The STS-111 crew spend time in the Space Station Processing Facility learning more about the payload they will be transporting: The Mobile Base System (MBS). Standing left to right in the back row are Expedition Five Commander Valeri Kozun, with the Russian Aviation and Space Agency; Mission Specialist Phillippe Perrin, with the French space agency CNES; Pilot Paul Lockhart; trainer Chris Hardcastle; Mission Specialist Franklin Chang-Diaz; and Commander Ken Cockrell. Flanked by trainers in the front row is (center) Peggy Whitson, another of the Expedition Five crew who will ferried to the International Space Station. The MBS will be installed on the Mobile Transporter to complete the Canadian Mobile Servicing System, or MSS. The mechanical arm will then have the capability to "inchworm" from the U.S. Lab Destiny to the MSS and travel along the Truss to work sites. The Expedition Five crew will be replacing Expedition Four. Launch of Endeavour on mission STS-111 is scheduled for April 18, 2002