To be launched in 2022, MicroCarb is a space mission project of the French Space Agency (CNES) that will measure the exchange of carbon dioxide present in the Earth's atmosphere over all regions of the globe, particularly in areas poorly covered by terrestrial instrumentation. It will be the first European mission entirely dedicated to CO2 measurement. Airbus Defence and Space has been selected by CNES to design, develop and qualify the MicroCarb instrument able to monitor very precisely CO2 concentrations, with an accuracy better than 1 part per million. It is an infrared passive spectrometer operating in four spectral bands and including a unique imaging channel. To meet the need for unprecedented stability, Airbus Defence and Space turned to a full-SiC solution for the mirrors and the structural elements of the instrument. These optics are embarked on the Myriades microsat platform which allocates them a low volume. This led the designers to squeeze the instruments into a compact volume and thus to design complex three-dimensional structures and also to implement mirrors of high freeform amplitudes. The present paper presents the manufacturing approach for such highly complex silicon carbide (SiC) parts, especially the grinding of complex interfaces and very precise freeform mirror blanks ready for polishing.

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Michel Bougoin, Florent Mallet, Jérôme Lavenac, Guillaume Gaudé, and Olivier Martin, "The full-SiC optics of MICROCARB," Proc. SPIE 11852, International Conference on Space Optics — ICSO 2020, 118524K (Presented at International Conference on Space Optics — ICSO 2021: 11 June 2021; Published: 11 June 2021); https://doi.org/10.1117/12.2599665.