Search

The most direct evidence that the icy Galilean satellite Callisto is able to sustain a significant neutral exosphere dates back to the detection of the CO2 non-LTE emission at 4.3 μm wavelength, measured by the NIMS instrument onboard the NASA Galileo spacecraft [1]. Other exospheric emissions have been observed in the UV spectral range, basically tracing the ionised exospheric component ([2], [3]). The analysis of such emissions in the framework of exospheric models (see e.g. [4], [5]) allowed to establish an overall composition dominated by O2 and H2O, with minor contributions by CO2 and CO. However, direct observations of neutral species other than CO2 are still missing, and their actual abundances, as well as spatial and temporal variability, are poorly constrained.The MAJIS (Moon And Jupiter Imaging Spectrometer, [6]) instrument, on board the ESA JUICE spacecraft, is expected to contribute in this field, by searching for non-LTE emissions falling in its spectral range, from 0.50 to 5.54 μm. In particular, we evaluate the chance of detection of signals at the satellite’s limb emitted by the CO2 complexes at 4.3 μm and 2.3 μm, by the H2O complex at 2.3 μm, by O2 at 1.27 μm, and by the CO bands at 4.7 μm and 2.3 μm. We calculate the populations of molecular levels by using the GRANADA algorithm [7], then the emissions intensities, for reference abundances of the molecular species and for limb-viewing geometry, by taking advantage of the KOPRA algorithm [8].Detection limits for all the abovementioned species are obtained in the approximation of horizontal uniformity of exospheric layers and adopting a vertical scaling compatible with the scale height in [1]. Surface density detection limits around 6.2 .106 cm-3, 6.6 .106 cm-3, 3.4 .109 cm-3, 3.4 .107 cm-3 are found for CO2, H2O, O2, and CO respectively. For both CO2 and H2O, these results indicate a high detection probability during the Callisto flybys planned in the current JUICE trajectory version (crema 5.0, [9]). Detection of O2 could also be possible if appropriate observing strategies are adopted. Detection of CO is instead very challenging, being its expected abundance well below the detection limit. AcknowledgementsThis work is supported by the Italian Space Agency (ASI-INAF grant 2018-25-HH.0). IAA researchers acknowledge financial support from the State Agency for Research of the Spanish MCIU through the Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (CEX2021-001131-S/fund by MICIN/AEI/10.13039/501100011033).References[1] Carlson,R.W.,1999, Science 283 (5403): 820–21. [2] Kliore,A.J., 2002, Journ.Geophys.Res. doi: 10.1029/2002ja009365. [3] Cunningham,N.J. et al., 2015, Icarus. doi:10.1016/j.icarus.2015.03.021. [4] Vorburger,A., et al., 2015, Icarus. doi:10.1016/j.icarus.2015.07.035. [5] Liang, M., 2005, Journ.Geophys.Res. doi:10.1029/2004je002322. [6] Guerri I., et al., 2018, Proc.of SPIE Vol.10690 106901L-1. doi: 10.1117/12.2312013. [7] Funke,B., et al., 2012, Journ.Quant.Sp.Rad.Tran. doi:10.1016/j.jqsrt.2012.05.001. [8] Stiller,G.P., et al., 2002. Journ.Quant.Sp.Rad.Tran. doi:10.1016/s0022-4073(01)00123-6. [9] ESA SPICE Service, JUICE Operational SPICE Kernel Dataset, doi:10.5270/esa-ybmj68p.

