Model-based spacecraft fault management design & formal validation

Abstract

A model-based method of software system logical design and formal validation will be discussed for the application of fault management throughout the project lifecycle. We have demonstrated that when modeling fault protection system behaviors during the design phases of a project, the expected behavior can be verified early on by executing the model. Correctly capturing the expected behavior in the model improves the system design so that is better defined and complete upon implementation. Additionally, performing model checking formally validates the behavior model against properties of correctness (assertions). The potential to generate and link additional model-based fault management products from the fault protection logical behavior model is key to projects adopting model driven design and retaining a single source of truth. When modeling heritage systems or if a dictionary-type database is needed, a standard for machine-readable import/export of fault management parameters allows for easier integration between flight software and the model-based products. Depending on if there is fault management information available while developing a behavior model, a method for auto-generating the model can be used that reduces human errors and speeds up the modeling process.