Soyuz 4

Soyuz 4 was the active spacecraft in the January 1969 Soyuz 4 / Soyuz 5 joint mission, the first docking of two crewed spacecraft. Vladimir Shatalov launched alone from Baikonur Site 31/6 on January 14, 1969. After Soyuz 5 launched the next day, Shatalov manually guided Soyuz 4 to docking on January 16. Because early Soyuz vehicles did not have an internal transfer tunnel, Yevgeny Khrunov and Aleksei Yeliseyev moved from Soyuz 5 to Soyuz 4 by EVA in Yastreb suits. Spacefacts records the EVA window as 53 minutes. Soyuz 4 then undocked and landed on January 17 with Shatalov, Khrunov, and Yeliseyev aboard. The operation proved key procedures for Soviet lunar-orbit mission planning: crewed rendezvous, docking, external transfer between spacecraft, and landing in a different spacecraft from the launch vehicle.