Guns in space

[Telperion]

Space is cold. In interstellar space, matter will cool to 2.7 K or -455 °F. I don't think barrel steel or bullet jacket will hold up well at that temperature.

 

[benEzra]

assuming the shooter is in earth orbit (rather than interstellar space,etc) the bullets ultimate trajectory is going to depend on the direction that it is fired, because the gun and shooter are already travelling about 18,000 mph

fired "forward", the bullet would eventually (if it doesn't hit anything) settle into a higher orbit. fired backward, it would probably drop to the earth and burn up in the atmosphere. fired sidways, the bullet would probably end up in an orbit at a different angle (inclination to the earth's axis)

It's even trickier than that. If you fire it forward, the bullet will settle into a more elliptical orbit with a higher apogee, but I believe the perigee will be the point where the bullet was fired. Meaning that once per orbit, your bullet will cross YOUR orbit, so you'd better do a small delta-V yourself to avoid putting a hole in your own spacecraft at some point, should you and the bullet happen to cross that point at the same time...

Fired backward, the apogee would be the same but the bullet's perigee would be lower than yours. If you are in low orbit, the perigee will be low enough to put the bullet into the atmosphere, but if you are in a higher orbit (say, geostationary or something), the bullet will probably continue to orbit. Meaning that once per orbit, it will cross YOUR orbit...

Another interesting tidbit...if you are in geostationary orbit and fire the gun backward, the bullet will soon pass you at a lower altitude. If you fire the gun forward, you will pass the bullet, with the bullet at a higher altitude than you. Rather counterintuitive, but putting the bullet in a lower orbit means that it circles the earth more quickly than you do, and putting it in a higher orbit means it circles more slowly.

 

[Johnny Guest]

Read Zero_DgZ's post (early in first page) for my thoughts.

I don't own a firearm that I don't think would function flawlessly, right now, in the vacuum of outer space.

 

[MechAg94]

Good point about possible low temperature. My company make cryogenic O2, N2, and argon. Generally, aluminum, bronze alloys, and austenitic stainless steels are the only metals used in cryogenic temperatures. They do make low temp carbon steels, but I don't think they go that low.
I am sure that could be overcome in design. I guess the mythical aluminum bolt/receiver in the AR15 would be useful.

 

[otomik]

Space is cold. In interstellar space, matter will cool to 2.7 K or -455 °F. I don't think barrel steel or bullet jacket will hold up well at that temperature.

okay buck rogers, we're really only talking about low earth orbit most likely. also I seem to recall that the space station and space shuttle have cooling difficulties because it's like a vacuum thermos, the heat generated by various things just stays around since there's no atmosphere to dissapate it. I think a gun you shoot in a space walk will just get hotter and hotter until you bring it inside with you.

 

[c_yeager]

What would happen is that the recoil from the shot would throw you backwards in a zero-g/zero atmosphere environment, and you'd run the risk of drifting away. If you have another shot you could fire in the other direction and stop yourself...

Based on my limited knowledge of physics I suspect that one would be sent spinning end over end at a fairly high rate rather than simply being pushed back.

 

[AJ Dual]

Space is cold. In interstellar space, matter will cool to 2.7 K or -455 °F. I don't think barrel steel or bullet jacket will hold up well at that temperature.

Yes, but there's not a whole heck of a lot to fight over in interstellar space.

It will also take a long time for a firearm to cool to that temperature just by raidiative cooling. Thermal conduction just from the spacesuit's gloves (and the warmth generated by it's power supply and the wearer) might be enough.

In space, the waste heat is often the problem. The International Space Station's radiator panels are almost as large as it's solar panels...

While the applications to firearms technology would be exotic, the areospace industry has been dealing whith these issues for decades. I'd be surprised if they couldn't be applied to firearms design.

For a "deep space" gun that would run the risk of cooling to near absolute zero, the answer could be as simple as putting a few pellets of Plutonium in strategic locations where the decay heat would conduct throughout the gun's parts.

This is a common tactic on probes to the outer planets. Aside from the Plutonium in the main RTG generator, little Plutonium packets are secreted areound the probe's superstructure for the purposes of conductive heating to a minimal level to garantee function of it's various parts.

While thier main power source is solar, the mars rovers also use Plutonium heaters to keep them functioning.

http://www.lanl.gov/source/orgs/nmt/nmtdo/AQarchive/01spring/researcher.html

But all in all, I am in the camp that thermal issues, cooling, heating, dumping waste heat from firing, various alloys expansion coefiicients vs. functional tolerances etc, are the biggest challenges to firearm function in the vaccuum of space.

But I think they can be overcome quite easily, at least as compared to the challenges of getting the gunfighters into space in the first place.

 

[LaEscopeta]

I seem to remember in the early days of the US space program, it was thought to be a good idea for space walking astronauts to carry a hand gun. Not to shoot aliens but to get back to a space capsule in case the tether broke and a guy found him self floating off into deep space. The idea was he would shoot away from his space ship to have the recoil propel himself back to safety. As noted in several post above, speed obtained by a single shot would be pretty minimal (a fraction of a foot per second) and unless the round fired was in line with your center of mass it would cause you to spin. I believe the propulsion firearm idea was eliminated before the first US space walk, in favor of the compressed gas handheld jet thing the astronauts still use now-a-days.

