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MarsSI (“Mars Système d’Information”, french for Mars Information System) is a platform and service to explore, process and retrieve data from orbiters. https://marssi.univ-lyon1.fr/MarsSI. This poster aim to help user to understand and use this service. Introduction Geological investigations of planetary surfaces require the combination of orbital datasets. Missions being often multiple-instruments platforms from multiple space agencies, the quantity of data available increased quickly. MarsSI is a platform designed to explore, process and retrieve Mars orbital data. It was certified in 2017 as french national Research Infrastructure by the Centre National de la Recherche Scientifique (CNRS) as part of the Planetary Surface Portal (PSUP, ). As of 2021, it indexes the optical (visible, multi and hyper-spectral) data from the recent orbiter missions, and allow to request the creation of Digital Elevation Models on demand. The focus, as highlighted by figure 1 is to allow the user to browse and request ”ready-to-use” products in regards of calibration, refinements and georeferencing. The user will be able to visualize and interpret the data in GIS or remote sensing software. MarsSI MarsSI aim to provide both a way to explore and use data from space agencies archives, such as the Planetary Data System (PDS), but also run data processing pipelines to make this data ready for analysis and as a shared, collaborative, repository. This allows a scientific user to more easily access data from their raw level and proceed to surface investigations and interpretation. Explore datasets MarsSI access is done through a web application. This interface, completely updated in 2021, provide a map where product footprints can be visualized over various backgrounds (MOLA, Themis, CTX) to put data in context. Instruments, and if needed, their acquisition modes, are available as layers to display. In this part of the interface, the user will be able to select products of interest and add them to a workspace summarizing the data he need to use. Until now, MarsSI has focused on the most recent missions (ODY, MEX, MRO) optical datasets (visible, NIR, hyperspectral) and derived products. Pipelines Pipelines execution is done on demand, and requested from the workspace pane of the interface. Each type of product (based on instrument) has a specific pipeline defined. The pipelines are designed to be fully automated, run on MarsSI's computing cluster, and to not require any user input. This is done partially to ease the usage of the service, to avoid managing and storing multiple versions with slight differences that would make references to products more complex. Basic pipelines operate to bring products to calibration and map projection (and georeferencing) steps. Those pipelines are usually based on ISIS (https://isis.astrogeology.usgs.gov/) for visible spectrum images. More advanced pipelines allows to calibrate and create spectral parameter maps from CRISM hyperspectral cubes using the CRISM Analysis Toolkit (CAT, https://pds-geosciences.wustl.edu/missions/mro/crism.htm), and another to create stereophotogrammetry-derived DEMs from the CTX and HiRISE datasets (in complement of the pre-processed DEM datasets available) based on Ames StereoPipeline (https://ti.arc.nasa.gov/tech/asr/groups/intelligent-robotics/ngt/stereo/). One notable feature is that the DEM datasets are computed from the optical imagery datasets, showing all the stereo pairs deemed feasibles (based on overlap calculation and having a difference of incidence angle of at least 10°). Documentation MarsSI is documented through a wiki that provide information on both the platform usage and the products. Conclusion MarsSI (https://marssi.univ-lyon1.fr) aims to offer a way to the scientific communities to easily explore and perform the necessary processing steps for the data needed in their projects. MarsSI itself has seen superficial and architectural changes since it was recognized as part of a french national service, and aim to extend its datasets range in the future. Use of the service require registration that is free for a non-commercial usage. Ackowledgements MarsSI is a national Research Infrastructure, recognised as such by the French Ministry of Higher Education and Research. It was supported by the Programme National de Planétologie (PNP) of CNRS/INSU, co-funded by CNES. It was initialy supported by the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013)/ERC Grant agreement No.280168.

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.

International audience; The Perseverance rover landed on the floor of Jezero crater on 18 February 2021. The landing site, named “Octavia E. Butler” is located ~2.2 km from the SE-facing erosional scarp of the western fan deposits, which are of strong interest for the mission [1-2]. Images obtained using the Mastcam-Z camera and the Remote Micro-Imager (RMI) of the SuperCam instrument provided the first Mars ground-based observations of this western fan (Fig. 1). At the distance images were taken, the RMI images offer a pixel resolution of 2.2 cm, thus enabling identification of objects of typically 7-8 cm (3-4 pixels). Observations of the residual butte Kodiak confirmed the presence of a lake within Jezero crater, but also showed that the lake deduced from the deltaic architecture at Kodiak had a level ~100 m lower than expected (-2495/-2500 m), and was thus a closed system for a significant period [3]. In addition, the coarser deposits (boulder conglomerates and pebbly sandstones) observed near the top of all of the scarps are typical of fluvial floods with high energy, reflecting a change in hydrology of the fluvial system. Here, we focus on the hydrological characteristics of fluvial deposits observed within the scarps of the delta, both as topsets and as boulder conglomerates.

International audience; Orbital and rover observations of relictgeomorphic features and stratigraphic architectures indicate Mars once had a warmer, wetter climate. Constraining the character, relative timing and persistence of ancient aqueous activity on Mars is possible through detailed interrogation of the stratal geometry of aqueously deposited sedimentary bodies. Such analyses inform interpretations of Martian climate evolution, potential habitability, and search strategies for rocks that might contain potential biosignatures. A prominent sedimentary fan deposit at the westernmargin of Jezero crater has been inferred to be a river delta that built into an ancient lake basin during the Late Noachian-Early Hesperian epochs on Mars (~3.6-3.8 Ga) [1, 2, 3]. The Perseverance rover landed on 18 February 2021 ~2.2 km from the western fan. During the early phase of mission investigations, highresolution images obtained from the Mastcam-Z camera and from the Remote Micro-Imager of the SuperCaminstrument provided the first ground-based observations of the western fan and an associated remnant outcrop, named Kodiak. Here, we report its sedimentology, which provide new constraints on the nature of the fan deposits, and their paleoenvironmental implications (4).

