Other effects, once an astronaut gets home, include dizziness and nausea, Chiao said. “To me, it feels like kind of like having the flu. It takes a couple of weeks to get back to normal,” he said.

In the early 2000s, Chiao was a commander on the International Space Station, the orbiting research facility where astronauts Butch Wilmore and Suni Williams have effectively been stranded since last ...