Living on the International Space Station is a sort of experiment for mankind, and the astronauts aboard are the test subjects.
The biggest surprise for astronaut Barry "Butch" Wilmore? The mental gymnastics of working in zero-gravity.
“You think you'll adjust quickly, and physically, I adjusted fine," he said. "But, I mean, you lose stuff. Things float away. You have to think about every single thing that you're doing at every moment, because what you're doing can have dramatic consequences if you don’t do it right.”