Answer: Oleg Kononenko
Notes: Russian cosmonaut Oleg Kononenko set the world record for the most time spent in space, breaking the record of fellow Russian cosmonaut Gennady Padalka. Kononenko is 59 years old and has spent more than 878 days and 12 hours in space. Padalka's record was 878 days, 11 hours, 29 minutes, and 48 seconds, set during five space missions until 2017. Kononenko works out regularly to deal with the physical effects of weightlessness. He has said that he doesn't feel deprived or isolated, but that he realizes how much life he missed out on when he returns to Earth.
