Solar array model corrections from Mars Pathfinder Lander data

Abstract

The MESUR solar array power model for the Mars Pathfinder spacecraft initially assumed values for input variables. After landing, early surface variables such as array tilt and azimuth or early environmental variables such as array temperature can be corrected. Correction of later environmental variables such as tau versus time, spectral shift, dust deposition and UV darkening is dependent upon time, on-board science instruments and the ability to separate effects of variables. Engineering estimates had to be made for additional shadow losses and Voc sensor temperature corrections. Some variations had not been expected such as tau versus time of day and spectral shift versus time of day. Additions needed to the model are thermal mass of lander petal and correction between Voc sensor and temperature sensor. Conclusions are: the model works well; good battery predictions are difficult; inclusion of Isc and Voc sensors was valuable; and the IMP and MAE science experiments greatly assisted the data analysis and model correction.