PROBABILITY OF FAILURE ANALYSIS STANDARDS AND GUIDELINES FOR EXPENDABLE LAUNCH VEHICLES

摘要

Recognizing the central importance of probability ofrnfailure estimates to ensuring public safety for launches,rnthe Federal Aviation Administration (FAA), Office ofrnCommercial Space Transportation (AST), the NationalrnAeronautics and Space Administration (NASA), andrnU.S. Air Force (USAF), through the Common StandardsrnWorking Group (CSWG), developed a guide forrnconducting valid probability of failure (POF) analysesrnfor expendable launch vehicles (ELV), with an emphasisrnon POF analysis for new ELVs. A probability of failurernanalysis for an ELV produces estimates of thernlikelihood of occurrence of potentially hazardousrnevents, which are critical inputs to launch risk analysisrnof debris, toxic, or explosive hazards. This guide isrnintended to document a framework for POF analysesrncommonly accepted in the US, and should be useful tornanyone who performs or evaluates launch risk analysesrnfor new ELVs. The CSWG guidelines providernperformance standards and definitions of key terms, andrnare being revised to address allocation to flight timesrnand vehicle response modes. The POF performancernstandard allows a launch operator to employ alternative,rnpotentially innovative methodologies so long as thernresults satisfy the performance standard. Current POFrnanalysis practice at US ranges includes multiplernmethodologies described in the guidelines as acceptedrnmethods, but not necessarily the only methods availablernto demonstrate compliance with the performancernstandard. The guidelines include illustrative examplesrnfor each POF analysis method, which are intended tornillustrate an acceptable level of fidelity for ELV POFrnanalyses used to ensure public safety. The focus is onrnproviding guiding principles rather than “recipe lists.”rnIndependent reviews of these guidelines were performedrnto assess their logic, completeness, accuracy, selfconsistency,rnconsistency with risk analysis practices,rnuse of available information, and ease of applicability.rnThe independent reviews confirmed the general validityrnof the performance standard approach and suggestedrnpotential updates to improve the accuracy each of thernexample methods, especially to address reliabilityrngrowth.