Metrics for Evaluating Survivability in Dynamic Multi-Attribute Tradespace Exploration

摘要

Survivability engineering is critical forminimizing the impact of disturbances to the operation of space systems.Tonimprove the evaluation of survivability during conceptual design, metrics are proposed for the assessment ofnsurvivability as a dynamic, continuous, and path-dependent system property. Two of these metrics, time-weightednaverage utility loss and threshold availability, are then incorporated into a tradespace study on the survivability ofnfuture space tug vehicles to orbital debris. A value-based design approach, dynamic multi-attribute tradespacenexploration, is taken to evaluate survivability based on the relationship between stochastic space tug utilityntrajectories and changing stakeholder expectations across nominal and disturbed environmental states. Results ofnthe tradespace study show that moderate levels of bumper shielding and access to an on-orbit servicingninfrastructure benefit space tugs with large exposed cross-sectional areas, whereas active collision avoidance onlyndelivers value to extremely-risk-averse decision-makers. Time-weighted average utility loss and thresholdnavailability are found to be discriminating metrics for navigating survivability tradespaces of thousands of designnalternatives.