At NASA's Kennedy Space Center in Florida, space shuttle Discovery begins its nighttime trek, known as ''rollout,'' from the Vehicle Assembly Building to Launch Pad 39A. It takes the shuttle, attached to its external fuel tank, twin solid rocket boosters and mobile launcher platform, about six hours to complete the move atop a crawler-transporter. 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/Frankie Martin Sept. 20, 2010
