Behind the Scenes with the Atlantis Crew

Photographer Smiley N. Pool documents the four astronauts who will ride the last space shuttle as they get ready for their historic mission
Smiley N. Pool / Houston Chronicle / AP

Astronaut Rex Walheim
Atlantis' final mission will be Walheim's third trip on a space shuttle. He is photographed here in the neutral buoyancy lab, March 2011.

Get the Latest Photos from
Get TIME photos and pictures of the week delivered directly to your inbox.