Mathematic modeling of spacecraft solar panels

The article considers the approach to mathematical modeling of the solar panels operation of a spacecraft flying in near-Earth orbit, that takes into account possible shading of the solar panels surface by the components of the spacecraft's external surface. Two models of the solar panel operation are being considered in the paper. The first one is based on the solution of the diode equation, the second one takes into account the area of the illuminated part of the solar array and the solar rays angle of incidence on its plane. The search for sunlit portions of the solar panels is carried out using an interactive geometric model of the spacecraft external surface by means of ray tracing. The said two models have been compared and examples have been given stating in which case one or another model is preferred. The current generated by the solar battery and calculated with the proposed mathematical model is compared with the processed telemetry data obtained from the Zvezda Service Module of the International Space Station.