"Would Bullets Work In Space?" Topic

Along the lines of this topic, TMP link , I've always wondered if bullets would fire in space where there is no oxygen. The primer firing and setting off the gunpowder in the casing are acts of combustion, which is the combining with oxygen, but there's no oxygen in space.

I am leaning towards my own speculation that in a sealed cartridge there's sufficient oxygen, but is the seal between projectile and casing completely airtight? Would the air/oxygen enclosed as part of the manufacturing process eventually leak out? Does the combustion of the main casing rely on oxygen outside the bullet, or in the barrel and/or chamber?

SOmeone might call me a twit and explain patiently like one would to a simpleton that if a missile works in space because it's a rocket, there's no reason why a bullet would not behave the same way. However, a missile has all the materials it needs for its combustion and energy release (does it not?), but I don't think the chemical process is the same as what happens with gunpowder, otherwise we wouldn't have needed Drs Goddard, Van Braun, et al to get us into space.

I'm interested in any comments or a definitive answer, thanks in advance!
--
Tim

For gunpowder working the oxidizer for the reaction is contained in the powder. In the case of gunpowder itself this is the Potassium nitrate. Edit: it works no external oxygen needed just like the rocket.

x42

Do all high explosives have to have their own oxidising agent else the reaction would be too slow to errrmmm explode?

As an aside, is an air fuel bomb technically an high explosive?

20 years ago we had this discussion at my RP group. The biggest problem could be recoil. Aside form that it was suggested the heat caused in a vacuum may weld the mechanism shut. Also Automatics that relied on gas pressure would not fire on auto.

link

'Course your pistol might cold-weld. Cold-welding, laymans, is sort-of like welding with microscopic points of contact which, via extreme pressure and lack of intruding oxides, "weld" together with van der Waals forces at contact. In short, a really powerful molecular attraction. Of course, this has been argued by the infamous Henry Spencer as of 2006 that there have been *no* unintentional occasions of cold-welding. So this may not apply. *Shrug*

It would seem to me that a beam or particle or gyrojet-based weapon would be preferable in some cases.

YMMV

Hussar,

You may be correct, but I was under the impression that the gas used in autos was waste gas from the exploding propellant, so no external gas is needed.

Mark

Of course once you fired the bullet there would be no way of ever stopping it. Techinically it would tear through the universe at the same speed for near infinity or until it collided with another object or was caught in the gravity of another object.

Not a very high velocity dean~, just about Mach one. And constant deceleration due to space dust and such small particles.

As an aside, is an air fuel bomb technically an high explosive?

no its not a high explosive, its a high combustion agent, it gets it power from its large area covered by the agent when it is iegnited, displacing very large amounts of air, making a presser wave more powerful then can be made using HE. This wave is what does most of the damage outside the flame/blast zone.

think of it like a grain silo explosion. only designed to get the most out of it
It can even be done with baking flower.

Of course once you fired the bullet there would be no way of ever stopping it. Techinically it would tear through the universe at the same speed for near infinity or until it collided with another object or was caught in the gravity of another object.

Just like on Earth.

I was under the impression that the 'gas' was air that was compressed by the passage of the bullet. Wiki supports you

a portion of the gases propelling the bullet from the barrel are ported off

but then it is wiki. I don't know enough about the mechanism to know if the second method would still work in space. Recoil is still going to be the biggest problem.

If the recent PBS Nova special I watched is correct, the Soviets had no problem getting the 23mm cannon mounted on their orbital platform to fire. This was back in the late 60's or early 70's.

link

The 23mm looked like it was taken from a MIG and bolted on the outside of the platforms superstructure.

Aiming-and recoil-were a bit of a problem.

At about 3 degrees Kelvin, how does one keep the gun barrel from shattering when firing?

Ralph

Gun powder in bullets is a "low explosive" in that the explosion is sustained. This saves the chamber and barrel from too much pressure and pushes the bullet along for the duration of the charge.

High explosives deliver their pressure very quickly compared to low explosives. Low explosives are often a mix or composite while high explosives are often an actual compound.

Low explosives are propellants and high explosives are used for destructive devices. I know all of this stuff because as a re-enactor years ago I did a lot of research on the powder mixes that were used in the cannons I worked on.

