Nuclear Powered SAR Satellite

The AA4871 Spacecraft Design course is the capstone class for the M.S. in Astronautics at the Naval Postgraduate School. Thc design team integrated a Topaz I1 nuclear power system with an EOS Synthetic Aperture Radar to design a low Earth orbit, three axis stabilized satellite flying in a gravity gradient stable orientation. The SAR is a high resolution, electronically stecrable, Earth science data collector for glaciology, hydrology, vegetation, occauography and geology which penetrates clouds, foliage and shallow soil layers. The antenna modulcs provide global, regional, and local high resolution mapping. Tradeoffs were analyzed to optimize coverage, satisfy nuclear safety issues, and to satisfy defined revisit and resolution requircmcnts. The design emphasized use of qualified and readily available components and subsystems. The satellite features a cylindrical monocoquc alumiiium structure, and a sun synchronous orbit simplifying thermal control design. It has a momentum bias attitude control system with momentum wheels and thrusters. The antenna has microstrip radiating elements on a honeycomb metal and composite structure and is articulated with respect to the spacecraft via an electric gimbal motor. Existing satcllitc control and data processing and distribution facilitics and an existing launch vehicle and launch site limit cost and tcchnical risk. -'