ABSTRACT:
This report outlines an approach to the development of a life prediction methodology for polymer encapsulated photovoltaic cell solar array hardware. The characteristics and output of an ideal life prediction model are described. Such a model depends on the development of quantitative intermediate relationships between the environmental exposure parameters and the basic chemical mechanisms of material aging. These are described conceptually along with suggested relationships which might be developed for two potential solar array failure modes, optical transmission loss and delaminations.

The use of accelerated/abbreviated testing in the development of a life prediction methodology is reviewed.

The distinction between testing to reveal failure modes and testing to define rates of degradation is presented. The point is also made that acceptance tests and performance tests which involve some degree of stress acceleration have very limited application to predicting module lifetimes.

This report presents a framework for integrating various technologies related to developing reliable long-life solar arrays. It is presented in this preliminary form as a basis for review, discussion and guidance in the formulation of program tasks to develop, evaluate and incorporate improved solar array encapsulation systems.