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Hyperspectral characterization of fluorescent organic contaminants on optical payloads

The increase of performance of new optical instruments for science and Earth observation always leads to higher requirements in terms of contamination due to particle sedimentation in cleanrooms and deposition of chemical species in vacuum environment. Specific cleanliness control procedures are implemented in order to mitigate the risks of contamination on optical sensors and sensitive diopters, especially when used for UV applications. Such procedures are commonly carried out in cleanrooms and are described in both European ECSS-Q-ST-70-50C and NASA SN-C-0005D standards. UV light at 365 nm is often used for the inspection of optical sensitive surfaces to localize and to evaluate the amount of fluorescent particles, essentially coming from textile fibers. But other groups of compounds can be observed with a different spectral response and distribution, like adhesives and resins or even organic residues. Therefore, we could take advantage of this spectral information closely linked to specific molecules for partial identification of these materials before further investigation involving wipe on flight model and measurement in a laboratory.