(The above comes with no source cited except my (faulty) memory. No warranty expressed or implied.)

(Also, 33 posts in the first 7 hours of this thread. No shortage of space nerds round here.)

 

[Mal H]

....so Jayne & Mal didn't need to shoot up a perfectly good spacesuit, right?....

Right. When I saw that episode, I was thinking, what the heck are they doing that for? Besides, as someone pointed out above, after the very first shot "Vera" was in a vacuum anyway, yet it continued to fire without a problem - at least on the sound stage it did.

Their science advisor must have been on vacation that day.

I suspect that one would be sent spinning end over end at a fairly high rate rather than simply being pushed back.

Possibly true, but intuitively I would say it would be a slow rate of revolution. It all depends on where the gun is discharged with relation to your center of mass and your what moment of inertia is. IOW, if the gun is a good distance away from your center of mass, say at eye level, you would experience a rotating reaction about that center. But, if the gun was fired in a straight line away from your CoM, you would only be pushed backward instead of having any rotation.

 

[CleverName]

Y'know, I think we are overlooking a very simple solution to all these physics issues.

Let's just send somebody into LEO with a couple guns and find out what happens. I'm sure if we all chip in a million each, why we could certainly get somebody into space within the decade!

 

[otomik]

the answer could be as simple as putting a few pellets of Plutonium in strategic locations

I say that about so many things!

 

[chinacave]

Russion guns (Big) in space...

Almaz
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The Almaz (Russian: Алмаз - "Diamond") program was a series of military space stations launched by the Soviet Union under cover of the Salyut program. Three Almaz stations were launched: Salyut 2, Salyut 3 and Salyut 5. Salyut 2 failed shortly after achieving orbit, but Salyut 3 and 5 both conducted successful manned testing. Following Salyut 5 the Soviet Military judged that the time consumed by station maintenance outweighed the benefits.

Almaz was promoted by Vladimir Chelomei as a response to the USAF's Manned Orbiting Laboratory project. In its original configuration Almaz and MOL were very similar, with the station being launched on a Proton rocket with a two man crew who would return to earth in a descent capsule after a month of military observation. Following the delays to the Soyuz project, Almaz also assumed the role of intercepting military satellites. Once launched Almaz would be resupplied by the TKS spacecraft that also used Chelomei's Proton booster.

In addition to reconnaissance equipment, the Almaz had an on-board cannon derived from 23mm Nudelmann aircraft cannon (other sources say it was a Nudelmann NR-30 30mm gun). Salyut 3 conducted a successful test firing on a target satellite. OPS-4, one of the last Almaz space stations built before the Almaz program was cancelled featured 2 unguided missiles instead of the aircraft cannon of previous stations. The OPS-4 was never flown.

Following the cancellation of the manned Almaz program, leftover Almaz spaceframes flew, a decade later, as unmanned radar satellites. The TKS spacecraft formed the basis of modules attached to the Mir space station and components of the International Space Station.

 

[unspellable]

Bottom line

I think the bottom line here is that given a minimal exposure a firearm would work pretty much in the normal fashion. All the complications come into play after longer exposure when lubricants might go gummy, temperatures may go high or low, etc. All problems that can be delt with.

The consequences of the recoil could be a problem, but that's not operation of the firearm itself.

As for the bullet going around and coming back to the same point, that's just the old safety rule, know where your shot is going.

 

[Hugo]

Bet a 1911 would fire a full clip.... JMB designed them that reliable!

 

[ArmedAmerican]

Rocketship Galileo by Robert Heinlein

Fond childhood memories! Gun battles with Nazis-- on the moon! I seem to remember a discussion of chemistry and physics reagarding gun use in a vacuum and low gravity, as well as the vulnerability of spacesuits-- I lost my original paperback from the 50's, darn it!

http://www.amazon.com/gp/product/04...ef=sr_1_1/002-6591669-1443253?ie=UTF8&s=books

Reviewer: R. Christenson

This was Heinlein's first novel published in book form, and the first in his excellent "juvenile" series which included Space Cadet, Time For The Stars, Starman Jones, The Star Beast, Tunnel In The Sky, etc., and it is still my all-time favorite. Heinlein manages to make believable the tale of a scientist (Dr. Cargraves) organizing three 18-year-old boys of a rocket club to build a nuclear powered moon rocket. If you have an interest in space travel you'll get sucked in and won't put the book down until it's over, no matter how dated and unlikely the premise at first appears. It is written with Heinlein's usual skill (that earned him four Hugo awards), and the characters are easy to identify with, especially for any young space enthusiasts. This was also the basis for the 1950 classic film Destination Moon, although about all that remains unchanged in the film is the name Dr. Cargraves. In the book there is a veiled threat from unknown enemies that turn out to be Nazis (this was the first thing Heinlein wrote after the war) - in the film there's just a veiled reference to a communist threat. I suspect the film also draws from Heinlein's more sophisticated treatment from the same period, The Man Who Sold The Moon.

