NASA is performing an unprecedented medical evacuation from the ISS

For the first time, astronauts are being evacuated from the International Space Station (ISS) for medical reasons. The exact nature of the “medical situation” has not been identified for privacy reasons, nor has the astronaut it has affected. But four of the seven crew members on board the ISS are coming home early.

The astronauts returning to Earth are the members of the Crew-11 mission, which launched on 1 August and was originally planned to return in late February. In an 8 January press conference, NASA administrator Jared Isaacman said that the decision to return the astronauts early was made in part because the mission objectives are nearly all complete, so ending the mission early is not as big of a deal. 

“Because the astronaut is absolutely stable, this is not an emergent evacuation,” said NASA’s chief health and medical officer, James Polk, during the press conference. “We’re not immediately disembarking and getting the astronaut down.” Emergency medical evacuations could be performed in a matter of hours, Isaacman said, but in this case the crew will be evacuated in the next few days.

There have been medical incidents aboard the ISS before, but until now all of them have been minor enough that they could be dealt with in orbit. “We have a very robust suite of medical hardware on board the International Space Station, but we don’t have the complete amount of hardware that I would have in the emergency department, for example, to complete a workup of the patient,” said Polk. “The medical incident was sufficient enough that we were concerned enough about the astronaut [and] we would like to complete that workup, and the best way to complete that workup is on the ground.”

The four members of Crew-11 – two NASA astronauts, one Russian cosmonaut and one Japanese astronaut – will ride home aboard the same Dragon spacecraft that shuttled them to the ISS, despite only one of them being ill or injured. Several medical facilities on Earth will be prepared ahead of time to take in the affected crew member for tests and treatment. While this situation is unprecedented, the actual evacuation operation is not significantly different from how crews usually return to Earth at the end of their missions, Isaacman said.

“In the 25 years of the history of the International Space Station we’ve had many models… that have said that we should’ve had a medical evacuation approximately every three years… and we’ve not had one to date,” says Polk.

The evacuation will leave just one NASA astronaut and two Russian cosmonauts aboard the ISS until the arrival of the Crew-12 mission, which was originally slated to launch around 15 February but may be moved up after this incident.