After watching the scene in Ad Astra, where there’s some combat on the lunar surface, I started wondering what sort of weapons would be better optimized for that environment than the old gun/bullet combination. So imagine you’re in your moon buggy, being chased around the craters by bandits. They are in faster moon buggies (don’t ask me why they’ve resorted to stealing when they can afford space suits, multiple high-performance buggies, and moon lodging). They care not for your life. What hand-carried weapon do you want to keep on the gun rack mounted behind your seat?
What I’ve come up with is just a variation on the gun and bullet. It doesn’t need to be a powerful round, because there’s no atmospheric drag. It would be more like a shotgun shell with dozens of tiny sharp needles instead of pellets, intended to rip multiple holes in a space suit. The gun will need a scope, because these bullets will carry a long ways.
You would still need to penetrate the spacesuit and hit the person inside, as a suit rupture wouldn’t necessarily immediately incapacitate attackers. A conventional armor-piercing round would still likely be used.
It occurred to me…if being shot by a firearm in the vaccuum of space becomes more and more of a thing, so will projectile resistant space suits.
Where a bullet could poke a hole in a suit, a layer of thick liquid rubber could suddenly extrude from an intermediate layer within and seal the breach, preventing asphyxiation.
In turn, “bullets” made of white phosphorous could be shot, igniting an unquenchable fire within the oxygen-rich atmosphere inside the suit.
(ouch:eek::()
I agree. It’s not because the environment is different that it’s sufficiently different to make guns & bullets less than the optimal option. Some minor characteristics like muzzle velocity, caliber, weight might be different but it would likely be quite similar on the whole.
It does bring up the question of what combat would even be like in such a situation, presuming that level of technological advancement. It might be as different from our current way of fighting as the US Civil War was to the present.
You do need a gun designed for vacuum. A normal gun might overheat due to there being no air to carry away the heat, or fuse solid due to “vacuum welding”.
I can’t comment vacuum welding but concerning the heat, I’ve heard many seemingly knowledgeable posters say that a lot of it gets radiated out in the IR spectrum where the absence of air isn’t as much of a problem.
But flechettes are fin-stabilized by the air through which they fly, which obviously wouldn’t apply on the moon. And I agree with your point that, because there’s no air drag, a shotgun blast at 2000 meters on the moon isn’t very much less energetic than it at 10 meters on earth.
If it were me, I’d probably go with the AA-12 shotgun. Its recoil impulse is very, very low and it’s fully automatic. I’d probably use conventional shotgun shells: 00 buckshot might be a good choice. Even if you could stabilize flechettes on the moon, many tiny needle-holes have no advantage over fewer-but-larger ones.
If I can mount something on my buggy, though, I’d probably install a standard 7.62-mm 6000-rounds-per-minute minigun. It would overheat quickly in a vacuum, but until it did, it would be very effective.
ETA: a shotgun would also need a heck of a choke to work at 2000 meters.
As for vacuum welding, wouldn’t that be a non problem as long as the weapon is manufactured in an enviroment that allows some thin layer of oxidation? My understanding was that for it to happen the sufaces have to be extremely clean or the process can’t happen
If you’re firing Earth-type projectiles on the moon at Earth-like-projectile velocities, be sure you either hit what you’re aiming at or keep dodging and weaving. Shooting yourself in the back might not be absolutely the most embarrassing way to die, but it’s probably in the conversation.
How much do air-resistance and gravity affect a bullet’s destructive power? Would a bullet be much more lethal on the moon than on Earth? Would an artillery shell fired on the moon possess so much kinetic energy that it would circumnavigate the moon and reach the spot it was fired from?
The orbital speed is nearly 4000 mph. The fastest rifle bullet is 2000+ mph. No worries.
Even with a special rifle/bullet the aim would have to be perfect and take into account masscons.
Regarding stability and flechettes: the whole point of being long and narrow with a pointy bit is to keep it aerodynamic. Without air, an equivalent roundish weight with with multiple pointy bits would work the same against a regular space suit. You just need mass and points. (Damaging a human would be a bit different. But like expanding bullets, the goal is to tear up a lot of tissue, not zip right through.)
