Are firearms feasible in a war in space?

[M1911Owner]

Billll has it pretty close--his orbital descriptions are correct. 17,500 is orbital velocity in LEO; escape velocity is around 24,000 mph. Or, in per-second terms, LEO is about 5 miles per second, escape velocity is about 7 miles per second.

If you start shooting stuff around up there, some of it's going to end up with a low enough perigee that it will reenter and be burned up. Unfortunately, a lot of it's going be around for a very long time. NASA is tracking thousands of pieces of man-made junk in orbit, including a glove from one of the Gemini missions in the 1960's. These are extremely dangerous to future space activities--depending on your relative orbit to the junk, you can be closing at thousands of feet per second; even something quite small will do a lot of damage at that speed, as most of us well know.

 

[Orthonym]

Glove? What about Mike Collins' Hasselblad?

He's kind of a neighbor, lives on an island near here. We're south of Canaveral, any of that stuff could fall on us if stout enough to last out the re-entry. (Thank God the human parts from Columbia came down in an old-fashioned part of Texas where the people didn't make gross revolting photos nor let anyone else do so (There are no photos like that on the Web, I looked. Yeup,that's me.))

Still kinda funny, though, to imagine Col. Collins lying out there on the beach getting brained by the largest red-hot chunk of that camera he mentioned losing, IN THE BOOK he wrote. Shoulda kept yer mouth shut, sir.

 

[Orthonym]

To get back on topic, here,

yah, sure. People have been trying to invent recoilless guns since they first got annoyed by recoil.

In the Kaiser War, there was a gizmo called the Davis Gun. It was mounted on US and Royal Navy flying boats. It looked really awkward, from the pictures I saw. Had a "back barrel"(?) as long as its front barrel sticking out behind its breech. I think it fired a cartridge composed of (from front to back) an HE shell, the propellant charge, and a nasty wad of lead shot and grease (same mass as the shell which went out the front).


IIRC, the thing wasn't very successfull. If you saw a sub on the surface, and your pilot got you in position, and you managed to get the thing swung around, well, by that time the U-boot was underwater.

The reason it took so long to get into action was that, not only did you have to be careful where you pointed it, you had to be careful where you weren't pointing it. (10 lbs of shot and grease flying out the back)



Seems most recoilless guns ever invented have the same problem; nasty blast out the back. Not much blast in a vacuum, but I think fragile spacecraft would have the same problems fragile aircraft had in 1917.

Anybody here ever fired a US Govt recoilless gun? Please share yer impressions with us.

 

[M1911Owner]

I read a really clever short story once about an attempted shooting on the moon. On the moon, [orbital velocity] is 1100 FPS, which, coincidentally, was the muzzle velocity of the .45ACP being used by the bad guy. GG stood on the horizon, which was not far off on the moon, and let the baddie empty the gun at him, knowing that he was almost totally ignorant of firearms, and unlikely to score a hit.

Baddie successfully shot himself in the back.

Figuring the moon is about 1/4th the diameter of the earth, say, 2000 miles for round numbers, or about 6,000 miles in circumference, 1100 FPS gives an orbital period of 8 hours. So the guy was standing there, stock still, for 8 hours??? Can anyone confirm the orbital period, or the story? (Yah, I know it's only a story, but since it's premised on technical details, it seems like this is fair game...)

 

[Penforhire]

If the moon rotated you'd have to account for that too...

Cool thread. But current cartridges aren't air tight, otherwise penetrating oil wouldn't ruin primers. My other thought is the oxygen trapped in the cartridge might not be enough to fully burn the powder?

 

[Glamdring]

I am surprised at the number of people here that don't understand how gunpowder works.

Here is an oversimplification.

Two main parts oxygen and nitrogen involved. The oxygen is bonded with the nitrogen. Nitrogen would prefer to be bonded with another nitrogen.

When you kick the oxygen/nitrogen bonds (primer/detonator/etc) the oxygen is knocked lose from the nitrogen, and the free swinging nitrogens bond with each other. Leaveing free oxygen floating around.

***
A bit more detailed explaination, using blackpowder as example.
http://inventors.about.com/library/inventors/blrocketfirework.htm

"Gunpowder, a mixture composing of: 75% Potassium Nitrate (KNO3), 15% Charcoal (Carbon), and 10% Sulfur, provides the thrust of most fireworks. This fuel is tightly packed into the casing, a thick cardboard or paper rolled up tube, forming the propellant-core of the rocket in a typical length to width or diameter ratio of 7:1.

A fuse (cotton twine coated with gunpowder) is lit by a match or by a "punk" (a wooden stick with a coal-like red-glowing tip). This fuse burns rapidly into the core of the rocket where it ignites the gunpowder walls of the interior core. One might think that the fuse would burn out once inside of the core, due to the lack of surrounding air but the chemistry of gunpowder solves this point. As mentioned before one of the chemicals in gunpowder is potassium nitrate, the most important ingredient. The molecular structure of this chemical, KNO3, contains three atoms of oxygen (O3), one atom of nitrogen (N), and one atom of potassium (K). The three oxygen atoms locked into this molecule provide the "air" that the fuse and the rocket use to burn the other two ingredients, carbon and sulfur. Thus potassium nitrate oxidizes the chemical reaction by easily releasing it oxygen. This reaction is not spontaneous though, and must be initiated by heat such as the match or "punk."

 

[Patent Works]

Here is my brief take:

The presence of ambient air (and other earthly factors like gravity) have almost nothing to do with the operation of a firearms. Air pressure is irrelevant to case integrity, and to bullet seating. Oxygen is not needed, because powder has its own.

A pistol shooter would perceive more recoil, because there is gravity pulling the gun down against recoil (zero-G guns would be better designed with barrels in line with the arm or shooters center of mass, a spade grip rifle being ideal).

There is already LOTS of pebble-sized junk in space, and a few zillion bullets wouldn't make much of a difference, nor would the bullet velocity mean much when the typical collision is over 10,000 FPS closing velocity.

 

[M1911Owner]

No, there's not lots of pebble-sized junk in LEO, and a few billion bullets would make safe space operations nearly impossible for generations to come.