The study of Jupiter’s atmosphere, its composition, evolution, distribution, structure, and dynamics around the planet, is of interest to the scientific community. Several missions, space observatories, and ground-based telescopes (even if limited by the telluric bands of water vapor), have studied Jupiter’s atmosphere. Some of them, such as Juno, the Hubble Space Telescope (HST), and the Very Large Telescope (VLT), continue providing information about the vertical structure and distribution of the atmosphere around the planet [1-3]. Although the main chemical composition of Jupiter’s atmosphere has been unraveled, many questions remain open, such as the global abundance of water, or the responsible chemistry for the coloration of the clouds [4]. Besides, a remarkable potential of VIS-NIR spectrometry for characterizing the composition and dynamics of planetary atmospheres has been demonstrated in the last years [5]. The next mission to the Jovian system from the European Space Agency (ESA) is the Jupiter Icy Moons Explorer (JUICE), to be launched in April 2023 with an arrival date on July 2031 [6]. One of the key scientific instruments onboard is the Moons And Jupiter Imaging Spectrometer (MAJIS), which will provide hyperspectral capabilities through two channels: VIS-NIR (0.5μm-2.35μm), and IR (2.25μm-5.54μm) [7]. We would like to perform simulations of different test cases with respect to the viewing geometries of MAJIS and assess its capabilities [8-9] to characterize the vertical structure of the Jovian atmosphere. For this purpose, we upgraded ASIMUT-ALVL, a Radiative Transfer (RT) code developed at BIRA-IASB, that has been extensively used to characterize Mars and Venus atmospheres [10-11]. During the implementation phase of the new Jupiter case in ASIMUT-ALVL, we applied the current knowledge of the physical and chemical characteristics of Jupiter, including the Rayleigh scattering contribution due to dominant atmospheric species, the refractive index of Jupiter’s atmosphere, and the Collision-Induced Absorption (CIA) due to H2-H2 and H2-He molecular systems. The typical temperature profile and atmospheric composition of Jupiter were retrieved from [12], although in our next studies we might use the CH4 abundance from the Volume Mixing Ratio (VMR) profile from [13], which is similar to that from [14]. The required line-lists were implemented from the HITRAN online database with line parameters adequate for an H2 and He dominant atmosphere, following the 2020 version release [15]. The extinction coefficient due to Rayleigh Scattering is obtained based on the calculation of its cross-section from [16], by considering the refractive indexes of H2 and He, obtained from the refractivities measured by [17] and [18], respectively. The atmospheric King correction factor is obtained from an adapted version of the formula of [19], considering the depolarization ratio of H2 as measured by [20]. To model the aerosols and hazes present in the atmosphere, we used the microphysical parameters defined by [21]. We validated the updated performances of ASIMUT-ALVL by individually comparing the main spectroscopic features of Jupiter’s atmosphere in the VIS-NIR range against KOPRA, an RT code originally developed for studying Earth’s atmosphere but later adapted to the atmospheres of Titan, Mars, and Jupiter [22]. We used the same geometry of observation, assuming solar occultations with a tangential altitude between 50km and 360km, a resolution of 0.3cm-1, a Signal-to-Noise Ratio (SNR) of 100, and an orbit around the planet of 5000km high. The mean difference in transmittance obtained between both models is below 3%. The next step was to validate our RT model against observational spectroscopic data, which was obtained from the Visible and Infrared Mapping Spectrometer (VIMS) observations during the Cassini flyby to Jupiter [23]. This imaging spectrometer consists of two channels: VIS (0.35µm-1.07µm) and IR (0.85µm-5.1µm). In this presentation, we will discuss the results we obtained from the complete validation of our RT model, and the perspectives for the future implementation of the performances and viewing geometries of MAJIS/JUICE. Acknowledgements We acknowledge the kind support of Gianrico Filacchione who provided the calibrated data of the VIMS/Cassini observations. This project also acknowledges the funding provided by the Scientific Research Fund (FNRS) through the Aspirant Grant: 34828772 MAJIS detectors and impact on science. References [1] Bolton, S.J., et al., Space Science Reviews, 2017. 