Reliability Assessment of Spacecraft Solar Array with Power Margin Varying over Operation Phases

SUMMARY & CONCLUSIONSThis paper presents a comprehensive study of reliability (probability of success) assessment of spacecraft solar arrays by considering power margin variation over different operation phases. Relationship between the power margin and allowable power loss percentage is described, which determines the amount of redundancy at solar strings and shunt circuits level. A set of phase-dependent reliability models is developed for a solar array operating in two phases. A study is conducted on validity of three commonly used approaches in consolidating phase power margins with an equivalent number. Results of an example solar array illustrate that, to avoid the reliability predictions being more optimistic, the only approach that may be acceptable from using a single power margin number for the entire mission life is the minimum power margin approach.