Mission Specialist Mike Fossum is dressed in his suit and ready to start the simulated launch countdown.

In the Operations and Checkout Building at NASA's Kennedy Space Center, STS-124 Mission Specialist Mike Fossum is dressed in his launch-and-entry suit and ready to start the simulated launch countdown. The simulation is the culmination 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