213(1): p. 5-37.[2] Nichols, J.D., et al., Geophysical Research Letters, 2017. 44(15): p. 7643-7652.[3] Antuñano, A., et al., The Astronomical Journal, 2019. 158(3): p. 130 (28).[4] MAJIS Team, JUICE Definition Study Report, 2014.[5] Langevin, Y., et al., Lunar and Planetary Science Conference, 2014. No. 1777: p. 2493.[6] Grasset, O., et al., Planetary and Space Science, Vol. 78, pp. 1-21, 2013.[7] Piccioni, G. et al., International Workshop on Metrology for AeroSpace, IEEE, 2019. pp. 318-323.[8] ESA, Consolidated Report on Mission Analysis (CReMA), Tech. Rep. 5.0b23.1. https://www.cosmos.esa.int/web/spice/spice-for-juice[9] Cisneros-González, M. E. et al., Space Telescopes and Instrumentation in Proc. SPIE 2020, 11443, 114431L.[10] Vandaele, A.C., et al., Planetary and Space Science, 2015. 119: p. 233-249.[11] Vandaele, A.C., et al., Optics Express, 2013. 21(18): p. 21148-21161.[12] Moses, J.I., et al., Journal of Geophysical Research: Planets, 2005. 110(E8).[13] Sánchez-López, et al., Astronomy & Astrophysics, 2022. Forthcoming article (ArXiv:2203.10086).[14] Seiff, A., et al., Journal of Geophysical Research: Planets, 1998. 103(E10): 22857-22889.[15] Gordon, I.E., et al., Journal of Quantitative Spectroscopy and Radiative Transfer, 2022. 277: p. 107949.[16] Sneep, M., et al., Journal of Quantitative Spectroscopy and Radiative Transfer, 2005. 92(3): p. 293-310.[17] Peck, E.R. et al., Journal of the Optical Society of America, 1977. 67(11): p. 1550-1554.[18] Mansfield, C.R., et al., Journal of the Optical Society of America, 1969. 59(2): p. 199-204.[19] Tomasi, C., et al., Applied optics, 2005. 44(16): p. 3320-3341.[20] Parthasarathy, S., Indian Journal of Physics, 1951. 25: p. 21-24.[21] López-Puertas, M., et al., The Astronomical Journal, 2018. 156.4: 169.[22] Stiller, G.P., et al., Optical Remote Sensing of the Atmosphere and Clouds, SPIE 2000, 3501.[23] Brown, R.H., et al., Icarus, 2003. 164(2): p. 461-470.

Icy bodies are the most numerous and diverse bodies in the Solar System, but only a few have been visited yet by space probes. Some of these icy bodies, mostly giant planet satellites like Callisto, are called ocean worlds as they likely host most of the liquid water of our Solar System within sub-glacial oceans [Sotin & Tobie 2004]. The presence of liquid water under the icy crusts of these bodies raises questions relative to exobiology. In the coming years and decades, these ocean worlds will be the focus of major planetary science missions, firstly with JUICE (ESA, launch scheduled in April 2023) and Europa Clipper (NASA, launch scheduled in October 2024) which will be targeting the Galilean moons, then with still conceptual missions as we speak such as (i) Uranus Orbiter and Probe and (ii) Enceladus Orbilander. Despite not being the prime target of any of these missions, Callisto will be investigated by JUICE and Europa Clipper through multiple flybys. One way to get information about Callisto’s sub-glacial ocean is to look at the moon’s surface, which may highlight markers of past or current activity and could lift the veil on its chemical composition. Spectroscopy is a powerful technique for such study, especially in the near-infrared domain where spectral signatures of H2O-ices, silicates, salts are detectable. Consequently, in preparation for future infrared spectroscopic data, and specifically those of the infrared imaging spectrometer MAJIS of the JUICE mission, a ground-based campaign was led with an instrument sharing some similar and also complementary characteristics: SINFONI (SINgle Faint Object Near-infrared Investigation), which was mounted on the UT4 of the VLT at ESO. Here we present the results derived from the analysis and the modeling of four full-disk observations acquired with this instrument. SINFONI combines an integral field spectrometer operating with different gratings with an adaptive optics module [Eisenhauer et al. 2003]. Our four observations were