(05/04/1998) --- The STS-91 flight crew poses for a crew portrait after arriving at Kennedy Space Center's Shuttle Landing Facility aboard T-38 jets. Their arrival was delayed by severe thunderstorm activity in the area. From left to right, they are Mission Specialists Janet Lynn Kavandi, Ph.D., and Valery Ryumin, with the Russian Space Agency; Mission Commander Charles J. Precourt; Mission Specialist Wendy B. Lawrence; Pilot Dominic Gorie; and Mission Specialist Franklin Chang-Diaz, Ph.D. They are here to participate in the Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. The STS-91 launch is targeted for June 2 with a launch window opening around 6:10 p.m. EDT. The mission will conclude Phase I of the joint U.S.-Russian International Space Station Program. Although it will be the ninth Shuttle docking with the Russian Space Station Mir, it will be the first Mir docking for the Space Shuttle orbiter Discovery. The STS-91 mission will also be the first flight for the new Space Shuttle super lightweight external tank. Andrew Thomas, Ph.D., will be returning to Earth with the crew after living aboard Mir since January 25, 1998