Valeri Polyakov

Valeri Polyakov was a Soviet and Russian physician and cosmonaut who holds the record for the longest single continuous spaceflight in history, spending 437 consecutive days aboard the Mir space station from January 1994 to March 1995. A flight surgeon by training, Polyakov undertook the extreme-duration mission partly to gather medical data relevant to a future crewed mission to Mars, studying how the human body adapts to more than a year of continuous weightlessness.