At NASA's Kennedy Space Center in Florida space shuttle Endeavour is illuminated.

At NASA's Kennedy Space Center in Florida, space shuttle Endeavour is illuminated by bright xenon lights on Launch Pad 39A after the rotating service structure (RSS) was moved away. The structure provides weather protection and access to the shuttle while it awaits lift off on the pad. RSS "rollback," as it's called, began at 11:52 p.m. EDT on April 28. The move was scheduled to begin at 7 p.m., but storms over Kennedy delayed pad operations for a few hours. STS-134 will deliver the Express Logistics Carrier-3, Alpha Magnetic Spectrometer-2 (AMS), a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. Endeavour was scheduled to launch at 3:47 p.m. on April 29, but that attempt was scrubbed for at least 72 hours while engineers assess an issue associated with the shuttle's Auxiliary Power Unit 1. STS-134 will be the final spaceflight for Endeavour. For more information visit, www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts134/index.html. Photo credit: NASA/Ken Thornsley