NASA has just revealed that the crew of the International Space Station was being evacuated for the first time in history after one of the astronauts suffered a medical emergency.

NASA administrator Jared Isaacman said in a press conference Thursday that Crew-11 would not continue its mission until its scheduled return date in February, and that the steps for their safe return would be worked out over the next 48 hours.

'I've come to the decision that it's in the best interest of our astronauts to return Crew-11 ahead of their planned departure,' Isaacman revealed.

The announcement came less than a day after NASA cancelled a Thursday spacewalk due to the medical issue, with officials saying they were 'erring on the side of caution for the crew member'.

Crew-11 includes four astronauts: NASA's Zena Cardman and Mike Fincke, Japanese astronaut Kimiya Yui, and Russian cosmonaut Oleg Platonov.

The group was recently joined by Japanese astronaut Koichi Wakata and NASA astronaut Chris Williams, who arrived at the station aboard a Russian Soyuz spacecraft in November 2025.

Isaacman said that Williams will remain on the station with the Soyuz crew to maintain America's presence in space.

While the astronaut who suffered the medical issue was not revealed, NASA's chief medical officer Dr James Polk said the astronaut was not in any immediate danger and they were being cared for by their fellow crewmates until their return.

Dr Polk added that the medical issue the astronaut suffered had nothing to do with the upcoming spacewalk or any other operations on board the station.

'It's mostly having a medical issue in the difficult areas of microgravity,' Polk explained without going into specific medical details. 

NASA officials noted that no special precautions would need to be taken to keep the ailing astronaut safe until their return and called their condition 'stable' until the evacuation plan is finalized. 

NASA has never had to bring an astronaut home for medical reasons, but an evacuation plan has been built into every ISS mission, with crew return vehicles kept on standby.

'We are looking for the correct opportunity to use our existing landing sites,' Isaacman said when asked if NASA would be making an emergency landing to get Crew-11 home faster.

'I´m proud of the swift effort across the agency thus far to ensure the safety of our astronauts,' the NASA chief added. 

The NASA administrator did note that the space agency did consider this a 'serious medical condition' which forced officials to conclude that the first ever evacuation was necessary.

However, Dr Polk stressed that the astronaut was not in immediate danger which would force NASA to consider rushing the evacuation into an unsafe flight window.

'The crew member is absolutely stable, so I don't foresee massive changes to the timeline or their activities,' Polk said.

Crew-11 arrived at the ISS on August 1, 2025, meaning their return date had been scheduled for late February.

The four astronauts were supposed to leave after Crew-12 arrived on a SpaceX Dragon capsule no earlier than February 15.

Isaacman said that any decision to potentially move up the launch of Crew-12 would not impact the upcoming Artemis II mission planned for February 2026.

He called the two launches 'totally separate campaigns,' meaning there should be no issue in launching Artemis on time. Artemis II will be the first manned spaceflight to orbit the moon since 1972.

Meanwhile, the ISS is required to have astronauts aboard at all times, as they are essential to carry out maintenance, repairs, operate complex experiments, manage life support and perform spacewalks, tasks that automation cannot fully handle, ensuring constant human oversight for safety and scientific output.

Until now, there had never been a crew evacuated ahead of their scheduled departure time from the ISS, however, two spacewalks were recently cancelled because of various health issues among the astronauts.

A mission was cancelled in 2021 when Mark Vande Hei experienced a pinched nerve and was unable to travel outside the ISS.

Another spacewalk in 2024 was called off at the last minute because an astronaut experienced 'spacesuit discomfort'.