STS-99 Mission Specialist Gerhard Thiele, with the European Space Agency, arrives at KSC aboard a T-38 training jet aircraft to take part in a Terminal Countdown Demonstration Test (TCDT). The TCDT provides the crew with simulated countdown exercises, emergency egress training, and opportunities to inspect the mission payloads in the orbiter's payload bay. Other crew members taking part are Commander Kevin Kregel, Pilot Dominic Gorie, and Mission Specialists Janet Lynn Kavandi (Ph.D.), Janice Voss (Ph.D.), and Mamoru Mohri, who is with the National Space Development Agency (NASDA) of Japan. 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