Presentation + Paper
13 December 2020 The primary mirror of the Ariel mission: cryotesting of aluminum mirror samples with protected silver coating
Paolo Chioetto, Paola Zuppella, Vania Da Deppo, Emanuele Pace, Gianluca Morgante, Luca Terenzi, Daniele Brienza, Nadia Missaglia, Giovanni Bianucci, Sebastiano Spinelli, Elisa Guerriero, Massimiliano Rossi, Colin Bondet, Gregory Chauveau, Caroline Porta, Catherine Grezes-Besset, Giuseppe Malaguti, Giuseppina Micela
Author Affiliations +
Abstract
Atmospheric Remote-Sensing Infrared Exoplanet Large Survey (Ariel) has been adopted as ESA “Cosmic Vision” M4 mission, with launch scheduled for 2029. Ariel is based on a 1 m class telescope optimized for spectroscopy in the waveband between 1.95 and 7.8 μm, operating in cryogenic conditions in the range 40–50 K. Aluminum has been chosen as baseline material for the telescope mirrors substrate, with a metallic coating to enhance reflectivity and protect from oxidation and corrosion. As part of Phase B1, leading to SRR and eventually mission adoption, a protected silver coating with space heritage has been selected and will undergo a qualification process. A fundamental part of this process is assuring the integrity of the coating layer and performance compliance in terms of reflectivity at the telescope operating temperature. To this purpose, a set of flat sample disks have been cut and polished from the same baseline aluminum alloy as the telescope mirror substrates, and the selected protected silver coating has been applied to them by magnetron sputtering. The disks have then been subjected to a series of cryogenic temperature cycles to assess coating performance stability. This study presents the results of visual inspection, reflectivity measurements and atomic force microscopy (AFM) on the sample disks before and after the cryogenic cycles.
Conference Presentation
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Paolo Chioetto, Paola Zuppella, Vania Da Deppo, Emanuele Pace, Gianluca Morgante, Luca Terenzi, Daniele Brienza, Nadia Missaglia, Giovanni Bianucci, Sebastiano Spinelli, Elisa Guerriero, Massimiliano Rossi, Colin Bondet, Gregory Chauveau, Caroline Porta, Catherine Grezes-Besset, Giuseppe Malaguti, and Giuseppina Micela "The primary mirror of the Ariel mission: cryotesting of aluminum mirror samples with protected silver coating", Proc. SPIE 11451, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation IV, 114511A (13 December 2020); https://doi.org/10.1117/12.2562548
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KEYWORDS
Mirrors

Coating

Aluminum

Silver

Telescopes

Cryogenics

Reflectivity

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