Space Mission Human Reliability Analysis (HRA) (SM-HRA)

The purpose of the Space Mission Human Reliability Analysis (HRA) Project is to extend current ground-based HRA risk prediction techniques to a long-duration, space-based tool.  Ground-based HRA methodology has been shown to be a reasonable tool for short-duration space missions, such as Space Shuttle and lunar fly-bys.  However, longer-duration deep-space missions, such as asteroid and Mars missions, will require the crew to be in space for as long as 400 to 900 day missions with periods of extended autonomy and self-sufficiency. Current indications show higher risk due to fatigue, physiological effects due to extended low gravity environments, and others, may impact HRA predictions.  For this project, Safety & Mission Assurance (S&MA) will work with Human Health & Performance (HH&P) to establish what is currently used to assess human reliability for human space programs, identify human performance factors that may be sensitive to long duration space flight, collect available historical data, and update current tools to account for performance shaping factors believed to be important to such missions. This effort will also contribute data to the Human Performance Data Repository and influence the Space Human Factors Engineering research risks and gaps (part of the HRP Program). An accurate risk predictor mitigates Loss of Crew (LOC) and Loss of Mission (LOM). The end result will be an updated HRA model that can effectively predict risk on long-duration missions.

The purpose of this project is to extend current ground-based Human Reliability Analysis (HRA) techniques to a long-duration, space-based tool to more effectively predict the risk associated with human actions on long-duration missions.  By doing so, the agency will be able to focus resources on the risk drivers, such as specific training, conditioning, procedures, exercising, etc. for these future missions.  NASA uses Probabilistic Risk Assessments (PRAs) to assess the probability of Loss of Crew (LOC) and Loss of Mission (LOM).  PRAs take into account multiple contributing factors and their interactions, such as how the crew, software, and hardware work together to achieve mission objectives.  HRA is used to assess the human contribution to risk in PRAs.  Current HRA techniques were developed for ground applications using Earth based human reliability data to estimate human error probability.  These ground-based HRA techniques have been shown to be a reasonable tool for short-duration space missions, such as Space Shuttle and lunar fly-bys.  However, longer-duration beyond Earth orbit missions, such as asteroid and Mars missions, will require crews to be in space for 400 to 900 days with periods of extended autonomy and self-sufficiency.  Current indications show higher risk due to fatigue, physiological effects due to extended low gravity environments, and others, which may impact HRA predictions by affecting the crew's cognitive abilities, as well as their physiology, and yield a higher probability for LOC and LOM (e.g. early return).  PRAs will need to account for these effects in order to provide management, designers, and the crew our best estimate of risk. With the funding of this IR&D project over the next three years, Safety & Mission Assurance (S&MA) will collaborate with Human Health & Performance (HH&P) to establish what is currently used to assess human reliability for human space programs, identify human performance factors that may be sensitive to long duration space flight, collect available historical data, and update current tools to account for performance shaping factors believed to be important to such missions.  JSC's Human System Integration (HSI) initiative is a work in progress to better understand how the crew, software, and hardware work together and ensure that HSI is accounted for in future space mission designs.