Nasa considers whether to bring sick crew member back to Earth

Nasa is considering an early return of some crew aboard the International Space Station (ISS) because of a medical issue involving one member of a four-strong team.

The unnamed crew member is described as stable, but the incident has already led to the last-minute cancellation of a spacewalk.

Mission managers are now weighing whether the safest option is to bring the entire Crew 11 team back to Earth months ahead of schedule. Three members of another crew would remain on board.

"Safely conducting our missions is our highest priority, and we are actively evaluating all options, including the possibility of an earlier end to Crew 11's mission," said a Nasa spokeswoman.

On Wednesday Nasa abruptly cancelled a spacewalk due for Thursday when two astronauts were set to step outside the ISS and announced that it was because one of the crew was unwell.

"The agency is monitoring a medical concern with a crew member that arose Wednesday afternoon aboard the orbital complex.

"Due to medical privacy, it is not appropriate for Nasa to share more details about the crew member," the space agency said.

Nasa is likely to be determining whether the astronaut can safely remain in orbit or should come home early with their crewmates.

"Our top priority is the safe execution of our missions, and we are thoroughly assessing all possibilities, including the option of concluding Crew 11's mission ahead of schedule," the spokeswoman added.

The four person Crew-11 team consists of Nasa astronauts Zena Cardman and Mike Fincke, Japan's Kimiya Yui from the JAXA space agency, and a Russian cosmonaut, Oleg Platonov.

They launched to the ISS in August 2025 on a SpaceX Crew Dragon and were expected to remain in orbit for about six months and return around late February 2026, after being replaced by another four person crew a few days earlier.

If Crew 11 leave together, the other crew on board would remain: Nasa astronaut Chris Williams and two Russian cosmonauts, Sergey Kud Sverchkov and Sergei Mikayev.

If the mission were to end early all four astronauts on Crew-11 would be brought home, according to Dr Simeon Barber, a space scientist at the Open University.

"They would all come back together as a team, because, you don't want to leave one or more team member behind."

The ISS has basic medical equipment, supplies and communication systems that let doctors on Earth talk privately with astronauts in space, assess their condition and advise treatment, much like a secure video or phone consultation with a GP.

Returning the four-person crew early would delay some experiments and maintenance tasks until the new crew arrive, according to Barber.

"The space station is a big, complex feat of engineering, it's designed to be operated by a certain minimum level of crew," he said.

"If Crew-11 were to return early, what the remaining crew would have to do is dial back on some of the more experimental work and focus more just on the housekeeping and keeping the station healthy, waiting for the full complement of crew to be restored."