NASA Conducts First-Ever Medical Evacuation from ISS

NASA has carried out the first medical evacuation in the history of the International Space Station after an astronaut aboard the orbiting laboratory suffered a serious medical condition, prompting the early termination of the Crew-11 mission.

NASA Administrator Jared Isaacman said during a press conference on Thursday that the agency had decided to end the mission before its planned conclusion in February, citing astronaut health and safety as the overriding priority. He said final details of the crew’s safe return to Earth would be determined within the next 48 hours.

Isaacman described the medical issue as serious enough to require an unprecedented evacuation, though he stressed the affected astronaut was not in immediate danger. The decision followed the cancellation of a scheduled spacewalk less than 24 hours earlier, with officials opting for maximum caution.

NASA’s chief medical officer, Dr James Polk, said the astronaut’s condition was stable and being managed on board the station by fellow crew members until return to Earth. He added that the issue was not related to spacewalk activities or operational duties and was likely linked to the effects of microgravity. No special precautions were deemed necessary during the waiting period.

The Crew-11 mission includes four astronauts: Zena Cardman and Mike Fincke from NASA, Japanese astronaut Kimiya Yui, and Russian cosmonaut Oleg Platonov. They were recently joined on the station by Japanese astronaut Koichi Wakata and NASA astronaut Chris Williams, who arrived aboard a Russian Soyuz spacecraft in November 2025.

Isaacman said Williams would remain aboard the station with the Soyuz crew to ensure continued US presence in orbit, in line with operational requirements that mandate a constant human presence on the ISS.

NASA confirmed that emergency evacuation plans exist for all space station missions, although they have never previously been activated for medical reasons. Return vehicles are kept in a constant state of readiness, the agency said.

Crew-11 arrived at the space station on August 1, 2025, and was originally scheduled to return in late February following the arrival of Crew-12 aboard a SpaceX Dragon capsule. Any potential changes to Crew-12’s schedule will not affect the Artemis 2 mission, planned for February 2026, Isaacman said.

Artemis 2 will be the first crewed mission to orbit the Moon since 1972.

NASA officials noted that the International Space Station has never previously required a full crew evacuation before the end of a mission, although several spacewalks have been cancelled in recent years due to health concerns. These included a 2021 cancellation involving astronaut Mark Vande Hei and another in 2024 after an astronaut reported discomfort inside a spacesuit.

The unprecedented evacuation highlights the medical risks of long-duration spaceflight and the critical role astronauts play in maintaining the station’s operations, systems and scientific research.