NASA astronaut Sunita “Suni” Williams has retired from the agency after 27 years of service, effective 27 December 2025, concluding a career that spanned three long-duration missions aboard the International Space Station and set multiple human spaceflight records.
Williams logged a total of 608 days in space, ranking second among NASA astronauts for cumulative time in orbit. She also completed nine spacewalks totalling 62 hours and six minutes, the most spacewalk time by a woman and the fourth-highest total in history. She ranks sixth for the longest single spaceflight by an American astronaut, tied with Butch Wilmore after both spent 286 days in space during recent Starliner and SpaceX missions. Williams was also the first person to run a marathon in space.
NASA Administrator Jared Isaacman said Williams’ leadership aboard the space station helped shape the future of human spaceflight and commercial operations in low Earth orbit. He said her work advancing science and technology laid the groundwork for Artemis missions to the Moon and future exploration of Mars, describing her career as an enduring source of inspiration.
Williams first flew to space in December 2006 aboard space shuttle Discovery on the STS-116 mission and returned on STS-117 aboard Atlantis. She served as a flight engineer during Expeditions 14 and 15, completing a then record-breaking four spacewalks.
In 2012, she launched from the Baikonur Cosmodrome in Kazakhstan as part of Expeditions 32 and 33, spending 127 days in orbit and serving as commander of Expedition 33. During the mission, she conducted three spacewalks to repair a station radiator leak and replace critical power system components.
Most recently, Williams and Wilmore launched aboard Boeing’s Starliner spacecraft in June 2024 for NASA’s Crew Flight Test mission. They later joined Expeditions 71 and 72, with Williams again serving as space station commander. She completed two spacewalks during the mission and returned to Earth in March 2025 as part of NASA’s SpaceX Crew-9 mission.
Vanessa Wyche, director of NASA’s Johnson Space Center, said Williams had been a pioneering leader throughout her career, highlighting her contributions to the space station and her role in the Starliner test flight as achievements that will inspire future generations of explorers.
Beyond her flight experience, Williams held a number of senior roles within NASA, including deputy chief of the Astronaut Office and director of operations in Star City, Russia. She also participated in NASA’s NEEMO underwater mission and most recently helped establish a helicopter training platform to prepare astronauts for future lunar landings.
A native of Needham, Massachusetts, Williams holds a bachelor’s degree from the United States Naval Academy and a master’s degree from the Florida Institute of Technology. A retired US Navy captain, she has logged more than 4,000 flight hours across 40 aircraft types.
Reflecting on her career, Williams said serving in the Astronaut Office and flying in space had been an incredible honour. She credited her colleagues, the International Space Station program, and decades of engineering and science with enabling the next steps of exploration to the Moon and Mars, adding that she looks forward to watching NASA continue to make history.
