STS-110 Commander Michael Bloomfield settles into his seat in Space Shuttle Atlantis as he prepares for a simulated launch countdown. The simulation is part of Terminal Countdown Demonstration Test activities. TCDT also includes emergency egress training and 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