H: Hull breach

An important consideration in any hard science fiction story. Some of my betas did bring up the question of whether my characters ought to be waving guns around in spaceships, given how deadly a hull breach would be.

Photo by Ivan Freaner, at sxc.hu

The speed at which a bullet leaves a gun (its muzzle velocity, in feet/sec or meters/sec) can range from 680 - 1300 f/s (207 - 396 m/s) in pistols ranging from .32s to .45s. Consider that here-and-now bullet-proof glass, steel doors, and protective vests can maintain integrity even when hit by higher-velocity weapons, getting into the 2000 - 2500 f/s (609 - 762 m/s) range.

Can damaged bullet-proof glass stand up to normal air pressure against a hard vacuum on the other side? I don't know. But I don't think it's unreasonable to say that such a thing could be built, right here, with today's technology.

It's probably expensive. It's probably heavy. Those are both problems when you're trying to put ships into space, but it's a good thing science fiction isn't limited to today's technology.

There's a good reason that you wouldn't want to go into space in anything that wasn't a minimum of bullet-proof, though: micro-meteorites. These are small rocks, generally less than a gram (smaller than bullets) but they travel at anything from one to eighty kilometers a second (0.6 to almost 50 miles a second, so even the slow ones are doing over 3100 f/s).

Ordinary meteoroids are up to one meter (about a yard) in diameter and have been recorded at speeds of up to 26 miles/s (42 km/s). You could run into one of those moving at bullet velocities, certainly.

Getting back to gunpowder weapons, though, I think they're reasonable enough on a spaceship once you take these factors into account. One could go to the trouble to invent a laser gun or some kind of energy blaster, but consider:

• Handheld gunpowder weapons already have a good 400 years of technological development behind them and a proven track record of efficient killing. The science and physics are well understood.
• Yes, gunpowder will burn in a vacuum. The oxygen it needs is already bound up in the molecules.
• Yes, automatics can be modified to function in zero gravity.
• Recoil can be minimized, or (I would guess) managed in such a way to distribute the force and cancel itself out. As much as possible. I've tried to have my characters "use" the generated force to their advantage. 
• They make loud noises and are scary. Yes, that sounds dumb but the intimidation factor should never be overlooked. It's why pistols in television shootouts are loud as shotgun blasts.
• And to address a pet peeve: they are far easier to use than a knife or, God forbid, a sword. A four-year-old can kill someone with a gun. Swords take years to master, and whenever one gets pulled in science fiction I roll my eyes.

But I'm a hard sci-fi aficionado, and I'm not going to deny anyone the use of a good blaster or a dramatic lightsaber if that's what they want in a story. What would you arm your sci-fi characters with?