“At NASA, we should allow computers to do what computers are good at, so people can do what people are good at.”

This perspective, explained by MBSE Pathfinder Study Co-Lead Jessica Knizhnik, is the main motive behind a Pathfinder study, sponsored by the NASA Engineering and Safety Center, to investigate how Model-Based Systems Engineering (MBSE) and Model-Based Engineering (MBE) techniques can be applied by NASA projects. The Pathfinder study was established to advance the agency's applications of MBSE and capture lessons-learned to inform the next steps as it explores MBSE through the project life cycle.

“Computers are good at cranking through information and people are good at making decisions,” said Knizhnik. “System modeling is meant to keep everyone on the same page and create a quick and simple process for researchers and engineers to find the correct information they need.”

Using the current process, researchers and engineers spend valuable time searching for the most recent documentation. In some cases, the documents conflict because the most current data has not been updated in all the related documentation.

MBSE creates a virtual model of the system, typically while it is still in the design or planning phase. The system model is used as a central form of communication rather than using a disparate set of documents. The idea is to have a single source of truth where designers and engineers can work with the same set of information. All types of models would work in tandem, creating one version-controlled model with the same information throughout. Engineers can have real time access to the project data repository across disciplines and stakeholders.

“We’re interested in working with a number of different groups,” said Knizhnik. “We believe system modeling can work well with some of the infrastructure that’s already in place.”

Safety and Mission Assurance (SMA) is one of several disciplines interested in teaming up with the study. SMA partnered with the Pathfinder team after recognizing the benefits MBSE has to offer and intends to use the emerging models for reliability modeling.

“We came to the Pathfinder project to capitalize on what they’re accomplishing,” said John Evans, Office of Safety and Mission Assurance Reliability and Maintainability manager. “I see it as a good partnership. Let’s work together with what the agency is going to do and assess what the agency needs. Together in a partnership, we can support their direction.”

The SMA approach is referred to as Model-Based Mission Assurance (MBMA). The Pathfinder team added safety elements to determine how engineers could use the models to answer safety and mission assurance questions. SMA will be able to perform assurance analyses earlier in the life cycle, reducing the occurrence of costly changes after the system design has been defined.

According to Evans, MBSE will allow engineers to be more efficient by dealing with complex missions without expanding resources needed to do other tasks. Automated processes with computer models would save work for the Software Assurance team, increasing efficiencies by using automated simulations.

“Instead of using documentation, we can put together code that describes the inputs of the models we need and extract them right from the system,” said Evans. “It’s the holy grail of modeling.”

In the future, Evans hopes to see a type of model called an Assurance Case, a logical structure that would support that the mission is as safe as reasonably possible. The structure would bring together all the information and ensure the project is meeting all requirements.

The Pathfinder team is working to create an “MBSE template,” which could be developed as both a teaching tool and baseline future projects could leverage. They are continuing to partner with other disciplines, centers and technical fellows to gain traction and include any party interested in the project.

If you are interested in learning more about the Pathfinder study, contact Knizhnik.