In space, no one can hear you scream. But in the early days of the space age, the Pentagon had a bigger problem—namely, earthly notions of ballistics and gun-design didn't apply in a vacuum.
As the United States had started to conquer space in the 1950s, the Pentagon envisioned troops in orbit and military bases on the moon. To defend themselves on these new battlefields, the US Army believed soldiers would need a whole new class of weapon.
"Because of the entirely new and different environment and conditions facing man in space, we cannot wait until the eleventh hour to 'crash' a weapon program through with any hope of success, for we may even now be standing on the edge of the battleground of Armageddon," engineers from the US Army Weapons Command's Future Weapons Office wrote in a now declassified 1965 study.
The entirely theoretical report had the colorful and lengthy title The Meanderings of a Weapon Oriented Mind When Applied in a Vacuum Such as on the Moon. Four years earlier, President John F. Kennedy urged Congress to make putting an American on the lunar surface by the end of the decade a national priority.
The future-minded weaponeers had clearly taken the message to heart, in their own way.
"Although the primary purpose of man in space (on the moon or other planets) will not be to fight, he requires the capability to defend himself if necessary," the engineers explained. "If space is truly for peace, we must be strong there just as we are on earth."
The Army had already been preparing for a less-than-welcoming environment beyond the earth's atmosphere. In 1959, the ground combat branch outlined their plans for a moon base as part of Project Horizon.
"The lunar outpost is required to develop and protect potential United States interests on the moon," the Army's top researchers explained in their final report. "The full extent of the military potential cannot be predicted."
But soldiers couldn't just carry normal rifles and submachine guns to a barracks on the moon or a space station circling the earth. For one, extreme temperatures—ranging from 250 degrees Fahrenheit at midday to minus 250 degrees at midnight—could easily wreak havoc on existing weapons.
A gun that would work fine on earth in temperate climates might freeze up at night or explode during the day. And days and nights on the moon are two weeks long.
The lubricants that help normal firearms function might evaporate in vacuum. The widely varying temperatures and the lack of gravity would have an impact on how well certain materials stood up to the shock of firing.
Perhaps most importantly, the Army worried that a soldier shooting a gun on the lunar surface might be blasted out into space by the recoil forces. Since the moon has only one-sixth of the gravity on earth, the engineers suggested building a weapon with a similarly reduced kick.
Alternately, some sort of personal energy cannon would get around most of these problems. Decades earlier, popular science fiction staples like Buck Rogers and Marvin the Martian wielded atomic laser blasters and other futuristic sidearms.
Unfortunately, the Army estimated that real laser guns were still at least two decades down the road. Without the benefits of this kind of fantastical technology, the Army had to focus on more realistic projectile-spitting guns. The Future Weapons Office's technicians proposed seven different concepts to "stimulate thinking." The first design looked like a movie prop.
This "spin stabilized micro gun" would shoot traditional propellant-powered bullets. In the vacuum of space the projectiles would fly 3,000 to 4,000 feet per second—up to 1,000 feet per second faster than a standard 7.62-millimeter rifle round.
The space gun would also be at least 15 inches shorter and three pounds lighter than the Army's relatively new M-16. Thanks to aluminum and plastic components rather than steel and wood parts, Armalite's revolutionary design was nearly 40 inches long but already lightweight at just over seven pounds.
Next up were two "sausage guns" that looked like miniature rocket pods with pen clips to hold them inside the pockets of a space suit. The guns would launch tiny rocket projectiles or darts from the preloaded tubes. The technicians also figured these two designs could be adapted to work as a sort of close-range space revolver or a single-shot self-defense gun.
The unique environment meant that not every weapon had to look like a conventional weapon. The engineers proposed a pen-shaped "gas cartridge gun" and a gas-powered needle-shooter that looked like a flimsy water pistol.
Without air slowing the projectiles down, a gun might not need explosives, gas or rocket motors to get a bullet up to a suitably lethal speed. The technicians estimated that a compressed spring could send a .20-caliber ball flying at more than 1,000 feet per second—the same as a .22-caliber rifle slug.
Of course, the Future Weapon Office came up with these specifications based on mathematical calculations and laboratory experiments. The Army does not appear to have ever built any prototype space guns.
"If the moon and other planets are explored and possibly colonized, the world could eventually see a second evolution of weaponry and protection therefrom," the engineers concluded.
"This proceeds through the mortar, howitzer, gun and tank stages until eventually you have missiles, antimissiles and nuclear weapons much as the earth had prior to World War III," the report noted, curiously blurring the existing state of affairs with an apparent future of war in space above a ruined planet.
While Americans did land on the moon four years later, Washington never followed through with its idea for military space bases. Thankfully, World War III never razed the planet and forced the survivors to the lunar surface. And without a future full of gun-toting space soldiers, the Army's planned space guns never left the drawing board.