On Launch Pad 39A space shuttle Atlantis is in full view after rollback of the rotating service structure.

On Launch Pad 39A at NASA's Kennedy Space Center in Florida, space shuttle Atlantis is in full view after rollback of the rotating service structure. The rollback enables delivery and transfer of Atlantis' payload on April 18. After space shuttle Endeavour's rollout to Launch pad 39B at NASA's Kennedy Space Center in Florida this morning, two different shuttles now are poised on two different launch pads in full view. Near the top of the shuttle is the White Room at the end of the orbiter access arm, 147 feet above the pad. When in place against the shuttle, the White Room provides access into the crew compartment on the shuttle. With the space shuttle fleet set for retirement in 2010, this is expected to be the final time two shuttles will be on launch pads at the same time. Endeavour will stand by at pad B in the unlikely event that a rescue mission is necessary during space shuttle Atlantis' upcoming mission. Atlantis is targeted to launch May 12. After Endeavour is cleared from its duty as a rescue spacecraft, it will be moved to Launch Pad 39A for its STS-127 mission to the International Space Station. That flight is targeted for launch June 13. Photo credit: NASA/Kim Shiflett