Ok, strange question. . . .

[towerwarlock]

Ok science guys out there. Can a firearm be fired in a vacuum such as space? Put aside the BAD idea of doing so in zero-g. I know that they can be fired underwater and have seen them done so. But what about a vacuum?

The reason I asked, is I remember the rifles used by the Starship troopers in the Roughneck Chronicles, and was thinking and wanted to know.

 

[rust]

Yep, rifles can be fired in a vacuum, because the propellant used includes
the oxidizer for the oxygen needed to burn the propellant.

 

[GypsyComet]

In modern slug-throwers, everything needed for bullet propulsion is IN the bullet, so that's not the issue.

In a hard vacuum, metals will tend to "weld" to each other, lubricants will volatilize, and temperature extremes will make some parts of a firearm very brittle. Any and all of these can lead to misfire or weapon self-destruction. They can also all be compensated for with the right materials.

Short Traveller answer: maybe.

Longer Traveller answer: If you bought the gun on a thriving member world of the Imperium, the gun has the stamp of a large multi-world corporation, or the gun is, by its in-game description, designed to fire under those circumstances, then you should have no problems. Just don't go buy an elephant gun from some backwater gunsmith who considers your starship a curiosity and expect to fire it in space...

 

[towerwarlock]

That is what I thought.

 

[klingsor]

Good answers except oxidizer is the wrong term if I have read you correctly - but I cannot recall what the right one is!

[Correction. Actually he is quite right and I am wrong - egg on face time!]

Recoil is the problem if you are in micro-gravity conditions, hence such things as the accelerator rifle and snub pistol.

One does wonder about the effects of hard vacuum on cartridges. Will they tend to loose volatiles and thus their effectiveness? Again my chemistry is hopelessly inadequate to answer this question. Modern fixed cartridges are pretty durable but do decay and I cannot see a vacuum helping. Ones made for use in space would have better sealing but would it be good enough for prolonged exposure?

 

[rust]

Good answers except oxidizer is the wrong term if I have read you correctly - but I cannot recall what the right one is!

In German it is "Sauerstoffträger" ... :lol:

 

[captainjack23]

Good answers except oxidizer is the wrong term if I have read you correctly - but I cannot recall what the right one is!

In German it is "Sauerstoffträger" ... :lol:

German is the coolest language for technical terms....

 

[aspqrz]

In modern slug-throwers, everything needed for bullet propulsion is IN the bullet, so that's not the issue.

In a hard vacuum, metals will tend to "weld" to each other, lubricants will volatilize, and temperature extremes will make some parts of a firearm very brittle. Any and all of these can lead to misfire or weapon self-destruction. They can also all be compensated for with the right materials.

Short Traveller answer: maybe.

Longer Traveller answer: If you bought the gun on a thriving member world of the Imperium, the gun has the stamp of a large multi-world corporation, or the gun is, by its in-game description, designed to fire under those circumstances, then you should have no problems. Just don't go buy an elephant gun from some backwater gunsmith who considers your starship a curiosity and expect to fire it in space...

Longer answer: Depends.

If you've just entered Hard Vacuum through an airlock, then the mechanics of the pistol don't *instantaneously* freeze/vacuum weld.

How quickly they might ... or might not ... would depend on how they are holstered, whether you/the weapon/the holster were in shadow or sunlight, and the speed at which the materials in question might lose (or gain) heat according to convection. conduction or radiation.

The bigger problem would be the lubricant ... but in arctic conditions I believe graphite based lubricants are used, which don't volatilise, and, where not available, cleaning the weapon and removing *all* traces of lubricant is an alternative ... just don't use said weapon on autofire, and, if a semiauto, don't fire off too many rounds too quick.

Phil

 

[Mongoose Pete]

The bigger problem would be the lubricant ... but in arctic conditions I believe graphite based lubricants are used, which don't volatilise, and, where not available, cleaning the weapon and removing *all* traces of lubricant is an alternative ... just don't use said weapon on autofire, and, if a semiauto, don't fire off too many rounds too quick.

There is also the very important question of what happens to the propellant. Although it will still explosively combust (assuming the ammunition's chemicals are still at something akin to room temperature), the material merely changes its state/volume... not its mass.

So with each round shot there will be a large cloud of gas & particulate residue expanding as a cloud from the barrel. This will condense and freeze as it hits vacuum, low temperature and any cold surface. This may rapidly clog the barrel of the weapon, depending on the gun's ambient temperature.

Thus firing a few rounds of ammunition may produce some rather pretty mist-like clouds of diffusing ice crystals, blocking your vision a few moments before the condensate vacuum freezes the firing mechanism. Or if the weapon remains warm from auto-fire, you might even get icicles building up at the end of the barrel!

 

[Vile]

Good answers except oxidizer is the wrong term if I have read you correctly - but I cannot recall what the right one is!

In German it is "Sauerstoffträger" ... :lol:

German is the coolest language for technical terms....

Yep, you can't beat them sour stuff carriers. And you want to make sure you carry lots of the sour stuff when you're high up in the flying stuff! :lol:

 

[Zemekis]

So with each round shot there will be a large cloud of gas & particulate residue expanding as a cloud from the barrel. This will condense and freeze as it hits vacuum, low temperature and any cold surface. This may rapidly clog the barrel of the weapon, depending on the gun's ambient temperature.

