Method of dependability assessment of spacecraft in design and engineering studies

Abstract

The paper examines the matters of operational dependability of space systems (SS), efficiency of complex systems, use of redundancy in spacecraft (SC) design. It presents methods of predicting the dependability of designed devices, design of devices with desired dependability and comparison of dependability of various SS. For that purpose, the authors set forth the fundamentals of the dependability theory for SS design, methods of collection and processing of data of equipment dependability based on the results of operation and special dependability tests. Methods, mathematical models are developed, the equipment architecture at the stage of design and manufacture is analyzed. The paper also cites the design ratios for various tested types of redundancy, lifetime extension of SC units based on the residual operating life estimation method. The existing methods of dependability analysis are classified and examined. The authors outline the problems of ambiguity of information of the input data in case of classical computing. The effect of nominal deviations of the external effects, irregularity of the failure rate, non-linear nature of the effect of external factors on the dependability are examined. The paper also takes a look at the way the external factors affect the dependability and the degree to which such factors are taken into consideration in the existing methods. It is noted that the qualitative, technical and organizational (design and software) requirements for dependability in the technical specifications for each stage of elements and SS development, shall be observed and confirmed at the respective stage of activities. The paper presents the methods of estimation of technical item operating life with the focus on those based on the physical premises of operating life depletion. Attention is drawn to the importance of the economic aspect in the research dedicated to SS lifetime extension.