In the White Room on NASA Kennedy Space Center's Launch Pad 39A, STS-123 Pilot Gregory H. Johnson (left) and Mission Specialist Rick Linnehan pause in front space shuttle Endeavour's open hatch. They are getting ready to enter Endeavour for the simulated launch countdown, which 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