In-situ Spectroscopy on Mars: ChemCam Activities and Preparations for the Raman Laser Spectrometer on ExoMars

Thesis aims to perform appropriate preparatory work for the Raman Laser Spectrometer (RLS) on ExoMars. In order to test the prototype instrumentation it is important to select analogue samples as close as possible to the drill core that ExoMars will analyse. Work with 200 thousand spectra from the first 1000 sols of ChemCam operation on the Mars Science laboratory detected the presence of a basalt – trachybasalt igneous compositional trend, rich in alkali feldspar. These studies informed analogue sample selection at a Martian analogue site in the Utah desert as part of the MURFI rover trials. A flight representative Raman spectrometer was used in the field to acquire spectra. These were used to select a collection of analogues for further studies with RLS prototype instruments. These samples were chosen to be representative of the diverse mineralogy of the analogue site, this included; quartz, gypsum, anhydrite, celestine, barite and calcite. Work to fully characterise these samples used grain scale 532nm and 785nm Raman microscopes and an X-ray diffractometer instrument in order to determine the full composition for comparison with the capabilities or RLS. Nine of these samples were then analysed with the RLS Engineering Qualification Model to give as representative a view of RLS mission operation as possible. These studies found that whilst the RLS data was lower in spectral resolution and SNR compared to the laboratory instrumentation, it still possessed clear Raman bands enabling identification of all but two samples. These two samples were further analysed with the UK RLS prototype where additional Raman observation points produced clear bands allowing for the identification of the remaining samples. Recommendations for RLS operation and further testing include increasing the number of observation points on each sample and further testing with phyllosilicate analogues of the possible ExoMars landing site Marwth Vallis and Oxia Planum.