In the white room on Launch Pad 39B, STS-116 Pilot William Oefelein is helped with his gear before entering Space Shuttle Discovery. The mission crew is taking part in a simulated launch countdown, part of the terminal countdown demonstration test that includes prelaunch preparations. The STS-116 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. Launch is scheduled for no earlier than Dec. 7. Photo credit: NASA/Amanda Diller