Cosmonaut Aleksei Leonov, leaving his spacecraft Voskhod 2 for 12 minutes, becomes the first person to walk in space - March 18, 1965

In 1960, Aleksei Leonov was one of 20 Soviet Air Force pilots chosen to be in the USSR’s first cosmonaut group. After 18 months of strenuous weightlessness training, Leonov made history as the first person to walk in space on March 18th, 1965. This historical event was supposed to have happened on the Vostok 11 operation but was cancelled and, instead, happened on the Voskhod 2 operation.

He was connected to the spaceship Voskhod 2 by a five-foot long cord and spent a total of 12 minutes outside the spacecraft. Due to the vacuum of space, Leonov’s suit become so inflated he was unable to reenter the spaceship. He opened a valve to let some of the pressure out and barely managed to get back inside. After this mission, Leonov was to have participated in a number of space missions, many of which were subsequently cancelled. He was chosen to become the first Soviet cosmonaut to land on the moon but this mission was later cancelled, as well. He did make history again in 1975 as the Soviet commander of the first joint Soviet-U.S.A. space mission.

http://en.wikipedia.org/wiki/Aleksei_Leonov