Integrated modeling based performance mode compliance analysis for the Giant Magellan Telescope

Abstract

The scientific performances of the Giant Magellan Telescope (GMT) Observatory are divided into Observatory Performance Mode (OPM) formally defined in the GMT Observatory Requirement Document (ORD) as a direct flow down from the GMT Science Requirement document (SRD). There are 3 main OPM categories: Natural Seeing, GLAO, and High Angular Resolution (e.g., NGAO, LTAO) that branched out into several sub-categories. For each OPM, system engineering has defined image quality metric standards: Key Performance Parameters (KPP) that acts as bounds to the Observatory overall performance within which design parameters are traded. During the course of the project, system engineering must assess the compliance of the current design solutions with respect to the KPPs. The GMT project has build an exhaustive integrated modeling computing framework allowing for bottom-up end-to-end modeling of the entire GMT Observatory. This integrated modeling framework brings together finite element, control, optical, thermal and fluid dynamics models. This paper introduces the integrated modeling framework and describes the whole process that is setting up bottom-up end-to-end simulations of GMT OPMs. For example, analytical error budgets and the project risk registers are used to identify and to down select the most relevant parameters and features of the telescope design that must be included into the GMT integrated model while keeping the size of the simulation manageable from a computing load standpoint. The paper also reports on how the model validation unfold with model audits at both system and subsystem levels using software management best practices. Finally, simulation results for several OPMs are presented and discussed in terms of their statistical meaning with respect to the foreseen on-sky estimation of the KPPs during the Assembly, Integration and Validation phase of the project.