A Gun for All Worlds

Summary: Based on real-life engineering and current technology, what sidearm would be most useful to a space explorer? And might there be any other reasons than combat for such a space gun? A thought experiment for hard science fiction weapon design.

Weapons from speculative fiction have, and always will, capture our imagination. Whether it's the laser swords of space opera or the sleek guns of cyberpunk, the means of combat helps capture the aesthetics of a setting. In this quest for visual distinctiveness, real life physics and engineering principles are often the first casualties. I honestly can't complain too much, since I can appreciate a good fantasy epic, irrationally awesome space dogfight, or energy blade duel as much as the next nerd can. However, I didn't become an engineer solely to nitpick my favorite franchises to death (although it is a guilty pleasure).

Personally, I think sending humans into long-term space missions makes about as much sense as trying to make jellyfish to survive on land. Artificial intelligence, brain uploading, cyborg bodies, robotic colonies, and external wombs are far more likely (and cost effective) ways to deal with the terrifying vastness of space. Hard science fiction generally relies on cryonics, relativity, and suspended animation if they want to bypass transhuman entities and intellects, so let's roll with that for a second. If you are an astronaut, cosmonaut, taikonaut, or similarly tech-inhibited space explorer, what kind of weapons would you pack? For purposes of this thought experiment, let's rule out advancements in directed energy weapons, more efficient coil guns and magnetic accelerators, and even breakthroughs in electrothermal guns. (Kudos if you know what those last ones are.)

Real-life space militarization is a terrifying concept, but there are other reasons to arm space travelers than conflict in fiction. One is as a tool, similar to utility firearms like maritime flare gun or line-launcher. Such practice is not completely without precedent, as Soviet cosmonauts even had a customized sidearm made exclusively for them, the TP-82. The TP-82 was essentially a double-barreled shotgun pistol with a third barrel for a 5.45mm rifle cartridge. It even included an optional stock that doubled as a machete. Why would a cosmonaut need such a device?

Like the current Chinese space program, the Soviet space program relied on overland retrieval of spacecraft and personnel. Capsules would land in remote parts of Eurasia, where they'd be recovered by aircraft. The returning cosmonauts could be attacked by bears or wolves, or may have to hunt for small game, so the weapon was intended to be used in such a role. The smoothbore shotgun barrels also meant it could double as a flare gun if necessary. The machete stock was intended as a compact survival tool. Similar weapons were used by German fliers in the Second World War. Even today, bush pilots carry collapsible survival rifles, such as the AR-7, and modern military pilots are issued sidearms as both a survival tool and means of resistance if shot down.

Presently, the TP-82 has been replaced by the standard Russian service pistols. However, the discharge of conventional firearms in space is problematic for a number of reasons. One is the lack of gravity and recoil, which means that an astronaut firing a gun would be propelled backwards with the same force the bullet was fired. Under such chances, accuracy would be greatly reduced. In addition, the temperature extremes of space mean that conventional firearms could have issues with moving parts.

For those reasons, many modern firearms could have issues with performance. Modern automatic pistols rely on the recoil generated by a cartridge's discharge to blow the slide back to catch the next round. Modern automatic rifles use the recoil or discharge of propellant cases to cycle the bolt to catch the next round. Modern cartridges are vacuum sealed, so they should discharge reliably. As modern guns rely on recoil and propellant gases, they are at risk of jamming and failing to cycle. But there are other ways to have a space gunfight.

Firearms that rely on manual and mechanical action may fare better. This category includes revolvers, pepperbox pistols, and manually-cycled weapons (such as lever-action, pump-action, and bolt action guns). Ironically, this might be a fun reason to use vintage Wild West-styled weapons in a space western. As a fan of revolvers in general, I'd be specifically curious if a classic black powder revolver (like a Remington 1858), properly loaded and sealed, could be discharged without incident in hard vacuum.

What might be other reasons for a space gun than combat? One might be deployment of specialized munitions for dealing with space trash. Orbital debris can be a real threat to satellites and crewed craft, and some scientists have proposed using a "gravitational tractor" to clear them out. That would be a larger object that pulls microdebris out of their orbit and into a graveyard orbit that would burn them both up. A semi-guided munition might serve in that role. Space trash collectors might use such weapons to prevent a Kessler syndrome scenario, where orbital debris cascade and destroy other spacecraft (as depicted in the film Gravity).

