NASA doesn’t often change course mid-mission. Astronauts’ schedules are planned down to the minute, spacecraft timelines are locked months in advance, and contingencies are carefully modeled long before launch. That’s why it is so surprising that they are bringing the SpaceX Crew-11 mission home from the International Space Station (ISS) earlier than planned due to a medical concern affecting one crew member.
The astronaut’s identity and the nature of the condition have not been disclosed, but NASA confirmed the crew member is now stable. The agency also cancelled its first planned spacewalk of the year because of the same health issue and expects to announce a target return date in the coming days. It marks the first time NASA has chosen to end an ISS mission early specifically because of an astronaut’s medical situation.
Why NASA Is Sending Crew-11 Home Early
Crew-11 launched from NASA’s Kennedy Space Center on August 1, 2025. The international crew includes U.S. astronauts Zena Cardman and Mike Fincke, Japanese astronaut Kimiya Yui, and Russian cosmonaut Oleg Platonov. Cardman and Fincke were scheduled to perform the cancelled spacewalk to prepare the station for a future rollout of new solar panels to boost power.
While early returns are rare, they are not unprecedented. The last time NASA brought astronauts home early was in 1997 during the STS-83 Space Shuttle mission, after one of Columbia’s fuel cells failed in orbit.
Still, Crew-11’s return is notable because it’s driven by human health, emphasizing how seriously NASA treats even potential medical risks at about 250 miles above Earth.
What Does Medical Care Look Like on the ISS?
The ISS is a floating lab that also acts as a remote medical outpost. Typical missions last about six months, during which astronauts are continuously monitored by a dedicated team of doctors, psychologists, and specialists on the ground.
According to NASA, each crew member is assigned a flight surgeon – physicians trained specifically in space medicine – who oversees health care before, during, and after flight.
Astronauts themselves receive extensive medical training and stay in regular contact with Earth-based doctors. The station carries a robust pharmacy and medical equipment designed to handle everything from minor injuries to more serious conditions. If an emergency exceeds what can safely be managed in orbit, astronauts can return to Earth in the same spacecraft they launched in for urgent care on the ground.
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Treating Medical Emergencies On the ISS
One of the most memorable examples of in-orbit medical care came when doctors treated a blood clot in an astronaut’s jugular vein during a mission aboard the ISS, which was described in a paper published in 2020. It was the first known case of deep vein thrombosis (DVT) in space, and there was no established treatment protocol for managing blood clots in microgravity.
Blood clot expert Stephan Moll, M.D., was consulted to help guide the response. For more than 90 days, the astronaut treated the condition in orbit, performing ultrasounds on their own neck with guidance from a radiology team on Earth, along with email and phone discussions with Moll. The clot was discovered incidentally during a research study examining how fluid shifts in the body in zero gravity.
“When I was young I wanted to be an astronaut, so when NASA called on me to help, it was pretty incredible,” said Moll in a press release. “And it’s been amazing to then continue working with NASA doing research on blood clots in space that will help develop the health and safety protocolsfor future space travel.”
The collaboration between Moll and NASA continues today, with their work informing decisions about medical supplies, blood thinners, and risk-reduction strategies as humans prepare to venture farther from Earth than ever before.
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