The rotating service structure on Launch Pad 39A begins to move away from space shuttle Discovery.

At NASA's Kennedy Space Center in Florida, the rotating service structure on Launch Pad 39A begins to move away from space shuttle Discovery. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 8:02 p.m. EST on Feb. 23 and wrapped up at 8:37 p.m. From here, cameras will catch the shuttle lift off amidst the space center's pristine wildlife refuge.

Scheduled to lift off Feb. 24 at 4:50 p.m. EST, Discovery and its six-member crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the International Space Station. Discovery, which will fly its 39th mission, is scheduled to be retired following STS-133. This will be the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Jack Pfaller