The crew pauses for photographers before getting on board the Astrovan for the ride to Launch Pad 39A.

The STS-124 crew pauses in front of the Astrovan for photographers before getting on board the Astrovan for the ride to Launch Pad 39A at NASA's Kennedy Space Center. The crew is taking part in a simulated launch countdown. From left are Mission Specialists Greg Chamitoff, Akihiko Hoshide, Mike Fossum, Ron Garan and Karen Nyberg, Pilot Ken Ham, and Commander Mark Kelly. The simulation is part of the launch dress 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