NASA astronauts are returning to Earth after nine months in space. Experts have said a prolonged period in space can come with changes to human physiology and psychology.

The US astronauts stranded on the International Space Station joyfully emerged from their rescue capsule following a dramatic but smooth return to Earth Tuesday — months after their days-long jaunt in orbit turned into a headline-grabbing space odyssey.

Butch Wilmore and Suni Williams are heading home after about nine months at the International Space Station. The two veteran NASA astronauts were only supposed to be in space for a little more than a week.