Thermal design, analysis, and experimental testing of a sun sensor for communications satellites

Thermal design, analyses and tests for a newly developed sun sensor for geostationary communications satellites have been performed. Equipment-level thermal analyses of a sun sensor are performed using the ANSYS 19.2 thermal module for steady-state and and transient orbital analyses are performed using Systema Thermica 4.8.P1. The steady-state thermal analyses of the sun sensor are performed for four different cases. Two of the cases are executed to compare the analysis results with the thermal vacuum cycle test (TVAC) temperature measurements. The thermal mathematical model developed for thermal analyses has been verified through thermal vacuum tests. The other two cases are performed to determine the maximum operating temperatures of the components in the sun sensor for the worst hot case (WHC) condition and the minimum non-operating temperatures of the components in the sun sensor for the worst cold case (WCC) eclipse condition. Three different types of thermal control materials (first surface mirror, second surface mirror, and multilayer insulation) and the need for a thermal filler pad are also analyzed. While all three thermal control materials are suitable, the application of the second surface mirror (SSM) as an external treatment results in lower temperature values for both the worst hot and worst cold cases. Using a thermal filler pad between the field-programmable gate array (FPGA) and the rear cover significantly reduces the temperature difference at the interface. The temperature results of the steady-state and transient analyses are consistent for the internal components of the sun sensor.