Unanswered questions after Astronaut’s mid-orbit medical emergency

Veteran astronaut Mike Fincke said doctors are still unable to determine the cause of a sudden medical episode he experienced aboard the International Space Station earlier this year, prompting a rare medical evacuation .

The 59-year-old astronaut said the incident occurred on January 7 while he was having dinner after preparing for a spacewalk. The episode lasted about 20 minutes , during which he was unable to speak but felt no pain and has no memory of what happened. His crewmates quickly recognised he was in distress and contacted flight surgeons on Earth , leading to an immediate response.

Doctors have since ruled out a heart attack , and Fincke confirmed he was not choking. However, the cause remains unknown, with experts exploring whether it could be linked to prolonged exposure to microgravity . At the time, he had spent more than five months aboard the station and accumulated 549 days in space .

The emergency forced the cancellation of a planned spacewalk and led to an early return of the crew . A SpaceX spacecraft brought them back on January 15 , after which they were taken to hospital for evaluation.

Fincke said NASA is conducting extensive medical reviews , including analysing past astronaut health data. The station’s onboard ultrasound equipment was used during the incident, and he has undergone multiple tests since returning to Earth. He reported feeling healthy and has experienced no recurrence.

Astronauts in space face unique health risks , including bone density loss , muscle atrophy , fluid shifts , and cardiovascular changes . They may also experience weakened immunity , neurological effects , and increased exposure to cosmic radiation .

Despite the incident, Fincke remains hopeful of returning to space , as NASA continues investigating the unexplained episode to better safeguard future missions.