Astronaut Mike Fincke Describes the ISS Medical Event Doctors Still Cannot Explain

Mike Fincke was eating dinner aboard the International Space Station on January 7 when he found he could not speak. He had just finished preparing for a spacewalk set for the next morning, which would have been his tenth and the first ever for crewmate Zena Cardman. There was no warning and no pain. Fincke, 59, a retired Air Force colonel and four-time space flier with 549 cumulative days in orbit, described the night to the Associated Press on Friday from NASA's Johnson Space Center in Houston.

The episode lasted about 20 minutes and ended as abruptly as it began. He told the AP it was completely out of the blue and amazingly quick, and he compared it to a very fast lightning bolt. He felt fine immediately afterward and says he has felt fine since. More than two months on, doctors cannot say what caused it.

His crewmates reacted at once. Besides Fincke, the station held Crew-11 members Cardman, JAXA astronaut Kimiya Yui and Roscosmos cosmonaut Oleg Platonov, plus NASA's Chris Williams and Russian cosmonauts Sergey Kud-Sverchkov and Sergei Mikaev. It was all hands on deck within seconds, Fincke said. Flight surgeons at Mission Control in Houston were contacted. The station carries medical equipment, including a portable ultrasound machine that he said came in super handy and that he thinks should be standard on future missions, but it lacks the diagnostic power of a hospital emergency room. The January 8 spacewalk was cancelled.

In the following days NASA's chief health and medical officer and senior agency officials assessed his condition and decided the crew should not wait out the rest of the mission. Fincke stresses it was not an emergency return but a coordinated plan to use advanced medical imaging that the station does not have. The SpaceX Dragon Endeavour undocked on January 14, and Crew-11 splashed down off San Diego on January 15, more than a month ahead of a late-February schedule. The crew went to Scripps Memorial Hospital La Jolla for evaluation. It was the first early crew return for medical reasons in the station's 25 years of continuous human occupation.

For weeks NASA did not say who was affected. The agency announced the early return at a January 8 press conference without naming the astronaut. On January 21 all four crew members appeared together at Johnson and also declined to say. Fincke said that day that the way they handled everything, from routine operations to the unforeseen, bodes well for future exploration, without revealing he was speaking from personal experience. On February 25, at his own request, NASA released his written statement identifying him. He said his status stabilized quickly thanks to his crewmates and the flight surgeons, said he was doing very well, and added that spaceflight is a privilege that sometimes reminds us how human we are.

Friday's interview supplied the specifics. Doctors have ruled out a heart attack, and Fincke says he was not choking. Everything else remains possible, including a link to the cumulative effects of his time in weightlessness. NASA is reviewing other astronauts' medical records for similar events. Fincke said he has been very lucky to be healthy, so this surprised everyone. Because there is no lingering symptom, no physical evidence and no recurrence, testing since January 15 has produced no clear answer.

The case carries weight beyond the station. Artemis II, the first crewed lunar flyby since Apollo, is targeting an April 2026 launch; Fincke is not on it. But the diagnostic gap matters more as distance grows: evacuation from low Earth orbit takes hours, from lunar orbit days, and from Mars months, if possible at all. The station's ultrasound helped, but it is not an MRI or a neurological scanner.

NASA Administrator Jared Isaacman, who flew privately and walked in space in 2024, told Fincke to stop apologizing to colleagues. His crewmates told him, in Fincke's words, that this wasn't him, it was space, and that he hadn't let anyone down.

Fincke is completing standard post-flight reconditioning at Johnson and hopes to fly again, though the open question makes any timeline uncertain. His latest mission lasted 167 days, with more than 140 experiments and nearly 71 million miles traveled. NASA has offered no update on what its diagnostic review has found.