MOSAIC at ELT: building a comprehensive engineering database

MOSAIC, the multi-object spectrograph for the ESO Extremely Large Telescope (ELT), being developed by a distributed consortium involving multiple institutes and engineering disciplines. Maintaining consistency between requirements, interfaces, product definitions, verification activities and engineering documentation is therefore a major engineering challenge. To address this, the project implemented a central engineering information model using ReqSuite® requirement management tool. Rather than limiting the repository to requirements management, the database also stores other engineering artefacts, such as the Product breakdown structure, interfaces, configuration items and verification information, providing a common technical reference for the project. Behavioural and parametric models are maintained in the specialised engineering tools best suited to them but are connected to the database through traceability links and application programming interfaces. The engineering database supports requirement flow-down, architecture definition, verification management and the generation of engineering documents required for ESO reviews. It is also connected to Python-based scripts for engineering automation and is progressively being integrated with Twinpicks, a custom-made performance calculator, to exchange engineering parameters and verification results. This paper describes the engineering information architecture adopted for MOSAIC, the organisation of its distributed repositories, the systems engineering processes supported by the database, and its integration with external engineering tools.