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Solar Array Degradation: A Monitoring and Predictive Tool
Authors: Dorotovic I., Pereira A., Viana N., Kovacevic J., Ribeiro R.A., Varas F.J., Donati A.
Ref.: 5th International conference on optimization (Optimization 2004), Lisbon, Portugal, 25 28 July 2004 (2004)
Abstract: The radiation environment encountered in space by satellites is extremely variable and depends mainly on the satellite position and space weather status. Satellites have usually solar arrays in their power subsystem. They are a critical component of a satellite and their lifetime limits the missions total duration. Therefore an important problem to address is the solar array performance over time. In this paper we present the software tool for monitoring and predicting the solar array performance degradation, denoted Solar Array Monitor (SAM), which was developed in the frame of the European Space Agency (ESA) project, Fuzzy Logic for Mission Control Purposes - Case 3 AO/1-3874/01/D/HK. SAM is capable of analysing solar array telemetry, mission orbit, environmental data, and estimation of the degradation rate of solar panels. The architecture of the software tool is divided into three main parts: a mission data warehouse, a set of functional blocks for pre-processing the input data, and a predictive model. The monitoring and predictive model developed to assess the degradation of the solar array is based on a Neural Network and is included in the mining module. Our predictive model provides either a 2-days or 4-days prediction. Various tests using sattelite data were performed and the results obtained were satisfactory. The Solar Array Monitor System has been successfully installed at the ESA/ESOC operation facilities (European Space Operational Centre, Darmstadt, Germany) and improved the decision for actions performed by spacecraft operators to minimise damage in extreme conditions. In addition, since the Sun is the main driver of space weather, some influencing aspects for the solar arrays performance, such as the level of solar, geomagnetic and ionospheric activity, are also discussed as future work.