In preparation for the operations of the ExoMars Rosalind Franklin rover, characterising its landing site in Oxia Planum is essential. Of particular interest is the extensive Clay-bearing Unit present at the site, a key target in the search for biosignatures. In this paper we provide a map based on variations in colour and spectral information within this unit, covering the 1σ landing envelope of the rover along with a 1 km buffer to account for minor shifts of the landing envelope ahead of launch (referred to going forward as the 1σþ landing envelope). We used imagery from the Colour and Stereo Surface Imaging System (CaSSIS) and High Resolution Imaging Science Experiment (HiRISE) instruments, along with CaSSIS Band Ratio Composites with enhanced colour sensitivity to the presence of ferric (Fe3þ) and ferrous (Fe2þ) iron bearing materials. Our map is of a far higher resolution (map-scale 1:2000) than those previously available and, in contrast to previously available maps of this unit, differentiates between an Orange Subunit and a Blue Subunit which make up the Clay-bearing Unit. This mapping covered the ~91% of the 1σþ landing envelope where there was CaSSIS coverage and split the Clay-bearing Unit into three categories: one for each of the clay subunits, and another for exposures of the Clay-bearing Unit where either both subunits were too intermixed to reliably separate, or where it was difficult to determine which of the two were present. The results from our mapping shows that at least ~35% of the 1σþ envelope is covered by exposures of the Clay-bearing Unit: ~18% by the Orange Subunit, ~9% the Blue Subunit, and ~12% were classified as Indeterminate. The spread of these two subunits varied substantially over the 1σþ landing envelope, with the south-east half of the landing envelope dominated by the Orange Subunit (~70% exposures in this area belonging to the Orange Subunit, ~10% to the Blue Subunit and ~20% to the Indeterminate category), while the north-west has more sporadic exposures of the Clay-bearing Unit (~22% Orange, ~37% Blue and ~41% Indeterminate). The colour distinction between the two subunits is thought to be due to constituent mineralogical differences rather than differences in dust coverage of the two subunits. The scale of the fracturing present in the two subunits has also been assessed in this study, via qualitative observations of the fracture length and quantitative mapping out of fracture networks. While there were differences in the scale of fracturing between the two subunits, these were not as great as had previously been identified.

International audience; Impact craters are widely used to investigate the geologic history of planetary surfaces. Their morphology bears clues on past surface processes that affected it such as erosion, sedimentary deposit and volcanic processes and their density is widely used to date planetary surfaces. In this study we propose to combine crater Density and morphology into a single representation, Crater Size and Depth Frequency Distribution (CSDFD) that offers a snapshot not only at the age but also at the obliteration history of the crater population. Using simple models, we interpreted the CSDFD in term of crater obliteration rates. This methods can be applied on any body featuring impact craters. We present here the results obtained on Mars, using a global crater database. The obliteration rates obtained from CSDFD are consistent with known geologic history of Mars. Reaching thousands of m/Gy during Noachian and rapidly dwindling as soon as 3.5 Gy. Moreover, our method highlighted an continuous activity of Northern Lowlands surface during Amazonian we interpret to be linked with the formation of the vastitas borealis formation. This study offer a continuous vision in time and space of Martian obliteration history.

International audience; In this publication, we explore the options to improve the quality and speed of DEM generation procedures from stereo-photogrammetry pipeline of the MarsSI online service. We study available algorithms, options and workflows. Taking inspiration on earth-based work, we propose a new workflow relying on the semi-global matching algorithms and a two steps approach with the result of artifacts/noise reduction in the products, and improved co-registration of the outputs. We use this new workflow in the production of mosaic of ground models and orthorectified images. We illustrate the pipeline with the example of the othorectified HiRISE images mosaic that has been used in the framework of Exomars project to perform a join mapping of Oxia Planum, the landing site of Exomars rover.

