On Launch Pad 39A at NASA's Kennedy Space Center poses outside the hatch of space shuttle Discovery.

On Launch Pad 39A at NASA's Kennedy Space Center, the STS-124 crew poses outside the hatch of space shuttle Discovery. Clockwise from left are Mission Specialists Akihiko Hoshide, Karen Nyberg and Greg Chamitoff, Commander Mark Kelly, Mission Specialist Mike Fossum, Pilot Ken Ham and Mission Specialist Ron Garan. Hoshide represents the Japan Aerospace Exploration Agency. The crew is at Kennedy for a dress launch rehearsal called the terminal countdown demonstration test. TCDT provides astronauts and ground crews with an opportunity to participate in various simulated countdown activities, including equipment familiarization and emergency training. On the STS-124 mission, the crew will deliver and install the Japanese Experiment Module – Pressurized Module and Japanese Remote Manipulator System. Discovery's launch is targeted for May 31. Photo credit: NASA/Kim Shiflett