Stamp commemorating the first spacewalk by the Soviet cosmonaut Alexei Leonov (1934-2019) on 18th March 1965 during the Voskhod 2 mission. This was the world's first extravehicular activity (EVA), or spacewalk. Voskhod 2 had launched earlier that day, and Leonov exited the spacecraft at 08:30 UTC. He remained outside for 10 minutes, before trying to re-enter. Because his suit had ballooned while outside, he had to let some of his air out before he could successfully re-enter the spacecraft.