Soyuz 7K-OK was the first generation of Soyuz spacecraft and was flown between 1967 and 1971. The 7K-OK was used for the first ferry flights to the Salyut space station program, beginning a long history of space station service that continues today with the International Space Station (ISS). As of 2022, the 7K-OK is notable for the only fatalities of the Soyuz programme, with Soyuz 1 in 1967 (sole crew-member killed by parachute failure) and Soyuz 11 in 1971 (three crew killed by depressurisation during reentry).