MEDIA RELATIONS OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL AERONAUTICS AND SPACE ADMINISTRATION PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011 PHOTO CAPTION P-49954AC July 8, 1998 This is a view of the Shuttle Radar Topography Mission mast after it has been fully extended during tests at AEC-Able Engineering Company, Inc., the mast subcontractor. In the foreground is the triangular tip-plate on which the outboard radar antennas will be mounted. Behind the tip plate is the "milk-stool", a three-legged support which will allow coarse mechanical adjustment of the antenna alignment once SRTM is on-orbit. Note the white ribbon cables in the box-like mast structure and the suspension wires hanging above the mast, which are needed to compensate for the mast's weight on earth. The box structure surrounding the mast in the background is a thermal test chamber. Set for launch on the space shuttle in September 1999, the Shuttle Radar Topography Mission is designed to collect three-dimensional images of nearly 80 percent of the Earth's land surface, except near the poles, with a resolution of 30 meters (98 feet). To collect the 3-D data, engineers will add the 60-meter- long (200-foot) mast, additional radar antenna, and improved navigation devices to the original Spaceborne Imaging Radar-C hardware, which flew twice on the shuttle in 1994. The mission is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and is managed by the Jet Propulsion Laboratory for NASA's Earth Science Enterprise.