The Perseverance rover (Mars 2020 mission, NASA) is exploring the mineral diversity within Jezero, the host crater of a paleolake, and is searching for potential biosignatures and past habitability evidence. Amongst its science payload, the SuperCam instrument (LANL/USA and a consortium of French laboratories) plays a central role in the Mars habitability investigation by providing rapid, synergistic, fine-scale mineralogy, chemistry, and color imaging [1]. In particular, it carries the first near-infrared spectrometer, IRS, to be operated on the Martian surface. IRS is a miniaturized point spectrometer (~1.15 mrad field of view) located in the SuperCam’s mast unit. Its spectral range (1.3 – 2.6 µm range) covers major silicate and hydrated mineral absorption features [2]. The instrument has been fully calibrated on ground before its launch [3] but flight measurements are necessary to check and refine its instrumental response after the cruise, entry, descent and landing. During the first 90 sols, observations of the SuperCam Calibration Targets (SCCT) were routinely performed in alternance with scientific targets.An opportunistic observation of the Mastcam-Z calibration target has also been acquired. The IRS sensitivity, measured on the White SCCT, appears to be generally compliant with the ground measurements, except at short wavelengths (Fig. 1). Flight calibrated measurements of the other SCCTs are compliant with their lab reference (Fig. 2) within 5 to 20 % for the Red and Cyan, but the evaluation of the absolute reflectance of the Black SCCT is far from expected, perhaps due to the ambient light misestimation. The calibration also consists in the removal of instrumental and environmental parasitic effects: CO 2 absorptions caused by the path of light through the Martian atmosphere are removed by dividing by a simulated spectrum of the gas; an EMI/EMC effect causing “glitches” in the AOTF’s RF power supply as well as in acquired data is mitigated by a specific detection algorithm; and readout spikes are eliminated by a statistical algorithm as well. Finally, datasets are cosmetically cleaned using higher level refinement algorithms (wavelets filtering and polynomial smoothing of the dark) to enhance band depth contrast without introducing significant biases. The remaining uncertainty on reflectance absolute level is mainly attributed to the error on the geometry of the illumination which requires a better modeling of local opography and the atmosphere diffusion. Some low frequency residuals are also miscalibrated by the current pipeline and still under investigation (e.g., RF power stability, thermal effects). Notwithstanding these calibration uncertainties, the instrument signal to noise ratio (SNR) is high enough, and the relative (i.e., spectral channel to spectral channel) calibration is precise enough to be sensitive to faint spectral features (down to a few percent band depth) even if few parts of the spectral range show very faint but high frequency effects. Thus we will present the assessment of the radiometric in-flight performance of the instrument and the evaluation of the detection threshold for specific spectral signatures. Figure 1: Radiometric instrument transfer function derived from ground calibration (blue) and flight measurements (orange), showing their divergence at short wavelength. Figure 2: Color SCCTs measurement performed on Sol 77. The lighter lines correspond to the lab reference of these calibration targets. References[1] Wiens, R.C. et al., 2017. Spectroscopy; [2] Fouchet et al., 2015, 46 th LPSC; [3] Royer et al., 2020, RScI

International audience; The Perseverance rover (Mars 2020 mission, NASA) landed in the ancient lakebed of Jezero crater, Mars on February 18th, 2021. The main science objectives of the mission are the characterization of past habitable environments, the search for preserved biosignatures and the collection of samples to be returned to Earth by the next MSR (Mars Sample Return, NASA/ESA) mission [1]. The payload includes the SuperCam instrument (under the leadership of LANL, USA and IRAP, France), which plays a critical role in the exploration strategy, as it combines various remote-sensing techniques to investigate the elemental and mineralogical composition of rocks and soils: high-resolution color imaging, laser-induced breakdown spectroscopy, Raman spectroscopy, visible and near-infrared (VISIR) reflectance spectroscopy, and acoustic sensing [2, 3, 4, 5]. In particular, the near-infrared spectrometer is a novel instrument on the Martian surface. The spectra, together with data from two additional visible spectrometers, cover 0.39-0.85 µm (VIS) and 1.3-2.6 µm (IR), which allows the identification of a wide variety of minerals.Figure 1. Enhanced-color mosaic of images taken by the Mastcam-Z Left camera of the rover workspace on sol 78 [6]. NASA/Caltech-JPL/MSSS/ASU. Orbital data show that the landing site exhibits diverse mineralogical assemblages in various geological contexts, attesting in particular of an ancient aqueous activity during the Noachian and Hesperian eras (> 3 Ga), and including mafic minerals, carbonates, phyllosilicates and opaline silica [7, 8, 9].We present the initial results of the SuperCam VISIR spectrometers, with calibrated [10] spectral data collected in the first months of operation of the instrument, with a focus on the rocks and soils present in the rover workspace and explored so far. Spectra have been obtained on nearby rocks so far within 50 m of the Octavia E. Butler landing site, at the boundaries of the Crater Floor Fractured Rough (CF-Fr) and Crater Floor Fractured (CF-F) units, which from orbit exhibit the spectral signatures of pyroxene and olivine, respectively [7]. A comparison with orbital data is presented in [11].Most of the rocks analyzed in the close vicinity of the rover so far consists of light-toned `pavers' and upstanding dark-toned rocks (Fig. 1). Some variability in reflectance levels and absorption bands is observed within and between the rocks (Fig. 2), but overall they share similar spectral characteristics in the VISIR. In particular, they all exhibit an absorption band near 1.9 µm (a spectral signature indicating the presence of the water molecule), a band that is usually not observed in the soils - at least not with the same depth. This absorption near 1.9 µm is also present in spectral observations of outcrops a few kilometers away from the rover [11]. In addition to this absorption at ~1.9 µm, a blue slope in the 2.1-2.5 µm region and subtle absorption bands near 1.4 µm and 2.28 µm show up locally, which suggests the presence of hydrated mineral species, such as an iron-rich phyllosilicate (like nontronite or hisingerite), potentially mixed with an oxy-hydroxide such as ferrihydrite (Fig. 2). The intensity of these absorption bands is consistent with at least a few weight percent of these hydrated species in the observed target, either in the bulk of the rock or in a varnish/coating. Finally, fewer spectra exhibit a weak absorption at 2.2 µm, suggesting the additional presence of an Al-OH or Si-OH-bearing phase. Overall, the detection of these widespread hydration features supports some pervasive water-rock interactions during the past, in the landing site of Perseverance. CRISM data suggest that we have landed in a relatively low hydration region, and that the rover will be driving through progressively increasing hydration throughout the mission, as it moves onto the delta, the olivine-carbonate and the region outside of Jezero crater. Future in situ measurements on these potentially more hydrated and diverse rocks are expected to bring new insights into the past aqueous environment at Jezero crater.Figure 2. Example of a SuperCam observation on a rock present in the workspace of the rover: 10x1 raster on target Bidziil. (a) RMI mosaic taken at 2.3 m from the rover mast on sol 56 with the IRS 68% field of view annotated in red. (b) Corresponding IRS spectra in color, compared to laboratory spectra of known minerals in black and grey. References[1] Farley, K. A. et al., 2020. Space Sci. Rev.; [2] Wiens, R.C. et al., 2017. Spectroscopy; [3] Maurice, S. et al., 2021 Space Sci. Rev.; [4] Cousin, A. et al., this conference; [5] Chide, B. et al., this conference; [6] Bell, J. F. et al., 2021. Space Sci. Rev. [7] Goudge, T. A. et al., 2015. J. Geophys. Res. Planets; [8] Ehlmann, B. L. et al., 2008. Science; [9] Tarnas, J. D. et al., 2019. Geophys. Res. Lett.; [10] Royer, C. et al., this conference; [11] Quantin-Nataf et al., this conference.

