3 Days in Space Were Enough to Change 4 Astronauts’ Bodies and Minds

Four people who spent three days off Earth in September 2021 experienced physical and mental changes that included modest declines in cognitive tests, stressed immune systems and genetic changes within their cells, scientists report in a package of papers published on Tuesday in the journal Nature and several other related journals.

Almost all of what changed in the astronauts returned to normal after they splashed down on Earth. None of the alterations appeared to pose a showstopping caution for future space travelers. But the results also highlighted how little medical researchers know...

Afshin Beheshti of the Blue Marble Space Institute of Science and NASA’s Ames Research Center in California pointed to molecular changes in the astronauts’ kidneys that might portend the formation of kidney stones. That would not be a problem during a three-day space trip but could become a medical crisis during a longer mission.

“Halfway to Mars, how are you going to treat that?” Dr. Beheshti said.