Thus firing a few rounds of ammunition may produce some rather pretty mist-like clouds of diffusing ice crystals, blocking your vision a few moments before the condensate vacuum freezes the firing mechanism. Or if the weapon remains warm from auto-fire, you might even get icicles building up at the end of the barrel!

I don't think so. There are only three ways the gas could lose temperature:
a) interacting with other way cooler materials, e.g. some of the aforementioned sour stuff or other gases
b) thermal radiation
c) instant decompression

Since we are speaking of a vacuum here with pressures of 10E-7 Pa (about 16 particles per cubic inch) and less option a) is out of the question which leaves b) and c). Thermal radiation is a rather slow process which leaves c) as the only way possible.

However, the entire mechanism of guns are built around a highly pressurized agent (usually pressurized gas generated by the explosion) which propels the bullet by decompressing quickly in one direction. The gun's natural function is to decompress and I have never seen ice crystals flying from a gun. A vacuum will only speed the process and help disperse the gases and residues faster after they left the muzzle. If a weapon generates a small cloud within the atmosphere the cloud will vanish even faster in vacuum.
I would even go so far and say you see no cloud in vacuum at all.

 

[rust]

Yep, you can't beat them sour stuff carriers. And you want to make sure you carry lots of the sour stuff when you're high up in the flying stuff! :lol:

I would expect the carriers to get quite sour if they have to carry the stuff
to high altitudes. :lol:

 

[Dave Chase]

So, who wants to propose the next civilian experiment for a shuttle launch.

Send up the following and require the astronaunts to fire at least 6 round each

38 special revovler
9mm (or 45) automatic
44cal blackpowder pistol
22cal semiauto rifle
12ga pump shotgun

Dave Chase

 

[simonh]

Some good, well though out answers here. This is one case where Firefly got it wrong - in one episode the crew hold a gun inside a space suit and fire it out of the faceplate because the gun won't work without oxygen. Doh!

Regarding degradation of cartridges, the propellant is in a sealed cartridge so I doubt there'll be any loss of volatiles.

None of the technical challenges seem intractable and as has been suggested, I'd expect most weaponry traded on the interstellar market to be fully usable in vacuum, and the rest to at least work in a reduced function mode (perhaps semi-auto only). For lower-tech weaponry (below TL9) I might impose a reliability penalty but player characters are rarely going to be stuck fighting in a vacuum with low tech firearms.

Simon Hibbs

 

[Zemekis]

I forgot to answer the initial question:
Yes, modern day weapons can be fired in space. The propellant is mostly based on nitrocellulose usually combined with nitroglycerin. Both contain enough oxygen for the reaction.
http://en.wikipedia.org/wiki/Smokeless_powder
http://en.wikipedia.org/wiki/Nitrocellulose
http://en.wikipedia.org/wiki/Nitroglycerin

However, I wouldn't rule out that Firefly's Vera still needs additional oxygen or air to work properly. The might not be enough pressure inside to rechamber the next round. Vera might turn into a single shot-weapon.

 

[GypsyComet]

Some good, well though out answers here. This is one case where Firefly got it wrong - in one episode the crew hold a gun inside a space suit and fire it out of the faceplate because the gun won't work without oxygen. Doh!

I've have to watch that one again, but I seem to recall that the gun in question had either an ammo cycling or other mechanism that might fire properly *once* in vacuum but not be reliable for further shots.

 

[Mongoose Pete]

I don't think so. There are only three ways the gas could lose temperature:
a) interacting with other way cooler materials, e.g. some of the aforementioned sour stuff or other gases
b) thermal radiation
c) instant decompression

Option a) is possible if the barrel is cold at the time of firing.

Option b) does work in space, since the smaller the particle (i.e. the greater the surface area to mass ration) the quicker it radiates its heat. Basically, the finer the mist the quicker it freezes. Most of the explosion's heat will radiate away very quickly as infrared radiation.

Option c) is basic physics, and is what drives your fridge or air conditioning. In fact the propellant in an earth fired gun does actually condense as part of its explosive expansion, which is why you have to regularly clean the residue from the barrel. Although firing the weapon in normal terrestrial pressure reduces the heat loss, the greater the pressure difference the more endothermic the decompression will be.

Cheers!

 

[Shiloh]

Good answers except oxidizer is the wrong term if I have read you correctly - but I cannot recall what the right one is!

Pretty sure "oxidiser" is entirely correct.

 

[klingsor]

I checked and I am wrong - I had it arse about face - the oxidiser has the oxygen and loses it in the reaction. Thanks for the correction.

 

[Woas]

Please excuse me, I don't mean to hijack the thread but I had a follow up question on this topic...

Ok, I understand that theoretically a single or maybe even a dozen or so bullets could be fired (successful explosive chemical reaction) in a vacuum because of oxidizer in casing. But what about the heat generated by a gun firing many bullets over time (auto/burst for example)? The friction of the bullets down the barrel and repetitive hot gases will quickly heat that puppy up. In a vacuum which lacks the atmosphere and thus medium to support convection and conduction the only choice is heat radiation. What problems would that cause? Could some sort of 'radiator' attachment work?