A computer program performs a unified analysis of the radiation exposure, the temperatures, and the power generation and distribution for predicting the performance of the TOPEX satellite on orbit and during maneuvers. The unified analysis is needed because all aspects are interdependent. The power-generating capacity of the solar array of the satellite depends on both the impinging radiation fluxes and the temperatures of the panels. The temperatures, in turn, depend on the power output of the array in addition to the radiation fluxes. Only by considering electric-power generation and consumption, radiation fluxes, and temperatures together can one predict any one of them as well as the state of charge, the voltage, and the current of the batteries. The present computer program predicts the power profile and the solar, albedo, and infrared fluxes on all surfaces of the satellite. It calculates the temperatures of the solar array and its power-generating capacity as function of radiation exposure and temperature. Battery currents and voltages are determined on the basis of the calculated state of charge of the batteries and the power-generating capacity of the solar array as a function of its radiation exposure and its temperatures. All pertinent values are stored in files with any desired time interval.
This program was written by Robert Richter of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Software category.
This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-21018.
This Brief includes a Technical Support Package (TSP).
Computing Radiation Fluxes, Power, and Temperature for TOPEX
(reference NPO-21018) is currently available for download from the TSP library.
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Overview
The document presents a technical support package from NASA detailing a sophisticated computer program developed for the TOPEX/Poseidon satellite, aimed at predicting radiation fluxes, power generation, and temperatures during its orbital operations and maneuvers. The program was created by Robert Richter at the California Institute of Technology for NASA's Jet Propulsion Laboratory and is based on a unified analysis that considers the interdependencies of thermal, radiation, and power systems.
The primary function of the program is to analyze the solar array's power-generating capacity, which is influenced by the impinging radiation fluxes and the temperatures of the solar panels. Conversely, the temperatures of the panels are affected by their power output, as well as the surrounding radiation environment. This interrelationship necessitates a combined approach to accurately predict the performance of the satellite.
The program generates detailed outputs, including flux files for all surfaces of the satellite, a temperature file specifically for the solar panel, and a power file. It calculates essential parameters such as battery currents, voltages, and the state of charge based on the solar array's power-generating capacity, which varies with radiation exposure and temperature. Users can specify the desired time intervals for data output, allowing for flexible monitoring and analysis.
The document also notes that while the vendor of the satellite, Fairchild Space Company, provided a SINDA thermal model, it was not verified or documented, highlighting the importance of the developed program as a reliable design tool prior to thermal vacuum testing.
Additionally, the software is available for commercial licensing, with contact information provided for interested parties. The document emphasizes that the work was conducted under the auspices of NASA, and it includes disclaimers regarding the use of trade names and the absence of government endorsement for specific products.
In summary, this technical support package outlines a critical tool for understanding and predicting the operational performance of the TOPEX satellite, integrating complex interactions between thermal dynamics, radiation exposure, and power generation to ensure effective satellite management and functionality.
