What Soviet cosmonaut performed the first spacewalk in 1965?

Alexei Leonov performed the first human spacewalk in 1965.

Leonov left the Voskhod 2 spacecraft on March 18, 1965, during a Soviet mission carrying him and commander Pavel Belyayev. He remained outside for 12 minutes and 9 seconds, connected to the spacecraft by a tether and wearing the Berkut spacesuit. The mission made the Soviet Union the first nation to accomplish an extravehicular activity.

The spacewalk was more dangerous than Soviet publicity initially suggested. In the vacuum, Leonov’s suit expanded and became difficult to bend, preventing him from easily re-entering the inflatable airlock. He reduced the suit’s internal pressure to make himself more flexible, a risky maneuver, and eventually got back inside. Voskhod 2 also experienced other technical problems before landing in the Ural Mountains.

Pavel Belyayev was the mission commander, not the spacewalker. Valentina Tereshkova was the first woman in space, in 1963, while Yuri Gagarin was the first human in space, in 1961. Leonov later commanded the Soviet crew in the 1975 Apollo-Soyuz Test Project.