NASA astronauts Sunita Williams and Butch Wilmore face significant physiological and psychological challenges upon returning from microgravity. They may experience muscle atrophy, bone loss, dizziness,

Suni Williams and Butch Wilmore are one more step closer to returning to Earth after an initially short mission became an extended, monthslong stay aboard the International Space Station.

The crew-swap mission will enable NASA’s Butch Wilmore and Suni Williams to return to Earth from the International Space Station.