Water bags called red water sausages are revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida.

Water bags, called red water sausages, are revealed on Launch Pad 39A at NASA's Kennedy Space Center in Florida following the move of the rotating service structure (RSS). RSS "rollback," as it's called, began at 11:44 a.m. EDT on May 15 and was completed at 12:24 p.m. The bags will dampen the wave of sound energy that is reflected back up toward space shuttle Endeavour when the solid rocket boosters ignite during launch. They suppress the powerful pulse of pressure to prevent dangerous stress on the wings of the shuttle.

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