Soyuz 9 was a Soviet crewed space flight launched in June 1970. The two-man crew of Andriyan Nikolayev and Vitaly Sevastyanov broke the five-year-old space endurance record held by Gemini 7, with their nearly 18-day flight. The mission enabled the Salyut space station missions, investigating the effects of long-term weightlessness on crew, and evaluating the work that the cosmonauts could do in orbit, individually and as a team. It was also the last flight of the first-generation Soyuz 7K-OK spacecraft, as well as the first crewed space launch to be conducted at night. As of 2026, Soyuz 9 marks the longest crewed flight by a solo spacecraft.