EngineeringAerospace EngineeringMaterials ScienceAerospace MaterialsGlobal Navigation Satellite SystemsHeat TransferCoatingsRadiation-resistant MaterialsSolar RadiationSpacecraft StructuresThermal Control SystemsThermal Management MaterialsAerospace Surface CoatingDegradationProtective Overcoat MaterialsSpacecraft Thermal ControlThermal ControlThermal Control Coatings
Six Navstar Global Positioning System (GPS) spacecraft were launched into highly inclined (63 deg) 20,182 km orbits between February 1978 and April 1980. Solar absorptances (<*s) have been deduced from the spacecraft temperature data and are presented in this paper. The coatings evaluated are silvered Teflon, fused silica mirrors, silvered Teflon with an electrically conductive overcoat, and S13G LO white paint. The <xs values for all of the coatings have increased significantly since launch. Possible causes for the high degradation rates are discussed.
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