EPSC Abstracts Vol. 13, EPSC-DPS2019-1926-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license.

Raman Spectroscopy and the RLS instrument for the characterization of soil on in-situ planetary missions

Guillermo Lopez-Reyes (1), Fernando Rull (1), Marco Veneranda (1), Jose Antonio Manrique (1), Aurelio Sanz (1), Emmanuel Lalla (2), Jesus Medina (1) (1) Erica group, University of Valladolid, Spain. Ave. Francisco Vallés, 8, Boecillo, 47151 Spain; (2) Center for research in Earth and Space Science, York University, Canada; ([email protected])

In-situ exploration of Mars Raman spectroscopy technique has proved to be considered as an essential tool for the chemical and The in-situ exploration of Mars with rover-based structural characterization of samples in planetary missions will be continued with the launch next year in-situ missions given its non-destructive nature, as of two new rover missions to the red planet: NASA well as the possibility of being used in micro or Mars 2020 and ESA ExoMars rovers. These rovers macro analysis, while providing very useful and will be the best equipped ever for the detection of accurate identification of the analyzed materials in biomarkers or organic molecules on Mars. On one with a short operation time. hand, Mars 2020 rover includes a very wide range of instruments, including two Raman spectrometers: The RLS instrument SuperCam, a remote Raman-LIBS instrument also featuring microimaging [1], and Sherloc, an Developed by an international consortium led by the ultraviolet Raman spectrometer placed in the rover University of Valladolid (UVa) and the National arm, especially suited for the analysis of organics [2]. Institute of Aerospace Technology (INTA), RLS will On the other hand, the ExoMars rover is equipped become the first Raman spectrometer ever used for with a 2-meter long drill to extract samples of space exploration. This instrument features a 532 nm Martian soil down to two meters -unexposed to continuous wavelength laser with a spot size on the ionizing or UV radiation- potentially preserving sample of 50 microns and an irradiance level around organic materials. In addition, it features a carrousel 0.3 kW/cm2, and a spectral resolution between 6 and that will allow the instruments of the Analytical 8 wavenumbers. Laboratory Drawer (MicrOmega IR imager [3], the RLS Raman Spectrometer [4] and the MOMA mass The flight model of the instrument has already been spectrometer [5]) to analyze the same sample in the delivered for integration in the rover, but other same spots. replicates and models have been widely characterized and tested in multiple environments to demonstrate the capability of the technique -and the instrument- Raman spectroscopy and the of fulfilling the ExoMars mission objectives, but also Martian sample-return missions paving the way for the use of this technique in the upcoming missions to Mars or other planetary bodies During the next years, following the needed such as Europa, or to comets. technology development, the logical path is to evolve to Martian return missions. In a first step, before Having a critical role in the development of the RLS, technology readiness for human exploration, the the Erica research group from UVa is involved in realistic approach consists on multi-phase sample numerous research fronts converging towards two return missions. Indeed, Mars 2020 features a series primary aims: 1) optimize the scientific outcome that of containers to store samples that might be could derive from the interpretation of RLS spectra, considered of high interest, for a potential future and 2) evaluate to which extend RLS data can recollection mission. Of course, the proper contribute in the fulfillment of the general objectives characterization and identification of the samples is of the ExoMars mission. To achieve these aims, of paramount importance to ensure that the right terrestrial analogues of Martian rocks and soils need samples are selected for collection. In this sense, the to be studied through Raman systems that ensure a spectral response and an operational mode comparable to the RLS. For this, two RLS- Conclusions representative analytical models have been developed by the Erica team to perform in-situ and laboratory Raman Laser Spectroscopy is a key technique for the studies of terrestrial analogues and further