Key performance parameter based systems engineering for the Giant Magellan Telescope through construction and commissioning

In the advanced design, construction, and commissioning phases of GMTO project, the critical role of systems engineering is tracking and managing expected observatory performance and ensuring that the scientific goals of the Giant Magellan Telescope (GMT) are met. GMTO’s approach to this role is defining Key Performance Parameters (KPPs) to measure technical performance. A set of KPPs have been established to assess the performance of the telescope through construction and Assembly, Integration, Verification, and Commissioning (AIVC). Each KPP has a threshold value representing the minimum acceptable performance, and an objective value representing the desired operational performance. KPPs are used to prioritize maturation plans for technologies and novel system-level design strategies. The KPPs directly characterize the performance of the telescope by ensuring focal plane (image), exit pupil (wavefront) and light collecting capabilities of the telescope. The paper demonstrates that the chosen KPPs properly represent key science capabilities, as image size, sensitivity, photometric, and astrometric accuracy. It is also shown how detailed error budgets link the KPPs to component technical specifications that in turn are closely monitored by simulations. Integrated modeling is crucial for the performance-based systems engineering approach of defining and then evaluating the objective and threshold levels for the KPPs. As described in other GMTO paper at this conference, contributions from individual subsystems and components are modeled to determine their effect on system performance. We describe how GMTO has implemented KPPs and is now using them to guide and coordinate technical development.