Astronauts Using Guns in Space Could Become a Reality


Astronauts Using Guns in Space Could Become a Reality

Kyle Mizokami
Tue, October 26, 2021, 6:26 AM·5 min read

The second season of the Apple TV+ series For All Mankind shows U.S. Marines in space using M16s.

Astronauts probably wouldn’t use real M16s in space—but they could still use guns.

Low gravity and crazy temperature swings would make traditional guns inoperable in space.

The Apple TV+ sci-fi series For All Mankind, set against the backdrop of the Cold War, just introduced a new element: space guns.

The ongoing second season of the acclaimed series, which imagines an alternate history in which the Soviets beat NASA to the moon and the global space race never ended, depicts spacefaring U.S. troops using M16s. In real life, however, a weapon like the M16 would be extremely difficult to operate in space.

Using weapons in the extremes of space, including wild temperature swings and low gravity, would present challenges for both those who design and carry the weapons.

In For All Mankind, NASA, stung by its crushing defeat in the space race, redoubles its efforts to take the lead against the Soviets. That includes sending women into the Apollo program and building a giant, sea-launched cargo rocket called “Sea Dragon.”

By the 1980s, the first American lunar colony, Jamestown, is firmly established on the moon, supplied by regular Space Shuttle missions. The seizure of an American lithium mine by Soviet cosmonauts triggers the deployment of five U.S. Marines to the Jamestown colony, all armed with space versions of the M16A2 rifle.

The M16 was obviously designed to function on Earth, in Earth gravity, within a band of temperatures normally found on Earth. The rifle can work in deserts in temperatures of 100 degrees Fahrenheit or higher and in “extreme cold weather,” the U.S. Army says. (That’s as specific as it gets.)

While those conditions seem broad by Earth standards, in space, it’s a different story.

Gravity itself will vary, from zero-gravity conditions far from planetary bodies to one-sixth of Earth’s gravity on the moon. Temperatures on the moon can swing wildly, from a high of 260 degrees Fahrenheit to minus 280 degrees.

Photo credit: Christopher Jensen - Getty Images

Gravity would affect all aspects of the M16, from how bullets are seated in the magazine to how the buffer spring would bounce the bolt carrier group back and forth inside the weapon. The internal action of the M16 is precisely timed, and a change in gravity would throw everything off.

Changing the mass of various internal parts, spring weights, and even the type and amount of gunpowder used might make a lunar M16 workable—but it would require a lot of testing under lunar conditions. One concern: The M16 uses gunpowder gases to cycle the weapon. Just how would that hot, pressurized gunpowder gas behave in low gravity?

Bullets in principle should work fine, since they use their own propellant and don’t rely on oxygen. But again, the big issue here would be gravity.

Under Earth gravity, an M16 bullet starts a slow, inexorable drop as soon as it exits the barrel, one that eventually ends up with the bullet plowing into the ground. Earth’s gravitational influence means a terrestrial M16 bullet will drop 24 inches at 400 yards. While a bullet fired under lunar gravity would still eventually plow into the lunar soil, at one-sixth gravity, the same bullet would fly a flatter, steadier trajectory for far longer.

There’s no wind in space or on the moon, so there would be no need to calculate for windage at longer ranges. At 400 yards, wind at 10 miles per hour will blow an M16 bullet 21 inches off course—enough to miss a man-sized target. A lack of wind will make it easier to hit a target, at least in the horizontal axis.

Photo credit: Historical - Getty Images

Temperatures would prove to be another challenge. Engineers could probably develop a lubricant that operates within a 500-degree band, but Space Marines would need to be careful with their rate of fire. A gun already heated to 280 degrees Fahrenheit would start to have heat issues more quickly than one on Earth, including bullet propellant igniting in the chamber before the trigger is pulled (“cooking off”) and even melting rifle parts.

And then there’s a problem totally unique to the moon: moon dust. The dust, a fine coating of lunar soil found up to 60 miles above the moon’s surface, could get into a rifle’s internals and cause it to jam. The M16 is particularly vulnerable to jamming, and is even equipped with a dust cover to prevent dust, dirt, and sand from entering the weapon before it’s fired. How would you keep moon dust out of an M16 during combat?

For All Mankind does give the space M16s some thought. On the show, the rifles are white and silver, colors that let them blend in with the moon dust, and they’re equipped with collapsing stocks and optical sights.

Real M16s in the 1980s featured fixed stocks and lacked optical sights. Collapsing stocks would be more ergonomic for shooters in large, bulky spacesuits. The raised optical sight, meanwhile, would be easier for an astronaut in a space suit to use, but a laser sight would allow the space shooter to shoot accurately without aiming.

Our reality has been spared a world with space rifles, but with the establishment of the Space Force and the increasing militarization of space, it seems inevitable that small arms will eventually make their way into space and beyond.