Handheld guns in space - LOX as propellant?

[SomeGuy12]

[I]Edit : I meant liquid hydrogen/oxygen, not straight oxygen. Please don't respond with "pure liquid oxygen isn't reactive by itself..."[/I]

So you need a Space Gun to holster in your Space Holster while you wear your Space Stetson hat and try to bring order to those scummy asteroid miners.

I am aware that conventional gunpowder works fine in space, because the oxidizer is part of the package.

But, suppose the Space Bean Counters are trying to shave every gram. Heck, they want you to 3d print your space gun after you arrive at the asteroid belt, instead of hauling it in your luggage. Your Space Sheriff badge unlocks the 3d printer so it can print this restricted item using metal mined from the asteroids.

So, could you make a gun, used while wearing a spacesuit in low gravity (so the mass and bulk of the cryogenic tanks isn't a big deal - also it might draw from the same tanks that your RCS pack runs on), that mixes liquid hydrogen and oxygen together behind the bullet and ignites it when the trigger is pulled?

A preliminary glance at the requirements seems to suggest this could work - liquid oxygen + fuel is an explosive in it's own right, and burning hydrogen has a rapid explosion velocity. The space gun would be a revolver, naturally, with a mixing chamber behind each bullet, so you can rapid fire. Each bullet would of course have onboard solid propellant thrusters and be "smart", obeying encoded instructions from the firing gun, so you can pick off those pesky asteroid miner outlaws from 10 kilometers away.

[Tex_NL]

A bit cumbersome but I do think it could work. At least in theory.
But if the [I]'bullet'[/I] has [I]'on board solid propellant thrusters'[/I] why would you even bother with liquid fuel/oxygen to fire it? Just fire the darn [I]'on board solid propellant thrusters'[/I]

[More Boosters]

[FONT=verdana]But why do we need this?
[/FONT]

[Tex_NL]

[quote name='More Boosters'][FONT=verdana]But why do we need this?
[/FONT][/QUOTE]

To play Cowboys and Aliens of course. :sticktongue:

[Sanic]

In spaaaaaaaaaaaace, no less.

Solid fuel is the way to go.

[J.Random]

The cold welding of the moving parts would be much bigger problem if you have a conventional firearm in mind.

[Kryten]

Getting mixing of LOX and propellant right would be hard, especially doing it very quickly as you'd pretty much have to do with this. Also, mass and bulk are still a pretty big deal in space; you might not have gravity to deal with, but there is inertia.

[micr0wave]

putting[URL="https://www.youtube.com/watch?v=lnL9YEuyE3A"] this here [/URL]because i like it and it's somewhat related.

Don't forget about the recoil ;)

[Nuke]

gunpowder works in space. what doesn't work is gun oil. all the lubricants that keep the gun in working order simply sublimate in a vacuum, after which time you are grinding metal. you can pop off a few shots before the gun jams up, but its gonna. you can get around the problem with engineering. minimize moving parts. for example striker and firing pin can be replaced with electronically primed rounds. systems have been demoed capable of a million rounds/minute, with tandem rounds and multiple barrels (looks more like a rocket launcher than a gun). most importantly the system has no moving parts other than bullets. i figure small arms in space would just be a scaled down version of that. probibly would be a pita to reload. you can also engineer better lubricants for vacuum operation, i think there are some candidates out there. but realistically if there was a need for guns in space, someone would have a product on the market in a week.

[SomeGuy12]

Solid propellant has low ISP. These are like tiny millimeter sized pits in the bullet capable of tiny course corrections, making up for irregularities in the gun barrel and the enemies jumping out of the way.

[Kryten]

[quote name='SomeGuy12']Solid propellant has low ISP. These are like tiny millimeter sized pits in the bullet capable of tiny course corrections, making up for irregularities in the gun barrel and the enemies jumping out of the way.[/QUOTE]
You'd need a pretty fat bullet to fit a guidance system in. Smallest that's been demonstrated at is .50 inch. One hell of a revolver.

[Nuke]

[quote name='SomeGuy12']Solid propellant has low ISP. These are like tiny millimeter sized pits in the bullet capable of tiny course corrections, making up for irregularities in the gun barrel and the enemies jumping out of the way.[/QUOTE]

then what you really want is called a missile.

