(05/15/2002) -- Astronaut Tracy Caldwell (left), a mission specialist candidate currently assigned to the Astronaut Office Space Station Operations Branch, joins Expedition 5 crew member Peggy Whitson (right) during a break in Terminal Countdown Demonstration Test activities at KSC. The TCDT includes emergency egress training at the pad and a simulated launch countdown. Expedition 5 will travel to the International Space Station on mission STS-111 as the replacement crew for Expedition 4, who will return to Earth aboard Endeavour. Known as Utilization Flight -2, the mission includes attaching a Canadian-built mobile base system to the International Space Station that will enable the Canadarm2 robotic arm to move along a railway on the Station's truss to build and maintain the outpost. The crew will also replace a faulty wrist/roll joint on the Canadarm2 as well as unload almost three tons of experiments and supplies from the Italian-built Multi-Purpose Logistics Module Leonardo. Launch of Space Shuttle Endeavour on mission STS-111 is scheduled for May 30, 2002