Electrical In-Orbit Dynamic of Solar Generators Equipped with Triple Junction Solar Cells

Background: The remaining satellite lifetime for scientific and commercial space mission can depend on the available electrical power from the solar generator. The prediction requires a detailed understanding of the degradation mechanism of the applied solar cells, their electrical parameters and the space weather conditions such as ultraviolet light, micrometeoroids or charged particles. Methods: A network simulation is performed for a high power solar generator containing solar cells, wires and protection diodes. The daily in orbit performance has been studied for operational cells, short circuited cells and cells in open circuit mode. The simulation is reinforced by comparing it to daily flight data of single cells, sections and the whole solar generator. Results: The daily in-orbit power has been successfully predicted and satellite lifetime has been assessed. For this goal the available telemetry only needs to contain view cell/section parameters but no current voltage curve measurements. Operational versus short circuit current coefficients offer an alternative approach for maximum power point voltage knowledge. Conclusion: The total generated in-orbit bus current at an operational point and the current/voltage characteristics can be simulated for various flight mission cases, so that the satellite lifetime can be assessed.