The last two decades have seen a growing number of Martian orbital missions with optical cameras of a various range of resolution. The topographic context of these images is crucial to decipher Martian surface processes. Thanks to stereo-photogrammetry, digital elevation models (DEM) can be produced from couple of images taken from different view angles. MarsSI [1] is a french Research Infrastructure that allows the users to easily and rapidly select observations, to process raw data via proposed automatic pipelines and to get back final products which can be visualized under Geographic Information Systems. MarsSI provide automated DEM generation based on the Ames Stereopipeline software (ASP) [2].DEM generationThe previously used workflow, which was used until the 1st of may, 2020, of MarsSI DEM pipeline was a straightforward use of ASP to create a DEM that would be fitted against the global MOLA DEM dataset to account for orbital imprecision in elevation and referencement. We were however not satisfied with the alignment results and artefact levels in the results.To optimize the pipeline, we first enable a bundle adjustment phase to improve future correlation between left/right image. We then consider our correlation options. Recent versions of ASP allowed to use the semiglobal matching (SGM) and derived correlators. Mars often present smooth and featureless areas that yield poor results for the traditional correlator function. The SGM correlator is a relevant way to address this issue, being able to find a correlation solution with smaller window size, which also improve computational times.Camera models and correction are provided within ASP, as well as images reprojection using an existing DEM to account for the topography. We consider using the MOLA dataset as the reference, but approximate orbital positions means that we will not match inputs to their exact position (sometimes by a few thousand meters) and introduce errors. One solution in that case is to first create a low resolution DEM with the input images we intend to use. Since at the beginning of the DEM creation, we match and align input images, this DEM fit them well despite having an approximate map-projection. Outputting this DEM at lower resolution minimize the correlation errors. We also enable missing data filling at this point by applying large maximum search distance method, to avoid loosing data from input images. This give us a result of enough quality to correct topography in the input images. We can then use these corrected images to create the high resolution DEM. During this phase, we decrease the filtering parameters compared to the first step. The result is a less smoothed DEM having sill few artefacts.We also aim to improve the alignment of the produced DEM to the MOLA dataset. This step can be accomplished by ASP’s pc_align tool. One of the first issue we have is the resolution gap between MOLA and our DEM so that alignment is a challenge. To mitigate this aspect, we switch our reference from pure MOLA reference data to the blended HRSC+MOLA dataset (200m/px). We also highligth that pc_align works best when outlier measurements can be filtered. This is usually done by invalidating points that have a distance above a threshold between the dataset and the reference. Since our orbital-based georeferencing error is quite limited, by simply vertically prealign the data and using the fast global registration algorithm , the result is improved. Using fast global registration would also mean that even if the alignement fails, it would still prevent large errors to be introduced at this step.With only minor parametrization differences, we applied the same workflow for both CTX and HiRISE imagery. Most notably, we applied stricter alignment maximum distance replacement.Oxia Planum mosaicsAside improving the overall quality of individual products, we also designed this new workflow having in mind to create mosaic of consistant, properly aligned to a common reference, datasets.We proceed to apply this method to 32 pairs of HiRISE imagery located on the ESA ExoMars2022 landing site, 24 of which were successfully generated. Alongside the DEM, we use ASP functions to generated a corresponding reprojection of the left image with the aim to produce both a DEM and an orthorectified imagery mosaics.However, while we find our alignment procedure to have a precision good enough for CTX scalemosaicking of products, automated HiRISE products alignements did not achieve an acceptable level. In addition to the previous workflow, we first coregistered a CTX mosaic at 10m/px against a HRSC mosaic processed and provided by the DLR[9]. This CTX mosaic was used t o align the HiRISE products whom coregistration was then refined again, manually, using ground control points against the corresponding orthorectified HRSC imagery corresponding to the DEM.This data was used in the context of the geological mapping exercice conducted by ESA in the summer of 2020 for the Exomars2022 mission and was the primary high-resolution layer used in the MMGIS environment deployed by ESA.ConclusionThis work allows the MarsSI infrastructure to produce DEM of greater quality that will also fit better in GIS environments, while requiring no user input. We now can also consider the automated production of mosaics using CTX data, and with user input for HiRISE data. While more time-consuming, this allowed us to provide a useful hi-resolution dataset for the mapping exercise of the Exomars2022 project.Data DOIS10.48326/IDOC.PSUP.MARSSI.CTX.OXIA10.48326/IDOC.PSUP.MARSSI.HIRISE.OXIAReferences C. Quantin-Nataf, L. Lozac’h, P. Thollot, D. Loizeau, B. Bultel, J. Fernando, P. Allemand, F. Dubuf- fet, F. Poulet, A. Ody, H. Clenet, C. Leyrat, S. Harrisson, MarsSI: Martian surface data process- ing information system, Planetary and Space Sci- ence 150 (2018) 157 – 170, ISSN 0032-0633, doi: https://doi.org/10.1016/j.pss.2017.09.014. R. A. Beyer, O. Alexandrov, S. McMichael, The Ames Stereo Pipeline: NASA’s open source software for deriv- ing and processing terrain data, Earth and Space Science 5 (9) (2018) 537–548.

