Integrating STPA Extended for Coordination into SysML Using RAAML

Model-Based Systems Engineering;system safety;STPA;coordination;RAAML

As Model-Based Systems Engineering (MBSE) becomes prevalent in engineering practice, the Department of Defense (DoD) requires a consistent methodology to conduct and record system safety analyses in the system model. Systems Theoretic Process Analysis (STPA) is a relatively new safety and hazard analysis method that utilizes the principles of Systems Theory and abstraction to analyze today’s complex systems. Systems Theoretic Process Analysis Extended for Coordination (STPA-Coord) provides a framework to design safe coordination among a system-of-systems architecture, which is needed for next-generation integrated military systems. This research presents results from conducting an STPA-Coord in Systems Modeling Language (SysML) using Risk Analysis and Assessment Modeling Language (RAAML), a recent extension to SysML that provides tools and guidance for multiple safety analyses. Results describe deviations from the RAAML standard and suggest extensions to RAAML for STPA-Coord. Results include qualitative and quantitative observations conducting an STPA-Coord using SysML, including time required for the effort and perceived benefit over document-based methodologies.