A worker watches the progress of space shuttle Discovery's payload bay doors as they close around the Japanese Experiment Module.

On Launch Pad 39A at NASA's Kennedy Space Center, a worker watches the progress of space shuttle Discovery's payload bay doors as they close around the Japanese Experiment Module—Pressurized Module. The launch of Discovery on its STS-124 mission is targeted for May 31. On the mission, Discovery will transport the pressurized module and the Japanese Remote Manipulator System to the International Space Station. Photo credit: NASA/Kim Shiflett