Guns in space!

[tedrick79]

Ok very simply. Would a firearm fire in space?

 

By firearm I would like to use the most widely known weapon on all the planet. The AK-47. Built for its rugged bile pocket making abilities. Would it function as advertised in the hard vacuum of space?

 

 

 

 

I tend to think it would. It is a gas operated weapon - the gas is contained in the gunpowder/cordite in the casing. The casing is sealed and requires no external oxygen - it will fire underwater although it might not recoil and reload properly due to water dragging on the internal parts.

 

Does anyone imagine that a firearm would not function in space? If so why not?

[Boerseun]

Firearms should fire perfectly well in space.

 

The oxidant required is included in the chemical mix in the shell casing, and the firing pin is a spring-loaded operation.

 

The only problem I can see is if half the weapon is in sunlight and the other half in the shade. The thermal difference might make the mechanism unpredictable, and the barrel might taper unevenly due to thermal expansion/contraction. If the tip of the barrel is in the shade (way below the freezing point of water) and the firing mechanism is in sunlight (way above 0 Celcius), the bullet might jam in the barrel. The bullets in the magazine might even go off due to heat. Simple preventative measures like a shiny reflective gold foil covering might prevent thermal stresses, but the vacuum of space will have no influence that I can foresee.

 

On second thought, you might also have lubrication issues, which is imperative for the smooth operation of any gun. It might fire once or twice and then just jam solid because the oil in the mechanism have boiled away in the vacuum. But then again, you are talking of an AK, which is famous for firing like a charm after having been shoved up a dead elephant's butt that drowned in a crocodile-infested swamp for thirty years.

[modest]

Some of the most reliable things used in space are explosive bolts and cable cutters. I would suspect bullets would perform equally well. Even with explosives which are not vacuum safe (e.g. RDX sublimates in a vacuum) the bullet itself should be vacuum safe so it would probably still work fine if it had RDX in the primer for example.

 

The mechanics of the gun on the other hand—I agree with Boerseun. First and foremost: the oil in the gun would most certainly freeze so if you're taking your firearm into space I'd recommend wiping it clean of oil first. :hihi:

 

~modest

[Moontanman]

I think the barrel on a gun such as the AK-47 would over heat and fail since there would be no air to cool it. Other than that i see no reason it wouldn't work. The recoil would make the operator spin so some action would be necessary to avoid that.

[modest]

Moony, I, for some reason, am assuming you know this. How much force is required to remove the bullet from the shell? If you hung 2.2 lbs on the bullet (of, say, a .45) holding the shell static would the bullet come out?

 

If that amount of force is not enough to remove the bullet from the shell then a hard vacuum should not be a problem for the bullet itself. The difference in pressure (of inside the shell to outside the shell) should not be enough to force the bullet from the shell. But, I've never done such a thing and a quick search doesn't turn up anything.

 

~modest

[Racoon]

What interests me most about this topic is the fired bullet!

 

How long/far/fast would the bullet travel at its original velocity? (assuming it doesn't intersect with an asteroid or satellite, and avoids any major gravitational pull from celestial bodies)

If there is no resisitance from atmosphere, conceivably the bullet would travel perpetually across the galaxy and universe.

 

Since even a floating paint chip from space debris is said to be a "dangerous projectile" traveling at extreme rates of speed,and the impact would be that of a gun-shot, I can only imagine an actual fired bullet :eek: ;)

[Moontanman]

What interests me most about this topic is the fired bullet!

 

How long/far/fast would the bullet travel at its original velocity? (assuming it doesn't intersect with an asteroid or satellite, and avoids any major gravitational pull from celestial bodies)

If there is no resisitance from atmosphere, conceivably the bullet would travel perpetually across the galaxy and universe.

 

Since even a floating paint chip from space debris is said to be a "dangerous projectile" traveling at extreme rates of speed,and the impact would be that of a gun-shot, I can only imagine an actual fired bullet :eek2: :shrug:

 

 

Actually the speed of the bullet as fired would be small compared to it's orbital velocity. a bullet fired in orbit would simply go into orbit around the body it was fired near. if you encountered that bullet in the same orbit it was in and in the same direction it wouldn't be any different than being hit by the bullet on the earth, But if you were in a different orbit and encountered the bullet at it's orbital velocity you would be in trouble for sure. a bullet is much bigger than a fleck of paint and would have tremendous energy on impact.

