Updated Nov. 27, 2025 — 5:52 AM EST
NASA astronaut Christopher “Chris” Williams launched to the International Space Station Thursday alongside two Russian cosmonauts, lifting off from Kazakhstan’s Baikonur Cosmodrome on a Soyuz 2.1a booster.
Commander Sergey Kud-Sverchkov piloted the Soyuz MS-28/74S vehicle with flight engineer Sergey Mikaev to his left and Williams to his right. The rocket ignited at 4:27 a.m. Eastern. About nine minutes and 45 seconds after liftoff the Soyuz separated from the upper stage, deployed its twin solar arrays and began pursuit of the station. An automated, two-orbit rendezvous was planned, with docking at the ISS Earth-facing Rassvet module scheduled for 7:38 a.m. Eastern.
Williams, formerly an astronomer and medical physicist, joined NASA’s astronaut corps in 2021 and is the second member of his class to fly. This mission is the first spaceflight for both Williams and Mikaev; Kud-Sverchkov is a veteran who logged 185 days aboard the station in 2020–2021.
Describing his crewmates as kind, curious and engaging, Williams said he enjoyed training with both Sergeys in Russia’s Star City and at NASA facilities in Houston. He credited his wife, Aubrey, with helping keep family life steady through the rigorous training and travel required by the Russian spacecraft program.
The new arrivals will replace Soyuz MS-27/73S commander Sergey Ryzhikov, flight engineer Alexey Zubritsky and NASA astronaut Jonny Kim, who launched to the station last April and are slated to return to Earth on Dec. 9 after an eight-month mission.
On the station, Williams and his crewmates were due to be greeted by the current residents: NASA Crew 11 commander Zena Cardman, Michael Fincke, Japanese astronaut Kimiya Yui and cosmonaut Oleg Platonov. That quartet launched on a SpaceX Falcon 9 in August and plans to remain until early next year when Crew 12 arrives. All 11 station residents were scheduled to join a traditional welcome video call with mission managers and family in Moscow, followed by a safety briefing and familiarization with the station’s systems.
Williams’ path to space is unconventional. He earned a bachelor’s degree in physics from Stanford University and a Ph.D. in astrophysics from MIT, where he conducted radio astronomy research. During graduate school he volunteered as an emergency medical technician and firefighter. A conversation with a physician steered him into medical physics and radiation oncology, and he later worked as a board-certified clinical and research medical physicist on staff at Harvard Medical School before being selected by NASA.
Williams has noted that many image-processing techniques used in radio astronomy translate directly to medical imaging, a connection that helped motivate his career shift. An Eagle Scout and private pilot, he said the primary goal for his planned eight-month stay aboard the ISS is to apply his training to advance the station’s science and research, work he described as important, interesting and inspiring.