'A trailblazer in human spaceflight': NASA astronaut Sunita Williams retires after 27 years

A former US Navy captain, Williams has logged more than 4,000 flight hours across 40 aircraft.

• NASA astronaut Sunita Williams retiring in December 2025 after 27 years of service
• Williams spent 608 days in space, completing nine spacewalks, a women's record.
• She visits India, focusing on space commercialization and debris concerns.

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NASA astronaut Sunita Williams has retired after 27 years of service, with her retirement taking effect on December 27, 2025, the US space agency announced on Tuesday.

Williams, one of NASA’s most experienced astronauts, flew three missions to the International Space Station (ISS) and logged 608 days in space, the second-highest cumulative time recorded by a NASA astronaut. She also completed nine spacewalks totalling 62 hours and six minutes, the most by a woman and the fourth-highest overall.

“Suni Williams has been a trailblazer in human spaceflight,” NASA Administrator Jared Isaacman said in a statement. "Her leadership aboard the space station shaped the future of exploration and helped pave the way for Artemis missions to the Moon and our journey toward Mars," he noted.

Williams ranks sixth among Americans for the longest single spaceflight, tied with astronaut Butch Wilmore, after both spent 286 days in orbit during missions involving Boeing’s Starliner and SpaceX Crew-9.

Her most recent mission began in June 2024, when she and Wilmore launched aboard Boeing’s Starliner spacecraft on its first crewed test flight. The mission, initially planned for about a week, stretched to more than nine months due to technical issues with the capsule. The astronauts eventually returned to Earth in March 2025 aboard a SpaceX spacecraft.

Williams again commanded the space station during Expedition 72 and completed two spacewalks on the mission.

“Over the course of Suni’s impressive career, she has been a pioneering leader,” said Vanessa Wyche, Director of NASA’s Johnson Space Center. “Her dedication and achievements will inspire future generations of explorers.”

Williams first flew to space in 2006 aboard space shuttle Discovery and later served as flight engineer for Expeditions 14 and 15. She returned to the ISS in 2012, launched from Kazakhstan’s Baikonur Cosmodrome, and commanded Expedition 33.

Beyond spaceflight, Williams held several leadership roles at NASA, including deputy chief of the Astronaut Office and Director of Operations in Star City, Russia. She also helped establish helicopter training programmes to prepare astronauts for future Moon landings.

A former US Navy captain, Williams has logged more than 4,000 flight hours across 40 aircraft. She holds degrees from the US Naval Academy and the Florida Institute of Technology.

“Anyone who knows me knows that space is my absolute favourite place to be,” Williams said. “It’s been an incredible honour to serve in the Astronaut Office and fly in space three times.”

Williams is currently visiting India, where she spoke about the commercialisation of space, calling it a major driver of innovation.

“Commercialisation of space is great. It means opportunities not just in rockets and spacecraft, but experiments, satellites and new technologies,” she said in New Delhi.

She also flagged concerns about space debris, noting that managing orbital clutter is emerging as a critical challenge, and spoke about the need for cleaner propulsion technologies as human exploration moves beyond low Earth orbit.

During her visit, Williams met the family of late astronaut Kalpana Chawla and described returning to India as a “homecoming,” given her Indian roots. “I’m super excited for NASA and its partner agencies as we take the next steps,” Williams said. “I can’t wait to watch the agency make history.”