 

[Vitamin G]

The latter requires a spark, a nifty chemical reaction that involves oxygen, which tends to be sorely lacking in space. However, forward-thinking manufacturers have packed an oxidizer within the bullet casing. Whether that's sufficient for an explosive launch is up for much debate.

I guess there's something to be said for the laquer sealing of ammo, then!

 

[Dr.Rob]

The plastic frame of your Glock would shatter like glass as it recoiled, hopefully not sending the slide back to crack for faceplate and really ruin your day.

It might shoot underwater,but space is a really hostile environment for ANY technology.

 

[GW]

Bullet shape would be inconsequential as aerodynamics are not an issue in space.

you will be propelled backward at a rate of 2700*150/200/7000 or 0.3 fps. Forget about finding your brass if you shoot an auto though. The brass will keep going and going and going.

So, how much force would be exerted on you from the ejection of the case?

 

[CajunBass]

This was Heinlein's first novel published in book form, and the first in his excellent "juvenile" series which included Space Cadet, Time For The Stars, Starman Jones, The Star Beast, Tunnel In The Sky, etc.

Awww yes. "Tunnel in the Sky. I think it's the only Heinlein book I ever read. I remember reading it when I was a kid, probably about 5th grade or so. Years later, I got another copy, and my sons read it and enjoyed it as much as I did.

And yes. I read it again too. Just as good that time as the first.

 

[akodo]

the aspect of a gun seizing up is not related to zero gravity or vaccumm, it is related to the temperature of a gun. Bring it to antartica and you will experience similar problems


And I am not so sure they woudl happen very fast in space either, here is my thinking.

How does windchill work? You have somethign warm (me) and when there is no air moving, it's just random air particles bumping into my skin, the cold air particle gets warmer, my skin gets colder. Start having a wind, and more air particles are bumping into my skin, so I get colder faster. So windchill factor helps me realize how fast i will get cold. Now, take a car. If the wind is really blowing fast, after you shut it off the engine will cool down faster than normal. However, once it is cooled down, the wind won't make any difference. A car that has trouble starting at -10 will start just fine if it is 10 above out, but with a big wind causing a windchill.

Now, how does a thermose work? You basically have two bottles, one inside the other. The interal and external bottle are just connected at the top lip, maybe at the bottom a little bit too. The space inbetween is vacuum. This means there is no air bouncing around inside there to transfer heat, either from a warm surface on the outside to a cold liquid inside, or to transfer heat from a hot soup to a warm surface outside.

So why wouldn't a gun in space be like a gun in a thermose? There are no air particles bumping into it leaching off heat. Now, space is not a true vacuum, so eventually it will cool down a lot, but that is going to take some time. I don't buy the theory that if you take a thermose of room temperature water with you out in space, and dump it out, it would immediately freeze. Because just like in the thermose, that water is mostly enclosed in a vacuum, so there is no place for the heat to go.

 

[berettashotgun]

Had to read thru this post first, although I really wanted to post a reply, and am amazed that the original "answer" was SOO retarded. First, the bullet would more than likely experience some sort of venting process to equalize the pressure( or lack of pressure) relative to the atmosphere; second, the shadowed side of the firearm would get cooled down at the surface,not very fast in the absolute vacuum of space, but the lite side would get VERY hot from the radiant energy from the sun (if it was black or shiny) as this energy has no problem being absorbed by the firearm. I'd bet a bigger problem would arise from the cloud of unburned powder that any reliability issue. BTW, who was that moron answering the question??

 

[Ditchtiger]

I've read through all this twice, maybe I missed it? Anyway,did anyone comment on the thought we don't need ear muffs in space?

 

[HerrWolfe]

You would probably hear about it from some Democrat somewhere , and they would probably try to have the cops come up there and get you or at least take your money in fines.
But if it really fires, the bullet would go one way and you with the gun the opposite way, each being acted upon by gravity, the result depending on where in space.

 

[Mal H]

I don't buy the theory that if you take a thermose of room temperature water with you out in space, and dump it out, it would immediately freeze. Because just like in the thermose, that water is mostly enclosed in a vacuum, so there is no place for the heat to go.

I'm not sure which theory you're referring to, but water in a vacuum does strange things when compared to the same temperature water at sea level. If you suddenly exposed a container of water (say at 70 deg F) to a vacuum, it would immediately boil - vigorously. The boiling point of water (and most liquids) will decrease as the pressure decreases. The act of boiling also lowers the temperature of the water so the water that remains might freeze in a short while.

I think you're forgetting about another form of heat transfer - radiation. A gun (or most any object) will radiate away the heat it contains, perhaps not as rapidly as if convection was involved as well, but rapidly enough that the gun (in shadow) will cool in a fairly short period of time in space.

Radiation is addressed in the thermos bottle you described by the silvered glass on the outer layer of the inner bottle. The mirror reflects any radiant heat back into the contents of the thermos, and it also reflects away any radiant heat that might get into the bottle.

 

[Boom-stick]

You'd probably have more luck with a spear gun in space.

We haven't developed any projectile based weapons that didn't factor in gravity and atmospheric pressure.

Until we do, we ain't gonna have 'space guns'.