Many of us may dream of going to space, but for a year? That's a long time to be "sitting in a tin can," as the David Bowie song goes, even if it's one as big as the International Space Station.

Scott Kelly left Earth in March 2015 and except for some spacewalks, has been aboard the International Space station ever since. He and Russian cosmonaut are returning to Earth on March 1 having spent 340 days in space. The unprecedented length of the mission allowed researchers to study the physical and psychological challenges astronauts face during long-duration spaceflight.

Above: The Soyuz spacecraft detaches from the International Space Station on March 1 as it carries American astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko back to Earth after their nearly yearlong stay at the station.