Soyuz 18
Soyuz 18 is launched toward space station Salyut 4 by the Soviet Union. Cosmonauts Pyotr Klimuk and Vitali Sevastyanov set a new Soviet record for long-duration stays in space, remaining about Salyut 4 for two months. They are also aboard Salyut 4 during the entirety of the Apollo-Soyuz Test Project, and are able to contact that international mission’s Soviet crew in another Soyuz vehicle. (Two mission control centers are used to prevent any confusion between the two Soyuz crews.) At the time the Soyuz 18 crew abandons Salyut 4 in July, the station’s environmental systems are failing, allowing the atmosphere inside the station to become humid enough for mold to begin growing on surfaces in the crew compartment; no further human crews will visit the station.