Soyuz 35

The Soviet Union launches Soyuz 35 en route to space station Salyut 6 for a long-duration stay. Cosmonauts Leonid Popov and Valery Ryumin set a new space endurance record with their 185-day stay, lasting until October 1980. Ryumin had been a member of the last Salyut 6 crew as well, having stayed on the station for six months in 1979, and was not originally scheduled for this mission, rotated into the prime crew due to the illness of the originally assigned crew member. Four other crews visit Salyut 6 during the Soyuz 35 crew’s stay. By the end of this mission, Ryumin holds a personal record for the most time accrued in space by a human being – 352 days, barely two weeks short of a full year of spaceflight experience.