Stack, K. et al., The Mars 2020 Perseverance rover landing site is located within Jezero crater, a ∼50km diameter impact crater interpreted to be a Noachian-aged lake basin inside the western edge of the Isidis impact structure. Jezero hosts remnants of a fluvial delta, inlet and outlet valleys, and infill deposits containing diverse carbonate, mafic, and hydrated minerals. Prior to the launch of the Mars 2020 mission, members of the Science Team collaborated to produce a photogeologic map of the Perseverance landing site in Jezero crater. Mapping was performed at a 1:5000 digital map scale using a 25 cm/pixel High Resolution Imaging Science Experiment (HiRISE) orthoimage mosaic base map and a 1 m/pixel HiRISE stereo digital terrain model. Mapped bedrock and surficial units were distinguished by differences in relative brightness, tone, topography, surface texture, and apparent roughness. Mapped bedrock units are generally consistent with those identified in previously published mapping efforts, but this study’s map includes the distribution of surficial deposits and sub-units of the Jezero delta at a higher level of detail than previous studies. This study considers four possible unit correlations to explain the relative age relationships of major units within the map area. Unit correlations include previously published interpretations as well as those that consider more complex interfingering relationships and alternative relative age relationships. The photogeologic map presented here is the foundation for scientific hypothesis development and strategic planning for Perseverance’s exploration of Jezero crater., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

International audience; The search for evidence of past or present life on Mars is the principal objective of the 2020 ESA-Roscosmos ExoMars Rover mission. If such evidence is to be found anywhere, it will most likely be in the subsurface, where organic molecules are shielded from the destructive effects of ionizing radiation and atmospheric oxidants. For this reason, the ExoMars Rover mission has been optimized to investigate the subsurface to identify, understand, and sample those locations where conditions for the preservation of evidence of past life are most likely to be found. The Water Ice Subsurface Deposit Observation on Mars (WISDOM) ground-penetrating radar has been designed to provide information about the nature of the shallow subsurface over depth ranging from 3 to 10 m (with a vertical resolution of up to 3 cm), depending on the dielectric properties of the regolith. This depth range is critical to understanding the geologic evolution stratigraphy and distribution and state of subsurface H2O, which provide important clues in the search for life and the identification of optimal drilling sites for investigation and sampling by the Rover's 2-m drill. WISDOM will help ensure the safety and success of drilling operations by identification of potential hazards that might interfere with retrieval of subsurface samples. Key Words: Ground penetrating radar—Martian shallow subsurface—ExoMars. Astrobiology 17, 565–584.

The exploration of Mars, which began in the 1960s, will soon be marked by a historic turning point, with the in situ investigation of two sites of Noachian age, the most primitive era of Mars. The selected landing sites, Jezero crater and Oxia Planum, exhibit from orbital data evidences for a hydrous past as well as good astrobiological potentials. The two rovers Perseverance and Rosalind Franklin (sent by the American and European-Russian agencies respectively) have a payload which includes the first visible and near-infrared (VNIR) reflectance spectrometers that will be used on the Martian surface, while this technique is the first to be used from orbit to assess and map the mineralogy of Mars. Our thesis is divided into two segments: first, an analysis of the two landing sites using remote sensing data was carried out, in order to characterize their geology and mineralogy. Second, terrestrial rocks similar to those on the landing sites were collected and analyzed using a reflectance spectrometer whose analysis beam is comparable in size to that of the VNIR channel of the SuperCam spectrometer onboard Perseverance. Our analysis on the Perseverance landing site allowed to examine the mineralogical variations of one of the most extensive geological units on the site, the olivine and carbonate unit. We suggest a pyroclastic origin for these deposits and date their emplacement at -3.82 +/- 0.07 Ga. This age will be useful to help calibrate the Martian chronology in the events of the Mars Sample Return mission. While Rosalind Franklin's landing site appears spectrally homogeneous from orbit, we show that there is textural, compositional, and mineralogical diversity at high resolution within the clays present at the site, which are the primary targets of the mission. During this thesis, we have produced a spectral database of samples analyzed in the laboratory. The reflectance spectra can be directly and automatically compared to those that will be measured in situ on rock outcrops. This database includes the first representative panel of Martian meteorites, natural magmatic rocks more or less altered and whose mineralogical compositions have been estimated, as well as synthetic mixtures of simplified composition and mineralogy that are directly comparable to those estimated on the landing sites. The reflectance spectra measured could be directly and automatically compared to future in situ measurements on Martian rock surfaces, L’exploration spatiale de la planète Mars sera marquée dans la prochaine décennie par une étape historique : l’exploration in situ de terrains d’âge noachien, soit faisant partie des plus anciens de la planète. Les sites d’atterrissage sélectionnés, le cratère Jezero et Oxia Planum, présentent depuis l’orbite les traces d’une activité hydrologique ancienne, ainsi qu’un potentiel exobiologique. Les deux rovers envoyés pour explorer ces sites (Perseverance par la NASA, et Rosalind Franklin par l’ESA et Roscosmos), sont équipés des premiers spectromètres de réflectance visible et proche-infrarouge (VNIR) à toucher le sol martien, alors que cette technique de détection est la première utilisée depuis l’orbite pour détecter et cartographier les minéraux en surface. Nos travaux de thèse sont découpés en deux axes : dans un premier temps, une analyse des deux sites d’atterrissage par télédétection a été effectuée, afin d’avancer sur leur caractérisation géologique et minéralogique. Dans un second temps, des roches terrestres analogues aux sites d’atterrissage ont été collectées et analysées à l’aide d’un spectromètre de réflectance dont le faisceau d’analyse est comparable en taille à celui de la voie VNIR du spectromètre SuperCam du rover Perseverance. Notre analyse sur le site d’atterrissage de Perseverance a permis de carter les variations minéralogiques d’une des unités géologiques les plus étendues sur le site, l’unité à olivine et carbonate, de proposer une origine pyroclastique, et d’en dater la mise en place il y a 3,82 +/- 0,07 Ga. Cet âge pourra être utilisé dans l’optique du retour des échantillons collectés par Perseverance, afin de calibrer la chronologie martienne. Là où le site d’atterrissage de Rosalind Franklin apparaît spectralement homogène depuis l’orbite, nous montrons qu’il existe à haute résolution une diversité morphologique, compositionnelle et minéralogique au sein des argiles présentes sur le site, cibles principales de la mission. Au cours de ces travaux de recherche, nous avons produit une base de données spectrale sur des échantillons analysés en laboratoire. Cette base de données inclut le premier panel représentatif de météorites martiennes, des roches terrestres naturelles dont la composition minéralogique a pu être estimée grâce à la diffraction de rayons X, ainsi que des mélanges synthétiques de composition simplifiée et de minéralogie directement transposable à celle estimée sur les sites d’atterrissage. Ces spectres de réflectance pourront être directement et automatiquement comparés à ceux mesurés sur des affleurements rocheux in situ

