NASA said it will return a four-person crew to the International Space Station (ISS), cutting their mission short a month early due to a “serious medical condition” affecting one of the astronauts.
The agency did not reveal the crew member’s name or medical condition, citing health privacy, but said the person was in stable condition.
“This is not an emergency evacuation,” a NASA official said, adding: “We always make mistakes regarding the health of the astronaut.”
On Wednesday, NASA suddenly canceled a spacewalk scheduled for Thursday, when two astronauts were scheduled to exit the International Space Station, due to “medical concerns.”
NASA Administrator Jared Isaacman and other agency officials announced the decision to bring the crew back early at a press conference on Thursday.
They provided few details, but said the medical problem was not related to space operations, and was not an injury.
They added that the timetable for the return of the astronauts is expected to be updated within 48 hours.
This is the first early evacuation in the history of the International Space Station, which has been continuously inhabited since 2000.
The four-person team is called Crew-11, and consists of NASA astronauts Zina Cardman and Mike Finke, Kimiya Yui of the Japanese space agency JAXA, and Russian cosmonaut Oleg Platonov.
Officials say that an American astronaut will remain on board the International Space Station, and will be accompanied by two Russian astronauts.
Dr. James Polk, NASA’s chief health and medical officer, told reporters that this is the first time in NASA’s more than 65-year history that a mission has returned early due to a medical issue.
Crew-11 was launched to the International Space Station in August last year aboard the SpaceX Crew Dragon spacecraft, and was expected to remain in orbit for about six months, returning around next month, after being replaced by another crew of four a few days ago.
The International Space Station has essential medical equipment, supplies and communications systems that allow doctors on Earth to talk privately with astronauts in space, assess their condition and advise treatment, just like a secure video or telephone consultation with a GP.
The early return of the four-member crew could delay some experiments and maintenance tasks until the new crew arrives next month, according to Dr. Simon Barber, a space scientist at the Open University.
“The space station is a large and complex engineering feat, designed to be operated by a certain minimum crew,” he said.
He added that the remaining crew would likely have to “call back for some pilot work and focus more on housekeeping and maintaining the health of the station, pending a full crew recovery.”