KSC-2009-3355

CAPE CANAVERAL, Fla. – On Launch Pad 39A at NASA's Kennedy Space Center in Florida, workers begin closing the rotating service structure, or RSS, around space shuttle Endeavour. The RSS provides protected access to the shuttle for changeout and servicing of payloads at the pad. The structure is supported by a rotating bridge that pivots about a vertical axis on the west side of the pad's flame trench. The RSS rotates through 120 degrees (one-third of a circle) on a radius of 160 feet. Support for the outer end of the bridge is provided by two eight-wheel, motor-driven trucks that move along circular twin rails installed flush with the pad surface. The track crosses the flame trench on a permanent bridge. Endeavour is targeted to launch June 13 on its STS-127 mission to the International Space Station. Photo credit: NASA/Tim Jacobs