US: NASA astronaut Sunita Williams has retired after 27 years of service with the US space agency, bringing to a close one of the most accomplished careers in human spaceflight. Her retirement took effect on December 27, NASA announced.
A former US Navy captain and test pilot, Williams joined NASA in 1998 and went on to become one of the most experienced astronauts in the agency’s history. Over three space missions, she spent 608 days in orbit, the second-highest total time in space by any NASA astronaut. She also completed nine spacewalks, logging 62 hours and six minutes outside the International Space Station, the most by a woman and the fourth-highest overall.
Williams first flew to space in December 2006 aboard Space Shuttle Discovery, serving as a flight engineer during Expeditions 14 and 15. During that mission, she set a then-record for female astronauts by completing four spacewalks. She returned to Earth in June 2007 aboard Space Shuttle Atlantis.
Her second mission came in 2012, when she launched aboard a Russian Soyuz spacecraft from Kazakhstan as part of Expeditions 32 and 33. During that flight, she carried out critical repair work on the space station, including fixing an ammonia leak and replacing a power distribution component. She later served as commander of the station, further cementing her leadership credentials.
Williams’ most high-profile mission came in 2024, when she launched aboard Boeing’s Starliner spacecraft on its first crewed test flight. The mission was expected to last about a week, but technical problems with the spacecraft forced NASA to keep Williams and fellow astronaut Butch Wilmore aboard the space station. The Starliner eventually returned to Earth without a crew, leaving the two astronauts in orbit for more than nine months.
After several contingency plans were explored, Williams and Wilmore finally returned to Earth in March 2025 aboard a SpaceX Crew-9 mission. During that extended stay, Williams again took command of the space station and completed additional spacewalks, turning an unexpected challenge into another milestone in her career.
.@NASA astronaut Suni Williams retires after 27 years, effective Dec. 27, 2025. Williams completed three missions aboard the International Space Station, setting numerous human spaceflight records. More… https://t.co/xrxErQKntr pic.twitter.com/CnRS693KSV
— International Space Station (@Space_Station) January 21, 2026
Beyond her flights, Williams held a range of key roles at NASA. She worked closely with the Russian space agency in Moscow, served as deputy chief of NASA’s Astronaut Office, and later became director of operations at Star City in Russia. She also took part in NASA’s extreme environment training, including spending nine days living underwater as part of the NEEMO mission. In recent years, she helped develop helicopter training programmes to prepare astronauts for future Moon missions.
Born in Needham, Massachusetts, Williams holds degrees from the US Naval Academy and the Florida Institute of Technology. She is an accomplished pilot with more than 4,000 flight hours across 40 aircraft types.
Williams’ retirement comes months after her crewmate from the Starliner mission, Butch Wilmore, also left NASA. Together, they were the first astronauts to fly Boeing’s long-delayed crew capsule, a mission that tested both technology and human endurance.
NASA officials have credited Williams with shaping the future of human spaceflight through her leadership, technical skill, and calm under pressure. Her work on the space station and in commercial crew missions is seen as laying important groundwork for upcoming Moon and Mars exploration.
