The European Space Agency's ERS‐1 radar altimeter is the first to include separate operating modes to optimise performance over both ocean and non‐ocean surfaces. As part of the ERS‐1 commissioning activities, we have carried out a study of the tracking performance of this instrument over non‐ocean surfaces. Statistics for land ice, sea ice, arid lands, and inland water are presented. Performance in both operating modes is shown to be better than that of previous missions.
Abstract The Earth Observation Centre (EODC), located at Farnborough, has been developed to serve the needs of users of data from Earth remote sensing missions, beginning with the European Space Agency's ERS-1 spacecraft. To this end, the facilities of the ESA Processing and Archiving Facility (PAF) for ERS-1 reside within the EODC. With the exception of the core Synthetic Aperture Radar processing algorithms, the majority of the scientific processing chains for exploitation of data from ERS-1 at the EODC were designed and specified by a Science Team, consisting of specialists from UK universities, industry, and government research institutes. These designs were implemented by an industrial consortium. The Science Team was supported by an Algorithm Development Facility (ADF) during the processing chain development. The Science Team currently provide operational support using the EODC Calibration and Validation Facility (CVF). This consists of the verification, calibration, validation, and continuous assessment of products. This paper describes the work and structure of the Science Team, the ADF and the CVF. The methodology adopted is evaluated, and implications for future projects of this kind are considered in the light of the lessons learned.
Radar observations of the main-belt, M-class asteroid 216 Kleopatra reveal a dumbbell-shaped object with overall dimensions of 217 kilometers by 94 kilometers by 81 kilometers (±25%). The asteroid's surface properties are consistent with a regolith having a metallic composition and a porosity comparable to that of lunar soil. Kleopatra's shape is probably the outcome of an exotic sequence of collisional events, and much of its interior may have an unconsolidated rubble-pile structure.
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