ISS medical evacuation: Mike Fincke says cause of sudden illness remains unknown

Astronaut Mike Fincke says doctors still cannot explain a sudden illness on the International Space Station that led to NASA’s first medical evacuation request this year. The episode lasted about 20 minutes, with speech difficulty but no pain. A heart attack and choking have been ruled out; other causes remain under review.

Mike Fincke, the astronaut at the centre of NASA’s first medical evacuation earlier in 2026, said doctors still cannot explain the sudden illness on the International Space Station. The four-time space flier said the event struck without warning during dinner on 7 January. Fincke said flight surgeons on the ground were contacted as crewmates saw clear distress.

Fincke, 59, said the episode lasted about 20 minutes and ended as suddenly as it began. Fincke said there was no pain and no memory of choking. Doctors ruled out a heart attack, Fincke said. Fincke was 5 ½ months into the mission and had spent 549 days in weightlessness across flights.

NASA medical evacuation and the sudden illness in orbit

Fincke said the incident happened after preparations for a spacewalk planned for the next day. "It was completely out of the blue. It was just amazingly quick,\" Fincke said in an interview with The Associated Press from Houston’s Johnson Space Centre. Fincke compared the onset to \"a very, very fast lightning bolt.\"

The crew responded within seconds, Fincke said, as all six gathered around. \"My crewmates definitely saw that I was in distress,\" Fincke said. \"It was all hands on deck within just a matter of seconds.\" The space station’s ultrasound machine was used during the event, Fincke said, while teams on Earth advised the crew.

NASA medical evacuation triggers early SpaceX return

The illness led NASA to cancel the planned spacewalk. Fincke said it would have been a 10th spacewalk. It would also have been the first for crewmate Zena Cardman. Fincke said the situation also led to an early return for Cardman and two other crewmates, changing the mission timeline.

SpaceX returned the crew on 15 January, more than a month earlier than planned. Fincke said the crew went straight to the hospital after landing. Fincke said many possible causes were still being considered. Fincke said the unexplained episode could be linked to long exposure to weightlessness, but nothing was confirmed.

NASA medical evacuation review and astronaut medical privacy

Fincke said NASA reviewed other astronauts’ medical records for similar events in space. Fincke said many tests were done after returning to Earth. Fincke also said there were limits on what could be shared. Fincke said the agency wanted astronauts to trust that medical privacy would remain protected if something happened.

Fincke identified himself late last month to stop public speculation. \"Ive been very lucky to be super healthy. So this was very surprising for everyone,\" Fincke said. Fincke said NASA’s new administrator Jared Isaacman told Fincke to stop apologising. \"This wasnt you. This was space, right?\" colleagues told Fincke. \"You didnt let anybody down.\"

Fincke said the episode had not happened before and had not returned since. Fincke said feeling normal afterwards made the situation harder to explain. Fincke said doctors still did not have a clear cause, even with added tests. Fincke remained hopeful about flying again, while NASA continued examining the medical mystery.

With inputs from PTI