Application of spectral linear mixing to rock slabs analyses at various scales using Ma_Miss BreadBoard instrument

Focus of this work is the analysis of rock slabs by means of the Ma_Miss BreadBoard instrument. Ma_Miss (Mars Multispectral Imager for Subsurface Studies, Coradini et al., 2001; De Sanctis et al., 2017) is the miniaturized imaging spectrometer onboard the ESA Exomars 2020 mission. Here we report the results of the analysis carried out on rock slabs using the Ma_Miss breadboard (BB) (De Angelis et al., 2014, 2015) and a Spectro-Goniometer (SPG). The samples are three volcanic rocks (from the Aeolian Islands and Montiferru volcanoes, Italy) and two carbonate rocks (from Central Apennines, Italy). Visible and near infrared spectroscopic characterization has been first performed on all the samples with a Spectro-goniometer (SPG). Successively, higher spatial resolution spectra were acquired with the Ma_Miss BB setup in each of the areas analyzed with the SPG. We compared the spectra of the same areas of the slabs, acquired with SPG and Ma_Miss BB. Three different analysis approaches have been performed on the spectra: arithmetical averaging of the spectra, linear mixing of reflectances and linear mixing of Single Scattering Albedoes (using Hapke model). The comparison shows that: (i) Ma_Miss instrument has great capabilities for the investigation of rock surfaces with high detail; a large number of different mineralogical phases can be recognized thanks to Ma_Miss high resolution within each millimeter-sized analyzed area; (ii) the agreement with SPG spectra is excellent especially when linear mixing is applied for the convolution of Ma_Miss BB spectra.