The NASA Electronic Parts and Packaging (NEPP) Program is bridging gaps between engineering and assurance disciplines using a Model-Based Mission Assurance (MBMA) tool built around NASA-STD-8729.1, NASA Reliability and Maintainability (R&M) Standard for Spaceflight and Support Systems. The tool — the Systems Engineering and Assurance Modeling (SEAM) platform — is a web-based collaborative platform for modeling assurance cases that can be integrated with the models of the system.
“SEAM will help advance and stabilize assurance practices across projects so that they are more interoperable,” said Dr. Jonny Pellish, Deputy NEPP Program manager and agency Electrical, Electronic and Electromechanical (EEE) Parts capability manager at Goddard Space Flight Center.
“It moves us from building safety cases at the end of the design process to proactive mission assurance throughout the design life cycle. MBMA makes mission assurance activities explicit and is included under the Model-Based System Engineering (MBSE) umbrella. The tools enable us to capture the logic of the arguments for system assurance and connect them to the actual models of the system design,” Pellish said.
Developed by Vanderbilt University through NEPP and R&M Program grants, SEAM provides template models based on NASA-STD-8729.1 to kick-start the development of assurance cases. The standard is based on a top-level objective, which ensures that systems perform as required over their life cycles to satisfy mission objectives including safety, Reliability, maintainability and Quality Assurance requirements. That objective is then decomposed into sub-objectives that address all necessary disciplines, including EEE parts and radiation effects.
SEAM supports the Goal Structuring Notations standard to build assurance case models, allows context specification through cross-referencing of modeling entities across the models and supports a subset of block diagram models in the SysML modeling standard. It also extends the internal block diagram models to allow specification of discrete fault propagation to capture the faults and their anomalous effects within a block and their propagation across the system through subsystem interfaces.
SEAM allows users to work simultaneously on the same project. Similar to Google Docs, it updates and shows all changes to each user concurrently, simplifying the way colleagues — regardless of where they’re located — collaborate.
“We’re all interested in the same things, but have different responsibilities,” said Pellish. “There are stovepipes that are built around different functions, and tools like SEAM that interact with MBSE tools will build some of those connections that need to exist.”
Vanderbilt developed the tool for NASA’s Office of Safety and Mission Assurance to improve the success rate of small missions. Vanderbilt is continuing to build use cases to manage Radiation Hardness Assurance across the life cycles of missions like CubeSats. Pellish and his team are developing practical use cases, examples and success stories to show the tool’s value to any agency- or center-level program or project. They plan to target opportunities to implement SEAM in operational contexts.
“This model-based approach is also a good opportunity for workforce development,” said Pellish. “We need a framework to transfer knowledge, discipline practice or to make apparent the way we are supposed to do the work. This is particularly important as the technologies required for implementation continue to evolve at accelerating rates.”
Pellish’s next step is to find volunteers to take on the challenge of using SEAM in content development and trying to “break” it in order to learn more about its functions and inform future model development. SEAM is now available to the Safety and Mission Assurance community on a trial basis.
To learn more, visit the SEAM website or contact Pellish.