performed using the H+K grating, ranging from 1.46 µm to 2.41 µm, with a spectral resolution R = 1.500, but each spectrum acquired was automatically resampled in order to get a spectral sampling of 5 x 10-4 µm. The campaign took place from January 2015 from March 2016, and the observations were acquired near the opposition to optimize the angular resolution with Callisto’s angular diameter close to 1.5 arcsec. As SINFONI’s field of view is 0.8 x 0.8 arcsec2 divided into 64 x 64 pixels, one observation actually corresponds to a mosaic of ten overlapping acquisitions, as described in a paper about Ganymede using the exact same technique [Ligier et al. 2019]. All in all, after removing the high solar incident angle pixels we could not recover after applying photometric corrections (basically all pixels above latitude 60°, north and south), our dataset covers approximately 70% of Callisto’s entire surface with a spectral and spatial sampling (~40 km/pix) which allow to detect and map the spectral absorptions that may exist in this wavelength range of the Callisto’s spectrum. Spatial resolution is in par with that of the partial Callisto mosaic from the NIMS imaging spectrometer of the NASA Galileo probe. The first results obtained concerns the physical properties of the moon’s surface directly derived from the reduction process and the photometric corrections; one obtains satisfactory results using the qualitative photometric model of Oren-Nayar, which is a generalization of the Lambertian model with the surface roughness (σ) as only additional parameter [Oren & Nayar 1994]. In the case of our study, the best results were obtained with ranging between 17° and 19° whatever the observation. These values are much lower than the values in the 30° – 45° range provided by previous studies [Buratti 1991, Domingue & Verbiscer 1997], however these values were obtained through the modeling of the solar phase curve via the Hapke model [Hapke 1984, Hapke 1986] using a combination of telescopic observations and Voyager data; the major differences between the approaches make the respective results hard to compare (our data are < 10° emergence angle). Our second result concerns the global shape and spectral signatures in the surface spectra: overall, they are much flatter and more distorted than those of Europa and Ganymede, especially the quite large 2-µm H2O-ice band. To the exception of crystalline ice absorptions at ~1.50 µm, ~1.57 µm, ~1.65 µm and the 2-µm band, Callisto does not show other clear signatures (figure 1). However, very subtle signature(s), like the one at ~2.21 µm (figure 1), might actually be observed and are being investigated to confirm the detection(s). If confirmed it could suggest the presence of hydrated materials like salts or silicates. We will address this point during the meeting. Figure 1: Comparison between Ganymede’s (blue) and Callisto’s (red) mean spectrum of the entire dataset. And lastly our third main result comes from spectral modeling, where both linear and non-linear unmixing were performed. Unlike previous studies on Ganymede and Europa [Ligier et al. 2019, Ligier et al. 2016], the linear model shows that all of Callisto’s spectra are satisfactorily modeled without needing any hydrated salt and that the only two constituents would be (i) a darkening agent, with abundances always exceeding 80% even for the iciest spectra, and (ii) multiple grain sizes of the crystalline form of H2O-ice, with an average abundance of 7% and exhibiting a strong latitudinal gradient for the smallest grains typical of the influence of the Jovian magnetospheric environment (figure 2). Such a low concentration overall of H2O-ice challenged us about the legitimacy of the linear unmixing approach, so we decided to run the Shkuratov non-linear unmixing model [Shkuratov et al. 1999]. Tests are ongoing but very preliminary results show that the overall concentration of the crystalline ice should be much higher than the 7% coming from the linear model and hence much more representative of what should be the surface composition of an icy satellite. By the time of the meeting, we will be able to present the final results of the study. Figure 2: Distribution of the smallest grains of crystalline ice.

