Top NASA Astronauts Who Spent the Most Days in Space – Full List and Records
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Space travel has always captured the imagination of humankind, and the men and women who venture beyond Earth’s atmosphere are nothing short of pioneers. NASA, at the forefront of space exploration, has sent many astronauts on long-duration missions, especially to the International Space Station (ISS). Here's a look at the record-holders who've spent the most time in space - and how their missions have shaped the future of space exploration.
1. Peggy Whitson – 675 Days
Peggy Whitson holds the record for the most days spent in space by any NASA astronaut, clocking an impressive 675 days. Her space career includes several ISS missions and a notable return with the Axiom-2 mission in 2023, adding nine more days to her unmatched total.
2. Sunita Williams – 608 Days
Known for her spacewalks and endurance, Sunita Williams has spent 608 days in space. Her missions include Expeditions 14/15, 32/33, and 71/72. She also holds the record for the longest spacewalk by a woman and famously ran a marathon aboard the ISS.
3. Don Pettit – 590 Days
Scientist and engineer Don Pettit accumulated 590 days in space. His missions contributed heavily to ISS operations and scientific research, especially in microgravity experimentation and technology demonstrations.
4. Jeff Williams – 534 Days
With four missions under his belt, Jeff Williams spent 534 days in orbit. He played a crucial role in shaping the ISS, particularly during his 2016 stint on Expedition 47, which focused on station upkeep and science experiments.
5. Mark Vande Hei – 523 Days
Mark Vande Hei is recognised for one of the longest single spaceflights by an American—355 straight days on the ISS between 2021 and 2022. His total time in space stands at 523 days, contributing valuable data on human endurance in space.
6. Scott Kelly – 520 Days
Scott Kelly gained global attention for his nearly year-long stay aboard the ISS, aimed at studying the effects of prolonged spaceflight. His work was central to understanding the physical and psychological impact of long-duration missions, with a total of 520 days in space.
7. Mike Barratt – 447 Days
Mike Barratt completed two missions and spent a total of 447 days in orbit. As a physician, his expertise brought crucial insights into space medicine and human health in zero gravity.
India’s Proud Moment in Space
Adding to the excitement in space news, India’s Group Captain Subhanshu Shukla made history on June 25, 2025, by joining the Axiom Mission 4 . As part of this collaborative mission between Axiom Space and NASA, Shukla became the first Indian to reach the ISS, and only the second Indian in space after Rakesh Sharma in 1984.
These astronauts have redefined human limits, contributing not just days but decades’ worth of knowledge from their time in space. Their missions continue to inspire future explorers and pave the way for deeper journeys into the solar system and beyond.
1. Peggy Whitson – 675 Days
Peggy Whitson holds the record for the most days spent in space by any NASA astronaut, clocking an impressive 675 days. Her space career includes several ISS missions and a notable return with the Axiom-2 mission in 2023, adding nine more days to her unmatched total.
2. Sunita Williams – 608 Days
Known for her spacewalks and endurance, Sunita Williams has spent 608 days in space. Her missions include Expeditions 14/15, 32/33, and 71/72. She also holds the record for the longest spacewalk by a woman and famously ran a marathon aboard the ISS.
3. Don Pettit – 590 Days
Scientist and engineer Don Pettit accumulated 590 days in space. His missions contributed heavily to ISS operations and scientific research, especially in microgravity experimentation and technology demonstrations.
4. Jeff Williams – 534 Days
With four missions under his belt, Jeff Williams spent 534 days in orbit. He played a crucial role in shaping the ISS, particularly during his 2016 stint on Expedition 47, which focused on station upkeep and science experiments.
5. Mark Vande Hei – 523 Days
Mark Vande Hei is recognised for one of the longest single spaceflights by an American—355 straight days on the ISS between 2021 and 2022. His total time in space stands at 523 days, contributing valuable data on human endurance in space.
6. Scott Kelly – 520 Days
Scott Kelly gained global attention for his nearly year-long stay aboard the ISS, aimed at studying the effects of prolonged spaceflight. His work was central to understanding the physical and psychological impact of long-duration missions, with a total of 520 days in space.
7. Mike Barratt – 447 Days
Mike Barratt completed two missions and spent a total of 447 days in orbit. As a physician, his expertise brought crucial insights into space medicine and human health in zero gravity.
India’s Proud Moment in Space
Adding to the excitement in space news, India’s Group Captain Subhanshu Shukla made history on June 25, 2025, by joining the Axiom Mission 4 . As part of this collaborative mission between Axiom Space and NASA, Shukla became the first Indian to reach the ISS, and only the second Indian in space after Rakesh Sharma in 1984.
These astronauts have redefined human limits, contributing not just days but decades’ worth of knowledge from their time in space. Their missions continue to inspire future explorers and pave the way for deeper journeys into the solar system and beyond.
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