Space Shuttle Discovery sits on Launch Pad 39B for launch of mission STS-116.

Space Shuttle Discovery sits on Launch Pad 39B for launch of mission STS-116. On the left can be seen the rotating service structure, which will be rolled to enclose the shuttle for servicing and payload transfer. Above the shuttle on the fixed service structure is the 80-foot tall lightning mast. The shuttle was harddown on the pad at 9:03 a.m. The rollout from the Vehicle Assembly Building began at 12:29 a.m. The mission is No. 20 to the International Space Station and construction flight 12A.1. The mission payload is the SPACEHAB module, the P5 integrated truss structure and other key components. The launch window for mission STS-116 opens Dec. 7. Photo credit: NASA/Jim Grossmann