Fuel trucks head for Launch Pad 39B to refill the external tank on Space Shuttle Discovery.

Fuel trucks head for Launch Pad 39B to refill the external tank on Space Shuttle Discovery. The top of the external tank can be seen above the rotating service structure that encloses the space shuttle. The launch attempt of Discovery on mission STS-116 was postponed Dec. 7 due a low cloud ceiling over Kennedy Space Center. The next launch attempt was scheduled for Saturday, Dec. 9, at 8:47 p.m. This will be Discovery's 33rd mission and the first night launch since 2002. The 20th shuttle mission to the International Space Station, STS-116 carries another truss segment, P5. It will serve as a spacer, mated to the P4 truss that was attached in September. After installing the P5, the crew will reconfigure and redistribute the power generated by two pairs of U.S. solar arrays. Landing is expected Dec. 19 at KSC. Photo credit: NASA/Ken Thornsley