Engineering Risk Assessment (ERA)
The Engineering Risk Assessment (ERA) project provides advanced risk analyses to support the development of complex space launch and exploration systems that are typically difficult to represent effectively using traditional risk assessment methods. The ERA approach quantifies system risks through a combination of probabilistic analyses, physics-based simulations of key risk factors, and failure timing and propagation models. ERA develops dynamic, integrated risk models to not only quantify the probabilities of individual failures, but also to learn about the specific systems, identify the driving risk factors, and guide designers toward the most effective strategies for reducing risk.
ERA Work
ERA was first developed and applied through NASA's Simulation Assisted Risk Assessment (SARA) Project, which generated detailed crew-risk probability estimates for the Ares I Crew Launch Vehicle. This assessment yielded progressively refined insight into primary risk-drivers, providing a direct means of evaluating launch vehicle design criteria, crew escape systems, failure mitigation strategies, and operational requirements as the vehicle developed. This risk assessment was heralded as representing a new level of crew safety for NASA during the Ares I Preliminary Design Review.
The ERA team has since gone on to perform risk assessments for other potential launch vehicle designs, exploration systems, and missions, including the heavy-lift Space Launch System, lunar base system architectures, and the Orion Multi-Purpose Crew Vehicle for traveling to a near-Earth object such as a comet or asteroid.
The ERA project is also contributing to NASA's broader safety policies and procedures by supporting key safety studies, helping to develop effective safety/risk guidelines for future space programs, and providing new chapters on ERA methods for the agency's risk assessment handbooks and training materials.
Benefits
Engineering Risk Assessment has exceptional potential to benefit the design and evaluation of a wide range of systems and technologies. Its dynamic, multi-fidelity approach provides more realistic representation of failures and their propagation, identifies sensitivities and dependencies within highly complex systems, and most importantly, facilitates risk-informed design throughout every stage of the development process. The ERA approach focuses on producing actionable risk data that enables designers to concentrate on the risks that make a difference rather than on just differentiating the various sources of risk.
ERA Achievements
Attaining New Levels of Safety Assessment
The ERA crew risk assessment for Ares I was the first probabilistic risk analysis to incorporate physics-based modeling and simulation of key vehicle failures and hazard environments, including: explosion blast waves, debris strike, fireballs, and fuel mixing resulting from tank rupture.
Growing Participation
Following its initial success with Ares, the ERA team has continued to provide risk models for numerous other projects, and is contributing new chapters and training materials on its risk methods to NASA's Office of Safety & Mission Assurance (OSMA) Probabilistic Risk Assessment Procedures Guide.
Selecting Effective Abort Triggers
Recently, ERA provided key risk analysis support for development and assessment of the SpaceX Dragon Rider spacecraft's launch abort capabilities. The ERA team delivered a series of analyses characterizing the debris field generated by activation of the Flight Termination System during ascent, and the resulting strike probabilities for an aborting capsule.