 

;) Fire all of your guns at once and

Explode into space! :eek:

[CraigD]

How long/far/fast would the bullet travel at its original velocity? (assuming it doesn't intersect with an asteroid or satellite, and avoids any major gravitational pull from celestial bodies)

If there is no resisitance from atmosphere, conceivably the bullet would travel perpetually across the galaxy and universe.

Solar escape speed from the Earth is about 42100 m/s. A typical assault rifle’s initial projectile speed is about 1000 m/s. The greatest chemical-powered projectile speeds are about double that. Earth’s orbital speed is about 30000 m/s. 30000 + 1000 to 2000 is less that 42100, so, no matter which way you fire it, you won’t be able to shoot a bullet free of the solar system.

 

Escape speed from a typical low Earth orbit is about 11000 m/s. A typical LEO orbital speed is about 8000 m/s. 8000 + 1000 to 2000 is less than 11000, so you won’t be able to shoot a bullet free of the Earth from LEO, either.

 

Starting with the formulae for orbital and escape speed, you can calculate the distance from its primary an orbiting body must be for a projectile shot from it to escape. The formula’s

[math] r=u \frac{(\sqrt2 -1)^2}{v^2} [/math], where [math]u = MG[/math], the primary’s standard gravitational parameter.

 

Working this out for a 1000 m/s projectile, Earth escape is possible at r= 68389024 m, about 62000000 m altitude, about 26000000 m above geostationary orbit, about 20% of the way to the Moon. For a 1000 m/s projectile escaping the Solar System, we get 22769854915837 m , about 152 AU, nearly 50 AU further out than Voyager 1. For a 2000 m/s projectile escaping the Solar System, it’s only about 38 AU, about the orbit of Pluto.

 

So, a really good tank gun in Pluto’s orbit (not actually on Pluto, but say, on one of it’s tiny icy neighbors) could shoot a projectile out of the solar system!

[modest]

Ok. I've figured a problem in our pirates-of-the-inner-solar-system plan. A typical .45 has a diameter of ~104mm. The pressure inside the cartridge is presumably 1 ATM which is 0.01033 kg/mm². This means there will be a force of ~1 kg (9.8 Newtons or 2.2 lbs) trying to force the bullet out of the shell in a hard vacuum.

 

I think a fair number of bullets placed in a hard vacuum would separate. The bullet would be forced from the shell before it is ever fired. I'm basing this on a youtube demonstration of a bullet remover where it seems very little force is required to remove a bullet from its shell:

 

YouTube - How To Use A Kinetic Bullet Puller http://www.youtube.com/watch?v=yAvLAsyTVC0

 

Yeah, I think if you put a bullet in a hard vacuum there would be a good chance the bullet would pop right out of the shell. Of course, this depends on how much gas there is inside a cartridge. Hummm....

 

~modest

[CraigD]

Ok. I've figured a problem in our pirates-of-the-inner-solar-system plan. A typical .45 has a diameter of ~10[.]4mm. The pressure inside the cartridge is presumably 1 ATM which is 0.01033 kg/mm². This means there will be a force of ~1 kg (9.8 Newtons or 2.2 lbs) trying to force the bullet out of the shell in a hard vacuum.

 

I think a fair number of bullets placed in a hard vacuum would separate. The bullet would be forced from the shell before it is ever fired.

You might be right, modest. Though I never measured it directly, I’ve reloaded thousands of cartridges of various rifle and pistol types, and on a few occasions had to pull the bullets from a batch of crimped cartridges after making a mistake in the powder load or bullet. I had a handy little tool for this, a kind of complicated pliers, so never directly pulled on a bullet, but would guess the force needed to be in the 2 to 10 N (1 kgf, 2 lb.) range.

 

1 atmosphere = 101325 N/m², so the force exerted by this pressure on a 0.009 m (9 mm) diameter bullet is [math]\Pi \cdot 0.0045^2 \cdot 101325 \dot= 6.4 \,\mbox{N}[/math], which might be enough to pop the bullet out of its case. The change in pressure would need to be fairly sudden, though, and the cartridge not in a magazine that would prevent the bullet from expanding much – though all the cartridges in a mag lock themselves in it with more force than the mag’s spring could overcome could be as dramatic a problem for our space-pirates as contending with a mess of lose bullet and powder. :(

 

It wouldn’t be a hard problem to overcome, though – just crimp your cases or notch your bullets a little bit to make a channel to assure the pressure inside and out are always equal. A bullet doesn’t depend on the tightness of its seal with its cartridge other than to keep water out and the powder in, so the worst this would do make your ammunition non-waterproof, which wise folk already assume to be the case.

