Standing underneath the orbiter Atlantis in the Orbiter Processing Facility are STS-110 Commander Michael Bloomfield and Mission Specialists Steven Smith and Rex Walheim. They and other crew members are taking part in Crew Equipment Integration Test activities, which include familiarization with the vehicle and payload. The mission, 13th assembly flight to the International Space Station, includes the Integrated Truss Structure S0. The ITS S0 is the center segment on the Space Station, part of the 300-foot (91-meter) truss attached to the U.S. Lab. By assembly completion, four more truss segments will attach to either side of the S0 truss. STS-110 is scheduled to launch April 4, 2002