neutralizing) the beams of directed energy weapons.

Won't work, the vapour cloud would have to be far too dense.

 

[Kevon Daye]

AFAIK Project Thor used tungsten rods, ranging in size from crowbars to telephone poles, not spheres.

I didn't know there was already a similar project idea by that name, I just thought it up (no really). Looking it up on wikipedia now.

Edit: Found
http://en.wikipedia.org/wiki/Project_Thor#Project_Thor

 

[Hartmann]

A few ideas for some weapons (and defense systems)

"Thor" Orbital Bombardment System: Releases(in orbit) hundreds of solid metal projectiles (no larger than baseballs) carried in racks. The projectiles would be shaped in such a way that they lose as little kinetic energy as possible during descent. On impact, they would be travelling at such speed as to give them the explosive force of a (rather large) artillery shell. The projectiles would also be semi-molten at the time of impact.To be used in support of ground operations in place of (or complimentary to) terrestrial artillery.

Vapor Diffraction Laser Defense System: Releases a cloud of water (or other liquid) vapor around the ship, diffracting (and therefore neutralizing) the beams of directed energy weapons.

Independently Controlled Rocket Propelled Projectile Launch System(Try saying that in one breath):Essentially a rocket launcher with RCS thrusters, independently controlled from within the spacecraft. Alleviates the problems of Recoil generally encountered with firing projectile weapons in zero-g.

Judge: A concrete block with a reentry shield and a round or balistic shape with all energy as possible for estrategical bombardment. The size could depend of the intended effects...

Reflective shields: coating material for spacecrafts and warheads to dissipate laser energy by reflection.

The spider: a net of wire that is fire in a orbit to destroy all satelites incoming missiles and spacecrafts in the same orbit, usually fired in retrograde orbit.Also could be covered with explosive contact grenades.

 

[eyu100]

If the net hit spacecraft fast enough, grenades wouldn't increase the damage much because the net because more (kinetic) energy would be dissipated in the collision than chemical explosives could ever contain.

EDIT: for example, a mixture of beryllium and oxygen has a specific energy of 23.9 MJ/kg. If the net's orbit is on the same path as the target but in the opposite direction, then it has a specific kinetic energy of roughly 125 MJ/kg in a reference frame where the target is stationary. Assuming the target's mass is much greater than the net's, almost all of this energy will turn into internal energy.

Source for first number:
[ame="http://en.wikipedia.org/wiki/Energy_density"]Energy density - Wikipedia, the free encyclopedia[/ame]

Source for second number (earth's escape velocity differs from its orbital velocity by a factor of sqrt(2)):
http://www.wolframalpha.com/input/?i=(2*+(earth+escape+velocity+/+sqrt(2)))^2+/+2

 

[Blacklight]

How about a swarm of radio controlled "bombletts" that you can fly out of one ship, to the skin of another ship, where they attach and then detonate or completely disable the craft by sawing into it or something. It would be like docking a bee swarm to a ship without having to dock to a docking port.

 

[jedidia]

it's nearly impossible to dock anything to a ship that doesn't want to be docked to...

 

[T.Neo]

Reflective shields: coating material for spacecrafts and warheads to dissipate laser energy by reflection.

Won't work. No mirror is perfectly reflecting, and the energy that it does absorb will cause the reflective layer to ablate, rendering the mirror useless.

The only solution against lasers, is putting a good deal of mass between the laser and the stuff you want to protect. If this can be one and the same with your propellant, it is a bonus (because rockets need large amounts of propellant, and carrying large amounts of armor is prohibitive).

The spider: a net of wire that is fire in a orbit to destroy all satelites incoming missiles and spacecrafts in the same orbit, usually fired in retrograde orbit.Also could be covered with explosive contact grenades.

Contact grenades are a waste of time. An object impacting at 3km/s delivers kinetic energy equal to it's mass in TNT.

 

[eyu100]

Won't work. No mirror is perfectly reflecting, and the energy that it does absorb will cause the reflective layer to ablate, rendering the mirror useless.

What about a large liquid mirror?

 

[jedidia]

how are you gona hold it in place?

 

[Ghostrider]

Why mirrors? Just have an ablative armor that disintegrates into reflective particles. That will scatter the beam a lot.
Besides, armor is not homogenous. It's made in layers, and you need multiple layers to dissipate the energy from both DEWs and kinetic weapons.

 

[Hartmann]

Another curious countermeasure

SUPERCONDUCTIVE ENERGY DISPERSIVE ARMOR
Tech Level: 15
If room-temperature superconductors are ever developed, an even more effective defense against lasers becomes available. Fabric interwoven with superconductor wire would instantly absorb the incoming electromagnetic energy of the laser beam and disperse it evenly over its entire surface area. The energy re-radiates almost instantly into the surrounding air as heat. The laser would have to pump enough energy to completely destroy the entire armor all at once before it could penetrate through to its true target. If the superconductor mesh in the armor were cooled via refrigeration unit or a heat sink, even more energy would be required to overcome the armor.

http://www.orbitalvector.com/Firearms/Laser%20Countermeasures/Laser%20Countermeasures.htm