A New LongDuration Spaceflight Record on This Week NASA

the longest single-duration spaceflight mission by a human was the 437-day mission of Valeri Polyakov, a Russian cosmonaut, onboard the Mir space station. He spent 437 days, 17 hours, and 58 minutes in space, from January 8, 1994, to March 22, 1995. Polyakov's mission was a part of the Mir-18 program and was intended to study the long-term effects of spaceflight on the human body.