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Hi all, I'm about to start a big writing project, and as I'm such a geek it's going to be set in space...but I want to keep it at least somewhat realistic, so need a few tips:

So, keeping it in as simple layman's terms here's what I'm trying to find out.

1 - Would projectile/ballistic weapons as we know them even function in a vaccum?

2 - Assuming the answer to the first question is "yes", in a vaccum, would projectile weapons (guns/cannons/etc) prove slightly more effective upon impacting their targets, as there is no air resistance to slow the shots down over large distances?

3 - Can things explode in a..uh, shall we say, cinematic sense in space? As in huge balls of fire? Or would it literally be an unseen wave of force?

4 - If the answer to the above is "yes", would more damage be caused through the actual heat/flames or simply the overpressure wave?

I've done a bit of poking around but can't seem to find anything I can get my head around. THanks in advance

As to 1: I'm fairly certain most modern firearms would work in a vacuum. There's air inside the shell itself, so it should be able to ignite.

I'd say recoil could be an interesting problem, though.

As to 3: I'm honestly unsure.

MetalHead wrote:So, keeping it in as simple layman's terms here's what I'm trying to find out.

1 - Would projectile/ballistic weapons as we know them even function in a vaccum?

Sort of. Something like a revolver would be your best bet but even then the alternating heat and cold soak of space would do awful things to lubricants and clearances in a precisely machined weapon. You'd likely get off a shot or two if the weapon was kept insulated in a safe place and only exposed to space for a few moments before being used but beyond those first few shots I wouldn't count on the weapon functioning.

Now, a heavily modified weapon could be made to work in a space but it would have to be precisely designed.

2 - Assuming the answer to the first question is "yes", in a vaccum, would projectile weapons (guns/cannons/etc) prove slightly more effective upon impacting their targets, as there is no air resistance to slow the shots down over large distances?

You wouldn't really notice much of a difference in terms of terminal effects until you start getting into extreme ranges. For instance a pistol shot at 50m in space or on earth is pretty much the same in terms of damage. A rifle shot at 300 yards in space vs. on earth pretty much the same thing. Theoretically you could fire at targets kilometers away with a pistol in space and hit with as much damage as you would at 25m but good luck aiming a pistol with that kind of accuracy.

3 - Can things explode in a..uh, shall we say, cinematic sense in space? As in huge balls of fire? Or would it literally be an unseen wave of force?

Unless you're shooting directly at a giant tank full of liquid oxygen, no. Even then the fireball would be a very short lived sort of thing. And you wouldn't really have a wave of force. What you see in a terrestrial explosion is actually a shock wave of compressed air. Well, no air in space and the gases released in a space explosion would dissipate very quickly. The main danger from an explosion in space is shrapnel.

4 - If the answer to the above is "yes", would more damage be caused through the actual heat/flames or simply the overpressure wave?

No real overpressure wave and no flames and minimal radiant heat. The only danger source is shrapnel.

3. There was a great Season 5 episode of B5 (season 5 did have a couple of them ) about 2 maintenance guys going about their lives during an attack on the stations. One of the guys points out to the other that when an Earth fighter explodes, theres a different colour flash then when an alien ship explodes, due to the different gases inside.

Tyyr sounds like he has the right of it, but are cartridges airtight? I never imagined that they were - and if not, no combustion and therefore no motive force for a bullet. At best the primer would be airtight, which would probably lead to either nothing or the the bullet (or whole cartridge) just dribbling slowly out the end of the barrel.

Mikey wrote:...are cartridges airtight?

Observe.

No, gun powder contains both a fuel and an oxidizer. Otherwise they'd never work.

very interesting video. The story is going to be in a futuristic enviornment, so a little sci-fi allowing for vaccum operable infantry weapons shouldn't be to hard to work out...I think however, that the best thing about the explosions will be helpful, so I reckon that most explosive devices like grenades, mortar fire, that sort of thing will be more geared towards just basically blowing huge amounts of tiny sharp objects everywhere, the key idea to be to rupture a pressure suit.

And actually, what about a shaped charge? Say if you're trying to breach a doorway or something of that nature?

That, and missiles. I'm assuming that missiles (dumb-fire) would still work in the normal way, where whatever chemical propellants drive them forward towards their intended targets?

To give some background, I'm going to be writing about a huge assault on a space station, where troops literally go EVA from their ships to try and take several large landing bays, and then move through the station. and by large landing bays I mean large enough to land something about twice the size of an Iowa-Class fast battleship

Explosives are explosives, they'll still work.

Something worth pointing out though if you plan to use conventional weapons. There's no air in space. Most assault rifles and machine guns are air cooled. With no air and only radiation to carry away heat most of your commonly carried weapons will start to overheat very rapidly without some form of active cooling system either tied to a large radiator or something like a block of ice.

Then of course there's the recoil issue as well.

Tyyr wrote:Then of course there's the recoil issue as well.

That, however, is dependant on what environment he's working in. If it's an atmosphereless body such as the moon (which is the impression I get due to the reference to mortars) then recoil shouldn't be much of a problem.

True, but I read space station and thought of something in orbit.

well, conventional weapons in the sense that they fire a type of projectile, similar to a bullet. Like I said, a bit of sci-fi will justify infantry weapons working in a vaccum, just want to try to make it seem realistic...that, and I'm sure I read somewhere that energy weapons, scientifically atleast, aren't really feaseable and wouldn't be as effective in causing damage to a target.

and of course recoil would mean alot of problems during EVA, but I think the idea is that none of them will fire until they enter an artifical gravity field on the station. What I meant by mortars was more a sense of general artillery, or weapons designed to cause an area of effect type damage. For example, as the troopers float towards the station, the defenders will launch shells into their midst, the shells will detonate and throw shrapnel everywhere.

Some form of self-propelled projectile, like a gyrojet, would help with recoil. You'd only have to deal with the (relatively light) recoil of the primer.

I was thinking that the guns themselves are normally designed to fire on a planet, or pressurized environment. However, there's special equipment that can easily make a rifle or other firearm capable of operation in a vacuum. Once the soldiers reach pressure and atmosphere, the kits are discarded to make the weapons lighter. I've got a lot of thinking to put into it but the focus will be more on the plot, rather than the science. I just wanted to get an idea of how feasible it would be to have a fire fight in a vacuum. Hopefully, with a bit of science...or maybe, psuedo-science, it will sound believable

Heres a thought. Instead of bullets propelled by an explosion (ie, regular gun), why not magnetic acceleration?