In the past decades, numerous hydrated silicates have been detected at the surface of Mars from orbital and in situ characterization. The study of their distribution and their quantification can enable to trace the history of water at the surface of the red planet. By quantifying the content of each minerals at the hydrated sites, we can have an estimation of the water content stored at the surface within these minerals. Our study is based on the modal compositional maps of 11 hydrated silicates that were detected with the OMEGA/MEx instrument (Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité). The maps were computed using a radiative transfer model applied to the hyperspectral images of OMEGA, where hydrated minerals features were previously detected. They results in global maps of modal composition at a resolution sub-kilometric of: Fe,Mg,Al-phyllosilicates, Al-smectite, AlSiOH, Opal, Mg-carbonates, Chlorite, Fe/Mg-Micas, Serpentine and Fe-hydroxide and were recently published in Riu et al., 2022. By estimating the water content of each individual end-members we were able to convert the 11 mineralogical maps into one final map of H2O content (in wt%). The average content of water, based on the content stored in hydrated silicates, is estimated to be slightly above 5 wt%, with some rare occurrences > 20 wt%. The ongoing studies now aim at a detailed analysis of the water distribution in order to look for new regions with high past aquability (stable liquid water) potential and/or exobiological potential, if such locations exist. The map will be studied locally in combination with high resolution images in order to correlate the high-water content with their context and highlight new regions of interest. A detailed analysis of the ExoMars22 Rosalind Franklin Rover is also foreseen in order to help the future in situ analysis of the ExoMars mission and contribute to ISRU (in situ ressource utilization).

On February 18, 2021, NASA’s Mars 2020 Perseverance rover landed successfully in Jezero crater. Several geological and compositional units were previously identified from orbital data analysis : a dark pyroxene-bearing floor unit; an olivine-bearing unit exposed in erosional windows and partially altered into phyllosilicates and carbonates ; a deltaic complex and its possible erosional remnants and a marginal carbonate-bearing unit. As of Sol 300 (December 2021), the rover has visited two geological units in situ: the dark pyroxene-bearing floor unit and the olivine-bearing floor unit. Others investigations of geological units of interest have been carried out using long distance (up to several kilometers) observations.The SuperCam instrument contains a suite of techniques including passive spectroscopy in the 0.40-0.85 (VIS) and 1.3-2.6 microns (IR) wavelength ranges, and a color camera (RMI- Remote Micro-Imager) providing high resolution context images. Since the landing, SuperCam has acquired thousands of VISIR spectra of nearby rocks (including both natural and abraded surfaces), as well as hundreds of spectra of distant targets (from 10s of m to 20 km). The VISIR field of view of each individual spectrum ranges from a few mm for the rock of the workspace to 20 m to 20 km. The aim of this contribution is to summarize the main results of VISIR spectra up to Sol 300.The two geological units investigated in situ have distinct spectra. The crater floor rough unit (Cf-fr) has a pervasive 1.9 µm absorption indicative of hydration. Additional absorption at 2.28 µm indicate the presence of iron-rich phyllosilicates. Correlations between 1.9 µm and 2.4 µm absorption bands or between 2.1 µm and 2.4 µm bands suggest the presence of both poly and monohydrated sulfates. Spectra similar to oxy-hydroxides have also been observed in some rocks. Unmixing methods such as factor analyses highlight a high calcium pyroxene component. To sum up, the Cf-fr is an altered pyroxene rich unit. The second unit investigated in situ is a region called Seitah, which is dominantly olivine-rich from orbital analyses. Supercam VISIR data confirm the strong signature of olivine of the unit and display a complex suite of absorptions in the 2.3 µm - 2.4 µm region suggesting the presence of iron and magnesium phyllosilicates and/or carbonates. The alteration signature seems to be associated with olivine grains. Distant observations were acquired on the western delta front, several remote mesas and hills, on Jezero floor unit (the unit on which Perseverance landed on and investigated in situ), on Seitah before being visited by the rover, and on even more distant targets such as the crater rim or the marginal carbonate-bearing unit. The observed spectral signatures form different clusters depending on the type of target, highlighting the spectral diversity of Jezero geological units. Remarkably, the long distance observations of Seitah region are in perfect agreement with the in situ measurements confirming the relevance of long distance observations to assess the geological/mineralogical context of Perseverance’s future traverses.

