NASA astronaut Doug Hurley crawls out of the Crew Compartment Trainer (CCT-2) mock-up while Rex Walheim waits as the crew of STS-135 trains in the Space Vehicle Mock-up Facility (SVMF) at NASA?s Johnson Space Center June 29, 2011. The training marked the crew's final scheduled session in JSC's Shuttle Vehicle Mock-up Facility. Photo credit: NASA Photo/Houston Chronicle, Smiley N. Pool