Comparative analysis of calculated and experimentally measured output capacity of the orbital space vehicle solar batteries on the example of the service module of the International Space Station Russian segment

The comparative analysis of calculated and experimentally measured output capacity of the service module solar batteries on the Russian Segment of the International Space Station (ISS) is presented. Special software is used for calculation; it considers the effect of partial shading of solar batteries upon the ISS structural units. The algorithm specifies shadowed cells definition by means of ray tracing and the electric current calculation based on the voltage balance equation. Input data includes the ISS three-dimensional computer model, orbit parameters, orientation parameters of the station and its movable units, current-voltage characteristics of photovoltaic cells and blocking diodes. The analysis assumed comparing of diagrams of calculated and measured electric current of the service module solar batteries; telemetric sensors are the source of experimental data. The analysis is executed for instantaneous and integrated values of current. The following factors of calculation accuracy are determined in the research resume: the necessity of simplifying of a geometrical model, the light reflection by the Earth and inadequate prediction of orientation of some ISS movable units (solar batteries and radiators of the ISS American Segment) cause of its depending upon the current need of electric power. The calculation accuracy is estimated, recommendations for software users are given and ways for its improvement are offered.