Introduction: On December 6, 2020, the Hayabusa2 mission successfully returned to Earth ~ 5.4 g of samples collected at the surface of the C-type asteroid Ruygu [1,2]. Its surface was first sampled on February 22, 2019, then on July 12, 2019, close to a 10-meter large artificial crater, so as to possibly access sub-surface material [3]. The collected samples are now kept at the Extraterrestrial Samples Curation Center of JAXA at ISAS in Sagamihara, Japan, for a first round of preliminary analyses, with the objective to characterize in a non-destructive manner both the bulk samples and a few hundreds of grains extracted from them [4]. In particular, the objective is 1) to support their further detailed characterization by the international initial analysis teams, which will start their activity in July 2021, and 2) to catalog the grains, accessible to the international community through AO selection, starting mid-2022. The preliminary characterization of these samples is being conducted with a visible microscope with four color filters, a FTIR spectrometer operating in the 1-5 µm range and MicrOmega, a hyperspectral NIR microscope developed at Institut d'Astrophysique Spatiale (Université Paris-Saclay/CNRS, Orsay, France), operating in the near-infrared range (0.99-3.65 µm) [5]. It is noteworthy that never before have the preliminary analyses of returned extraterrestrial samples included the characterization by a NIR hyperspectral microscope. Results: Preliminary outcomes of the analyses performed with MicrOmega will be presented at the conference. In particular, the question of the representativity of the samples collected by the Hayabusa2 spacecraft will be addressed thanks to the comparison of the spectra obtained by MicrOmega and the NIRS3 remote sensing IR spectrometer [6] which performed a spectral characterization (1.8-3.2 µm) of Ryugu's surface, including the sites of the samples' collection [7,8]. A preliminary analysis of the spatial compositional heterogeneity will be presented. Specific signatures, detected in grains typically present in References: [1] Binzel R. P. et al. (2002), Physical Properties of Near-Earth Objects. pp. 255-271, [2] Vilas F. (2008) The Astronomical Journal 135 (4), 1101-1105, [3] Morota et al. (2020) Science 368, Issue 6491, pp. 654-659, [4] Yada T. et al., in preparation, [5] Bibring J.-P. et al. (2017) Astrobiology 17, Issue 6-7, pp.621-626, [6] Iwata T. et al. (2017) Space Science Reviews 208 (1-4), 317-337, [7] Kitazato K. et al. (2019) Science 364 (6437), 272-275, [8] Kitazato K. et al. (2020) Nature Astronomy, Volume 5, p. 246-250.

The PTAL project [1] aims to build an Earth analogues database, the Planetary Terrestrial Analogues Library, to help characterizing the mineralogical evolution of terrestrial bodies, with a focus on Martian analogues (www.PTAL.eu). A set of natural Earth rock samples have been collected, compelling a variety of igneous and sedimentary rocks with variable compositions and levels of alteration. Those samples are characterized with thin section observations and XRD analysis, NIR spectroscopy, Raman spectroscopy and LIBS.This abstract focuses on the NIR (Near Infrared) spectroscopy analysis performed using the MicrOmega instrument, a NIR hyperspectral microscope (e.g. [2]). The MicrOmega instrument used within the PTAL project is the spare model of the ExoMars rover laboratory. It has a total field of view of 5 mm x 5 mm, with resolution of 20 µm/pixel in the focal plane. It covers the spectral domain from 0.98 µm to ~3.6 µm. Its capabilities enable the identification of grains of different mineralogy in the samples [2].Each MicrOmega observation produces >65,000 spectra, hence automatic analysis is needed as a first step. After data calibration, a quick-look data analysis based on a set of ~16 spectral parameters based on the detection of single or multiple absorption bands was performed to produce spectral indices maps and average spectra, then guiding the manual analysis in a second step. After spectral endmembers are identified, they are compared to reference spectral libraries to identify the presence of minerals species in the sample. Spectral parameter maps can then be used to map the extent of the identified mineral species on the surface of the sample. Final products of the analyses will feed the online PTAL spectral database, and a paper describing these analyses has recently been submitted to Astrobiology.Mineral