Temperature Estimation of A GEO Satellite Solar Array Using Analytical and Numerical Methods, With Comparison to Orbital Temperatures

Satellites obtain all their energy from the Sun when exposed to sunlight and rely on batteries during eclipses. The temperature of solar arrays plays a crucial role in power generation. During an eclipse, the power for the satellite's systems is supplied entirely by the batteries. The satellite's temperature before entering the eclipse, during the maximum eclipse duration of 72 minutes, and upon exiting the eclipse can be determined analytically. Solar array temperature must be determined, because it is a crucial factor affecting its efficiency. In the current study, the solar array temperature in geostationary orbit was predicted using a 3-axis stabilized satellite. A one-dimensional analytical equation was used to calculate temperature values that were then compared with the results from commercial software and the measured temperatures in orbit. Analytical predictions estimated the solar array temperatures as 55.1°C, 49.7°C, and 52.3°C for winter solstice, summer solstice, and equinox, respectively, while ESARAD/ESATAN simulations gave 64.4°C, 55.7°C, and 62.4°C. In-orbit measurements were lower at 45.6°C, 41.2°C, and 43.7°C, with an average deviation of ~17% between analytical and measured values, primarily due to simplified assumptions in the analytical model and the detailed geometric and radiative effects captured in the simulations. It was observed that the analytically derived results showed a moderate agreement with both the commercial software outcomes and in-orbit temperature measurements, with absolute deviations of 8-10 oC relative to in-orbit data and 9-14 oC relative to ESATAN, which are considered acceptable for preliminary thermal sizing of solar arrays in GEO given the simplified 1-D analytical approach employed.