NASA Orders ISS Medical Evacuation—but Here’s the Real Surprise

A medical issue affecting one of the Crew-11 astronauts will bring an early end to their mission aboard the International Space Station (ISS), NASA confirmed in a Thursday press briefing. Their return will mark the agency’s first controlled medical evacuation from the space station, but statistically, this should have happened a long time ago.

“In our 25-year history of the International Space Station, we’ve had many models and Monte Carlo analysis models that have said that we should have had a medical evacuation approximately every three years in that 25-year history, and we’ve not had one to date,” Dr. James Polk, NASA’s chief health and medical officer, said during the briefing. A Monte Carlo analysis uses repeated random simulations on a computer to estimate the likelihood of outcomes in uncertain situations.

NASA has not shared any details about what the medical issue is nor which crew member—NASA’s Mike Fincke and Zena Cardman, Japanese astronaut Kimiya Yui, or Russian cosmonaut Oleg Platonov—is affected but said the ailing astronaut is “absolutely stable.”

The crew does not yet have an official return date but will depart the space station “within the coming days,” according to NASA Administrator Jared Isaacman.

The hazards of living in space

Keeping astronauts healthy in space for six months, or sometimes longer, is a feat of engineering and medical science. Astronauts aboard the ISS endure long-term exposure to microgravity, space radiation, and isolation and must undergo extensive reconditioning once they return to Earth.

In that sense, it’s a wonder it took 25 years for there to be a health concern serious enough to warrant an evacuation. But the ISS has a well-stocked pharmacy and a suite of medical equipment to periodically assess crew health, perform self-diagnoses, and treat certain illnesses and injuries. What’s more, all astronauts undergo medical training and have regular contact with a team of doctors closely monitoring their health on the ground.

Before this medical issue arose, two Crew-11 astronauts were preparing to conduct a spacewalk. Cardman and Fincke were supposed to venture outside the space station on Thursday morning to complete several maintenance tasks, but NASA postponed the EVA after a member of the crew fell ill.

Prior to conducting a spacewalk, astronauts must prebreathe pure oxygen to purge their bodies of nitrogen and prevent decompression sickness, also known as “the bends.” In rare cases, complications can arise from denitrogenation, such as absorption atelectasis (a type of lung collapse) and hypoxemia (low oxygen in the blood), if done poorly or interrupted.

The medical issue that’s sending Crew-11 home early, however, “had nothing to do with the operational environment and preparing for a spacewalk at all,” Polk said. “This was totally unrelated to any operations on board,” he added.

What happens now?

Crew-11 launched to the ISS ​​aboard a SpaceX Crew Dragon capsule on August 1. The four astronauts are now heading home roughly six weeks before the scheduled end of their mission in mid-February.

NASA officials will take a few days to assess weather and sea conditions and determine the best opportunity for Crew-11’s splashdown in the Pacific Ocean. SpaceX will dispatch a recovery vessel from Southern California to retrieve the crew and its Dragon spacecraft. As always, medical personnel will be aboard this ship to examine the astronauts after they exit the capsule.

This long-overdue incident will serve as a real-world test of NASA’s ISS medical evacuation protocol, validating the agency’s ability to return an ailing astronaut safely and expediently. After 25 years of preparing for this exact scenario, officials are confident that Crew-11 will make it home without further risk to their health.