Valery Polyakov is a Russian cosmonaut known for holding the record for the longest single spaceflight. He spent 437 days aboard the Mir space station from 1994 to 1995, contributing significantly to scientific research in microgravity. Born on April 22, 1942, Polyakov trained as a physician before joining the Soviet space program. His extensive experience in space missions has made him a prominent figure in the field of human spaceflight and a key contributor to the understanding of long-duration space travel effects on the human body.