The crew members stride out of the Operations and Checkout Building eager to get to Launch Pad 39B and the start of their mission to the International Space Station.

The STS-115 crew members stride out of the Operations and Checkout Building eager to get to Launch Pad 39B and the start of their mission to the International Space Station. This is the second attempt at launch after a week's postponement due to weather and technical concerns. On the left side, front to back, are Pilot Christopher Ferguson and Mission Specialists Steven MacLean and Heidemarie Stefanyshyn-Piper. On the right side, front to back, are Commander Brent Jett and Mission Specialists Daniel Burbank and Joseph Tanner. On its second attempt for launch, Atlantis is scheduled to lift off at 11:41 a.m. EDT today from Launch Pad 39B. During the STS-115 mission, Atlantis' astronauts will deliver and install the 17.5-ton, bus-sized P3/P4 integrated truss segment on the station. The girder-like truss includes a set of giant solar arrays, batteries and associated electronics and will provide one-fourth of the total power-generation capability for the completed station. This mission is the 116th space shuttle flight, the 27th flight for orbiter Atlantis, and the 19th U.S. flight to the ISS. STS-115 is scheduled to last 11 days with a planned landing at KSC. Photo credit: NASA/Kim Shiflett