Development and Application of Spaceflight Performance Shaping Factors for Human Reliability Analysis

摘要

The importance of crew performance during space missions is widely recognized as being essential to success. This operationally-driven necessity motivates the desire to better characterize factors that can influence crew performance so that those with positive effects can be enhanced, while those with negative impacts can be minimized. Established Human Reliability Analysis (HRA) methods exist for analyzing performance within the context of myriad terrestrial operational scenarios. Many of the existing methods have their roots in nuclear power plant operations. While perhaps similar, the factors influencing performance used in these methods do not take into account the unique conditions encountered during spaceflight. Therefore, this research has identified unique factors that influence human performance of tasks during space missions. For example, a crewmember's presence in microgravity causes physiological changes to occur, such as reduced aerobic capacity and muscle strength, which can in turn alter their physical ability to perform a given manual task. Psychological and cognitive factors are also introduced from living in an Isolated and Confined Environment (ICE), by vehicle habitability limitations, and from working under high public interest and visibility. This research is aimed at incorporating these performance shaping factors into an existing HRA method, which can subsequently be included in a Probabilistic Risk Assessment (PRA) for analyzing human space missions. These techniques can then be used to help define risk mitigation strategies including biomedical countermeasure incorporation, defining spacecraft functional and operational requirements, and determining crew training needs. This paper summarizes the factors that influence performance in space and offers a hierarchy for organizing them. It will also introduce an approach for using Bayesian Belief Networks (BBNs) for quantifying the effects of these factors on reliability using existing human performance data from space and ground studies to inform the BBN statistics.