This proposal seeks to enhance science return from the chemcam instrument by improving its capability to provide accurate chemical analyses of martian surface materials, relating its results to…

This proposal seeks to enhance science return from the chemcam instrument by improving its capability to provide accurate chemical analyses of martian surface materials, relating its results to those of the more mature apxs instrument and enhancing our understanding of geochemical processes that occur on the surface of mars. To deal with chemical matrix effects that cause interactions in the libs plasma, we will use multivariate statistical methods to improve the accuracy of quantitative elemental analyses. These will facilitate effective use of geochemical classifications so that results can be use to inform our understanding of both magmatic evolution on mars and subsequent alteration processes. To this end, we will undertake four separate science tasks, all directly related to solicited investigations in the announcement of opportunity. 1) we plan to broaden the representation of compositions and increase the size of the chemcam calibration suite by an order of magnitude using well-characterized mars-analog samples; statistical methods will identify gaps in composition space where standards are lacking, and the P.I. Will find or create samples to fill those gaps. We will also undertake to provide and study cross-platform standards for much-needed comparisons between laser-induced breakdown spectroscopy (libs) and apxs data. 2) we will use multivariate statistics to develop automated procedures to choose an optimal combination of predictive samples for each element from among those in that calibration suite, producing geochemical analyses with the lowest possible errors. 3) we will improve upon our existing end-to-end models that simulate signal degradation resulting from misalignment or decreases in signal amplitude and evaluate their effects on multivariate model predictions; these insights can then be used to extract meaningful results from libs data even in low signal-to-noise conditions. 4) we will staff our libs lab and provide samples for use in validation during the mission. This work will allow chemcam to better address two specific science objectives of mars science laboratory by focusing on determination of chemical composition, and allowing better characterization of aqueous processes on mars. By contributing to improvements in the accuracy of chemcam results and an understanding of how its results relate to those of the apxs, we will help provide the best possible geochemical data for integration with results from other MSL instrumentation, particularly chemin.