Martian- analysis of samples in planetary in-situ missions. The related samples. On one hand, the RAD1 (RAman use of this technique has been amply demonstrated in Demonstrator) is a field-portable prototype that has field and laboratory tests around the world and will the same geometrical concept and spectral be corroborated during the upcoming ExoMars and characteristics of the RLS instrument, mostly built Mars2020 missions due to its non-destructive with COTS elements (with the exception of the analytical capabilities, combined with a powerful diffraction grating, which is identical to the RLS chemical and structural identification of the analyzed instrument one). RAD1 also make use of the same materials. This positions this technique as essential algorithms employed by RLS to automatically for any in-situ exploration mission, including the calculate the optimal analytical parameters to be set future Martian-sample return missions. during analysis [6]. In addition of being employed for the in-situ mineralogical screening of terrestrial analogue sites (important in the selection of the References optimal samples to be collected for further laboratory [1] Gasnault, O., et al. SuperCam Remote Micro-Imager on studies), RAD1 has been successfully used to Mars 2020. in LPSC 2015. emulate RLS procedures during ExoMars mission [2] Abbey, W.J., et al., Deep UV Raman spectroscopy for simulations, as is the case of the ExoFiT field planetary exploration: The search for in situ organics. campaigns recently carried out in Almeria (Spain) Icarus, 2017. 290: p. 201-214. and Atacama (Chile). On the other hand, RLS [3] Bibring, J.P., et al., The MicrOmega Investigation ExoMars simulator is a laboratory prototype that, Onboard ExoMars. Astrobiology, 2017. 17(6-7). compared to RAD1, is coupled to a vertical and [4] Rull, F., et al., The Raman Laser Spectrometer for the horizontal positioner emulating the Sample ExoMars Rover Mission to Mars. Astrobiology, 2017. 17. Preparation and Distribution System (SPDS) of the [5] Fred, G., et al., The Mars Organic Molecule Analyzer ExoMars rover. The RLS ExoMars Simulator has (MOMA) Instrument: Characterization of Organic been used to demonstrate that the analytical routine Material in Martian Sediments. Astrobiology, 2017.17(6-7). chosen for the RLS (between 20 and 39 spot of [6] Lopez-Reyes, G. and F. Rull Pérez, A method for the analysis por sample) allows to obtain a full picture of automated Raman spectra acquisition. Journal of Raman the mineralogical heterogeneities of powdered Spectroscopy, 2017. 48(11): p. 1654-1664. samples [7]. Furthermore, it also helped [7] Lopez-Reyes, G., et al., Analysis of the scientific corroborating that, depending on the mineralogical capabilities of the ExoMars Raman Laser Spectrometer complexity of the sample, a limited number of instrument. European Journal of Mineralogy, 2013. 25(5) spectra can ensure a reliable semi-quantification of [8] Lopez-Reyes, G., et al., Multivariate analysis of Raman the detected mineral phases [7]. spectra for the identification of sulfates: Implications for ExoMars. American Mineralogist, 2014. 99(8-9) The intensive use of these models in the framework of the development of the RLS instrument for the [9] Manrique, J.A., et al., Raman-Libs Combination And ExoMars mission has provided a huge amount of Datafusion Evaluation For Solar System Exploration. JRS, data and results that have helped developing a series 2019. In review. of analytical techniques including multivariate [10] Veneranda, M., et al., PTAL multi-spectral database of analysis [8] and/or data fusion techniques [9]. The planetary terrestrial analogues: Raman data overview, JRS, study of analogues has resulted in the development of 2019. In press. databases such as the Planetary Terrestrial Analogue [11] Veneranda, M., et al., ExoMars/Raman Laser Library (PTAL) [10], and also with interesting results Spectrometer (RLS) – state of the art analytical tool for the on the potential identification of wet-target craters potential recognition of wet-target craters on Mars. XXX, based on Raman spectroscopy data [11]. The use of 2018. In press. these techniques will help improve the scientific return from the Raman spectroscopy data from in-situ This work is funded by the Spanish MINECO grants instruments on Mars. ESP2014-56138-C3-2-R and ESP2017-87690-C3-1-R.