A Model-based Approach for Verification of the Large Lenslet Array Magellan Spectrograph (LLAMAS)

The Large Lenslet Array Magellan Spectrograph (LLAMAS) is a fiber-fed spectrograph developed at the MIT Kavli Institute for Astrophysics and Space Research. It is a facility-class instrument that will be installed on the Magellan Telescope at the Las Campanas Observatory, and will be available to the scientific community by 2024. This paper describes the methodology that was developed and partially implemented on LLAMAS for continuous requirements verification using a model-based systems engineering (MBSE) approach. MBSE enables all systems engineering data products to share heritage with a central system model, ensuring the coherence and consistency of a design. We leverage a model-integrated approach to plan and execute V&V, by coordinating data in engineering models and performance simulations with a central system model. We take a moderate approach to integrating MBSE into the LLAMAS SE workflow, implementing MBSE tools and procedures later in the project lifecycle and only in the context of V&V, in order to examine the benefits of a model-integrated approach to verification while limiting the overhead associated with an MBSE workflow. Two model-based verification activities are shown: thermal budget analysis using a comprehensive system model, and science performance verification with simulated observation scenarios. We find that we are able to increase confidence in the performance of the system at earlier stages in AI&T than in a traditional approach.