Space shuttle Atlantis, attached to its external fuel tank and solid rocket boosters atop a mobile launcher platform, slowly inches out of the Vehicle Assembly Building for the final time. "Rollout," as it's called, to Launch Pad 39A at NASA's Kennedy Space Center in Florida took place on 31 May 2011. It took the crawler-transporter about six hours to carry the shuttle stack to its seaside launch pad. The milestone move paves the way for the launch of the STS-135 mission to the International Space Station, targeted for 8 July. STS-135 will be the 33rd flight of Atlantis, the 37th shuttle mission to the space station, and the 135th and final mission of NASA's Space Shuttle Program.