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The evolution of the Ladon basin has been marked by intense geological activity and the discharge of huge volumes of water from the Martian highlands to the lowlands in the late Noachian and Hesperian. We explore the potential of the ExoMars Trace Gas Orbiter/Color and Stereo Surface Imaging System color image data set for geological interpretation and show that it is particularly effective for geologic mapping in combination with other data sets such as HiRISE, Context, and Compact Reconnaissance Imaging Spectrometer for Mars. The study area displays dark lobate flows of upper Hesperian to early Amazonian age, which were likely extruded from a regional extensional fault network. Spectral analysis suggests that these flows and the underlying rocks are ultramafic. Two distinct altered levels are observed below the lobate flows. The upper, yellow-orange level shows hundreds of structurally controlled narrow ridges reminiscent of ridges of listwanite, a suite of silicified, fracture-controlled silica-carbonate rocks derived from an ultramafic source and from serpentine. In addition to serpentinite, the detected mineral assemblages may include chlorite, carbonates, and talc. Kaolin minerals are detected in the lower, white level, which could have formed by groundwater alteration of plagioclase in the volcanic pile. Volcanism, tectonics, hydrothermal activity, and kaolinization are interpreted to be coeval, with hydrothermal activity and kaolinization controlled by the interactions between the aquifer and the hot, ultramafic lobate flows. Following our interpretations, East Ladon may host the first listwanite ridges described on Mars, involving a hydrothermal system rooted in a Hesperian aquifer and affecting ultramafic rocks from a magmatic source yet to be identified.

Anomalously bright basal reflections detected by MARSIS at Ultimi Scopuli have been interpreted to indicate the presence of water-saturated materials or ponded liquid water at the base of the South Polar Layered Deposits (SPLD). Because conventional models assume basal temperatures (≤200 K) much lower than the melting point of water, this interpretation has been questioned and other explanations for the source of the bright basal reflections have been proposed, involving clay, hydrated salts, and saline ices. Combining previous published data, simulations, and new laboratory measurements, we demonstrate that the dielectric properties of these materials do not generate strong basal reflections at MARSIS frequencies and Martian temperatures. Plausible candidates remain perchlorates and chlorides brines that exhibit a strong dielectric response at much lower temperatures than other materials. This explanation might require that metastability could be maintained for a long period of time on a geological scale.

Astrobiology is an interdisciplinary science involving many different sources, and disciplines including geology. Biosignature identification on Earth is consequential and strictly linked with the definition of a solid geological context in order to recognize the present and past processes, environments, controls, and their potential to host life. In planetary settings, that can be studied only (or mostly) remotely, the comparative geological analysis with Earth potential analogue is essential. Despite that, the importance of geology is often understated. We stress the importance of geological analyses in association and support of astrobiological investigations in the selection, understanding, and analyses of the study areas and in bridging the gap between the different observation scales on Earth and planets, also in the process of mission planning of remote and in situ missions. Effective comparative studies are possible because of data acquired in the last decades on many planetary surfaces that allow Earth-like field geological investigations: this is especially true on Mars but increasingly important in all of the other planetary bodies, including the icy satellites. In order for a mission to be effective, as an example, the collected samples must be representative of a larger body and reflect some specific feature of variation of it. This implies that the sample representativity is largely dependent on the accuracy of the geological observations that precede sampling. In particular, planning a sampling mission aimed at testing the astrobiological potential of a given target on a planetary surface, is based on the understanding of where to focus (depositional environment), which tools are needed (instruments), and finally to set the precise place where to sample within the selected environment with the ultimate goal to collect a significant sample and not just a stone. Accordingly, the knowledge derived from Earth analogues represents the base to plan the exploration of planetary settings, in order to on one side select the right science target to look for fossil or present life traces and on the other side to test the proper techniques, that should be effective and at the same time low invasive/destructive to be suitable for planetary exploration. Protocols for the sampling (i.e., collection, preservation, and treatment) and for the data analyses (i.e., facies analysis, instruments, combination of instruments) phases are needed both in the field and in the laboratory in order to identify the presence of biosignatures. Still, biosignatures in the rock record include many different organic or organically mediated structures and biochemical signals, which occurrence and evolution are controlled by the specific geological conditions. As a consequence, different types of biosignatures depend on different geological conditions and consequently necessitate different analytical approaches (e.g., Cavalazzi et al., 2019). In turn, this implies that different protocols depend on different geological conditions. Several problems may hamper the possibility to constrain the analogy between Earth and planetary settings, the main issues being the problems of scale and of equifinality (Baker, 2014). The regional analyses to constrain the geological context on Earth and in the planetary settings occur at similar scales, but the scales of the observations and measurements even in the most favorable condition on Mars cannot exceed the meter scale, while on Earth even singe grains or crystals can be recognized and described already in the field. In addition to that, the problem of equifinality arises from similar effects that may be generated by different combinations of causative processes (Baker, 2014), which implies that single morphologies (landforms) can be rarely unequivocally interpreted from remote sensing analysis in terms of genetic origin. To face these issues, the reconstruction of a broader geological context (landscape) is necessary as a pre-requisite to understand environments and processes of deposition (e.g., Pondrelli et al., 2008, 2011, 2015, 2019). Unraveling the vertical and lateral stratigraphic relations in order to correlate different coeval deposits, landforms, and structures, and comparing similarities and differences at all scales with different potential analogues on Earth, using the typical multiple working hypothesis approach (Baker, 2014), allows solid interpretations. A solid reconstruction of the geological context must be carried out comparatively also on the potential Earth analogues. On Earth, the depositional environments and processes can be characterized, defining the facies, facies association, lateral transitions, and structure distribution at the outcrop scale, specifically the ones that are suitable for sampling and laboratory analyses, and ultimately understanding the controls on deposition (e.g.., Cavalazzi et al., 2019). This set of information provides fundamental elements to reconstruct the vertical and lateral facies/structures distribution in an analogue planetary setting (e.g., Pondrelli et al., 2008, 2011, 2015, 2019) and drives the sampling site selection but also the choice of more appropriate instrumentation. This approach can provide not only a basic knowledge of the landing site/mission object area but is mandatory for a sample return mission and the selection of the right samples one can take a rock home, but not an outcrop. Thus, context geology is the first requirement to understand where the most significant sampling should be taken. References Baker, V. R. (2014). Terrestrial analogs, planetary geology, and the nature of geological reasoning. Planetary and Space Science, 95, 5–10. Cavalazzi, B., Barbieri, R., Gómez, F., Capaccioni, B., Olsson-Francis, K., Pondrelli, M., et al. (2019). The Dallol Geothermal Area, Northern Afar (Ethiopia)-An Exceptional Planetary Field Analog on Earth. Astrobiology, 19(4), 553–578. Pondrelli, M., Rossi, A., Marinangeli, L., Hauber, E., Gwinner, K., Baliva, A., & Lorenzo, S. (2008). Evolution and depositional environments of the Eberswalde fan delta, Mars. Icarus, 197(2), 429–451. Pondrelli, M., Rossi, A., Platz, T., Ivanov, A., Marinangeli, L., & Baliva, A. (2011). Geological, geomorphological, facies and allostratigraphic maps of the Eberswalde fan delta, Planetary and Space Science, 59(11–12). Pondrelli, M., Rossi, A. P., Deit, L. L., Gasselt, S. van, Fueten, F., Glamoclija, M., et al. (2015). Equatorial layered deposits in Arabia Terra, Mars: Facies and process variability. Geological Society of America Bulletin, 127(7/8). Pondrelli, M., Rossi, A., Deit, L. L., Schmidt, G., Pozzobon, R., Hauber, E., & Salese, F. (2019). Groundwater Control and Process Variability on the Equatorial Layered Deposits of Kotido Crater, Mars. Journal of Geophysical Research: Planets. https://doi.org/10.1029/2018JE005656

