JSC2011-E-059420 (17 May 2011) --- NASA astronauts Chris Ferguson, left, and Rex Walheim walk past the space shuttle Atlantis as it is moved from the Orbiter Processing Facility to the Vehicle Assembly Building at NASA?s Kennedy Space Center on May 17, 2011. The move, known as rollover, is a milestone in the preparation for launch as the orbiter leaves its processing hangar to be prepped for its final flight. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool