According to the report of Live Science, the record of staying in space for the most days was made by Valeri Polyakov. He stayed in space for 437 days from January 1994 to March 1995. However, he spent that time not on the ISS but on the Mir Space Station, which is now closed. Scientists wanted to study what effect staying in space for a long time has on human health and Polyakov chose this mission of his own free will.
Talking about staying on the International Space Station for the longest time, America’s Frank Rubio, Russia’s Sergei Prokopyev and Dmitry Petelin have stayed on the ISS for 371 days. All three made this record from September 2022 to September 2023.
These astronauts were part of the same mission. The spacecraft by which all three were to return was damaged by a space debris. In such a situation, all three had to wait for 6 months on ISS.
How many days will Sunita Williams stay in space?
If Sunita Williams returns by February 2025, she will spend about 240 days in space. If she returns in March, she can stay in space for 270 days. This means that Sunita and Butch will not be able to break the old records.