This work focuses on the characterization of background levels of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in seabed marine sediments of the central Adriatic Sea, collected up to 10 km far from the Abruzzo region coastline (Italy). The used approach follows the guidelines established by the Decree of the Italian Ministry of Environment, n. 173/2016, concerning the determination of threshold values of metal concentration, and including only samples with low or absent toxicological content. A statistical analysis, using the adjusted Tuckey's boxplot to identify the percentiles and potential outliers, was performed. The background concentrations were calculated as the values of the 90th percentile of distribution, according to the national regulation. This study represents the first attempt to calculate the background levels of marine sediments done at regional level in Abruzzo. A few outliers have been found, and interpreted as potential anthropic contamination.

Arabia Terra is a region of Mars where signs of past-water occurrence are recorded in several landforms. Broad and local scale geomorphological, compositional and hydrological analyses point towards pervasive fluid circulation through time. In this work we focus on mound fields located in the interior of three casters larger than 40 km (Firsoff, Kotido and unnamed crater 20 km to the east) and showing strong morphological and textural resemblance to terrestrial mud volcanoes and spring-related features. We infer that these landforms likely testify the presence of a pressurized fluid reservoir at depth and past fluid upwelling. We have performed morphometric analyses to characterize the mound morphologies and consequently retrieve an accurate automated mapping of the mounds within the craters for spatial distribution and fractal clustering analysis. The outcome of the fractal clustering yields information about the possible extent of the percolating fracture network at depth below the craters. We have been able to constrain the depth of the pressurized fluid reservoir between ∼2.5 and 3.2 km of depth and hence, we propose that mounds and mounds alignments are most likely associated to the presence of fissure ridges and fluid outflow. Their process of formation is genetically linked to the formation of large intra-crater bulges previously interpreted as large scale spring deposits. The overburden removal caused by the impact crater formation is the inferred triggering mechanism for fluid pressurization and upwelling, that through time led to the formation of the intra-crater bulges and, after compaction and sealing, to the widespread mound fields in their surroundings.

In this paper we present new data on weathering and soil formation processes affecting alkaline pillow basalts on the summit of Mt. Cerviero (Calabria, southern Italy). We investigated two representative soil profiles using an integrated approach, including pedological, petrographic, mineralogical and geochemical investigations. We distinguished the main features inherited from the hydrothermal alteration of the pillow basalts in a submarine environment from the chemical weathering processes under meteoric conditions. Irregular geochemical patterns and chemical index of alteration values across the soil profiles indicate a lithological discontinuity between the bedrock and the upper soil horizons, as a response to soil rejuvenation, in turn controlled by erosive processes and an allochthonous pyroclastic input. The soil profiles display poor horizonation and an incipient to intermediate degree of weathering, in line with the clay mineralogy (chlorite or hydroxy-interlayered vermiculite, illite, kaolinite and varying mixed-layers). The degeneration microtextures of clay and iron-manganese coatings in one soil profile suggest their relict genesis, with an emplacement under warm-humid conditions during the last interglacial. A Late Pleistocene to Holocene age of soil development is supported by the trachytic composition of volcanic micropumices, correlated to explosive eruptions from the Campania Province or the Aeolian Islands, in both soil profiles. Geochemical indices obtained from selective extractions of pedogenetic Al, Fe and Si pools point to poor andic properties with humus-Al-complexes prevailing over short-range order minerals. Nonetheless, the latter are consistent with the presence of volcanic glass, an optically isotropic pedogenic matrix and the Andosol-like field features of the soil profiles, even if they developed in a non-volcanic area. This should lead to a partial reassessment of the volcanic versus non-volcanic origin of certain Andosols worldwide and claims a good field work as a basis for choosing the best-suited laboratory methods to fill the gap between ordinary lab and field results.

The HYPerspectral Stereo Observing System (HYPSOS) is a novel remote sensing pushbroom instrument able to give simultaneously both 3D spatial and spectral information of the observed features. HYPSOS is a very compact instrument, which makes it attractive for both possible planetary observation and for its use on a nanosat, e.g. for civilian applications. This instrument collects light from two different perspectives, as a classical pushbroom stereocamera, which allows to realize the tridimensional model of the observed surface, and then to extract the spectral information from each resolved element, thus obtaining a full 4-dimensional hypercube dataset. To demonstrate the actual performance of this novel type of instrument, we are presently realizing a HYPSOS prototype, that is an instrument breadboard to be tested in a laboratory environment. For checking its performance, we setup an optical facility representative of a possible flight configuration. In this paper we provide a description of HYPSOS concept, of its optomechanical design and of the ground support equipment used to characterize the instrument. An update on the present status of the experiment is finally given.

