(NEW YORK) — A mission to the International Space Station may end early due to a medical situation involving one of the astronauts aboard the station.
NASA announced that it was postponing Thursday’s spacewalk because “the agency is monitoring a medical concern with a crew member that arose Wednesday afternoon aboard the orbital complex.”
The space agency then followed up with a statement saying, “Safely conducting our missions is our highest priority, and we are actively evaluating all options, including the possibility of an earlier end to Crew-11’s mission.”
The crew of four was gearing up for the first spacewalk of 2026, which was slated for Thursday morning.
“These are the situations NASA and our partners train for and prepare to execute safely. We will provide further updates within the next 24 hours,” the agency wrote.
If NASA needs to end the Crew-11 mission early, there are two spacecraft capable of returning humans to Earth docked to the station, including the SpaceX Dragon that brought the crew to the ISS in August. There are currently seven astronauts aboard the station, and three would remain should Crew-11 return early. The launch window for the Crew-12 mission opens Feb. 15.
NASA astronauts Mike Fincke and Zena Cardman were scheduled to work outside of the ISS for more than six hours to install a modification kit and route cables for a future roll-out solar array, according to the agency. They were also planning to add jumper cables, photograph the hardware and collect five microorganism samples near the station’s airlock.
“Obviously the challenge in space tends to be yet again that they don’t have the immediate medical personnel,” Dr. Farhan Asar, a space medicine researcher and the Associate Dean at the Toronto Metropolitan University School of Medicine, told ABC News on Thursday.
At the time, the agency said it was not appropriate to share additional details due to medical privacy reasons, but confirmed the situation was stable and that a new date for the spacewalk would be announced later.
“On Earth over here, we could basically just go to the emergency, go to your family doctor who could assess the situation. They could order a plethora of tests,” Dr. Asrar said. “In space, however, basically the diagnostics tends to be quite limited to, let’s say, taking the vitals, the ECG.”
According to Dr. Asrar, a mission could be cut short if a medical issue escalates to the point where it needs immediate treatment on Earth, especially if staying in space could worsen the condition due to isolation and limited medical resources.
“These are some of the concerns that would entail them to basically say, let’s scrap the mission, bring the individual home,” he said.
While NASA hasn’t revealed which astronaut is affected by the medical issue, the crew consists of two American astronauts, one Japanese astronaut and a Russian cosmonaut. The American astronauts were scheduled to participate in the postponed spacewalk.
The four members of Crew-11 traveled to the ISS on Aug. 1, 2025, aboard a SpaceX Dragon spacecraft. It was the first time in space for two of the four crew members — NASA astronaut and mission commander Cardman and Roscosmos cosmonaut and mission specialist Oleg Platonov. The mission is NASA astronaut and mission pilot Fincke’s fourth trip to the station and Japan Aerospace Exploration Agency astronaut and mission specialist Kimiya Yui’s second trip.
NASA selected Cardman to be part of the 2017 class of astronauts. A Williamsburg, Virginia, native, she holds degrees in biology and marine sciences.
Fincke is a space veteran, having spent more than a year in orbit and having performed nine spacewalks. The retired Air Force colonel previously served as an ISS commander and mission specialist.
Yui, a mission specialist, is returning to the ISS for a second visit after previously spending 142 days aboard the station as part of Expeditions 44 and 45.
Platonov, a graduate of the Krasnodar Air Force Academy, became a cosmonaut in 2018 and will serve as a mission specialist.
“I cannot tell you enough how meaningful it is to have a crew that is as kind and as thoughtful and as wonderful as they are incredibly technically competent, incredible astronauts, cosmonauts coming from multiple agencies, many different backgrounds. They make my job very, very easy as commander,” Cardman said during a pre-launch press conference.
The crew marked a historic milestone for the ISS in November, when NASA celebrated 25 years since the first crew arrived at the station.
The mission is part of NASA’s Commercial Crew Program that partners with private companies to deliver humans to and from the ISS. According to NASA, Crew-11 is the “11th crew rotation mission of SpaceX’s human space transportation system and its 12th flight with astronauts.”
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