Space Shuttle Atlantis atop the mobile launcher platform sits on Launch Pad 39B after a crawl from the Vehicle Assembly Building.

Space Shuttle Atlantis, atop the mobile launcher platform, sits on Launch Pad 39B after a nearly 8-hour crawl from the Vehicle Assembly Building. At left is the open rotating service structure and fixed service structure with the 80-foot lightning mast on top. Extended from the fixed structure is the orbiter access arm, with the White Room adjacent to Atlantis. At right is the 290-foot high, 300,000- gallon water tank that aids in sound suppression during launch. The water releases just prior to the ignition of the shuttle engines and flows through 7-foot-diameter pipes for about 20 seconds, pouring into 16 nozzles atop the flame deflectors and from outlets in the main engines exhaust hole in the mobile launcher platform. Atlantis' launch window begins Aug. 27 for an 11-day mission to the International Space Station. The STS-115 crew of six astronauts will continue construction of the station and install their cargo, the Port 3/4 truss segment with its two large solar arrays. Photo credit: NASA/Troy Cryder & George Shelton