[modest]

A typical .45 has a diameter of ~104mm.

 

A typical .45 has a diameter of ~10[.]4mm.

 

Yes. It seems my posts of late are mostly, but not entirely, unlike something legible. :D

 

A .45 indeed has not a diameter of 104 mm, but a rear surface area of 104 mm² which might then make apparent why I'd multiply that by 0.01033 kg/mm² to give ~1 kg or ~9.8 Newtons. ;)

 

You might be right, modest. Though I never measured it directly, I’ve reloaded thousands of cartridges of various rifle and pistol types, and on a few occasions had to pull the bullets from a batch of crimped cartridges after making a mistake in the powder load or bullet. I had a handy little tool for this, a kind of complicated pliers, so never directly pulled on a bullet, but would guess the force needed to be in the 2 to 10 N (1 kgf, 2 lb.) range.

 

Excellent. It didn't even occur to me that someone loading their own cartridges would occasionally have to pull one that set bad. That's excellent confirmation.

 

 

1 atmosphere = 101325 N/m², so the force exerted by this pressure on a 0.009 m (9 mm) diameter bullet is [math]\Pi \cdot 0.0045^2 \cdot 101325 \dot= 6.4 \,\mbox{N}[/math], which might be enough to pop the bullet out of its case.

 

Yes. Agreed. My only question...

 

The change in pressure would need to be fairly sudden, though

 

I intuitively think you're right, but logically have not convinced myself of it. In my experience, the best way to remove a cork from a wine bottle is with a slow and steady force. An equal force which is quick and fleeting doesn't seem to accomplish as much.

 

In other words...

 

While watching that youtube video I considered that the bullet probably had a mass around 30 grams (a complete guess, I have no clue) and the hammer maybe accomplished 20 gees giving a force somewhere in a very large vicinity of .6 x 10 = 6 Newtons. I didn't think to consider that the force was a jerking one. Should that matter? Does going from 0 to 6 Newtons in an instant accomplish more in the way of bending metal or overcoming static friction than building up to 6 Newtons slowly and sustaining it?

 

, and the cartridge not in a magazine that would prevent the bullet from expanding much – though all the cartridges in a mag lock themselves in it with more force than the mag’s spring could overcome could be as dramatic a problem for our space-pirates as contending with a mess of lose bullet and powder. :(

 

Either way the results could be hilarious :hihi:

 

Dirty Harry: I know what you're thinking. "Did he fire six shots or only five?" Well, to tell you the truth, in all this excitement I kind of lost track myself. But, being as this is a .44 Magnum, the most powerful handgun this side of the solar system, and would blow your head clean off, you've got to ask yourself one question: Do "I feel lucky?" Well, do ya, punk?

 

Criminal: I was actually thinking "Did he fire five shorts or only four" because it looks like the sixth has popped clean out of your revolver and is now floating over that way...

 

:eek:

 

~modest

[SaxonViolence]

The Bullet's spin gives it Gyroscopic Stability when fired in Atmosphere.

 

Without Air, the Bullet would tumble.....End over End.....but in a Vacuum, that wouldn't effect Accuracy. It probably would Wreak Havok on the Penetration though. (Hitting Broadside is not conductive to good penetration--the area to be breached is necessarily so much larger...)

 

For Space use, Hardened Round Balls might be the way to go.

 

As far as Atmospheric Pressure forcing the Bullet out--I don't think so. Fighter pilots--who get very close to space sometimes--are regularly issued Guns and Ammo for Survival kits. Most modern cartridges burn more efficiently if the bullet doesn't move during the first few microseconds, letting heat and pressure build momentarily. I'm fairly sure that the starting pressure is several of Earth's Atmospheres.

 

I know that I've seen this topic discussed several times over the Decades, in "The American Rifleman", the NRA's Periodical.

 

If you're a Member, you can send them any Gun related question in care of the "Dope Bag" {Back when they named it, "Dope" meant insider info...}

 

I've sent them a many technical questions, sadly my membership is currently expired, and on $850/month, I'm not likely to rejoin anytime soon.....

 

If I were looking for a Pro-Gun PAC, I'd much prefer the JPFO { Jews for the Preservation of Firearms Ownership}. They do not compromise. However, the NRA does have a fine Magazine, and a fine Museum, a fine Library and an Excellent Staff to answer Technical Questions.....

 

But they are Constantly compromising.....

 

But if anyone is a member still, Write to "Dope Bag" and ask Them.

 

Saxon Violence

[suresh123]

According to me the bullets can be fired with some changes in gun in the space.

