Space shuttle Discovery stands on Launch Pad 39A as the sun sets over NASA's Kennedy Space Center in Florida as space center workers prepare to move the rotating service structure into place. On its final mission, Discovery will take the Permanent Multipurpose Module (PMM) packed with supplies and critical spare parts, as well as Robonaut 2 (R2) to the International Space Station. Image credit: NASA/Dimitri Gerondidakis Sept. 21, 2010
