We† provide an overview of the Model Based Systems Engineering (MBSE) language, tool, and methodology being used in our development of the Operational Plan for Large Synoptic Survey Telescope (LSST) operations. LSST’s Systems Engineering (SE) team is using a model-based approach to operational plan development to: 1) capture the topdown stakeholders’ needs and functional allocations defining the scope, required tasks, and personnel needed for operations, and 2) capture the bottom-up operations and maintenance activities required to conduct the LSST survey across its distributed operations sites for the full ten year survey duration. To accomplish these complimentary goals and ensure that they result in self-consistent results, we have developed a holistic approach using the Sparx Enterprise Architect modeling tool and Systems Modeling Language (SysML). This approach utilizes SysML Use Cases, Actors, associated relationships, and Activity Diagrams to document and refine all of the major operations and maintenance activities that will be required to successfully operate the observatory and meet stakeholder expectations. We have developed several customized extensions of the SysML language including the creation of a custom stereotyped Use Case element with unique tagged values, as well as unique association connectors and Actor stereotypes. We demonstrate this customized MBSE methodology enables us to define: 1) the rolls each human Actor must take on to successfully carry out the activities associated with the Use Cases; 2) the skills each Actor must possess; 3) the functional allocation of all required stakeholder activities and Use Cases to organizational entities tasked with carrying them out; and 4) the organization structure required to successfully execute the operational survey. Our approach allows for continual refinement utilizing the systems engineering spiral method to expose finer levels of detail as necessary. For example, the bottom-up, Use Case-driven approach will be deployed in the future to develop the detailed work procedures required to successfully execute each operational activity.
The Large Synoptic Survey Telescope (LSST) project has evolved from just a few staff members in 2003 to about 100 in
2010; the affiliation of four founding institutions has grown to 32 universities, government laboratories, and industry.
The public private collaboration aims to complete the estimated $450 M observatory in the 2017 timeframe. During the
design phase of the project from 2003 to the present the management structure has been remarkably stable. At the same
time, the funding levels, staffing levels and scientific community participation have grown dramatically. The LSSTC
has introduced project controls and tools required to manage the LSST's complex funding model, technical structure and
distributed work force. Project controls have been configured to comply with the requirements of federal funding
agencies. Some of these tools for risk management, configuration control and resource-loaded schedule have been
effective and others have not. Technical tasks associated with building the LSST are distributed into three subsystems:
Telescope & Site, Camera, and Data Management. Each sub-system has its own experienced Project Manager and
System Scientist. Delegation of authority is enabling and effective; it encourages a strong sense of ownership within the
project. At the project level, subsystem management follows the principle that there is one Board of Directors, Director,
and Project Manager who have overall authority.