Sunita Williams, Butch Wilmore return to Earth: Which astronauts have spent the longest time in space?

NASA astronauts Sunita Williams and Barry Wilmore have safely returned to Earth after an unexpected nine-month mission aboard the International Space Station. Despite being in space for nine months, astronauts Butch Wilmore and Suni Williams won’t break any records regarding the number of days they spent in space. Jeff Williams: He was the record holder of cumulative time of 543 days in space until he was surpassed by Whitson Christina Koch: She established a record for the longest solo spaceflight of 328 days by a female astronaut while on board the ISS from March 2019 to February 2020. Valeri Polyakov: Polyakov holds the world record for the longest single continuous stay in space aboard Russia’s Mir space station from January 1994 to March 1995.