Characterization of Operator-Reported Discrepancies in Unmanned on-Orbit Space Systems

The purpose of this research is to characterize the number and type of problems satellite operators encounter during the course of routine daily activities. In the context of this paper, a discrepancy is defined as the perception by an operator that some portion of the space system has failed to operate as designed. Discrepancies can therefore include ground system malfunctions, procedural errors, and even misdiagnosis that a problem exists, in addition to actual spacecraft anomalies. The study is designed to test the following hypotheses using a verifiable, quantitative analysis: (1) the majority of problems encountered by an operator do not involve the spacecraft at all, but are attributed to other elements of the space system; and (2) correlations exist between aspects of a space system design and the nature of problems experienced by the operations staff over the long term. To perform an applied, rather than theoretical, analysis, several representative aerospace organizations provided historical discrepancy reports for satellites currently being flown. Government civilian and military organizations participated in the study, which encompassed spacecraft from several mission areas, including remote sensing, research & development, communications, and observatories. Raw discrepancy data was collected from each organization in the form of electronic databases or hand- written logs. Data conversion consisted of selecting similar fields of interest from each database; removing references to the program, organization, or spacecraft; replacing program-specific terminology with standardized nomenclature; and merging the individual databases into one data set. Statistical analysis of the entire data set was performed to test the two hypotheses above.Air Force Inst of Tech Wright-Patterson AFB OH is the author of 'Characterization of Operator-Reported Discrepancies in Unmanned on-Orbit Space Systems', published 2001 under ISBN 9781423527015 and ISBN 1423527011.