Leonov was one of the 20 pilots selected to be part of the first cosmonaut group in 1960. Like all the Soviet cosmonauts Leonov was a member of the Communist Party of the Soviet Union. His walk in space was originally to have taken place on the Vostok 11 mission, but this was cancelled, and the historic event happened on the Voskhod 2 flight instead. He was outside the spacecraft for 12 minutes and nine seconds on 18 March 1965, connected to the craft by a 5.35-meter tether. At the end of the spacewalk, Leonov's spacesuit had inflated in the vacuum of space to the point where he could not re-enter the airlock. He opened a valve to allow some of the suit's pressure to bleed off and was barely able to get back inside the capsule. Leonov had spent eighteen months undergoing intensive weightlessness training for the mission.. Leonov was to have been commander of the 1971 Soyuz 11 mission to Salyut 1, the first manned space station, but his crew was replaced with the backup after one of the members, cosmonaut Valery Kubasov, was suspected to have contracted tuberculosis (the other member was Pyotr Kolodin).. Leonov was to have been commander of the 1971 Soyuz 11 mission to Salyut 1, the first manned space station, but his crew was replaced with the backup after the cosmonaut Valery Kubasov was suspected to have contracted tuberculosis..