On Dec. 10, 1977, the Soviet union launched the first crew to complete a long-duration mission to the Salyut 6 space station.

Salyut 6 was a small space station that launched without a crew three months earlier. Another cosmonaut crew was supposed to be the first to visit this space station, but they couldn't get their Soyuz spacecraft to dock, and the mission was aborted. The second cosmonaut crew blasted off two months after that little mishap, and they were able to dock with the space station the next day. The two cosmonauts, Yuri Romanenko and Georgi Grechko, spent 96 days in orbit before safely returning to Earth.