Stock Photo - 01/13/2000 ___ In the Operations and Checkout Building, STS_99 Mission Specialist Janet Lynn Kavandi Ph.D. is helped by a suit technician during flight crew equipment fit check prior to her trip to Launch Pad 39A. The crew is taking part in Terminal Countdown Demonstration Test TCDT activities that provide 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