STS-134 Pilot Greg H. Johnson prepares to board space shuttle Endeavour through the crew hatch in the background.

In the White Room at Launch Pad 39A at NASA's Kennedy Space Center in Florida, STS-134 Pilot Greg H. Johnson prepares to board space shuttle Endeavour through the crew hatch in the background. Members of the Closeout Crew, in white uniforms, are there to assist astronauts with their launch-and-entry suits and the boarding process. Johnson piloted space shuttle Endeavour during its STS-123 mission in 2008.

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/Sandra Joseph and Kevin O'Connell