(01/12/2000) --- During Terminal Countdown Demonstration Test (TCDT) activities, STS-99 Mission Specialist Janice Voss (Ph.D.) is ready to practice driving the M-113, an armored personnel carrier. Part of Terminal Countdown Demonstration Test (TCDT) activities, the M-113 could be used by the crew in the event of an emergency at the pad during which the crew must make a quick exit from the area. In the rear (right) is Commander Kevin Kregel. TCDT provides the crew with simulated countdown exercises, emergency egress training, and opportunities to inspect the mission payloads in the orbiter's payload bay. STS-99 is the Shuttle Radar Topography Mission, which will chart a new course, using two antennae and a 200-foot-long section of space station-derived mast protruding from the payload bay to produce unrivaled 3-D images of the Earth's surface. The result of the Shuttle Radar Topography Mission could be close to 1 trillion measurements of the Earth's topography. Besides contributing to the production of better maps, these measurements could lead to improved water drainage modeling, more realistic flight simulators, better locations for cell phone towers, and enhanced navigation safety. Launch of Endeavour on the 11-day mission is scheduled for Jan. 31 at 12:47 p.m. EST