Super polished mirrors for the Roman Space Telescope CoronaGraphic Instrument: design, manufacturing, and optical performances

A. Caillat; M. Ferrari; M. Marcos; C. Pariès; A. Bonnefoi; V. Vitrac; M. Roulet; E. Hugot

doi:10.1117/12.2627240

27 August 2022 Super polished mirrors for the Roman Space Telescope CoronaGraphic Instrument: design, manufacturing, and optical performances

A. Caillat, M. Ferrari, M. Marcos, C. Pariès, A. Bonnefoi, V. Vitrac, M. Roulet, E. Hugot

Author Affiliations +

Proceedings Volume 12180, Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave; 121801Y (2022) https://doi.org/10.1117/12.2627240
Event: SPIE Astronomical Telescopes + Instrumentation, 2022, Montréal, Québec, Canada

Abstract

The Coronagraphic Instrument (CGI) of the Roman Space Telescope NASA space mission is a demonstrator of critical technologies for future space coronagraphs aiming at imaging and spectroscopy of exoplanets and debris disks. Extremely high optical performances are required in term of optical quality of the components inside this instrument. The Stress Mirror Polishing (SMP) technique have been developed for several decades at Laboratoire d’Astrophysique de Marseille (LAM). SMP allows reaching exquisite optical quality on the optics demonstrated through very low Surface Figure Errors (SFE): <5nm RMS on low frequencies, <2nm RMS on middle frequencies (from 3 to 10 cycles per pupil), an extremely low level of high frequencies (no ripples) and micro-roughness < 5Å RMS. In the frame of a scientific international collaboration between NASA and CNES, the French space agency, LAM is selected for the manufacturing of all Off-Axis Parabolas (OAP) for the WFIRST-CGI. LAM has delivered 17 models including one prototype, 8 flight models in July 2021 and 8 flight spares delivered in May 2022. In this paper, we give an overview of the SMP process, from design to manufacturing and verification tests validating the performance. We will present the performance obtained on the first models that have been manufactured compared to theoretical calculations based on requirements for these OAPs.

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Citation Download Citation

A. Caillat, M. Ferrari, M. Marcos, C. Pariès, A. Bonnefoi, V. Vitrac, M. Roulet, and E. Hugot "Super polished mirrors for the Roman Space Telescope CoronaGraphic Instrument: design, manufacturing, and optical performances", Proc. SPIE 12180, Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave, 121801Y (27 August 2022); https://doi.org/10.1117/12.2627240

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