In 1975, Soviet Union sent a cannon to space and tested it from Salyut 3 station, just six months before US and Soviet astronauts met in orbit for the Apollo-Soyuz mission during the Cold War

In January 1975, the Soviet Union fired a 23mm cannon from its Salyut 3 military space station as a test of its orbital defence system. The weapon was intended mainly to protect the station from a possible close-range attack or capture attempt, months before the historic Apollo-Soyuz mission brought the two Cold War rivals together.