CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building at NASA's Kennedy Space Center, STS-124 Mission Specialist Akihiko Hoshide has his communications adjusted in the helmet of his launch-and-entry suit. Hoshide represents the Japan Aerospace Exploration Agency, or JAXA. He has donned the suit for the simulated launch countdown the crew is starting. 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

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building at NASA's Kennedy Space Center, STS-124 Mission Specialist Karen Nyberg gets help donning her launch-and-entry suit for the simulated launch countdown the crew is starting. 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

CAPE CANAVERAL, Fla. -- On Launch Pad 39A at NASA's Kennedy Space Center, STS-124 Mission Specialist Mike Fossum gets a close look the bottom of the Japanese Experiment Module – Pressurized Module in space shuttle Discovery's payload bay. The payload bay walkdown 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

CAPE CANAVERAL, Fla. -- In the Operations and Checkout Building at NASA's Kennedy Space Center, STS-124 Mission Specialist Greg Chamitoff dons his launch-and-entry suit for the simulated launch countdown the crew is starting. 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

CAPE CANAVERAL, Fla. -- On Launch Pad 39A at NASA's Kennedy Space Center, STS-124 crew members get a close look at the Japanese Experiment Module – Pressurized Module and other equipment in space shuttle Discovery's payload bay. At left is Commander Mark Kelly; on the floor looking up is Pilot Ken Ham. The payload bay walkdown 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

CAPE CANAVERAL, Fla. -- On Launch Pad 39A at NASA's Kennedy Space Center, STS-124 Pilot Ken Ham (right) and Mission Specialist Ron Garan get on their backs for a different view of the payload in space shuttle Discovery's payload bay. The payload bay walkdown 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