On Wednesday, Nasa abruptly cancelled a spacewalk due to take place on 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.
