Program Predicts Radiation Forces on a Satellite

A computer program predicts the radiation forces on the TOPEX/ Poseidon satellite at any point in its orbit around the Earth. The program performs a unified analysis of the thermal, radiative, power-generation, and orbital-mechanics aspects of operation because these aspects are inter- dependent: The power-generating capacity of the solar panel of the satellite depends on both the impinging radiation and its temperature, which, in turn depends on both its power output and the radiative environment. The radiative environment depends on the trajectory and attitude of the satellite relative to the positions of the Earth and Sun. Only by considering all of the aforementioned phenomena together can one predict the temperature and power generation of the solar panel and the battery charges, currents, and voltages. Then the radiation forces are calculated from the results of the foregoing unified thermal/power/radiative analysis. Output is available in two forms: (1) a tabulation of all components of radiative forces over a single orbit, based on the day of the year and the relative orientations of the Sun, Earth, and orbit; and (2) a tabulation of the average radiation forces over a single orbit for any number of specified beta prime angles and the corresponding days of the year.