Russian cosmonaut Valery Polyakov, who holds the record for the longest space journey for any human, has died at the age of 80, the Roscosmos space agency has announced.
Polyakov was a “hero” of the Soviet Union and Russia, Roscosmos said in a statement on Monday.
Polyakov, who trained as a physician, joined the Soviet space program in the early 1970s. As a cosmonaut, he flew to the Mir space station twice in the 1980s and 1990s.
During the Soyuz TM-18 space mission from 1994 to 1995, he spent a total of 437 days, 17 hours and 58 minutes in space. He still holds the world record for the longest single stay in space.
Over the course of his career, Polyakov spent more than 678 days in space in total.
However, unlike most of his other colleagues, the cosmonaut never ventured outside the station for a spacewalk.
Polyakov wrote more than 50 scientific papers on space medicine.
He is survived by his wife and daughter and two grandchildren.