Lights on Launch Pad 39A reveal space shuttle Atlantis following the rollback of the rotating service structure.

Lights on Launch Pad 39A at NASA's Kennedy Space Center reveal space shuttle Atlantis following the rollback of the rotating service structure, or RSS. Rollback was complete at 9:49 p.m. EST. The orbiter access arm, at left, extends from the structure to a position next to Atlantis' crew compartment. The White Room at the end of the arm provides the crew with an entryway into the orbiter. The RSS also provides protected access to the orbiter for changeout and servicing of payloads at the pad. Rollback of the pad's RSS is one of the milestones in preparation for the launch of mission STS-122. Launch was originally set for Dec. 6 but was rescheduled to 3:21 p.m. Dec. 9. The delay was caused by problems with the external tank's engine cutoff sensor system that arose during tanking on Dec. 6. Atlantis will carry the Columbus Laboratory, the European Space Agency's largest contribution to the construction of the International Space Station. It will support scientific and technological research in a microgravity environment. Permanently attached to the Harmony node of the space station, the laboratory will carry out experiments in materials science, fluid physics and biosciences, as well as perform a number of technological applications. Photo credit: NASA/Amanda Diller