Yes, guns do work in space in a vaccuum. Yes, automatic guns work in a vaccuum as they use the "gas" of the propellant/burning of the gun powder and recoil to propel the shell casing backwards and the springs in the weapon bring it back forward. As for the cold – if you took the weapon out into the vaccuum and immediately fired it – it would not have sufficient time to bleed off all of the heat already in the weapon so it would work fine as a vaccuum is rather poor at dissapating heat. The problem then would be the recoil as there is nothing solid to absorb the recoil. However, they are researching various recoil dampening systems which will allow a man to fire weapons like 80mm mortars from the shoulder without recoil killing you which might have applications in space.

I am assuming the idea is if one fired a weapon as is in a condition found on Earth…off the shelf and into space?

I would say no.

But there are lots of ways to fire a "bullet". Compressed gasses work just fine to move the fellows around in space suits so it should work for a projectile. Magnets would work fine, no real heat…although I am unsure as to the value of magnets off the Earth…I had never considered that before, how weird…but their are examples of magnetic boots, so I am assuming electro-magnets would work fine. And self propelled would be fun.

Interesting thought process though.

Supposedly, greater care will need to be exercised in cleaning weapons, since if excess oil, and other material are left on, it could freeze, causing the weapon to jam.

The barrel won't be 3 degrees after it's been in sunlight for a bit.

There will be cooling problems with the weapon after it's fired -- no air to convect heat away.

The bullet casing contains air (in with the powder). The lack of counterpressure on the outside may cause either the casing/bullet seal to break or the casing to distort.

The bullet won't be able to rely on aerodynamic effects to stablise it; although it'll be spinning, there won't be the re-centring forces from the pointed nose. On the plus side there'll be no air friction..

short answer: Yes, you could take a Colt .45 auto (M1911A1) and shoot it off in space. It will fire just fine, and the (recoil-based) operating system will load the next shot without trouble. Even the oft-maligned M16 will fire and load the next cartridge, as gas pressure from behind the bullet is used to push the bolt back and cock the hammer. The internal springs will push the bolt/slide forward in either case.

However, you will very shortly have temperature-related problems due to the hot barrel expanding faster than the cold(er) slide, causing a jam that will last until the two get closer to the same temperature. Also, you would have to use special ammunition with a slightly smaller projectile for the first couple shots.

Cold-gas (ie, airgun) or rail/coilguns would be better, but you do still have to obey Mr. Newton. There's a great illustration of this in an episode of Cowboy Bebop (Heavy Metal Queen), where Spike uses his pistol as an emergency maneuvering unit.

If your weapon is tied into the space-suit's maneuvering system, then you could have it set up so that every time you pull the trigger the MMU compensates for it.

The *best* weapons for use in space are those that have no recoil, like gyrojets, missiles, or lasers. Gyros and missiles would need to be big enough to have a real explosive payload, probably at least 12gage/18mm, otherwise they'll have trouble at close range due to the low initial velocity.

Well, there is the scene from Firefly where Jayne shoots his gun from a space suit

Erik M wrote:

Not a very high velocity dean~, just about Mach one.

And what speed is mach one in a vaccum, do tell?

All the best,

John.

I'll take a 10 or 12 gauge, with birdshot, and an open choke…..

Not a very high velocity dean~, just about Mach one.

And what speed is mach one in a vaccum, do tell?

333 metres per second. Mach numbers are independent of the vagaries that adjust the speed of sound up and down, of course, as they are set measurements of the average velocity of sound waves at standard temperature and pressure.

Nice try, John :)

As has been stated, the argument I've always heard is that the bullets carry their own gas with them in the casing (even if it is in a solid form pre-ignition). I've always wondered if that would be ENOUGH gas for proper operation, but it seems that it would be.

Doug

Covert Walrus wrote:

And what speed is mach one in a vaccum, do tell?

333 metres per second. Mach numbers are independent of the vagaries that adjust the speed of sound up and down, of course, as they are set measurements of the average velocity of sound waves at standard temperature and pressure.

Utter nonsense. The whole point of the Mach number is that it relates the speed of an object to the speed of sound in the medium it is travelling through. But, hey, don't believe me:

link

NASA says you're wrong.

All the best,

John.

Tell you what. Let's get NASA to have the shuttle take a number of guns up with them next time so we can rest this puppy once and for all.

