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.
The unified analysis was developed and this program was written by Robert Richter of Caltech for NASA’s Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393- 3425. Refer to NPO-21019.
This Brief includes a Technical Support Package (TSP).
Program Predicts Radiation Forces on a Satellite
(reference NPO-21019) is currently available for download from the TSP library.
Don't have an account?
Overview
The document presents a technical support package from NASA detailing a sophisticated computer program designed to predict radiation forces acting on the TOPEX/Poseidon satellite during its orbit around Earth. Developed by Robert Richter at the California Institute of Technology for NASA's Jet Propulsion Laboratory, this program performs a unified analysis of thermal, radiative, power-generation, and orbital mechanics aspects, recognizing the interdependence of these factors.
The program's primary function is to analyze three interrelated subsystems: thermal dynamics, power generation from solar panels, and orbital mechanics. It calculates the radiation forces on the satellite as a function of solar panel position and satellite attitude. The power-generating capacity of the solar panels is influenced not only by the incoming solar radiation but also by their temperature, which is affected by the satellite's power output and the surrounding thermal environment. By integrating these elements, the program can accurately predict the temperatures of the solar panels, their power generation capabilities, and the state of charge of the satellite's batteries, including their currents and voltages.
The output of the program is available in two formats: one provides a detailed tabulation of all components of radiation forces over a single orbit, based on the day of the year and the relative positions of the Sun, Earth, and satellite; the other offers a summary of average radiation forces for various specified beta prime angles across multiple days.
This comprehensive approach allows for a more accurate understanding of how radiation forces impact satellite operations, which is crucial for mission planning and execution. The program is available for commercial licensing, and interested parties are directed to contact Don Hart at Caltech for further information.
Overall, this document highlights the importance of a holistic approach to satellite analysis, emphasizing the need to consider multiple interrelated factors to enhance the accuracy of predictions regarding satellite performance in space. The work described was conducted under NASA's sponsorship, and the document includes a disclaimer regarding the use of specific commercial products and the absence of government endorsement.