The quantity, quality, and type of available datasets on Mars have improved in the last couple of decades. Context Camera (CTX) (Malin et al., 2007) on board the NASA Mars Reconnaissance Orbiter (MRO) provides a global coverage with an average resolution of 6 meters/pixel while the High Resolution Imaging Science Experiment (HiRISE) on board MRO (McEwen et al., 2007) allows up to 30 cm/pixel analyses at the local scale. These data allow at places also the DTM generation, but extensive topographic reconstructions at an average scale of 50 meters/pixel are possible using the High Resolution Stereo Camera (HRSC) on board of ESA Mars Express (MEX) (Neukum et al., 2004). Moreover compositional constraints can be provided by the spectral data coming from Observatoire pour la Minéralogie, l’Eau, les Glaces, et l’Activité (OMEGA) on board MEX and from Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on board the NASA Mars Reconnaissance Orbiter (MRO) (Murchie et al., 2007). These relatively recent datasets coupled with the older datasets and Geographical Information Systems (GIS) provide an impressive suite of tools to develop meaningful planetary geological maps. In principle, these new data allow to add to the traditional geomorphological or chronostratigraphic mapping approaches, also a geological map approach somewhat akin to the one well-known on Earth, although, a ‘true’ geological map should be based on the lithological characters of the mapped units; using tone, texture, absence/presence of sedimentary structure, and, if possible, compositional hints to define the units, may represent an adequate ‘planetary perspective’, obviously in addition to the stratigraphic position within the succession. This map approach has the advantages to be relatively objective (and so potentially more useful for geological context analyses) and to represent the stratigraphic complexity within a region. This approach is complementary to the more interpretative (because it includes the processes/environments of formation of the different features) one of the geomorphological maps, which has the obvious advantage to describe the environments/processes active in the region. In the framework of the GMAP (Geologic MApping of Planetary bodies) project, we present here an attempt to merge these two cartographic products taking advantage of GIS-based tools. Moreover, we aim at testing, where possible, the Earth-born symbols designed for the Geological Map of Italy (ISPRA, 2009, 2018) to try to make the ‘language’ of geological maps as uniform as possible. In order to perform these analyses, we selected a series of putative fluvio-lacustrine landforms located in Holden crater, along the south-eastern inner rim (coordinates 26.9°S-33.5°W). The geological map allowed to distinguish several units separated by unconformities. In particular, the Impact unit, equivalent to the one recognized by Tanaka et al. (2014) is nonconformably covered by the materials located inside the crater and along the crater rim. These materials can be distinguished in two groups separated by a disconformity, the first characterized by a relatively large lateral extension of the units and the second by a scattered appearance of the units. Within the first group, a disconformity separates a lower part from the upper part of the succession. The geomorphological map allows to genetically interpret these units, defining: i) a first impact stage, correspondent to the emplacement of Holden crater, ii) a ‘water-related’ phase (correspondent to the lower group of the geological map), and iii) an aeolian phase made of mega-ripples and dunes (correspondent to the upper group of the geological map). The ‘water-related’ phase can be further divided in a fluvio-lacustrine and a glacial phase. We propose the realization of a unique geologic and geomorphologic product that includes a polygon layer with the geological units map described above, a linear layer with the unit contacts (i.e., stratigraphic characterization), and a linear shapefile with tectonic features and geomorphological interpretations. The polygonal units’ layer might be also suitable to subdivide the units in lower-order ranked units, using appropriate fields (i.e., formation/members on Earth). This approach might be best suited for projects developed at the local scale, similar to what is done on Earth, while a chronostratigraphic approach is more fitting and recommended at the regional and global scale. We will identify a possible set of graphical symbols describing the surface features, locating potential limits in current GIS symbology implementation. The GMAP project represents an opportunity to share our experience and to collect current practices in planetary and terrestrial geological and geomorphological mapping, identifying what elements are still lacking and need to be discussed or developed. References ISPRA (2009) - Carta Geologica d’Italia. Guida alla rappresentazione cartografica. Modifiche e integrazioni ai Quaderni 2/1996 e 6/1997. Roma, pp. 166 ISPRA (2018) - Carta Geomorfologica d’Italia. Guida alla rappresentazione cartografica. Modifiche e integrazioni al Quaderno 4/1994. Roma, pp. 95 Malin, M. C., J. F. Bell, B. A. Cantor, M. A. Caplinger, W. M. Calvin, T. R. Clancy, K. S. Edgett, L. Edwards, R. M. Haberle, and P. B. James (2007), Context camera investigation on board the Mars Reconnaissance Orbiter, Journal of Geophysical Research: Planets(1991–2012), 112(E5). McEwen, A. S., E. M. Eliason, J. W. Bergstrom, N. T. Bridges, C. J. Hansen, A. W. Delamere, J. A. Grant, V. C. Gulick, K. E. Herkenhoff, and L. Keszthelyi (2007), Mars reconnaissance orbiter’s high resolution imaging science experiment (HiRISE), Journal of Geophysical Research: Planets (1991–2012), 112(E5). Murchie, S. et al. (2009), Evidence for the origin of layered deposits in Candor Chasma, Mars, from mineral composition and hydrologic modeling, Journal of Geophysical Research: Planets, 114, E00D05, doi:10.1029/2009je003343. Neukum, G, R Jaumann, and H. the and Team (2004), HRSC—The High Resolution Stereo Camera of Mars Express, European Space Agency Special Publication, SP-1240, 17–35. Tanaka, K., J. Skinner, J. Dohm, R. Irwin, E. Kolb, C. Fortezzo, T. Platz, G. Michael, and T. Hare (2014), Geologic map of Mars, USGS Scientific Investigations Map 3292, doi:10.3133/sim3292.

