A Go Endeavour banner adorns the perimeter gate on Launch Pad 39A at NASA's Kennedy Space Center in Florida.

A "Go Endeavour" banner adorns the perimeter gate on Launch Pad 39A at NASA's Kennedy Space Center in Florida. The rotating service structure (RSS), which has been providing weather protection and access to space shuttle Endeavour while it awaits lift off on the pad, soon will move away in preparation for launch. RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m.

STS-134 will deliver the Alpha Magnetic Spectrometer-2 (AMS), Express Logistics Carrier-3, a high-pressure gas tank and additional spare parts for the Dextre robotic helper to the International Space Station. May 16 at 8:56 a.m. will be the second launch attempt for Endeavour. The first attempt on April 29 was scrubbed because of an issue associated with a faulty power distribution box called the aft load control assembly-2 (ALCA-2). 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/Jack Pfaller