Who’s spent the most time in space? NASA’s top 7 astronauts, including Axiom-4’s Peggy Whitson

NASA astronauts have cumulatively spent thousands of days aboard the International Space Station (ISS), enabling critical research into the effects of long-duration space travel. Among them, seven have stood out for their exceptional time spent in orbit, shaping our understanding of human endurance and systems vital for deep space exploration. The agency maintains two key metrics: time spent on a single spaceflight and cumulative time across an astronaut’s career. While Frank Rubio holds the record for the longest single mission at 371 days, it is Peggy Whitson who leads overall with a total of 675 days in space.

Leading the list: Peggy Whitson to Mark Vande Hei

Peggy A. Whitson tops NASA’s cumulative time-in-space chart with 675 days over multiple missions, including a recent nine-day stint on the Axiom-2 mission in 2023. She is currently commanding the private space mission led by Axiom Space to the ISS. Sunita L. Williams follows with 608 days, having participated in four missions, known especially for her spacewalks and marathon in orbit.

Don Pettit is third with 590 days, contributing significantly to science and engineering aboard the ISS. Jeff Williams comes next with 534 days over four missions, the last of which was in 2016. Mark Vande Hei logged 523 days in total, 355 of which were from a single long-duration mission between 2021 and 2022.

Completing the top seven: Scott Kelly and Mike Barratt

Scott Kelly, known for his nearly year-long stay on the ISS, accumulated 520 days in total. In 2016, Kelly and Russian cosmonaut Mikhail Kornienko completed a historic 340-day mission aboard the ISS. His mission yielded valuable insights into the physical and mental effects of long-term spaceflight.

Rounding out the list is Mike Barratt, with 447 days across two missions. Mike went on two missions. Each of these astronauts played a crucial role in the ongoing research into human health, spacecraft systems, and life-support technologies, advancing NASA’s preparations for future missions beyond low Earth orbit.