Full list of authors: Cremonese, G.; Capaccioni, F.; Capria, M. T.; Doressoundiram, A.; Palumbo, P.; Vincendon, M.; Massironi, M.; Debei, S.; Zusi, M.; Altieri, F.; Amoroso, M.; Aroldi, G.; Baroni, M.; Barucci, A.; Bellucci, G.; Benkhoff, J.; Besse, S.; Bettanini, C.; Blecka, M.; Borrelli, D.; Brucato, J. R.; Carli, C.; Carlier, V.; Cerroni, P.; Cicchetti, A.; Colangeli, L.; Dami, M.; Da Deppo, V.; Della Corte, V.; De Sanctis, M. C.; Erard, S.; Esposito, F.; Fantinel, D.; Ferranti, L.; Ferri, F.; Ficai Veltroni, I.; Filacchione, G.; Flamini, E.; Forlani, G.; Fornasier, S.; Forni, O.; Fulchignoni, M.; Galluzzi, V.; Gwinner, K.; Ip, W.; Jorda, L.; Langevin, Y.; Lara, L.; Leblanc, F.; Leyrat, C.; Li, Y.; Marchi, S.; Marinangeli, L.; Marzari, F.; Mazzotta Epifani, E.; Mendillo, M.; Mennella, V.; Mugnuolo, R.; Muinonen, K.; Naletto, G.; Noschese, R.; Palomba, E.; Paolinetti, R.; Perna, D.; Piccioni, G.; Politi, R.; Poulet, F.; Ragazzoni, R.; Re, C.; Rossi, M.; Rotundi, A.; Salemi, G.; Sgavetti, M.; Simioni, E.; Thomas, N.; Tommasi, L.; Turella, A.; Van Hoolst, T.; Wilson, L.; Zambon, F.; Aboudan, A.; Barraud, O.; Bott, N.; Borin, P.; Colombatti, G.; El Yazidi, M.; Ferrari, S.; Flahaut, J.; Giacomini, L.; Guzzetta, L.; Lucchetti, A.; Martellato, E.; Pajola, M.; Slemer, A.; Tognon, G.; Turrini, D. -- This is an open access article, The SIMBIO-SYS (Spectrometer and Imaging for MPO BepiColombo Integrated Observatory SYStem) is a complex instrument suite part of the scientific payload of the Mercury Planetary Orbiter for the BepiColombo mission, the last of the cornerstone missions of the European Space Agency (ESA) Horizon + science program. The SIMBIO-SYS instrument will provide all the science imaging capability of the BepiColombo MPO spacecraft. It consists of three channels: the STereo imaging Channel (STC), with a broad spectral band in the 400-950 nm range and medium spatial resolution (at best 58 m/px), that will provide Digital Terrain Model of the entire surface of the planet with an accuracy better than 80 m; the High Resolution Imaging Channel (HRIC), with broad spectral bands in the 400-900 nm range and high spatial resolution (at best 6 m/px), that will provide high-resolution images of about 20% of the surface, and the Visible and near-Infrared Hyperspectral Imaging channel (VIHI), with high spectral resolution (6 nm at finest) in the 400-2000 nm range and spatial resolution reaching 120 m/px, it will provide global coverage at 480 m/px with the spectral information, assuming the first orbit around Mercury with periherm at 480 km from the surface. SIMBIO-SYS will provide high-resolution images, the Digital Terrain Model of the entire surface, and the surface composition using a wide spectral range, as for instance detecting sulphides or material derived by sulphur and carbon oxidation, at resolutions and coverage higher than the MESSENGER mission with a full co-alignment of the three channels. All the data that will be acquired will allow to cover a wide range of scientific objectives, from the surface processes and cartography up to the internal structure, contributing to the libration experiment, and the surface-exosphere interaction. The global 3D and spectral mapping will allow to study the morphology and the composition of any surface feature. In this work, we describe the on-ground calibrations and the results obtained, providing an important overview of the instrument performances. The calibrations have been performed at channel and at system levels, utilizing specific setup in most of the cases realized for SIMBIO-SYS. In the case of the stereo camera (STC), it has been necessary to have a validation of the new stereo concept adopted, based on the push-frame. This work describes also the results of the Near-Earth Commissioning Phase performed few weeks after the Launch (20 October 2018). According to the calibration results and the first commissioning the three channels are working very well. © 2020, The Author(s)., We gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0. The SIMBIO-SYS instrument has been developed by Leonardo under ASI contract I/054/10/0.

The present investigation aims at providing a reliable evaluation of the geometric and radiometric accuracy of the airborne Daedalus-Coastal Zone Color Scanner (CZCS), through cal/val techniques. To this aim, on November 2014, we accomplished a remote sensing campaign over the Peligna Valley (Italy). Together with the personnel of the III Nucleo Aereo of the Italian Coast Guard, based at the Pescara Airport, we deployed the Daedalus AA1268EM1 CZCS scanner on board the fixed-wing aircraft type ATR42MP and a ASD FieldSpec spectroradiometer for a simultaneous field survey. We used vicarious calibration and secondary non-parametric geometric correction to achieve absolute atmospheric correction and geometric calibration, respectively. Although the validation and calibration targets used in this study were similar in nature, correlation coefficients of the prediction equations between at-sensor radiance and ground reflectance were > 0.90 for each of the 10 CZCS wavebands and the independent error assessment demonstrate that the empirical line method can be applied to correct CZCS imagery with satisfactory results.

This study proposes an integrated methodology which includes pedological, petrographic, mineralogical and geochemical analyses of transparent heavy-minerals, to reconstruct the weathering patterns and pedogenetic processes in a transport-limited erosion regime. Three representative soil profiles developed on crystalline bedrocks, located in Calabria, southern Italy, were studied in detail including the complete weathering profile along the transect bedrock/grus/soil. Differences in the amounts of heavy minerals in each soil profile appear to be controlled by the nature of the local bedrocks. The addition of allochthonous parent material and a varying extent of chemical weathering, likely influenced by topography and duration of pedogenesis. The heavy mineral shapes and surface microtextures, together with the vertical distribution of major and trace elements, the values of the chemical index of alteration and the relative abundance of the clay mineral types along the profiles highlight the different weathering degrees among the profiles. These features are consistent with iron/manganese oxy-hydroxides and clay neogenesis observed on femic heavy minerals. Moreover, they mark a lithological discontinuity between the bedrock and the upper soil horizons, which led to rejuvenation by erosive and colluvial processes along the slopes and/or aeolian deposition of allochthonous material, presumably including a Late Pleistocene to Holocene pyroclastic input. Chemical weathering affecting the majority of heavy minerals is consistent with high rainfall rates, soil moisture availability and acidic pH conditions likely favored by organic acids, prone to chemical reactions and leaching processes. The clay coatings and iron/manganese segregations in the Bt horizons of all the profiles studied suggest that they developed in a warmer humid climate during the interglacial stages of the Pleistocene.

Our research focuses on the detailed study of the aeolian deposits within Moreux crater using multi-resolution imaging and spectral data from the Mars Reconnaissance Orbiter. The morphometric analysis on the dune slip faces and wind streak orientations allowed us to reconstruct the sand transport pathways and the changes of the transport pattern. We used a new automatic procedure based on the Line Detection algorithm in PCI Geomatics’ Geomatica software to characterize small scale aeolian structures as ripples within Moreux crater from HiRISE images. After validation on a previously studied area in Herschel crater, we apply this method to reconstruct the wind regime at high spatial resolution in Moreux and reconstruct the wind circulation forming the aeolian bedforms. Moreover, we used three pairs of CTX images to perform a multi-temporal analysis of the wind streaks. We mapped more than 500 features with data acquisition spanning over four Earth years and the observed wind streak changes may reflect present day atmospheric variations due to local winds. CRISM datasets show an olivine and clinopyroxene mixture characterizing most of the dunes within Moreux crater, while the dark dunes in the northern sector of the crater showed an enrichment in Mg-olivine. This composition is similar to that detected in the central peak bedrock suggesting that central peak erosion contributes to the formation of the northly dunes meanwhile recent northeast wind flows and Moreux topography influence the wind circulation and determine the formation of the sand transport pathways within the crater. These results are consistent with the hypothesis that aeolian sands are generally sourced locally on Mars.

