943. Spacecraft Reliability/Maintainability Optimization

Paper

Abstract

This paper describes a procedure to develop a methodology to optimize man-serviced systems for reliability and maintainability. The spacecraft systems arc analyzed using failure modes and effects analysis (FMEA) and maintenance analysis, component mean-time-between failure (MTBF), duty cycle, type of redundancy, and cost information to develop parametric data on various time intervals. Included are crew time-to-repair, cost, weight, and volume effects of increasing subsystem reliability above the baseline.
Results are presented for space systems using the existing data from Research & Applications Module (RAM). These results show the minimum cost of sustaining mission operations. The cost of providing the high degree of space systems reliability needed for a long-life system without maintenance is traded off with the alternative cost of achieving long-life through maintenance. The level of supporting subsystem reliability with the associated repair that result in the lowest program cost consistent with missions and crew limitations is defined. The lowest-cost combination of subsystem reliability and maintenance is determined.