Analytical and numerical approaches of a solar array thermal analysis in a low-earth orbit satellite

Abstract This paper researches the thermal analysis of a fixed-type solar array in a low-earth orbit satellite through both an analytical method with a simplified thermal model and a numerical method with a detailed thermal model. An analytical solution is derived from the simplified one-dimensional thermal governing equation. Because the current solar array is thermally decoupled from the spacecraft bus, its thermal analysis can be performed independently. The worst hot temperature of the current solar array can be predicted using an analytical solution of a single-lumped mass node. For better solar cell efficiency, a thermal surface finish of the backside of a solar array is required to ensure that the solar array temperature remains as low as possible in orbit. There are four ideal thermal surface types for a thermal surface finish. Based on the analytical solutions of the solar array temperature under the worst hot condition corresponding to each ideal thermal surface type, a solar reflector type gives the lowest temperature. Thus, SG121FD white paint was selected as an actual application of a thermal surface finish. A detailed solar array thermal model included in the system-level satellite thermal model was developed and solved numerically. From the detailed thermal analysis, in-orbit thermal characteristics of the solar array were determined and the thermal safety of the current solar array was verified with satisfying the allowable temperature limits. And the usefulness of the analytical approach to predict the worst hot temperature of the current solar array was also confirmed in comparison with the numerical analysis result of the detailed thermal model.