Soyuz 23

Soyuz 23 was an attempted crewed visit to Salyut 5 during the Almaz station program. Vyacheslav Zudov and Valery Rozhdestvensky launched from Baikonur Site 1/5 on October 14, 1976, as the next crew after Soyuz 21. The spacecraft approached Salyut 5, but a rendezvous sensor problem caused the automated Igla system to waste propellant during final approach, leaving too little margin for a safe manual docking attempt. The crew returned to Earth on October 16 after 2 days, 0 hours, 6 minutes, and 35 seconds in orbit. Soyuz 23 became famous for its emergency landing on frozen Lake Tengiz during a nighttime snowstorm. Spacefacts describes a difficult recovery in which rescue teams could not immediately reach the capsule through ice, fog, and poor terrain, while GCTC identifies the mission as the first and only Soviet crewed spacecraft landing on water. Zudov and Rozhdestvensky survived the long recovery, and the failed docking fed into later understanding of Soyuz approach-system limits around Salyut 5.