NASA will return 4 astronauts home early in 1st-ever medical evacuation from the International Space Station

For the first time ever, astronauts will depart the International Space Station early due to a medical issue.

The agency announced on Thursday afternoon (Jan. 8) that it has decided to bring the four astronauts of SpaceX's Crew-11 mission home from the International Space Station (ISS) ahead of schedule due to a medical issue experienced by a crewmember in orbit.

It will be the first medical evacuation in the history of the orbiting lab, which has hosted rotating astronaut crews continuously since November 2000. But there's no reason to panic, agency officials stressed: The affected astronaut is in stable condition and should be just fine.

'"It is not an emergency de-orbit, even though we always retain that capability, and NASA and our partners train for that routinely," recently confirmed NASA Administrator Jared Isaacman told reporters during a press conference on Thursday.

"The capability to diagnose and treat this properly does not live on the International Space Station," Isaacman added, explaining why he ultimately decided to speed up the departure timeline.

Crew-11 consists of NASA astronauts Zena Cardman and Michael Fincke, Japan's Kimiya Yui, and Oleg Platonov of the Russian space agency Roscosmos.

The quartet launched toward the ISS aboard the SpaceX Crew Dragon capsule Endeavour on Aug. 1, 2025. They're already nearing the end of their planned six-month mission aboard the orbiting lab, a fact that perhaps made the evacuation call a bit easier.

"We're always going to do the right thing for our astronauts, but it's recognizing it's the end of the Crew-11 mission right now. They've achieved almost all of their mission objectives," Isaacman said. "Crew-12 is going to launch in a matter of weeks anyway. This is an opportune time — when the vehicle is ready, when weather supports — to bring our crew home."

The departure timeline has not yet been worked out, but we should get an update about that in the next few days, he added.

The health issue arose on Wednesday (Jan. 7), when NASA announced that it was postponing a planned Jan. 8 spacewalk because of a "medical concern" involving an astronaut. That spacewalk was to have been conducted by Cardman and Fincke.

NASA has not identified the affected astronaut or provided many details about the medical issue, citing privacy concerns. But during Thursday's press call, Dr. James Polk, NASA's chief health and medical officer, said that the issue had nothing to do with the spacewalk or preparations for it.

"This is not an operational issue. This was not an injury that occurred in the pursuit of operations," Polk said. "It's mostly having a medical issue in the difficult areas of microgravity, and with the suite of hardware that we have at our avail to complete a diagnosis."

A medical evacuation from the ISS is not exactly surprising. In fact, it's long overdue: Statistical modeling suggests that there should be one such incident every three years or so, according to Polk.

Crew-11's successor mission, the four-astronaut Crew-12, is currently targeted to launch in mid-February. NASA is looking at possibly accelerating that timeline, but it's unlikely that Crew-12 could leave the ground before Crew-11 comes home.

So, after Crew-11's departure, the ISS will probably be staffed for a bit by just three people — NASA's Christopher Williams and cosmonauts Sergey Kud-Sverchkov and Sergei Mikayev. The trio arrived at the orbiting lab on a Russian Soyuz spacecraft on Nov. 27.

Williams will therefore be the only American on the station for a spell. But it's a responsibility that he can handle, NASA officials said.

"Chris is trained to do do every task that we would ask him to do on the vehicle," NASA Associate Administrator Amit Kshatriya said on Thursday.

"Of course, we also do a lot of the operations of the vehicle from our various control centers all over the world," Kshatriya added. "So he will have thousands of people looking over his shoulder, like our crew do all the time, to help ensure that they continue the groundbreaking science."