Space Shuttle Discovery on top of the mobile launcher platform and crawler-transporter passes for launch of STS-116.

Space Shuttle Discovery, on top of the mobile launcher platform and crawler-transporter, passes through the gate to Launch Pad 39B for launch of mission STS-116. 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