Probabilistic risk analysis applied to the Space-Shuttle main engine

Risk analysis, which had its roots in the aerospace industry, was developed in the commercial nuclear power industry in the 1970s. Even though this approach has since been applied broadly as a decision-making tool in both the government and commercial sectors, there has been some hesitancy to implement it in the aerospace industry. Even successfully completed limited scope applications have failed to spur enthusiasm toward full scope applications. Recently, however, there has been a change in focus and NASA program managers have begun to embrace this important quantitative decision-making tool. This paper discusses an application of risk analysis. It presents an explanation of the two definitive thrusts, scenario development and uncertainty analysis, that distinguish it from other approaches. The discussion then addresses a representative set of the basic elements included in the risk analysis specialist\´s "tool kit", why each was developed, and the purpose each serves in the risk analysis process. The paper then considers the application of the risk analysis process to the specific case of the SSME. Discussions of this application include the difficulties encountered when the analysis is directed at such a high performance, interactive, and integrated design, and the levels of application. Finally, the particular focus of a recent effort of two diverse elements of the engine are discussed