Improved modeling and validation of command sequences using a checkable sequence language

We describe an approach to modeling and validation of command sequences for space missions that is intended to improve the likelihood of mission success by (i) making a closer connection between requirements and model specification, and (ii) increasing coverage of possible execution paths by using model checking to supplement or supplant simulation. Our approach features the use of a single language for modeling, sequencing, and flight rule requirements in the form of assertions. We summarize our experience applying this language to real mission flight rules and models.