ISS astronauts return to Earth early due to illness of crew member

NASA’s Crew-11 landed back on Earth on Thursday from the International Space Station (ISS), cutting short their six-month stint in space after an unknown crew member suffered an undisclosed medical condition.

"For NASA itself, this has been unprecedented," said Dr. Farhan Asrar, associate dean at Toronto Metropolitan University's school of medicine.

"When we look at the ISS 25-year history, this is the first time that, any time, a mission has been cut short specifically for a medical reason or undergoing a medical evacuation," he said. "There have been … [ISS] medical issues over time, though, as well, but not to the extent that led to a medical evacuation."

In 1976, a Soviet mission was cut short due to a noxious smell in the spacecraft, Asrar noted.

During last week's news conference announcing the early return of the crew, Dr. James Polk, chief health and medical officer at NASA, stressed that it wasn't an "emergent" issue but that they felt best to return the astronaut to Earth in order to provide the necessary medical attention.

"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 a patient," Polk said.

"And in this particular incident that the medical incident was, was sufficient enough that we were concerned about the astronaut, that we would like to complete that workup. And the best way to complete that workup is on the ground where we have the full suite of medical testing hardware."

The astronauts returned on a SpaceX Crew Dragon, which landed early Thursday.

The Crew-11 return comes after NASA cancelled a scheduled spacewalk by astronauts Zena Cardman and Mike Fincke last week, later revealing a "medical issue" with an unnamed astronaut.

Although the crew returned a month earlier than expected, three people will remain on the ISS: Russian cosmonauts Sergei Mikaev and Sergey Kud-Sverchkov and NASA astronaut Chris Williams.

Crew-12, consisting of NASA astronauts Jessica Meir and Jack Hathaway, along with Russian cosmonaut Andrey Fedyaev and European Space Agency astronaut Sophie Adenot, is scheduled to head to the ISS on Feb. 15.

Meanwhile, NASA is preparing for its Artemis II mission, which will see Canadian Space Agency astronaut Jeremy Hansen, along with NASA astronauts Reid Wiseman, Christina Koch and Victor Glover, go around the moon. The launch is scheduled for no earlier than Feb. 6.

Asrar said while this serves as a reminder about the challenges of space, it also shows how important crew safety is to NASA.

"Agencies and the decision-makers are willing to even cut [missions] short because [they view] astronaut health and safety as paramount," he said.