Thermal analysis of a 1-unit CubeSat (³Cat-4)
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Tutor / director / evaluatorSureda Anfres, Miquel
Document typeMaster thesis
Rights accessOpen Access
This TFM consists ofdeveloping, executing,and assessing the results of a thermal analysis aimed to demonstrate that the ³Cat-4nanosatellite complies with all necessary thermal requirements established by the European Space Agency (ESA).³Cat-4is an educational space mission developed at UPC’s NanoSat Lab as part of the second edition of the Fly Your Satellite program of the European Space Agency academy. The satellite and several of its subsystems have been developed by bachelor, master,and PhD students, with the rest being taken from specialized manufacturers. The satellite is a technology demonstrator for its payload, the Flexible Microwave Payload (FMPL-1), which integrates different mission experiments in a single subsystem with the goal of efficiently obtaining a set of earth observables. The analyses performed are based on a simplified thermal desktop model of the satellite, which was already built in a previous project. In this project, the model was updated due to a recent change in the OBC and IB subsystems, anda stowed geometry was developed from the original one. All versions of the model are built with the aim ofobtaining a model able to replicate the thermal behavior of the real satellite but with a simpler geometry which would reduce the time and computational cost of the thermal simulations. The recent knowledge provided by ESA of the orbit made necessary toperform specific studies to obtain the most restrictive hot and cold environments to be faced during the mission, which, together with the subsystems consumptions and satellite attitude states, are demonstrated in a sensibility Studio to play a major rolein the satellite thermal behavior.After the simplified model and the orbital characteristics are obtained, they are studied to perform a set of simulations in a thermal software environment, according to each operational mode in where the satellite may be. Afterwards, the results are analyzed,and the fulfillment of the thermal requirements is assessed by applying a series of margins to the computed results and comparing them to the operational temperatures of the components as provided by the manufacturers. In general, the subsystems are expected to operate inside the desired temperature range even in the most limiting conditions; however,the battery component proved to be critic, since it tended to overcoolfor the current orbit. Therefore, a set of studieshave been performed toassess the best possible thermal control mechanisms. Results have determined that the best practice is to utilize a specific combination of thermal paints for the exterior panels and use the battery heater to generate additional heat when needed.A final problem was caused by the high battery heater consumptions needed to maintain the batteries temperature inside the expected margins in the coldest scenarios. In order to solve this issue, a study for the calibration of the heater component has been performed, which allows to minimize the power consumptions of this component while generating the maximum possible amount of heat to avoid the overcooling of the batteries.
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