This study aims to assess the spatial and visible/near-infrared (VNIR) colour/spectral capabilities of the 4-band Colour and Stereo Surface Imaging System (CaSSIS) aboard the ExoMars 2016 Trace Grace Orbiter (TGO). The instrument response functions for the CaSSIS imager was used to resample spectral libraries, modelled spectra and to construct spectrally (i.e., in I/F space) and spatially consistent simulated CaSSIS image cubes of various key sites of interest and for ongoing scientific investigations on Mars. Coordinated datasets from Mars Reconnaissance Orbiter (MRO) are ideal, and specifically used for simulating CaSSIS. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) provides colour information, while the Context Imager (CTX), and in a few cases the High-Resolution Imaging Science Experiment (HiRISE), provides the complementary spatial information at the resampled CaSSIS unbinned/unsummed pixel resolution (4.6 m/pixel from a 400-km altitude). The methodology used herein employs a Gram-Schmidt spectral sharpening algorithm to combine the ∼18–36 m/pixel CRISM-derived CaSSIS colours with I/F images primarily derived from oversampled CTX images. One hundred and eighty-one simulated CaSSIS 4-colour image cubes (at 18–36 m/pixel) were generated (including one of Phobos) based on CRISM data. From these, thirty-three “fully”-simulated image cubes of thirty unique locations on Mars (i.e., with 4 colour bands at 4.6 m/pixel) were made. All simulated image cubes were used to test both the colour capabilities of CaSSIS by producing standard colour RGB images, colour band ratio composites (CBRCs) and spectral parameters. Simulated CaSSIS CBRCs demonstrated that CaSSIS will be able to readily isolate signatures related to ferrous (Fe2+) iron- and ferric (Fe3+) iron-bearing deposits on the surface of Mars, ices and atmospheric phenomena. Despite the lower spatial resolution of CaSSIS when compared to HiRISE, the results of this work demonstrate that CaSSIS will not only compliment HiRISE-scale studies of various geological and seasonal phenomena, it will also enhance them by providing additional colour and geologic context through its wider and longer full-colour coverage ( $\sim9.4 \times 50$ km), and its increased sensitivity to iron-bearing materials from its two IR bands (RED and NIR). In a few examples, subtle surface changes that were not easily detected by HiRISE were identified in the simulated CaSSIS images. This study also demonstrates the utility of the Gram-Schmidt spectral pan-sharpening technique to extend VNIR colour/spectral capabilities from a lower spatial resolution colour/spectral dataset to a single-band or panchromatic image greyscale image with higher resolution. These higher resolution colour products (simulated CaSSIS or otherwise) are useful as means to extend both geologic context and mapping of datasets with coarser spatial resolutions. The results of this study indicate that the TGO mission objectives, as well as the instrument-specific mission objectives, will be achievable with CaSSIS.

The Mars South Polar Layered Deposits (SPLD) are the result of depositional and erosional events, which are marked by different stratigraphic sequences and erosional surfaces. To unambiguously define the stratigraphic units at regional scale, we mapped the SPLD on the basis of observed discontinuities (i.e., unconformities, correlative discontinuities and conformities), as commonly done in terrestrial modern stratigraphy. This methodology is defined as “Discontinuity-Bounded Units” or allostratigraphy, and is complemented by geomorphological mapping. Our study focuses on Promethei Lingula (PL) and uses both high-resolution images (CTX, HiRISE) and radargrams (SHARAD) to combine surface and sub-surface observations and obtain a 3D geological reconstruction of the SPLD. One regional discontinuity (named AUR1) was defined within the studied stratigraphic succession and is exposed in several non-contiguous outcrops around PL as well as observed at depth within the ice sheet. This is the primary contact between two major depositional sequences, showing a different texture at CTX resolution. The lower sequence is characterized mainly by a “ridge and trough” morphology (Ridge and Trough Sequence; RTS) and the upper sequence shows mainly by a “stair-stepped” morphology (Stair-Stepped Sequence; SSS). On the basis of the observations, we defined two regional “discontinuity-bounded” units in PL, respectively coinciding with RTS and SSS sequences. Our stratigraphic reconstruction provides new hints on the major scale events that shaped this region. Oscillations in Martian axial obliquity could have controlled local climate conditions in the past, affecting the PL geological record.

An ultra-miniaturised (mass 1.5 kg; volume ~22 × 6 × 12 cm3) instrument which combines X-ray diffraction and fluorescence has been developed for the mineralogical and chemical characterization of Martian soils/rocks and was included in the ExoMars-Pasteur payload. The simultaneous in situ acquisition of elemental and mineralogical information would significantly improve any robotic missions and may unravel doubtful points regarding the mantle composition, crustal evolution and resource potential. The instrument employs a fixed reflection geometry to fulfil the diffraction principle which can be applied to unprepared sample as well. The instrument basically consists of a radioisotope as source of X-rays and a CCD-based detection system. This is the first successful diffraction experiment using a radioisotope since the early tests in the 60s. For terrestrial application the radioisotope can be easily replaced with a cathodic tube. The reduced dimension as well as the possibility to perform non-destructive analysis makes it suitable for terrestrial applications, particularly in the archaeometry field. We are envisaging an X-ray tomographer to map the mineralogical and elemental composition of an artefact (i.e., painting, pottery) directly on the object without sample preparation. Nowadays, X-ray radiography or computer tomography are becoming standard techniques widely used and accepted by art historians, archaeologists, curators and conservators as these methods enable information about the manufacturing process and the condition of an object without touching the artefact or even taking original sample material.

Recently it has been shown that the relatively low closure temperature (Tc) of 500 (100)°C calculated for augite from Miller Range nakhlite (MIL 03346,13) using the available geothermometers would correspond to a slow cooling rate inconsistent with the petrologic evidence for an origin from a fast-cooled lava flow. Moreover, previous annealing experiments combined with HR-SC-XRD on an augite crystal from MIL 03346 clearly showed that at 600 °C, the Fe2+-Mg degree of order remained unchanged, thus suggesting that the actual Tc is close to this temperature. In order to clarify this discrepancy, we undertook an ex situ annealing experimental study at 700, 800, and 900 °C, until the equilibrium in the intracrystalline Fe2+-Mg exchange is reached, using an augite crystal from Miller Range nakhlite (MIL 03346,13) with a composition of about En36Fs24Wo40. These data allowed us to calculate the following new geothermometer calibration for Martian nakhlites: where The application of this new equation to other Martian nakhlites (NWA 988 and Nakhla) suggests that for augite with composition close to that of MIL 03346, the Tc is up to 170 °C higher with respect to the one calculated using the previous available geothermometer equation, thus suggesting a significantly faster cooling in agreement with petrologic evidence.

The Colour and Stereo Surface Imaging System (CaSSIS) is the main imaging system onboard the European Space Agency’s ExoMars Trace Gas Orbiter (TGO) which was launched on 14 March 2016. CaSSIS is intended to acquire moderately high resolution (4.6 m/pixel) targeted images of Mars at a rate of 10–20 images per day from a roughly circular orbit 400 km above the surface. Each image can be acquired in up to four colours and stereo capability is foreseen by the use of a novel rotation mechanism. A typical product from one image acquisition will be a $9.5~\mbox{km} \times {\sim}45~\mbox{km}$ swath in full colour and stereo in one over-flight of the target thereby reducing atmospheric influences inherent in stereo and colour products from previous high resolution imagers. This paper describes the instrument including several novel technical solutions required to achieve the scientific requirements.