The only thing which can be a problem is chemical reactions ,atmospheric pressure and the gas propulsion system.

[Moontanman]

The Bullet's spin gives it Gyroscopic Stability when fired in Atmosphere.

 

Without Air, the Bullet would tumble.....End over End.....but in a Vacuum, that wouldn't effect Accuracy. It probably would Wreak Havok on the Penetration though. (Hitting Broadside is not conductive to good penetration--the area to be breached is necessarily so much larger...)

 

For Space use, Hardened Round Balls might be the way to go.

 

I think you are mistaken in this assertion. gyroscopic stability does not depend on an atmosphere, in fact space probes are sometimes spun to attain stability.

[CraigD]

gyroscopic stability does not depend on an atmosphere, in fact space probes are sometimes spun to attain stability.

True. But the reasons spacecraft are spun is primarily to permit them to maintain the orientation of their communication antennae and rocket motors without expending as much RCS propellant. A large spacecraft like the ISS maintains its attitude entirely through the use of internal gyroscopes, needing to expend propellant only in the case of a failure of its gyros, and to make small orbital maneuvers to maintain its orbit, and, occasionally, dodge possible space debris collisions.

 

This thread seems to have proceeded nicely from “can you fire an AK is space?” (having decided that the cartridges wouldn’t pop their bullets before they were fired, I think we reached a consensus of yes on that question) to “what’s a good shape of a space bullet?” and “should it be spun (via rifling, etc)?”

 

Since there’s no (or, to be completely accurate, not much) air in space, the shape of bullet doesn’t affect how far and at what speed it will travel. This leaves 2 domains of interest – how the shape of the bullet and the gun’s barrel effect their performance under pressure in the barrel – its “internal ballistics”, how fast and accurately the bullet is projected – and how they affect what they hit – how effectively they damage their target.

 

My guess is that the internal ballistics of a gun fired is space wouldn’t be much different than in an atmosphere. Rifling might prevent “rattling around in the barrel” that would affect accuracy, and as most small firearms, including our example Kalashnikov, already have it, see no need to change anything.

 

Though, as SV notes, it doesn’t affect their accuracy or range if bullets tumble in space. With no air friction, bullets in space would, I think, be effectively limited in range only by the accuracy with which they could be aimed, and be moving faster when they hit their targets than they usually do, when fired in an atmosphere.

 

How effectively the bullet works when it hits its target is, as on Earth, more complicated, depending on what’s being shot. Though not armored in the traditional military sense, spacecraft have and surely will continue to be built to minimize damage from micrometeorites, which while mostly smaller than bullets, are mostly much faster, so it’s reasonable, I think, to consider a typical spacecraft to be proof against a small number of bullets, but not against many, much like a typical armored passenger car.

 

People is spacesuits are much more vulnerable, because in addition to the trauma of being shot, could die quickly due to loss of air from bullet holes in their suits, or damage to air-supply hardware. Given how bad this would be, and since mass is less of a burden in the microgravity of space, I’d expect that if there were much chance of being shot at there, you’d want to armor as much of your spacesuit as possible, and build in self-repair features.

 

I hope speculation like this never has application outside of science fiction, and humankind maintains its perfect record of no gunfights, or fights of any kind, in space.

[Moontanman]

I honestly wonder if a gun has ever been taken into space... like a just in case type thing?

[modest]

Though not armored in the traditional military sense, spacecraft have and surely will continue to be built to minimize damage from micrometeorites, which while mostly smaller than bullets, are mostly much faster, so it’s reasonable, I think, to consider a typical spacecraft to be proof against a small number of bullets, but not against many, much like a typical armored passenger car.

For some reason I find that aspect interesting.

 

I did a google image search for 'whipple shield velocity' and found ballistic limit curves for a couple different shielded ISS modules,

 

-source

 

Anything above the solid line is projected to penetrate the shielding on the Destiny ISS module and anything above the dotted line could penetrate the better-shielded Columbus module.

 

I put the red and blue dots on, blue for a .22LR and red for a 30 ought 6.

 

It looks like high power rifles would have a good chance of penetrating at least some of the shielded areas but that the shielding would be good protection against less energetic rounds.

 

I honestly wonder if a gun has ever been taken into space... like a just in case type thing?

I thought it was funny when I heard soviet era cosmonauts took vodka with 'em. Guns somehow don't seem like a huge leap. Pilots in combat are sure to have a sidearm and there's no telling where a returning capsule might have to ditch—like an apollo craft having to touch down in north vietnam :o