Sunita Williams flew to space on June 5, 2024 to test Boeing’s first crewed Starliner flight.
NASA astronauts Sunita Williams and Butch Wilmore set out on an eight-day mission aboard Boeing’s Starliner. They ended up spending 286 days on the International Space Station (ISS) after their spacecraft suffered propulsion failures.
Launched on June 5, 2024, their mission was to test Boeing’s first crewed Starliner flight and return home. With Starliner unable to bring them back, NASA had to keep them on the ISS until a safe return was arranged. On March 19, 2025, their SpaceX Crew-9 Dragon spacecraft splashed down off the coast of Florida.
Their time aboard the ISS places them among astronauts who have had prolonged stays in space.
From Valeri Polyakov to endurance pioneers like Scott Kelly and Pyotr Dubrov, here’s a list of astronauts who spent the longest time in space on a single mission, according to NASA and Space.com.
Top 10 Longest Space Missions By Astronauts
- Valeri Polyakov – 437 days: Holds the record for the longest single spaceflight aboard Mir (1994-1995), orbiting Earth over 7,000 times.
- Sergei Avdeyev – 379 days: Spent 379 days on Mir (1998-1999) after an unexpected mission extension.
- Frank Rubio – 371 days: Set the US spaceflight record aboard ISS (2022-2023) after a coolant leak extended his mission.
- Vladimir Titov & Musa Manarov – 365 days: First to complete a full orbit around the sun while in space aboard Mir (1987-1988).
- Mark Vande Hei – 355 days: Spent 355 days on ISS (2021-2022), contributing to research on muscle loss and space farming.
- Scott Kelly & Mikhail Kornienko – 340 days: Completed NASA’s “One-Year Mission” aboard ISS (2015-2016), aiding Mars exploration studies.
- Christina Koch – 328 days: Spent 328 days on ISS (2019-2020), completing six spacewalks, including the first all-female ones.
- Peggy Whitson – 289 days: Held the record for the longest spaceflight by a woman (2016-2017), with 675 total days in space.
- Sunita Williams and Butch Wilmore – 286 days: Stayed aboard ISS longer than planned (2024-2025) due to propulsion issues with the Boeing Starliner.
- Andrew Morgan – 272 days: Spent 272 days on ISS, performing seven spacewalks and conducting dark matter research.
Sunita Williams holds the record for the most cumulative spacewalking time by a woman, with 62 hours and six minutes, surpassing Peggy Whitson’s 60 hours and 21 minutes.