On other planets, the atmospheric conditions could be suitably different. Thin atmospheres and low gravity, like Mars, mean that conventional ballistic weapons have longer range. A denser atmosphere or aquatic environment means that bullets would encounter more atmospheric friction and pressure, hence shorter range. Likewise, even a weapon with mechanical moving parts could have issues with the thick atmosphere or ambient pressure.

Specific niche firearms in history were designed for underwater use. Examples include the Soviet APS underwater assault rifle, which fired drag-stabilized darts, and the Heckler and Koch P11, an electronically fired pistol for combat divers. The P11 was a pepperbox pistol, meaning it had several barrels that were independently discharged. When all rounds were expended, a new assembly of barrels (pre-loaded with cartridges) were loaded onto the weapon's frame. The grip held the battery. However, the weapon did not include rifling due to the short effective ranges the weapon would be discharged at.

Another relevant development was the super-posed load or stacked charge. In this case, a weapon's barrel is loaded with separate projectiles and charges, like a cross between a Roman candle and musket. This concept is not new, as it's appeared occasionally in the design of early black powder muzzleloaders. Given the unreliability of such weapons (and their nasty habit of blowing up in the user's faces), they were rarely used. A modern incarnation of the idea was the Metal Storm system, an Australian invention that used electronically fired stacked charges in barrels stacked on top of each other (with different barrels for different types of ammunition). While such weapons lacked rifling, they were able to fill the air with a lot of projectiles quickly, which would be useful for point defense and area denial. However, these weapons lacked accuracy.

A possible solution originated from guns used on big game hunts. In the era of classic African big game hunting, express rifles were used to bring down large animals with cartridges that would not be surpassed until the development of anti-tank rifles by Imperial Germany. A British manufacturer of expensive game rifles, Holland and Holland, developed a "paradox gun" able to be used as both a rifle and shotgun, based upon a unique barrel design putting limited rifling towards the end of the barrel. Such a design might help compensate for a lack of conventional rifling.

As far as projectiles go, conventional bullets still would generate unpleasant recoil in microgravity. The solution to such an issue was actually developed decades ago, with the MBA Gyrojet pistol. Gyrojets are miniature rockets, which are discharged and accelerate over time. As such, they become more powerful with range. Despite appearing in the Bond film You Only Live Twice, the weapon became a victim of legal technicalities and low quality ammunition production. The result was the company, and the fascinating weapon concept, largely vanished into obscurity. As the gyrojets are self-accelerating, they entirely lack recoil. Electronic ignition could greatly improve the reliability problems of the problematic mechanical ignition in the MBA Gyrojet designs. Given advancements in self-guided bullets, even inaccuracy could be compensated for.

My final proposed design would take aspects of all of these designs. My proposed design, the Star-6, would essentially be a six-barreled pepperbox pistol. Why six? Because it's a standard value with a lot of cultural legacy to it, and the classic Ethan Allen pepperbox pistols had that many barrels. More barrels means more ammunition, although too many becomes ungainly. although four barrels might also work (similar to the Metal Storm prototype pistol). Each barrel would be full of stacked charges (similar to Metal Storm) for gyrojet rounds, with the end of each barrel possessing a short span of rifling (like a paradox gun). The system would use electronic ignition, so there would be no moving parts, aside from the trigger and bullets. The pistol grip would hold a battery (like the P11). Once all rounds were expended, you'd load a new assembly of barrels onto it.

What would this weapon be used for? In addition to the historical precedents of a survival and signaling item, it could be used for utility purposes in space. For example, it could be used to deploy specialized rounds that pull microdebris into graveyard orbits, deflecting incoming debris, or perhaps even repairing a damaged spacecraft with some low-velocity epoxy-filled rounds. Perhaps military, law enforcement, and civilian variants might have other rounds (like rubber rounds for less-lethal purposes, distress flares, tracking microchips for animals, powder actuated nails/rivets, or blanks for line-launchers), or more conventional bullets for combat. Given the precedent of the P11, the weapon might also find a use as a maritime weapon or even utility item.

I believe the Star-6 would be grossly outclassed by conventional weapons in a firefight. This is because it's intended as a utility item instead of a combat weapon. However, it would be able to function without incident in microgravity, in hard vacuum, underwater, on extraterrestrial atmospheres, and on Earth. A device such as this is entirely feasible with technologies that have been wallowing in obscurity for decades. It's sad the history of technology is overlooked so often in speculative fiction, especially as the circumstances surrounding many inventions are even more bizarre than fiction. So, thanks for reading about my idea for a gun for all worlds.