Impact crater are often used in the study of planetary surfaces. On the one hand, statistics on crater number provide the age of the surface, on the other hand, their shapes reflect the surface processes they witnessed. This study combines the statistic and morphology approaches in order to investigate the timing and intensity of sedimentary and volcanic processes of planetary surfaces. The use of crater depth measurements add a dimension to frequency distributions with the introduction of size and depth frequency distribution (SDFD). SDFSs can be interpreted in term of crater obliteration rates thanks to crater chronology models. We also developed models of crater population taking into account obliteration. Mars surface is highly cratered with many craters displaying signs of modifications by volcanic process, sedimentation and erosion. We interpreted SDFDs using a classic crater chronology system, to produce global maps of obliteration at different epochs of Mars. During Noachian, obliteration rates reach several thousands m/Gy, but rapidly decrease during early Hesperian and are close to 0 during Amazonian. Obliteration on the province of Tharsis decreased slower, suggesting a persistence of volcanic activity until early Amazonian. Northern lowlands witness Amazonian obliteration rates one order of magnitude higher than the rest of the planet, which may indicate the continuous formation of Vastitas Borealis during middle Amazonian. In addition to our global approach, we computed recent obliteration rates from mapping of high resolution images on landing sites of rover missions. Mawrth Vallis and Oxia Planum present significant obliteration rates, especially on units containing hydrated minerals, Les cratères d'impact sont indispensables dans l'étude des surfaces planétaires. D'une part, les statistiques de leur nombre permet de dater les surfaces planétaires, d'autre part, leur forme révèle les processus de surface qu'ils ont connu. Cette thèse propose de coupler les études statistiques et morphologiques afin d'étudier la temporalité et l'importance des processus sédimentaires et/ou volcaniques des surfaces planétaires. L'utilisation de la profondeur des cratères permet de rajouter une dimension aux distributions avec l'introduction des distributions en fréquence de taille et de profondeur (SDFD), offrant ainsi un aperçu des modifications morphologiques des cratères. Nous avons développé en conséquence des modèles permettant de modéliser l'évolution d'une population de cratères en prenant en compte les phénomènes d'oblitération. La surface Mars est largement cratérisée, mais ils ont pour la plupart été fortement modifiés par des processus volcaniques et/ou sédimentaires. A partir des SDFDs, nous avons estimé les taux d'oblitération martiens à une échelle globale. Ces taux sont, au Noachien, de plusieurs milliers de m/Ga, mais décroissent rapidement dès l'Hespérien inférieur et sont proches de 0 à l'Amazonien. L'oblitération sur la province de Tharsis a décru beaucoup moins rapidement suggérant une persistance du volcanisme à l'Amazonien inférieur. Les plaines du nord à l'Amazonien sont marqué par des taux d'oblitération un ordre de grandeur au-dessus du reste de la planète, qui pourraient indiquer la mise en place continue de la Vastitas Borealis Formation au cours de l'Amazonien moyen. En complément de notre approche à l'échelle globale, nous avons déterminé des taux d'oblitération actuels à partir de cartographies de cratères réalisées à haute résolution spatiale sur des sites d'atterrissage de rovers actuels et futurs. Les sites de Mawrth Vallis et d'Oxia Planum présentent les taux d'oblitération actuels les plus importants en particulier au niveau de leurs unités geologiques riches en minéraux hydratés

