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While the vast majority of ESA’s funding for Mars exploration in the 2020s is planned to be invested in ExoMars and Mars Sample Return, there is an interest to assess the possibility of implementing a small mission to Mars in parallel with, or soon after, the completion of the MSR programme. A study was undertaken in the Concurrent Design Facility at ESA ESTEC to assess low-cost mission architectures for small satellite missions to Mars. Given strict programmatic constraints, the focus of the study was on a low-cost (

After the successful landing of the Mars Science Laboratory rover, both NASA and ESA initiated a selection process for potential landing sites for the Mars2020 and ExoMars missions, respectively. Two ellipses located in the Mawrth Vallis region were proposed and evaluated during a series of meetings (3 for Mars2020 mission and 5 for ExoMars). We describe here the regional context of the two proposed ellipses as well as the framework of the objectives of these two missions. Key science targets of the ellipses and their astrobiological interests are reported. This work confirms the proposed ellipses contain multiple past Martian wet environments of subaerial, subsurface and/or subaqueous character, in which to probe the past climate of Mars, build a broad picture of possible past habitable environments, evaluate their exobiological potentials and search for biosignatures in well-preserved rocks. A mission scenario covering several key investigations during the nominal mission of each rover is also presented, as well as descriptions of how the site fulfills the science requirements and expectations of in situ martian exploration. These serve as a basis for potential future exploration of the Mawrth Vallis region with new missions and describe opportunities for human exploration of Mars in terms of resources and science discoveries.

International audience; We used a grid-mapping technique to analyze the distribution of 13 water- and ice-related landforms in Acidalia Planitia as part of a joint effort to study the three main basins in the northern lowlands of Mars, that is, Acidalia, Utopia, and Arcadia Planitiae. The landforms were mapped at full Context Camera resolution along a 300-km-wide strip from 20 degrees N to 84 degrees N. We identified four landform assemblages: (1) Geologically recent polar cap (massive ice), which superposes the latitude-dependent mantle (LDM) (LA1); (2) ice-related landforms, such as LDM, textured terrain, small-scale polygons, scalloped terrain, large-scale viscous flow features, and gullies, which have an overlapping distribution (LA2); (3) surface features possibly related to water and subsurface sediment mobilization (LA3; kilometer-scale polygons, large pitted mounds, small pitted mounds, thumbprint terrain); and (4) irregularly shaped pits with raised rims on equator-facing slopes. Pits are likely the result of an energetic release of volatiles (H2O, CO2, and CH4), rather than impact-, volcanism-, or wind-related processes. LDM occurs ubiquitously from 44 degrees N to 78 degrees N in Acidalia Planitia. Various observations suggest an origin of air fall deposition of LDM, which contains less ice in the uppermost tens of meters in Acidalia Planitia than in Arcadia and Utopia Planitiae. However, LDM may be thicker and more extended in the past in Acidalia Planitia. The transition between LDM-free terrain and LDM is situated further north than in Utopia and Arcadia Planitiae, suggesting different past and/or present climatic conditions among the main basins in the northern lowlands.Plain Language Summary We studied water and ice-related landforms in the Acidalia Planitia, Mars. We used a new approach, a grid system of 20x20-km cells, along a 300-km-wide strip (east-west) from latitude 20 degrees N to 84 degrees N (south-north). This work is a joint effort to study three major basins in the northern plains: Acidalia, Utopia, and Arcadia Planitiae. We conducted a regional mapping of specific landforms at 6m/pixel resolution data and compared the results to different data products, such as geological maps, topography, radar, and climatic models. We proved that latitude-dependent mantle occurs from 44 degrees N to 78 degrees N in Acidalia Planitia and has an air fall origin related to past climatic cycles. These deposits are composed of mixture of fine-grained ice and dust. The distribution of this landform extends further south in Utopia and Arcadia Planitae suggesting different past/present climatic conditions in the northern lowlands.

International audience; A project of mapping ice-related landforms was undertaken to understand the role of subsurface ice in the northern plains. This work is the first continuous regional mapping from CTX (ConTeXt Camera, 6m/pixel; Malin et al., ) imagery in Arcadia Planitia along a strip 300km across stretching from 30 degrees N to 80 degrees N centered on the 170 degrees W line of longitude. The distribution and morphotypes of these landforms were used to understand the permafrost cryolithology. The mantled and textured signatures occur almost ubiquitously between 35 degrees N and 78 degrees N and have a positive spatial correlation with inferred ice stability based on thermal modeling, neutron spectroscopy, and radar data. The degradational features into the LDM (latitude-dependent mantle) include pits, scallops, and 100-m polygons and provide supporting evidence for subsurface ice and volatile loss between 35 and 70 degrees N in Arcadia with the mantle between 70 and 78 degrees N appearing much more intact. Pitted terrain appears to be much more pervasive in Arcadia than in Acidalia and Utopia suggesting that the Arcadia study area had more widespread near-surface subsurface ice and thus was more susceptible to pitting or that the ice was less well buried by sediments. Correlations with ice stability models suggest that lack of pits north of 65-70 degrees N could indicate a relatively young age (similar to 1Ma); however, this could also be explained through regional variations in degradation rates. The deposition of the LDM is consistent with an air fall hypothesis; however, there appears to be substantial evidence for fluvial processes in southern Arcadia with older, underlying processes being equally dominant with the LDM and degradation thereof in shaping the landscape.Plain Language Summary We mapped ice-related landforms In Arcadia on the northern plains of Mars. This was the first continuous map at this scale. The maps of these ice related landforms were used to understand the role of ice has in shaping the Martian landscape. We found evidence that suggest that ground ice occurs almost everywhere between 35 degrees N and 78 degrees N. We also found landforms associated with loss of ground ice to be widespread suggesting that Arcadia used to have even more ground ice in the recent past. The pattern of landforms we see suggests that the ground ice is sourced from the air, either as snowfall or direct condensation onto or into the near surface.