In this report, we show evidence for ripple and dune migration in Herschel Crater on Mars. We estimate an average dune migration of 0.8 m and a minimum ripple migration of 1.1 m in a time span of 3.7 Earth-years. These dunes and ripples are mainly shaped by prevailing winds coming from the north, however we also report the presence of secondary winds which elongate the barchans’ horns. Such a complex wind scenario is likely caused by the influence of winds blowing off the western crater rim as suggested by the Mars Regional Atmospheric Modeling System (MRAMS), an atmospheric mesoscale model. A multi-directional wind regime at the local scale is also supported by the observed bimodal distribution of the ripple trends. For the first time, a survey integrating the assessment of dune and ripple migration is presented, showing how dune topography can influence the migration patterns of ripples and how underlying topography appears to control the rates of dune migration.

The mapped area of Harmakhis Vallis, at the eastern Hellas Planitia region (35°30–42°50′S; 91°00–97°30′E), covers the surface area of about 212,000 km2. The region displays an enhanced modification of the initial topography formed by the Hellas impact. The long and complex history of degradation and alteration involves mass-wasting processes, volcanism and fluvial activity, confronting effects of climate-induced slow mass-wasting processes to effects caused by temporary, catastrophic events (impact cratering, volcanism, etc.). Geological mapping at scale of 1:1,500,000 (full scale at 1:540,000) have been carried out on multiple co-registered data sets available from the past and ongoing orbiter missions to Mars. The mapped geomorphic features of small- and medium-scales reveal in detail events that shaped the topography of the region throughout history, providing specific constraints on the geologic and climatic history of the region. This study highlights events from the most recent Martian history, including fluvial activity recorded in relation to a debris apron flanking Centauri Montes, and evidence of recent positive geothermal anomalies of a high heat-flux with relatively small spatial extents, on the timescale of several million years ago.

A variety of sedimentary deposits is observed in Xanthe Terra, Mars, including Gilbert-type deltas, fan deltas dominated by resedimentation processes, and alluvial fans. Sediments were provided through deeply incised valleys, which were probably incised by both runoff and groundwater sapping. Mass balances based on High-Resolution Stereo Camera (HRSC) digital terrain models show that up to ∼30% of the material that was eroded in the valleys is present as deltas or alluvial fan deposits. Stratigraphic relationships and crater counts indicate an age of ∼4.0 to ∼3.8 Ga for the fluvial activity. Hydrologic modeling indicates that the deposits were probably formed in geologically very short time scales. Our results point to episodes of a warmer and wetter climate on early Mars, followed by a long period of significantly reduced erosion rates.

The Eberswalde crater and its contributing basins have been analyzed in detail in order to reconstruct the geological evolution of the water-related landforms with particular focus on the Eberswalde delta-like feature. Based on a complex strata organization characterized by a topset–foreset–bottomset geometry, typical of delta progradation on Earth, we interpret the Eberswalde feature to be a fan delta associated with a lacustrine system. Depositional sub-environments have been recognized and mapped and the sedimentary processes discussed. A sequence stratigraphy approach has been used to evaluate the system, which we interpret to result from three depositional sequences. These sequences suggest relative water level fluctuations and a longer trend over time towards decreasing water content inside the basin.

The Shallow Radar (SHARAD) on the Mars Reconnaissance Orbiter has imaged the internal stratigraphy of the north polar layered deposits of Mars. Radar reflections within the deposits reveal a laterally continuous deposition of layers, which typically consist of four packets of finely spaced reflectors separated by homogeneous interpacket regions of nearly pure ice. The packet/interpacket structure can be explained by approximately million-year periodicities in Mars' obliquity or orbital eccentricity. The observed ∼100-meter maximum deflection of the underlying substrate in response to the ice load implies that the present-day thickness of an equilibrium elastic lithosphere is greater than 300 kilometers. Alternatively, the response to the load may be in a transient state controlled by mantle viscosity. Both scenarios probably require that Mars has a subchondritic abundance of heat-producing elements.

The paradigm of an ancient warm, wet, and dynamically active Mars, which transitioned into a cold, dry, and internally dead planet, has persisted up until recently despite published Viking-based geologic maps that indicate geologic and hydrologic activity extending into the Late Amazonian epoch. This paradigm is shifting to a water-enriched planet, which may still exhibit internal activity, based on a collection of geologic, hydrologic, topographic, chemical, and elemental evidences obtained by the Viking, Mars Global Surveyor (MGS), Mars Odyssey (MO), Mars Exploration Rovers (MER), and Mars Express (MEx) missions. The evidence includes: (1) stratigraphically young rock materials such as pristine lava flows with few, if any, superposed impact craters; (2) tectonic features that cut stratigraphically young materials; (3) features with possible aqueous origin such as structurally controlled channels that dissect stratigraphically young materials and anastomosing-patterned slope streaks on hillslopes; (4) spatially varying elemental abundances for such elements as hydrogen (H) and chlorine (Cl) recorded in rock materials up to 0.33 m depth; and (5) regions of elevated atmospheric methane. This evidence is pronounced in parts of Tharsis, Elysium, and the region that straddles the two volcanic provinces, collectively referred to here as the Tharsis/Elysium corridor. Based in part on field investigations of Solfatara Crater, Italy, recommended as a suitable terrestrial analog, the Tharsis/Elysium corridor should be considered a prime target for Mars Reconnaissance Orbiter (MRO) investigations and future science-driven exploration to investigate whether Mars is internally and hydrologically active at the present time, and whether the persistence of this activity has resulted in biologic activity.

A set of children’s maps on the solid-surfaced planetary bodies of the solar system was developed in the framework of the program Europlanet 2012. The surfaces of the six bodies were illustrated by planetary scientists and graphic artists. This is the first project in which such detailed, hand-drawn lunar and planetary maps were created specifically for children, in the most common spoken languages of Europe. The map pages, prepared according to the latest data from space probes, are accompanied by a website where background information and interesting facts can be found in a form understandable for children. The topics covered were compiled with the help of questions that children asked about the maps. The map series was prepared with the support of the International Cartographic Association Commission on Planetary Cartography.