Over the past 50 years, our knowledge of the Moon has grown immensely. Progress in lunar science occurred through several phases. The first phase happened in the 1960s and 70s, during the Apollo and Luna missions, with the study of samples returned from the lunar surface. Petrological characterisation of lunar samples sparked the Lunar Magma Ocean concept, from which ensued the traditional view of the lunar crust and mantle organisation: the crust is plagioclase-rich, and its mafic content increases with increasing depth. The lunar mantle is commonly thought to be olivine-rich, like that of the Earth. The second lunar exploration phase happened in the 1990s, when satellites were launched into lunar orbit, collecting the first global remote sensing datasets. Owing to their wide to global coverage, remote sensing brought new insight into lunar science that is complementary to that provided by lunar samples. During the third, current phase of lunar exploration, new datasets were collected by spacecrafts orbiting the Moon between the 2000s and today. The remote sensing datasets acquired during the second and third phases of lunar exploration progressively complicated the initially simple picture that scientists drew from earlier studies. Indeed, high resolution remote sensing images and radar data led to the identification of volcanic features (domes, irregular mare patches), and the unambiguous discovery of volatiles in permanently shadowed regions and in lunar samples originating at depth in the Moon, demonstrating the Moon’s complex geological history. During this PhD, impact craters were used as natural drill holes through the lunar crust to sample material located underneath the surface. During impact, rocks from depth are emplaced in crater central peaks through elastic rebound, making it possible to investigate the composition of the crust at depth. Spectroscopic data from Chandrayaan-1’s Moon Mineralogy Mapper instrument were exploited to gather information on the composition of the crust in those central peaks. This work illustrates the use of remote sensing data on crater central peaks in order to constrain the shallow interior of the Moon. Remote sensing data can also be used to help locate which type of samples would need to be returned in the future from the lunar surface, in order to contribute to further elucidating the organisation of the lunar crust and upper mantle, Au cours des cinquante dernières années, notre niveau de connaissance sur la Lune a fortement évolué. Les progrès en science lunaire sont survenus selon plusieurs phases. La première phase eut lieu pendant les missions Apollo et Luna dans les années 1960 et 1970, avec l’étude des échantillons de roches lunaires rapportées pendant les missions du même nom. La caractérisation pétrologique des échantillons lunaires a fait naître le concept d’Océan de Magma Lunaire, qui est à l’origine de la vue traditionnelle de la croûte et du manteau lunaires. Ce modèle prédit que la croûte lunaire est riche en plagioclase et que sa composition devient plus mafique en profondeur. Il est communément admis que le manteau lunaire est riche en olivine et qu’il contient du pyroxène, conformément au manteau terrestre. La seconde phase de l’exploration lunaire eut lieu dans les années 1990, lorsque des satellites lancés en orbite lunaire collectèrent les premiers jeux de données globaux de télédétection. En raison de leur couverture spatiale globale, les données de télédétection apportèrent une vision complémentaire à celle conférée par l’étude des échantillons lunaires. Pendant la troisième phase de l’exploration lunaire, qui a commencé dans les années 2000 et a toujours cours aujourd’hui, de nouveaux jeux de données ont été collectés par des satellites en orbite autour de la Lune. Les données de télédétection acquises durant ces deux dernières phases ont permis de prendre connaissance de processus complexes encore inconnus et de nuancer l’image initialement simple que les scientifiques se faisaient de la Lune. En effet, l’étude des jeux de données de haute résolution et des données radar a conduit à l’identification d’édifices volcaniques (dômes ; zones de mare irrégulières, dites irregular mare patches ou IMP), et à la découverte sans équivoque de volatils dans les régions ombragées en permanence. Des volatils ont également été découverts dans des échantillons lunaires issus de l’intérieur de la Lune, démontrant ainsi la complexité de l’histoire géologique de la Lune.Durant cette thèse, des cratères d’impact ont été utilisés comme forages naturels de la croûte lunaire. En effet, lors de l’impact, des roches profondes sont excavées et mises à l’affleurement dans le pic central du cratère par rebond élastique. Il est alors possible d’étudier la composition des roches crustales profondes en examinant le pic central d’un cratère à la surface d’une planète. Ici, le pic central de cratères échantillonnant la croûte lunaire a été étudié avec les données spectroscopiques de l’instrument Moon Mineralogy Mapper (Cartographe de la Minéralogie de la Lune, aussi noté M³) à bord de la mission Chandrayaan-1. Ce travail illustre l’utilisation de données de télédétection sur le pic central de cratères, dans l’optique de caractériser l’intérieur peu profond de la Lune. Les données de télédétection peuvent également être utilisées pour aider à cibler des régions à la surface de la Lune dont le retour d’échantillons pourrait donner des indices importants sur l’organisation de la croûte et du manteau supérieur lunaires

