The status of the contract for the preliminary design of the EST ASM is presented.
The EST M2 Preliminary Design (PD) contract was awarded to the Netherlands Organisation for Applied Scientific Research (TNO) at the end of 2020. The EST M2 is referred to as an Adaptive Secondary Mirror (ASM) with adaptive optics capabilities for correction of quickly evolving atmospheric high-order turbulence as well as slow and fast positioning. The slow positioning functionality will be part of the active optics system of EST. The fast positioning functionality will be part of the overall pointing and tracking strategy and will be used to correct fast image motion caused by atmospheric turbulence.
The EST ASM PD contract formally started on April 16, 2021 with the celebration of the kick-off meeting. During Phase 1 TNO developed the baseline model to tackle the trade-offs identified by the EST PO (which were mandatory as part of the bidding contract) as well as other aspects TNO regarded of interest for the design of their proposed baseline: design and geometry of the actuators, the thermal aspects of the ASM unit, the strategies allowing to cover the functionalities of slow and fast positioning, and the overall ASM architecture to be compliant with mass and volume limitations. The EST ASM PD Phase 1 Review Meeting took place on September 22, 2021 but it was officially closed on November 6, 2021.
CAD model for the actuator breadboard. Credit: TNO
Phase 2 started right after the Phase 1 Review Meeting on September 22, 2021 and its Review Meeting was celebrated on February 16 2022. Phase 2 was officially closed on March 28, 2022. Among the milestones achieved during Phase 2 we can mention the consolidation of the EST ASM specifications, the detailed study of the ASM interface with the telescope structure, the control model of the EST ASM unit and the detailed design of the thermal and actuator prototypes (see accompanying figure for a CAD model of the latter). During Phase 2, TNO continued developing systems engineering models for the error budgets of the unit, the active thermal control model needed by the ASM and an identification and preliminary proposal of laboratory tests with the prototypes.
Starting on March 28, 2022 we are into Phase 3 of the ASM PD contract which will be completed by September 30, 2022. During Phase 3, TNO will build the thermal and actuator breadboards according to the designs presented and approved by the EST PO during Phase 2. Those thermal prototypes will be used to run extensive tests in the laboratory. At the moment of writing this newsletter, TNO has nearly completed the thermal prototype and delivered a first draft with the detailed thermal test procedures to be executed with this prototype.
During the upcoming SPIE Astronomical Telescopes & Instrumentation 2022 meeting to be held in Montreal on July 17-22, 2022, the EST PO will present an oral talk with the title “Adaptive Optics at the European Solar Telescope: status and future developments” with emphasis on the current status of the EST adaptive secondary mirror. Additionally, TNO will give an oral presentation entitled “Preliminary design of the Adaptive Secondary Mirror for the European Solar Telescope”. Both oral presentations are scheduled in the “Adaptive Optics Systems VIII” conference.