(04/28/1999) --- At Launch Pad 39B, STS-96 Mission Specialist Julie Payette, with the Canadian Space Agency, and Pilot Rick Douglas Husband practice putting on oxygen gas masks as part of Terminal Countdown Demonstration Test (TCDT) activities. The TCDT provides the crew with emergency egress traiing, simulated countdown exercises and opportunities to inspect the mission payloads in the orbiter's payload bay. Other crew members taking part in the TCDT are Commander Kent V. Rominger and Mission Specialists Tamara E. Jernigan (Ph.D.), Daniel Barry (M.D., Ph.D.), Ellen Ochoa (Ph.D.) and Valery Ivanovich Tokarev, with the Russian Space Agency. Scheduled for liftoff on May 20 at 9:32 a.m., STS-96 is a logistics and resupply mission for the International Space Station, carrying such payloads as a Russian crane, the Strela; a U.S.-built crane; the Spacehab Oceaneering Space System Box (SHOSS), a logistics items carrier; and STARSHINE, a student-led experiment