Workers watch closely as space shuttle Discovery's payload bay doors close around the Japanese Experiment Module.

Workers in the payload changeout room on Launch Pad 39A at NASA's Kennedy Space Center watch closely as space shuttle Discovery's payload bay doors 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