Crawler transporter No. 2 sits outside the Vehicle Assembly Building.

Crawler-transporter No. 2 sits outside the Vehicle Assembly Building. Workers will be driving the crawler to test it before it is needed to move the STS-116 stack from VAB high bay 3 to high bay 2 and allow the rollback of Space Shuttle Atlantis into high bay 3. The rollback will be determined by the mission management team based on information about Hurricane Ernesto and its path through Florida. Atlantis has been poised on Launch Pad 39B for liftoff on mission STS-115 to the International Space Station to deliver the P3/P4 truss segment. Photo credit: NASA/Jack Pfaller