This work in Utopia Planitia is the first continuous regional mapping of ice‐related landforms integrated into an effort to study the three main basins (Arcadia, Acidalia, and Utopia Planitiae) in the northern plains. The distribution and morphotypes of these landforms, SHAllow RADar detections, and crater size‐frequency distribution measurements (>50 m in diameter) were used to understand the permafrost cryolithology and its past evolution in relation to climate in Utopia Planitia. Three assemblages of landforms were identified based on their spatial correlation and correlation with Mars Orbiter Laser Altimeter surface roughness along a strip from 30°N to 80°N. At 30°–38°N, the assemblage is formed by kilometer‐scale polygons, high‐albedo mounds, and thumbprint terrains. This assemblage is associated with a lobate deposit of 30 m in thickness with a crater retention age of 1 Ga. At 38°–47°N, the assemblage is comprised of large scallops, 100‐m‐diameter polygons, pits, and mantled deposits. This assemblage is correlated with a deposit of 80 m in thickness containing excess ice (~50–85% by volume) with a crater retention age of about 10 Ma. At 47°–78°N, the assemblage is composed of mantled deposits, textured terrains, and 30‐m‐diameter polygons. This assemblage is related to the ice‐rich, debris‐covered, latitude‐dependent mantle that has a crater retention age of about 1.5 Ma. Utopia Planitia appears to be a region of combined depositions of sediment and continuous cold climatic conditions that leaded to a complex distribution of ground ice.

This work was carried out through the 2016 Exploration Science Summer Intern Program hosted by the Lunar and Planetary Institute (LPI) and Johnson Space Center (JSC). This research was supported in part by the NASA Solar System Exploration Research Virtual Institute (SSERVI). This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole /Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (National Research Council, 2007) scientific concepts. Postprint

International audience; The investigation of the Martian surface through remote sensing allowed the identification of mound-like topo-graphically positive features that, based on geomorphological observations, have been ascribed to different phenomena. New observations will be performed in the forthcoming future to look for possible methane sources, hence discriminating morphologically similar features is a key objective to efficiently investigate and target the Martian surface. Here, we performed fractal analysis on five Martian fields of mound-like features that have been interpreted respectively as mud volcanoes, pingos, tumuli, rootless cones and monogenetic volcanic vents successfully validating the major interpretations of these features and in turn, the applicability of the fractal clustering method for discriminating among such features. Indeed, this technique is able to assess if the analyzed features are directly related to underlying systems of connected percolating fracture networks and estimates their extension in the subsurface. Accordingly, volcanic vents and mud volcanoes appeared to be connected to percolating systems involving several kilometers of crust, pingos and tumuli resulted to be unequivocally unrelated to active percolating fractures while rootless cones outputted weak relationship with shallow active fracture systems.

International audience; The increased volume, spatial resolution, and areal coverage of high-resolution images of Mars over the past 15 years have led to an increased quantity and variety of small-scale landform identifications. Though many such landforms are too small to represent individually on regional-scale maps, determining their presence or absence across large areas helps form the observational basis for developing hypotheses on the geological nature and environmental history of a study area. The combination of improved spatial resolution and near-continuous coverage significantly increases the time required to analyse the data. This becomes problematic when attempting regional or global-scale studies of metre and decametre-scale landforms. Here, we describe an approach for mapping small features (from decimetre to kilometre scale) across large areas, formulated for a project to study the northern plains of Mars, and provide context on how this method was developed and how it can be implemented. Rather than “mapping” with points and polygons, grid-based mapping uses a “tick box” approach to efficiently record the locations of specific landforms (we use an example suite of glacial landforms; including viscous flow features, the latitude dependant mantle and polygonised ground). A grid of squares (e.g. 20 km by 20 km) is created over the mapping area. Then the basemap data are systematically examined, grid-square by grid-square at full resolution, in order to identify the landforms while recording the presence or absence of selected landforms in each grid-square to determine spatial distributions. The result is a series of grids recording the distribution of all the mapped landforms across the study area. In some ways, these are equivalent to raster images, as they show a continuous distribution-field of the various landforms across a defined (rectangular, in most cases) area. When overlain on context maps, these form a coarse, digital landform map. We find that grid-based mapping provides an efficient solution to the problems of mapping small landforms over large areas, by providing a consistent and standardised approach to spatial data collection. The simplicity of the grid-based mapping approach makes it extremely scalable and workable for group efforts, requiring minimal user experience and producing consistent and repeatable results. The discrete nature of the datasets, simplicity of approach, and divisibility of tasks, open up the possibility for citizen science in which crowdsourcing large grid-based mapping areas could be applied.