In the middle of the Cold War, the Soviet Union secretly built something no other country had ever placed in orbit: a military space station armed with a rapid-fire cannon. Hidden behind the civilian name Salyut 3, the station was actually part of the classified Almaz reconnaissance program, designed to photograph military targets from orbit while defending itself against spacecraft the Soviets feared might approach or attack it.
Its weapon was a modified Rikhter R-23 cannon, capable of firing roughly 2,000 rounds per minute at around 850 meters per second. But there was a bizarre problem: the cannon couldn't move independently, meaning operators had to rotate the entire 20-ton space station just to aim it, while maneuvering thrusters were needed to counteract the enormous recoil.
The vibrations were considered so dangerous that Soviet engineers refused to test-fire it while cosmonauts were aboard. Only after Salyut 3's crew had returned to Earth and its reconnaissance film had been recovered did controllers finally activate the weapon remotely.
Shortly before the station was deliberately destroyed in 1975, the cannon fired backward against its orbital path in what became the first and, according to the script, only known firing of a gun in space. Exactly how many rounds were fired remains disputed, with accounts ranging from several short bursts to roughly 20 shells, while claims that the Soviets destroyed a target satellite are not supported by the account presented here.
Even stranger, the American Manned Orbiting Laboratory that had helped inspire Soviet fears had already been canceled years earlier. The USSR had effectively armed a space station against a threat that never arrived, fired its cannon at nothing, and kept the entire operation secret for decades.
Source: Dark Space