[More Boosters]

Yeah if you want to kill poor miners from 10 kilometers away, why not go for a recoilless gun?

[SomeGuy12]

[quote name='More Boosters']Yeah if you want to kill poor miners from 10 kilometers away, why not go for a recoilless gun?[/QUOTE]

That's just a hole in the back of the gun that lets gas escape the other direction, right?

And those "poor" miners are adequately compensated and our internal investigation reveals their conditions meet minimal UN requirements for humans. They are showing a flagrant disregard for the law and must be dealt with.

[Guest]

Gunpowder contains its own oxidizer, therefore it works in space. It wouldn't have as much air resistance, therefore it would be able to go faster and travel further.

[pincushionman]

If you're worried about moving parts fouling up in a pistol-type weapon because the lubricant going away, you'd do something like the Metal Storm concept and have a stick of, say, ten rounds that are cast together and shoved into the chamber at once, individually fired from the front to the back by electronics. No casings or moving parts at all.

[TheSaint]

One of your main problems with firearms in space is recoil. In microgravity, any recoil is going to be very difficult to compensate for, and will probably send you spinning out of control unless you are using one of your hands to hold on to some sort of fixed object. Which is why a recoilless firearm like the [URL="https://en.wikipedia.org/wiki/Gyrojet"]Gyrojet[/URL] would be a much better choice.

[Bill Phil]

I don't think this is practical. You'd have to inject the H2 and LOX, let alone carry enough at all times. The products may cause problems as well.

Solids might just be better. Something like Estes Motors, but more energetic.

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[quote name='TheSaint']One of your main problems with firearms in space is recoil. In microgravity, any recoil is going to be very difficult to compensate for, and will probably send you spinning out of control unless you are using one of your hands to hold on to some sort of fixed object. Which is why a recoilless firearm like the [URL="https://en.wikipedia.org/wiki/Gyrojet"]Gyrojet[/URL] would be a much better choice.[/QUOTE]

That's why mounting weapons on an MMU style jetpack at the center of mass would be a good idea. Although gyrojets would certainly help.

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[quote name='CliftonM']Gunpowder contains its own oxidizer, therefore it works in space. It wouldn't have as much air resistance, therefore it would be able to go faster and travel further.[/QUOTE]

It would travel indefinitely, not counting other factors.

[More Boosters]

[quote name='SomeGuy12']That's just a hole in the back of the gun that lets gas escape the other direction, right?

And those "poor" miners are adequately compensated and our internal investigation reveals their conditions meet minimal UN requirements for humans. They are showing a flagrant disregard for the law and must be dealt with.[/QUOTE]

Okay then tase them, chop them up and use them as fertilizer. And yes it's a cannon with a two holes.

[insert_name]

another major problem with this idea is that 3D printing technology is not at the point where it beats conventional methods of firearm production in terms of reliability, this gun might be just as dangerous to the person shooting it

[RainDreamer]

Since the story is on an asteroid mining colony, it is already sci-fi enough to handwave the 3d printing tech.

Though I still wonder why we can't just go for micro missiles, gyrojet style.

[Jovus]

If you're capable of solving the storage/mixing/use problems of LH2/LOX for use in a personal sidearm, so far as I can tell, by all rights you should be able to make a gauss weapon. Which would have a higher specific impulse. (Given that your optimization category is specific impulse, and the rest is just window dressing to ask that quesiton.)

[Nuke]

[quote name='pincushionman']If you're worried about moving parts fouling up in a pistol-type weapon because the lubricant going away, you'd do something like the Metal Storm concept and have a stick of, say, ten rounds that are cast together and shoved into the chamber at once, individually fired from the front to the back by electronics. No casings or moving parts at all.[/QUOTE]

those exist irl [video=youtube;q5Y5-Zw5TW0]https://www.youtube.com/watch?v=q5Y5-Zw5TW0[/video]

[More Boosters]

[quote name='Nuke']those exist irl [URL]https://www.youtube.com/watch?v=q5Y5-Zw5TW0[/URL][/QUOTE]

Yes and that's why he mentioned them lmao.

[fredinno]

Lox /H2 uses more complex equipment, so I think you might be better off designing your gun to use the RCS of the spacecraft you arrived in- say, NO2. I don't think that you would need all of the fuel in the craft anyways.