(05/02/1998) -- Space Shuttle Discovery sits atop a mobile launcher platform at Launch Complex 39A after its move this morning from Vehicle Assembly Building high bay 1, where it was mated to the first Space Shuttle super lightweight external tank/solid rocket booster stack. The Orbiter Access Arm, with the white room located at its outer end, is being positioned into place on the orbiter. This white room provides personnel entry into the orbiter while it is on the pad. Discovery will be launched on mission STS-91, concluding Phase I of the joint U.S.-Russian International Space Station Program, on June 2 with a launch window opening around 6:10 p.m. EDT. This will be the ninth Shuttle docking with the Russian Space Station Mir, but the first Mir docking for Discovery. The STS-91 flight crew includes Commander Charles Precourt; Pilot Dominic Gorie; and Mission Specialists Wendy B. Lawrence; Franklin Chang-Diaz, Ph.D.; Janet Kavandi, Ph.D.; and Valery Ryumin, with the Russian Space Agency. Andrew Thomas, Ph.D., will be returning to Earth with the crew after living more than four months aboard Mir