Mission Specialist Garrett Reisman is helped before entering space shuttle Endeavour for the simulated launch countdown.

STS-123 Mission Specialist Garrett Reisman is helped with his launch and entry suit before entering space shuttle Endeavour for the simulated launch countdown. The countdown is the culmination of the terminal countdown demonstration test, or TCDT. The TCDT provides astronauts and ground crews with an opportunity to participate in various countdown activities, including equipment familiarization and emergency egress training. Endeavour is targeted to launch at 2:28 a.m. EDT March 11 on the 16-day STS-123 mission to the International Space Station. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Photo credit: NASA/Jim Grossmann