This study investigates the geomicrobiological potential of Upper Pleistocene evaporite deposits of the Chott el Gharsa, a wide continental sabkha in southern Tunisia. Organic and inorganic-derived biosignatures are mostly contained in microcrystalline, laminated gypsum lithofacies consisting of light/dark alternations of concordant laminae, which have precipitated from high salt concentrated waters. These biosignatures include mineralized microbial-interpreted morphologies, such as mucilage, rods, and microfibers, and dumbbell morphologies in the hollow cores of dolomite crystals that are associated with sulfates. Mineral products that are induced by microbial activity and their organic compounds lead to the formation of lenticular-shaped gypsum crystals, with a high length/width ratio, dolomite precipitation and formation of pyrite framboids. Morphological and structural aspects of these biosignatures, and their composition, in laminated, dolomite-rich sulfate deposits could be detected through microscopic investigations and micro-analyses performed by the instrumentation that is planned for ongoing Mars sample return missions.

Laser induced breakdown spectroscopy (LIBS) has significant potential for remote terrestrial and extraterrestrial applications, nonetheless a number of correlated problems are still to be properly understood and possibly solved. This study focuses on several samples of terrestrial provenience, mostly volcanic rocks, which have importance as analogue to expected Martian samples. They were analysed after vaporisation with a frequency tripled Nd:YAG laser emitting at 355 nm , and measurements were made in an environment similar to the Martian one. Quantitative data were obtained by adopting the calibration free LIBS approach. A comparison with SEM-EDX data from the same samples is reported. Present results on Mars rocks analogues suggest that, in spite of residual interpretative ambiguities, LIBS technique permits elemental qualitative identification and quantitative analysis on silicate minerals examined in a rarefied atmosphere.

The martian shallow crust has been studied through two subsurface sounding radars, MARSIS and SHARAD which operate at 3-5 and 20 MHz, respectively. The capability of radar to resolve the subsurface structures and the stratigraphy relates both on the radar features and the electromagnetic parameters of the shallow crust. For small grain size sediments, like clay minerals, the dielectric properties strongly affect the penetration depth of the radar signal. In this study, we measured several clayey samples, collected from various geological settings, with different mineralogy and water content using a Vector Network Analyzer (VNA) in the frequency range 1MHz-6GHz. The electrical properties were estimated as a function of temperature (200-298K) via the Nicolson-Ross-Weir algorithm using a coaxial-cage probe connected to the VNA. These measurements are used to interpret radar data in terms of depth penetration and surface echoes strength which could be affected by the temperature diurnal variation of martian surface.

Sedimentary deposits within Eberswalde Crater are generally interpreted as having formed in a fluviolacustrine depositional environment. The Eberswalde fan delta consists of five lobes (four deltaic), the relative stratigraphy of which can be unravelled through simple cross-cutting relationships, allowing inferences to be made of the approximate water level from the transition between delta plain and delta front. Switching between different lobes is inferred to have been controlled by allogenic control. We distinguish three water-level fluctuations, possibly associated with system tracts, on which a higher order regressive trend is superimposed. The three lower-order cycles may partly reflect control by transient and/or localized processes, but the cyclic behaviour suggests the presence of climatic control.

We conducted a stratigraphic analysis of the South Polar Layered Deposits (SPLDs) in Promethei Lingula (PL, Mars) based on the identification of regional unconformities at visible and radar wavelengths. According to the terrestrial classification, this approach constrains the stratigraphy of the region and remedies the ambiguous interpretation of stratigraphy through marker layers, bypassing the problem related to the morphologic and radiometric appearance of the layers. Thus, the approach does not exclude diverse classifications, but complements them, whereas other discriminant elements are doubtful or difficult/impossible to be defined. Using this approach, we defined two stratigraphic units (or synthems: PL1 and PL2) in PL, which are morphologically different and divided by a regional unconformity (AuR1). This stratigraphic architecture implies that the geological history of PL has been conditioned by periodic changes in climate, which in turn are related to orbital variations of Mars.

Hyperspectral remote sensing is recognized as a powerful tool for mineralogical mapping of exposed surfaces on Earth and planets, as well. It allows for more rigorous discrimination among materials than multispectral imaging. Nevertheless, the huge data volume that comes with single observations results in severe limitations to successful data exploitation. Many techniques of feature reduction that have been developed so far do not allow for the complete exploitation of the informational content of the hyper-dimensional space. The present investigation aims at providing a feature reduction technique that preserves the spectral information and improves the classification results. We accomplished the feature reduction of synthetic and real hypercubes through exponential Gaussian optimization (EGO) and compared the results of k-means, spectral angle mapper (SAM), support vector machines (SVMs), and CLUES clustering techniques. The results show that the k-means clustering of hyper-dimensional spaces is the most efficient technique, but it does not automatically retrieve the optimal number of clusters. The SAM and SVM techniques give discrete results in terms of data partitioning, although the process of endmembers' selection is challenging and the definition of model parameters is not trivial. The combination of EGO modeling and CLUES algorithm allows for correctly estimating the number of clusters and deriving the accurate partitions when the cluster separability lies on two variables, at least. With real data, the CLUES clustering in the reduced space allows for higher overall performances than the more conventional techniques, although it underestimates the number of categories. © 2014 IEEE.

The investigated area comprises an arcuate mountain belt, Akna Montes, in Western Ishtar Terra, associated with an outboard plateau, Atropos Tessera, to the west and a volcanic plateau, Lakshmi Planum, to the east. Eight geologic units have been recognized on the basis of their geomorphic and structural characteristics as they appear on Magellan radar images. Our stratigraphic analysis shows that the geological evolution of the study area can be explained by four main steps: (1) formation of the older substrata of Atropos Tessera and Lakshmi, (2) extensive plains emplacement, (3) an orogenic phase including the formation of Akna Montes, and (4) local emplacement of younger plains. The tectonic evolution shows a deformational sequence characterized by contraction, shear, and topographic relaxation. This sequence is interpreted to be a consequence of the variation of crustal stresses and crustal thickening during orogenic events as observed for terrestrial high plateaus associated with a mountain belt (i.e., Himalaya and Tibet, Andes and Altiplano). In order to estimate the amount of crustal shortening associated with the Akna Montes, we considered two end-members for structural style of the mountain belt: a symmetric fold model and a fault-bend fold model. The models are theoretical because terrestrial orogenic belts are often formed by a combination of different compressional structures. However, symmetric and fault-bend faults represent the minimum and maximum crustal shortening, respectively, and thus they do place bounds on the amount of strain recorded by Akna Montes. The first model yields a shortening value less than 1%, whereas a range of 17–34% is derived for the second model. The large difference between these values underscores the importance of fold geometries for estimating strain and to place constraints on geodynamic models for mountain belt formation. On the basis of our study we think that a combination of mantle downwelling and horizontal convergence may provide a good explanation of the geology and tectonics we observed in the Akna Montes-Atropos Tessera region.

