1970-06-01 USSR Soyuz 9

A Soyuz 9 First Day Cover from "KNIGA", postmarked in Moscow with a hand cancel on July 7, 1970, signed by Andriyan Nikolayev and Vitali Sevastyanov.

Soyuz 9 was a Soviet crewed spaceflight launched on June 1, 1970, carrying cosmonauts Andriyan Nikolayev and Vitali Sevastyanov. The mission focused on studying the effects of prolonged spaceflight on the human body and testing crew procedures and spacecraft systems for future long-duration missions and space stations. Soyuz 9 remained in orbit for 17 days, 16 hours, and 59 minutes, returning to Earth on June 19, 1970. At the time, it was the longest crewed spaceflight ever completed, surpassing the nearly 14-day endurance record set by the U.S. Gemini 7 mission in 1965.

During their record-setting mission, the cosmonauts completed hundreds of orbits while conducting a wide range of biomedical, biological, geological, and meteorological experiments, along with observations and photography of Earth and the Sun. They also performed daily physical exercises using specially designed load suits to help counter the effects of prolonged weightlessness. After nearly 18 days in orbit, Soyuz 9 successfully landed on June 19, approximately 76 kilometers west of Karaganda, Kazakhstan.