The generated power degradation of a satellite in a low earth orbit during high solar activity period has been compared with the power degradation of a satellite during low solar activity period. A degradation prediction method is developed for this study. As a result, the effect of a large solar flare on solar cell degradation is found to be negligible in a low earth orbit. This is because the effects of shield thickness and inclination are thought to be greater than that of degrees of solar activity. (C) 2002 Published by Elsevier Science B.V.