Mechanical engineering of the support structure for the MOSAIC spectrograph of the Extermely Large Telescope

Abstract

The multi-object MOSAIC is to be installed at the Extremely Large Telescope (ELT) of ESO. It is a complex instrument, consisting of 6 spectrographs, 4 near-infrared (NIR) and 2 optical spectrographs, operating at two resolutions of R~5,000 and 20,000, and can be used simultaneously in the NIR and optical. Phase A (Conceptual Design) was approved by ESO, and in 2023 it entered in Phase B, and more precisely presently in phase B1. Our participation include the workpackage of Instrument Core Support Structure (ICOS), participation in the robotics of the 200-300 arms for location of fibers, contributions to the optical fiber work, and to the gratings. FAPESP has approved the proposal 2020/15245-2 for these tasks, starting on 01/August/2023. The task of this project is to be the central person for themechanical engineering process of the design, supervision, and(future construction) of the Instrument Core Support Structure (ICOS) platform,with the following steps:Prepare a conceptual design based on a comprehensive review of availabledesigns and add specific features required for this project;Make a low-fidelity design for initial analysis and use finite element analysis to finalize the concept design;Manage detailed design in a high-fidelity model for more reliable analysis andperformance verification;Design for assembly with fitting tolerances.Check drawings and bill of material for parts to be manufactured or provided from the off-the-shelf products;Archive documents of design in a design history file (DHF);Collaboration with a third-party company to build the structure, inspect it, and prepare a device master record (DMR).