Did the Soviet Union really fire a cannon from a space station?

During the Cold War, the Soviet Union mounted and fired a rapid-fire cannon aboard a secret military space station, according to historical accounts. The weapon was built for the Almaz military reconnaissance program and carried into orbit aboard the Salyut 3 spacecraft in 1974. Historian Anatoly Zak confirmed the weapon's existence and appearance after Russian military television broadcast hardware footage, enabling him to build a detailed 3D reconstruction.

Designed by Aleksandr Nudelman's bureau, the weapon was adapted from Aron Rikhter's aircraft gun technology. Historical accounts vary on specifications, but Zak identified it as a 14.5-millimeter cannon. Because the weapon attached directly to the station, aiming required orienting the entire 20-ton spacecraft. The cannon was fired in space on January 24, 1975, after the crew departed, as officials feared the recoil in microgravity.

Station thrusters fired simultaneously to counter the recoil, and an estimated 20 rounds were discharged before burning up in the atmosphere. It remains unclear what engineers learned from the test, as no detailed results were made public. Soviet officials likely found the weapon impractical, shifting focus toward uncrewed reconnaissance satellites and interceptor missiles.