(03/19/2002) -- The STS-110 crew poses on the 225-foot level of the Fixed Service Structure on the launch pad during Terminal Countdown Demonstration Test activities. Kneeling in front are Pilot Stephen Frick and Mission Specialist Jerry Ross. Behind them are Mission Specialists Ellen Ochoa and Rex Walheim. In the rear are Commander Michael Bloomfield and Mission Specialists Lee Morin and Steven Smith. The TCDT, which includes emergency egress training and a simulated launch countdown, is held at KSC prior to each Space Shuttle flight. Scheduled for launch April 4, the 11-day mission will feature Shuttle Atlantis docking with the International Space Station (ISS) and delivering the S0 truss, the centerpiece-segment of the primary truss structure that will eventually extend over 300 feet