Although they've already had a married couple up in space and they didn't answer the one question that was nagging every one's mind at that time. How is sex in zero g's?

WOW….didn't know all these rocket scientists hung out on the TMP website…

"Tell you what. Let's get NASA to have the shuttle take a number of guns up with them next time so we can rest this puppy once and for all".

No need to.

The Russians already have them. They claim they are for protection from bears and wolves, when their capsules land, but I am a bit skeptical of that. I imagine pepper spray would work just as well.

Just ask them to open the hatch, and fire at will.

Are you saying the Russians have fired them off in orbit just to see if they still work already?

And Richard we're all rocket scientists here, I was just suggesting we put this to NASA physicists just like the writers of Babylon 5 did for some of the technical effects and problems for the series. They after all put forward the question of explosions and fire in space, NASA figures as long as there is a gas escaping from the ship there can be fire and a close proximity boom sounds.

Lion in the Stars said

the (recoil-based) operating system will load the next shot without trouble.

I would not be confident of that statement. A recoil based system in micro gravity may have the firer moving rather than fully work its internal mechanism. It would depend on the firer's mass, the mass of the parts moved in the weapon and the spring tensions of the weapon. I believe that it would work but would not be confident until I saw the calculations or knew of a test firing.

x42

@Richard1967 – LOL, nice one!

"Are you saying the Russians have fired them off in orbit just to see if they still work already"?

Not that I know of, and I doubt they would like to share that info. Besides, they are only to be used to fend off bears and wolves. ;-)

Wouldn't surprise me though, nor would it to find out the NASA astronauts have done the same. Many of the missions conducted by NASA, and the spaceshuttle were military in nature.

I remember reading in the seventies that NASA on a moom mission did take a 45 to the moon and used it just fine. also heard this from a NASA employee that was a friend of the family.

Lord Ghee

Actually, muzzle velocity depends on weapon. My example Colt .45 auto bullet is moving at about 200m/s, while the M16 bullet is moving at about 900m/s.

x42, the .45 does move the firer, even in 1 gee. Your arm rises up from the recoil, and a sensitive pressure plate under the feet can measure the force transferred into the ground. The difference is that the 200lb soldier in full gear only moves back at about 3m/s, while a 400lb space-suited astronaut would barely be moving @ 1.5m/s. Also, the recoil force vectors are perpendicular to the gravity vectors, so gravity pretty much doesn't impact the operation of the weapon.

You see, the .45 (and every other delayed-blowback pistol) has parts intended to start moving about the time the recoil force hits the shooter's hand. These parts have all absorbed some portion of the energy of the shot, and move 'independently' of the weapon/shooter to load the next shot.

If you have time/motivation, stand at the top of a cliff with a pistol in hand, and shoot past your toes straight down. The pistol will still work, and now gravity is fighting the action.

So the Russians have shot space-wolves? Quick, tell the National Enquirer and the Daily Sport!

My theory is if they can conquer space travel they can develop bullets that will work in space.

What, the wolves?

John--Good question--As there is no sound in space the speed of sound (and therefore Mach number) would be 0 or something equally silly…..
Also as force(newtons)=mass x velocity a .45 could have the force of a 16inch shell if fired at a target in a vacuum with no friction or much gravity……

John D Salt, thank you for that, I stand corrected; I thought like most measurements, Mach numbers were standardised.

And thank you for your typically American charm and grace in correcting me. :)

Covert Walrus wrote:

John D Salt, thank you for that, I stand corrected; I thought like most measurements, Mach numbers were standardised.

They are standardised -- just not the same way other things are. ;-)

And thank you for your typically American charm and grace in correcting me. :)

As Americans are in my experience vastly more polite than we Brits are, I take that as a compliment.

And I promise not to mistake you for an Aussie.

All the best,

John.

If the recent PBS Nova special I watched is correct, the Soviets had no problem getting the 23mm cannon mounted on their orbital platform to fire. This was back in the late 60's or early 70's.

link

The 23mm looked like it was taken from a MIG and bolted on the outside of the platforms superstructure.

Aiming-and recoil-were a bit of a problem.

I saw a special that talked about a machine gun being mounted to the exterior of the Soviet Salyut 3 military space station. Some reports say that the machine gun was fired while in outer space, but a few cosmonauts have claimed that there was no machine on the station.