In 1975, the USSR actually fired a cannon from an orbiting space station. Forty years later, we finally got a good look at this gun.

A quarter of the century after the end of the Cold War, the only cannon that has actually fired in space finally comes to light.

Installed on the Almaz space station in 1970s, the R-23M Kartech was derived from a powerful aircraft weapon. The original 23-millimeter cannon was designed by Aron Rikhter for the Tupolev Tu-22 Blinder supersonic bomber. That gun is relatively well known. However, its space-based cousin had largely remained in obscurity.

The Soviets had to turn the entire 20-TON station to point the cannon towards its target. Salyut-3 diagram. Wikimedia Commons

Until now. This year, thanks to a Russian television show, the world got to see grainy footage of the space gun. Using that footage, we created the virtual model of the R-23M that you see above. Here’s the inside story:

Here’s the inside story: From the dawn of the Space Age, the secrecy-obsessed Soviet military was terrified by the prospect of American spacecraft approaching and inspecting Soviet military satellites—which, according to the Kremlin’s propaganda, were not even supposed to exist. This wasn’t crazy. The fear of attack on spacecraft was real, with both sides of the Iron Curtain developing anti-satellite weapons. It seemed perfectly logical in the 1960s that military and piloted spacecraft would need self-defense weapons.

For this project, Nudelman’s team developed a 14.5-millimeter rapid-fire cannon that reportedly could hit targets as far as two miles away. Depending who you ask, the 37-lb. weapon could fire from 950 to 5,000 shots per minute, blasting 200-gram shells at a velocity of 690 meters per second (1,500 miles per hour).

The early Soviet space station project code-named Almaz (“diamond”) became the first real candidate for defensive space weaponry.

Only after the fall of the USSR did Russian sources revealed that the cannon had actually fired in orbit. It happened on Jan. 24, 1975, on-board the Salyut-3 space station.