Application of chemometrics on Raman spectra from Mars: Recent advances and future perspectives

Abstract

The SuperCam and SHERLOC instruments onboard the NASA/Perseverancerover are returning the first Raman spectra to be ever collected from anotherplanet. Similarly, the RLS instrument onboard the ESA/Rosalind Franklinrover will collect Raman spectra from powdered rocks sampled from thesubsurface of Mars. To optimize the scientific exploitation of Raman spectrareturned from planetary exploration missions, tailored chemometric tools arebeing developed that take into account the analytical capability of the men-tioned Raman spectrometers. In this framework, the ERICA research groupis using laboratory simulators of SuperCam and RLS to perform representa-tive laboratory studies that will enhance the scientific outcome of bothMars2020 and ExoMars missions. On one hand, preliminary studies provedthe chemometric analysis of RLS datasets could be used to obtain a reliablesemi-quantitative estimation of the main mineral phases composing Martiangeological samples. On the other hand, it was proved the data fusion ofRaman and LIBS spectra gathered by SuperCam could be used to enhancethe discrimination of mineral phases from remote geological targets. Besidesdescribing the models developed by the ERICA group, this work presents anoverview of the complementary chemometric approaches so far tested in thisfield of study and propose further improvements to be addressed in thefuture.