NASA astronauts Sunita Williams and Butch Wilmore finally returned to earth with their SpaceX capsule making a slashdown off the Florida coast on Tuesday. Their return marks the end of a dramatic nine-month stay at the International Space Station.

Nine months is a long time to be in orbit. But Butch Williams and Suni Wilmore aren't alone in facing extraordinary circumstances in space. Here are some of the "final frontier's" most memorable incidents.