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Proceedings Paper • Open Access

Black coatings for combined stray light and thermal passive management for the challenging environmental conditions of Solar Orbiter
Author(s): Luca Montemurro; Francesco Zanetti; Antonia Simone; Tiziano Schillaci; Marco Castronuovo; Dina Katsir; Keren Shabtai

Paper Abstract

In the context of ESA’s Cosmic Vision 2015-2025 scientific program, Solar Orbiter (SolO) represents the first M-class mission, currently under implementation for a launch planned in October 2018.
One of the SolO solar remote-sensing instruments is the Multi Element Telescope for Imaging and Spectroscopy (METIS), under development by an Italian consortium ATI composed by CGS and TAS-I. METIS is a coronagraph that will perform simultaneously broad-band imaging in visible light and narrow-band imaging in UV of the Sun corona with unprecedented spatial resolution.
The surfaces of several Ti-6Al-4V components of the METIS Optical Unit must have a very low reflectance in order to minimize straylight and therefore ACKTAR Magic BlackTM coating was specified. An example is represented by the internal surface of the Inverted External Occulter (IEO) - the front part of the instrument - which is exposed to the direct solar flux and experiences challenging environmental conditions. Qualification for 450°C was required whereas Acktar's Magic BlackTM qualified maximum temperature was 380°C.
A dedicated thermal-vacuum cycling test (100 total cycles, −120°C − 450°C) was conducted to qualify Magic BlackTM to quantify any performance degradation under these conditions:
• optical (reflectance)
• thermal (∝ and ε values) to allow calculation of the radiative heat transfer of the METIS parts during mission
• mechanical performances

The following success criteria were established:
• total reflectance at wavelengths of 400−1000nm <;5%
• degradation of absorptance ∝ and emissivity ε to be <10%
• surface resistivity <5 kΩ/square

Paper Details

Date Published: 12 July 2019
PDF: 7 pages
Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 111804Y (12 July 2019); doi: 10.1117/12.2536097
Show Author Affiliations
Luca Montemurro, OHB CGS (Italy)
Francesco Zanetti, OHB CGS (Italy)
Antonia Simone, Thales Alenia Space (Italy)
Tiziano Schillaci, Thales Alenia Space (Italy)
Marco Castronuovo, Agenzia Spaziale Italiana (Italy)
Dina Katsir, Acktar Ltd. (Israel)
Keren Shabtai, Acktar Ltd. (Israel)

Published in SPIE Proceedings Vol. 11180:
International Conference on Space Optics — ICSO 2018
Zoran Sodnik; Nikos Karafolas; Bruno Cugny, Editor(s)

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