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The thermal design strategy is discussed as it relates to the production of up to 34 identical small satellites in a relatively short period of time. Tight production and launch schedules and the need to design for low mass, risk, and cost presented a design challenge for all disciplines. A specific arrangement of passive thermal control features, including ITO-coated AgTef covered structure radiators, MLI, and software controlled heaters established a robust design. Thermal modeling of the bus and unique antenna are presented including a comparison between the predicted and required component temperature ranges. Also described are the primary mission objective, the spacecraft configuration, requirements and design drivers, mission environments, and design parameters.

In August, 1995, the TOPEX/Poseidon satellite completed its third year in orbit and met its operational life requirement. The satellite TCS is performing as expected with the telemetry indicating that all components are operating within their allowable temperature ranges during normal mission modes. This paper assesses the performance of TCS from the start of the mission through 3 years in orbit at 1335 km altitude and 66.25° inclination. This orbit is in the Van Allen Belt in which few spacecraft fly. Specific attention is paid to environmental, operational, and attitude control conditions and their effects on the satellite thermal performance. The thermal telemetry data of each satellite module is discussed with respect to thermo-optical property degradation and the effects of varying orbital sun angles.

An automated procedure has been developed for correlating thermal models with test or flight data. The procedure achieves model correlation by determining the best combination of changes to a thermal model's conductor properties in order to minimize the differences between model temperature predictions and measured data. This procedure has been developed for use with the SINDA thermal analyzer program, but the methods are general and apply equally to other thermal programs, such as ESATAN. The method is based on design sensitivity and optimization techniques and utilizes the solution sequences available in MSC/NASTRAN. The thermal model is reformulated into an equivalent structural model, which is then optimized using built-in MSC/NASTRAN routines to match specified results. Continued effort has been expended in improving the performance of the correlation techniques.