species detected with MicrOmega in the PTAL samples include: Olivine, High Calcium Pyroxene, Low Calcium Pyroxene, Amphiboles, Epidotes, Zeolites, Opals, Phyllosilicates, Oxides and Hydroxides, Carbonates, and Sulfates.Preliminary comparisons with XRD and Raman analyses show general consistency in the identification of olivine, pyroxene and hydrated phases. As expected, quartz and plagioclase for example are challenging to be identified in NIR, but MicrOmega shows well the capacity in hydrated minerals identification and qualitative estimation of major and minor mineral species thanks to its spectral-imaging capabilities.The PTAL spectral database will assist in particular in interpreting in situ data from the next Mars surface missions. The target-rocks in Oxia Planum and Jezero Crater, the landing sites of the next surface missions, have compositional similarities with some samples of the PTAL collection, in particular with the orbital identification of clay minerals and serpentine. The NIR spectrometers on board the rovers will be involved at multiple stages of the surface operations and will be crucial to understand the geologic history of each landing site, and in particular the context of the water alteration of the rocks.References: [1] Werner et al. (2018) Second International Mars Sample Return, No. 2071, 6060. [2] Pilorget and Bibring (2014) PSS 99, 7-18.Acknowledgements: This project is financed through the European Research Council in the H2020-COMPET-2015 program (grant 687302).

In 2022, ESA/ROSCOSMOS will launch the ExoMars2022 rover mission to Mars. The selected landing site for the mission is Oxia Planum, a wide, Noachian-age, phyllosilicate-bearing plain located on the SE border of Chryse Planitia. The Fe,Mg-rich clay mineral deposits at Oxia Planum are one of the largest exposures of this type on Mars, with a thickness of more than 10 m. They clearly record complex water-rock interactions and as such are a promising target to answer scientific questions posed by the ExoMars 2022 mission pertaining to the history of water and the geochemical environment in the shallow Martian subsurface, and the ancient and present habitability of the planet.From the spectral analysis by CRISM and OMEGA, bedrock deposits at Oxia appear to contain vermiculite, a hydrous 2:1 phyllosilicate. But the exact mineralogy of the deposits and their origin is not yet fully understood. To fill this gap, and to better prepare for in-situ analyses by the ExoMars2022 rover, we performed a survey of potential terrestrial analog rocks by determining their mineralogy and NIR spectra for comparison with CRISM and OMEGA spectra of bedrock deposits at Oxia. The study focused on Fe-rich, trioctahedral vermiculite.Two terrestrial sites were identified and studied: Otago, New Zealand with vermiculitized chlorite-schists that underwent alteration without significant oxidation; and Granby, Massachusetts with basaltic tuffs containing Fe-rich clays of apparent hydrothermal origin filling amygdales. Both analogues have been added to a newly built Planetary Terrestrial Analogue Library (PTAL) collection. The PTAL collection aims to provide the scientific community with analogue rocks to help characterize and define the mineralogy and geochemistry of landing sites on Mars chosen for in-situ analyses (www.ptal.eu).The analogue comparisons reveal that Oxia bedrock deposits consist of Fe-rich, trioctahedral vermiculite, which is well crystallized and probably mixed with minor saponite. Additionally, NIR data analysis suggests that the deposits were not oxidized, nor illitized after formation. Based on this study, Oxia’s bedrock deposits may have formed from: (1) hydrothermal or magma fractionation-related origin of phyllosilicates and formation as an ash-fall deposits or (2) chlorite-rich sediment transported to a basin where chlorite was subsequently altered to vermiculite under anoxic, reducing conditions. The detailed characterization of the analogues and discussion of processes inferred for the evolution of Oxia Planum will be presented during the meeting.Vermiculite, with its high surface area and exchange capacity, has great potential to store organic compounds. The mineralogy of the bedrock deposits at Oxia, along with the anoxic, reducing conditions that might have been prevalent during Noachian time would be advantageous for retaining and preserving organic matter and make it a promising site for future analysis.