On the surface of Titan liquids can be present in three types of environments : (i) oceans, (ii) seas and lakes, and (iii) fluvial channels. The liquid in these environments will be affected by several types of motion: progressive (tidal) waves, wind-generated waves and unidirectional currents. The physical parameters of the liquid on Titans surface can be reconstructed using the Peng–Robinson equation of state. The total energy of the waves, both tidal and wind, depends on the gravity and liquid density ; both values are lower on Titan than on Earth. Thus, the same total energy will produce larger waves on Titan. This is also valid also for the progressive waves, as it is confirmed by the physical relationship between horizontal velocity, wave amplitude, and depth of the liquid. Wind-driven waves also will tend to be larger, because the viscosity of the liquid (which is lower on Titan) controls the deformation of the liquid under shear stress. Wind-generated waves would be rather large, but the dimension of the liquid basin limits the size of the waves ; in small lakes or seas the wave power cannot reach large values. Unidirectional currents are also affected by the liquid properties. Both the relations from driving and resting forces and the Reynolds number suggests that the flows exhibit a large erosional capacity and that, theoretically, a true fluvial network could be formed. However, caution should be exercised, because the cohesion of the sedimentary interface can armour bottom and induce laterally extensive, unchanelled sheet flows with small erosional capacity.

Recent studies have focused on the question of the stratigraphic sequence and thus the stages of tessera formation, specifically, if tessera are formed by contractional deformation followed by extensional deformation or vice versa. A major question centers on the interpretation of specific lineaments within tesserae as graben (bounded by faults ∼60°) or, alternatively, open tension fractures (dipping ∼90°). We document and assess the origin of extensional structures in tesserae at several locations on Venus, noting the morphology, continuity along strike, parallelism of walls, stratigraphic position and interaction with other structures, and variability due to radar viewing geometry. In each study area, our analyses demonstrate that (1) the extensional structures have variable widths, interior subparallel lineaments, and ramp terminations; (2) ridges and lineaments are continuous across the troughs, where the floors of many of these structures contain the lowered sections of preexisting structures; and (3) intratessera plains are seen to embay ridges and an impact crater is superposed on a ridge and in both cases these features are subsequently deformed by the extensional structures. We conclude that the morphology of these extensional structures is consistent with an origin as graben, not open tension fractures, and that these graben postdate the ridges in each study area. Both the graben and the ridges of the sizes found in our survey can be formed when the brittle crust is of the order of 1 to 10 km thick. To further test the tension fracture model, we examine the conditions of a Venus that could produce tension fractures of the dimension (∼1 km width) of extensional structures found in tessera terrain and find that thermal gradients of a minimum of 400 to 1500 K km−1 (heat flows of 800 to 3000 mW m−2) are required for a range of diabase rheologies and strain rates thought typical of Venus during tessera formation. Such a thermal structure would favor partial melting at depths

Mars-XRD is an X-ray diffractometer developed for in situ mineralogical analysis of the Martian soil. Mars-XRD main components are 55 Fe radioactive source, collimator and CCD-based detector. For spectroscopic requirements the beam section should be smaller than 1x10 mm 2 at sample distance. To improve X - ray flux and tuning capability a collimator with converging blades (Soller slits) has been implemented. A dedicated C++ program (XRC-PhOBOS, 1 Photon Output and Blade Optimization Software) investigates for the best Soller slits configuration comparing billion of combinations. The out-coming optimized collimator transmits a flux twice higher than a system with blades with the constant angular aperture and five times higher than a two apertures collimator. Software algorithm, updates and examples are illustrated in present paper.

Acute myelitis is an aetiologically heterogeneous inflammatory disorder of the spinal cord. We report on a 71-year-old woman with a recurrent cervical and thoracic myelitis who presented with a new relapse of the disease. Neuromyelitis optica was ruled out such as other possible causes of acute and/or recurrent myelopathy. Serum immunoglobulin levels and specific antibody responses were consistent with the diagnosis of common variable immunodeficiency (CVID). She was treated with high-dose methylprednisolone and intravenous immunoglobulin. As a remission-maintaining drug, we decided to treat her with subcutaneous immunoglobulin (CSL Behring) at 0.2 g/kg/week at doses higher than usually employed in replacement therapy in CVID. At 3-year follow-up, the response to treatment was good. No relapses occurred. Our case suggests the effectiveness and safety of subcutaneous immunoglobulin in maintaining remission and in sparing prednisone in a woman with recurrent myelitis associated with CVID.

In: Platz, T., Massironi, M., Byrne, P. K. & Hiesinger, H. (eds) 2015. Volcanism and Tectonism Across the Inner Solar System. Geological Society, London, Special Publications, 401, 203–218.

Mars-XRD is an X-ray diffractometer developed for the in situ mineralogical analysis of the Martian soil. The main components of the Mars-XRD experiment are: a Fe55 radioactive source, a collimator and a CCD-based detector system. For spectroscopic requirements and quality of the machined micrograin of the sample, the beam section should not be larger then 1 × 10 mm 2 at sample distance. The current collimator baseline is based on a two-windows system that uses about 20% of the total source emitting surface. To improve the X-ray flux, we are studying a collimator with converging blades which permits to use the entire source emission and tune the beam section. In order to better estimate the efficiency of this collimator and because of the high number of variables, a C++ program has been written that look for the best blades configuration among billion of combinations. In addition to the collimator configuration, this software simulator gives the sample photons distribution for different angles of the tilt of the source and for each couple of blades. The optimized collimator transmits a flux 30% higher than a system with blades with the same angular aperture and 5 times higher than a two windows collimator. Moreover the target photon distribution is a triangle function well focused on the sample surface instead of an irregular function obtained with the previous system. Higher performances arise with the source perpendicular to the source-sample direction. Thanks to this optimization we expect to strongly improve the resolution of the diffraction pattern which is the main goal of the current activities of the instrument development. This software simulator could be used also for the optimization of collimator system for the other wavelength and applications (e.g. radiotherapy).

International audience; The limited knowledge about the majority of the Mercury surface leaves many open questions regarding its geological evolution, the anomalously high metal/silicate ratio, the magnetic field generation and exosphere evolution. An integrated suite of instruments, Spectrometer and Imagers for MPO BepiColombo-Integrated Observatory SYStem (SIMBIO-SYS), which includes a stereo imaging system (STC), a high-resolution imager (HRIC) and a visible-near-infrared imaging spectrometer (VIHI), has been selected for the ESA BepiColombo mission to Mercury. SIMBIO-SYS will scan the hermean surface with the three channels and map the physical, morphological, tectonic and compositional properties of the entire planet. The availability of high-resolution images will unveil details of specific target at an unprecedented resolution. The main scientific objectives and performances along with technical characteristics of SIMBIO-SYS are described in this paper.