Development of innovative non-destructive analytical strategies for Mars Sample Return tested on Dar al Gani 735...

This work proposes an innovative non-destructive analytical strategy, based on Confocal Raman micro-spectroscopy, High Resolution Raman Imaging and micro-X-Ray Fluorescence imaging, as part of the quick non-destructive techniques that could be used to characterize the Martian samples from the Mars Sample Return mission when back on Earth. Until that moment, Martian Meteorites are the only Martian samples in our hands to develop such Analytical Strategies. To demonstrate its capabilities, this analytical strategy has been applied to characterize the Dar al Gani 735 Martian Meteorite with the aim to identify the terrestrial and non-terrestrial alterations suffered by the meteorite as a very valuable complementary methodology to the more traditional petrographic analyses and single point measurements. The combination of these techniques allows extracting at the same time elemental, molecular and structural information of the studied area of the sample. The most relevant results on the analyzed DaG 735 shergottite thick samples revealed the presence of several altered mineral phases originated from the temperature and pressure conditions during the shock on Mars (anhydride, calcite and ilmenite), as well as from terrestrial weathering processes that degraded the meteorite from its landing on Earth (calcite and hematite in fractures together with gypsum, mirabilite and thenardite). As most of the conclusive results come from Raman spectroscopy, this study shows the potential of Raman spectroscopy as a key technique in the upcoming new explorations of Mars materials by the Rosalind Franklin rover (Exomars2022 mission from ESA) and the Perseverance rover (Mars2020 mission from NASA), where Raman spectrometers are mounted for the first time in an extra-terrestrial research in the field.