TerraSAR-X

TerraSAR-X (TSX) is an Earth observation satellite mission. It provides high-resolution X-band data for use in climatology, environmental and disaster monitoring, hydrology, geology, oceanography and cartography. The TSX SAR instrument is an active phase array X-band antenna system that provides multispectral SAR imagery in numerous operational modes such as ScanSar, Spotlight and Stripmap. Each distinct mode of TSX SAR functions as a radar system that builds reconstructions of desired landscapes for Earth observation purposes. TSX also includes a Tracking, Occultation and Ranging payload (TOR), which functions as a dual-frequency GPS receiver IGOR (Integrated GPS Occultation Receiver) that collects atmospheric radio occultation (RO) data to be used in the improvement of weather forecasting, climate change studies and space weather monitoring. The IGOR GPS receiver also has tracking capabilities that allow for precise orbit determination (POD) and works in conjunction with the Laser Retro Reflector (LRR) to evaluate GPS-based orbital data independently. Additionally, the TOR payload involves support modes that are able to provide processing of additional GPS occultation missions, including TOR-SAR, which focuses on precise science orbit (PSO) and SAR instrumentation, TOR-RO, which is responsible for ultra-rapid science orbit (USO), atmospheric excess phases, occultation tables, and ionospheric profiles, and TOR-POD, which focuses on PSO and USO. TSX also has a communication function which is built into the Laser Communication Terminal (LCT) that provides bidirectional communications for binary digital data transfer between satellites in different orbits (lower Earth orbit to mid-Earth orbit) or between a satellite and its constituent ground segment. The TSX bus has a total height of about 5m with a diameter of roughly 2.4m and includes the SAR instrument, the solar array and the DNepr-1 launcher fairing (for payload protection). The SAR antenna is mounted upon the hexagonal side of the spacecraft, which in flight points toward 33.8° off the nadir. The Laser Retro Reflector (LRR) is maintained by a global network of 40 ground stations of the International Laser Ranging Service (ILRS) and functions as an optical device for accurate satellite tracking. The DLR bases are composed of DLR/GSOC (Communication and Ground Station) which provide spacecraft operations support, DLR/HR (Microwaves and Radar Institute) that functions as an Instrument Operation and Calibrations Segment (IOCS), Payload Ground Segment (PGS) which involves DLR data processing, analysis and simulation, and a DLR Ground Segment that provides main functions of space and ground segment planning, orbital control, telemetry, command and product generation of user services. TerraSAR-X1 (also referred to as TSX or TSX-1 ) is a German SAR satellite mission for scientific and commercial applications (national project). The project is supported by BMBF (German Ministry of Education and Science) and managed by DLR (German Aerospace Center). In 2002, EADS Astrium GmbH was awarded a contract to implement the X-band TerraSAR satellite (TerraSAR-X) on the basis of a public-private partnership agreement (PPP). In this arrangement, EADS Astrium funded part of the implementation cost of the TerraSAR-X system. hydrology, geology, climatology, oceanography, environmental and disaster monitoring, cartography (DEM generation) making use of interferometry and stereometry. The TerraSAR X-band satellite, built by Airbus Defence and Space Geo-Intelligence/Infoterra GmbH (formerly EADS Astrium GmbH, Friedrichshafen, Germany) employs a mission-tailored AstroSat-1000 bus (successor of Flexbus and LEOSTAR due to industrial merger - initially AstroSat-1000 was referred to as AstroBus) concept with a heritage of CHAMP and GRACE missions. The S/C bus design features a central hexagonal CFRP structure as the main load-carrying element. The cross-sectional view of Figure 6 illustrates