Over the past 50 years, our knowledge of the Moon has grown immensely. Progress in lunar science occurred through several phases. The first phase happened in the 1960s and 70s, during the Apollo and Luna missions, with the study of samples returned from the lunar surface. Petrological characterisation of lunar samples sparked the Lunar Magma Ocean concept, from which ensued the traditional view of the lunar crust and mantle organisation: the crust is plagioclase-rich, and its mafic content increases with increasing depth. The lunar mantle is commonly thought to be olivine-rich, like that of the Earth. The second lunar exploration phase happened in the 1990s, when satellites were launched into lunar orbit, collecting the first global remote sensing datasets. Owing to their wide to global coverage, remote sensing brought new insight into lunar science that is complementary to that provided by lunar samples. During the third, current phase of lunar exploration, new datasets were collected by spacecrafts orbiting the Moon between the 2000s and today. The remote sensing datasets acquired during the second and third phases of lunar exploration progressively complicated the initially simple picture that scientists drew from earlier studies. Indeed, high resolution remote sensing images and radar data led to the identification of volcanic features (domes, irregular mare patches), and the unambiguous discovery of volatiles in permanently shadowed regions and in lunar samples originating at depth in the Moon, demonstrating the Moon’s complex geological history. During this PhD, impact craters were used as natural drill holes through the lunar crust to sample material located underneath the surface. During impact, rocks from depth are emplaced in crater central peaks through elastic rebound, making it possible to investigate the composition of the crust at depth. Spectroscopic data from Chandrayaan-1’s Moon Mineralogy Mapper instrument were exploited to gather information on the composition of the crust in those central peaks. This work illustrates the use of remote sensing data on crater central peaks in order to constrain the shallow interior of the Moon. Remote sensing data can also be used to help locate which type of samples would need to be returned in the future from the lunar surface, in order to contribute to further elucidating the organisation of the lunar crust and upper mantle; Au cours des cinquante dernières années, notre niveau de connaissance sur la Lune a fortement évolué. Les progrès en science lunaire sont survenus selon plusieurs phases. La première phase eut lieu pendant les missions Apollo et Luna dans les années 1960 et 1970, avec l’étude des échantillons de roches lunaires rapportées pendant les missions du même nom. La caractérisation pétrologique des échantillons lunaires a fait naître le concept d’Océan de Magma Lunaire, qui est à l’origine de la vue traditionnelle de la croûte et du manteau lunaires. Ce modèle prédit que la croûte lunaire est riche en plagioclase et que sa composition devient plus mafique en profondeur. Il est communément admis que le manteau lunaire est riche en olivine et qu’il contient du pyroxène, conformément au manteau terrestre. La seconde phase de l’exploration lunaire eut lieu dans les années 1990, lorsque des satellites lancés en orbite lunaire collectèrent les premiers jeux de données globaux de télédétection. En raison de leur couverture spatiale globale, les données de télédétection apportèrent une vision complémentaire à celle conférée par l’étude des échantillons lunaires. Pendant la troisième phase de l’exploration lunaire, qui a commencé dans les années 2000 et a toujours cours aujourd’hui, de nouveaux jeux de données ont été collectés par des satellites en orbite autour de la Lune. Les données de télédétection acquises durant ces deux dernières phases ont permis de prendre connaissance de processus complexes encore inconnus et de nuancer l’image initialement simple que les scientifiques se faisaient de la Lune. En effet, l’étude des jeux de données de haute résolution et des données radar a conduit à l’identification d’édifices volcaniques (dômes ; zones de mare irrégulières, dites irregular mare patches ou IMP), et à la découverte sans équivoque de volatils dans les régions ombragées en permanence. Des volatils ont également été découverts dans des échantillons lunaires issus de l’intérieur de la Lune, démontrant ainsi la complexité de l’histoire géologique de la Lune.Durant cette thèse, des cratères d’impact ont été utilisés comme forages naturels de la croûte lunaire. En effet, lors de l’impact, des roches profondes sont excavées et mises à l’affleurement dans le pic central du cratère par rebond élastique. Il est alors possible d’étudier la composition des roches crustales profondes en examinant le pic central d’un cratère à la surface d’une planète. Ici, le pic central de cratères échantillonnant la croûte lunaire a été étudié avec les données spectroscopiques de l’instrument Moon Mineralogy Mapper (Cartographe de la Minéralogie de la Lune, aussi noté M³) à bord de la mission Chandrayaan-1. Ce travail illustre l’utilisation de données de télédétection sur le pic central de cratères, dans l’optique de caractériser l’intérieur peu profond de la Lune. Les données de télédétection peuvent également être utilisées pour aider à cibler des régions à la surface de la Lune dont le retour d’échantillons pourrait donner des indices importants sur l’organisation de la croûte et du manteau supérieur lunaires

Over the last 3 billion years liquid water has an extremely limited presence on Mars. However, the multiple data available on the planet show evidences of a significant presence of liquid water from the accretion of the planet until about 3.7 billion years. The prevailing hypothesis today is that Mars had a denser atmosphere (possibly rich in CO2) early in its history. Much of this atmosphere and water were lost in space. Another possibility for reducing the amount of liquid water available and the reduction of the atmosphere is the water storage of water and CO2 in the crust. The Martian crust is studied via CRISM spectro-imaging data to characterize the early hydrothermal alteration of the planet. Serpentine and carbonates of detections confirm that the storage of a portion of the water and the atmosphere of Mars occurred. Additional constraints are provided by the geochemical modeling of serpentinization and carbonation of the Martian crust through EQ3/6 programs. The importance of serpentinization and carbonation of the Martian crust is thus reassessed. The results allow to open the debate on the role of serpentinization and carbonation on the evolution of the liquid water available and the evolution of the atmosphere. In addition, the thermodynamic conditions help provide constraints on the exobiology potential of the Martian crust, Depuis ces 3 derniers milliards d'années l'eau liquide est extrêmement peu présente sur Mars. Cependant les multiples données disponibles sur la planète montrent des preuves d'une présence importante d'eau liquide depuis l'accrétion de la planète jusqu'à environ 3,7 milliards d'années. L'hypothèse dominante aujourd'hui est que Mars possédait une atmosphère plus dense (possiblement riche en CO2) au début de son histoire. Une grande partie de cette atmosphère et de l'eau auraient été perdu dans l'espace. Une autre hypothèse pour la diminution de la quantité d'eau liquide disponible et pour la diminution de l'atmosphère est le stockage d'eau et de CO2 dans la croûte. La croûte martienne est étudiée via les données de spectro-imagerie CRISM pour caractériser l'altération hydrothermale primitive de la planète. Des détections de serpentine et de carbonates confirment que le stockage d'une partie de l'eau et de l'atmosphère martienne a eu lieu. Des contraintes supplémentaires sont apportées par de la modélisation géochimique de la serpentinisation et de la carbonatation de la croûte martienne via les programme EQ3/6. L'importance de la serpentinisation et de la carbonatation de la croûte martienne est ainsi réévaluée. Les résultats permettent d'ouvrir la réflexion sur le rôle de la serpentinisation et de la carbonatation sur l'évolution de la quantité d'eau liquide disponible et sur l'évolution de l'atmosphère. En outre, les conditions thermodynamiques permettent d'apporter des contraintes sur le potentiel exobiologique de la croûte martienne