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The icy satellites of the Solar System, such as Europa and Ganymede, show widespread evidence for tectonic structures that provide insights to infer the kinematics and the mechanical properties of their crusts. Their investigation is pivotal for the understanding of the regimes responsible for their formation and the connection with subsurface layers. Icy satellite tectonics is dominated by extension and shear regimes, while paucity evidence for compression represents an open issue. Structural investigation is constrained at regional-scale coverage of the remote sensing imagery. The research of analogues on Earth represents a strong support for the geologic analysis of the icy satellites. Glaciers represent optimal terrestrial analogues, showing deformation styles similar to those in the icy satellites, and being the excellent sites to further explore, verify and confirm what observed through remote sensing on the icy satellite geology. Although the formation processes differ, the similarity of their structures at surface allows quantifying and predicting the state of deformation in the icy satellites at different scales of investigation. Moreover, glacier deformation shows corridor-like pattern, analogous to the main tectonic setting recognized in the icy satellites. The UPSIDES project aims to investigate and compare the tectonic structures of the glaciers with those on the icy satellites, by means of multi-scale approach of both remote-sensing and field survey. We propose a structural investigation in the Russell and Isunguata Sermia glaciers, located at the western margin of the Greenland Ice Sheet, where field campaign has been conducted under the Europlanet 2024 RI's Transnational Access field analogue in Kangerlussuaq. This project aims i) to achieve knowledge of the tectonic setting at local-scale, ii) to compare with that at regional-scale, and in turn iii) to better understand the tectonic process and to characterize structures that are exclusively identified at regional-scale (such as in the icy satellites). Field measurements of brittle structures (fractures/faults), concerning the quantification of their azimuth, dip, length, width, throw and spacing, have been performed. In parallel, remote sensing analysis, concerning structural mapping on areas covering the locations of the investigated outcrops, allowed to derive the same quantities at regional-scale. In this way, both local- and regional-scale tectonic setting has been investigated, and the stress analysis has been performed. Obtained results have been compared and in turn related with areas that show similar tectonic setting on Ganymede. In particular, the lack of detection of the regional-scale counterpart of the compressional structures that have been recognized at local-scale in the investigated glaciers, has been related to the lack of evidence of such structures in the icy satellite’s surfaces. Such comparison allows us to prepare a tectonic model that suggests deep zones of existence of compressional structures and explains their limited detection at surface and regional-scale investigations.Acknowledgments: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149. The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

The AEg̅IS collaboration at CERN’s AD produces antihydrogen atoms in the form of a pulsed, isotropic source with a precisely defined formation time. AEg̅IS has recently undergone major upgrades to fully benefit from the increased number of colder antiprotons provided by the new ELENA decelerator and to move toward forming a horizontal beam to directly investigate the influence of gravity on the H̅ atoms, thereby probing the Weak Equivalence Principle for antimatter. This contribution gives an overview of these upgrades as well as subsequent results from the first beam times with ELENA.

The icy satellites of the Solar System, such as Europa, Ganymede and Enceladus, show widespread evidence for brittle morphotectonic structures (fractures/faults) that provide insights to infer the kinematics and the mechanical properties of their crusts. Their investigation is pivotal for the understanding of the tectonic regimes responsible for their formation. In addition, stress-related structures represent potential conduits or enhanced pathways for fluid migration thus connecting the surface and the sub-crustal layers. Such processes are significant to understand internal processes of icy bodies. Their investigation is constrained at regional-scale coverage of the remote sensing imagery. Glaciers and ice sheets represent optimal terrestrial analogues, showing deformation styles similar to those in the icy satellites, and being the excellent sites to further explore, verify and confirm what observed through remote sensing on the geology of icy satellites. Although the formation processes differ, the similarity of their structures at surface allows quantifying and predicting the state of deformation in the icy satellites at different scales of investigation. The UPSIDES project aims to investigate and compare the tectonic structures of the glaciers with those on the icy satellites, by means of multi-scale approach of both remote-sensing and field survey. We propose a structural investigation in the Russell and Isunguata Sermia glaciers, located at the western margin of the Greenland Ice Sheet. Their investigation attempts: i) to identify scaling laws between the tectonic structures measured in the glacier outcrops and their equivalent mapped on satellite images; ii) to relate and compare such scaling laws with structures mapped on deformed areas of the icy satellites; and iii) to infer the tectonic styles at local-scale on the icy satellites. The knowledge of the tectonic setting at local-scale and its comparison with that at regional-scale, allow us to better understand the tectonic process and to characterize structures that are exclusively identified at regional-scale (such as in the icy satellites). In this contribution we present the preliminary results of the analyses of data collected during the field campaign conducted on July 2021 in Greenland, at the Russell and Isunguata Sermia Gl., in the Europlanet 2024 RI's Transnational Access field analogue in Kangerlussuaq. Field measurements include the characterization of the ice brittle deformation (e.g., fractures and fault) by the quantification of their azimuth, dip, length, width, throw and spacing. This allow us to recognize the tectonic settings and regimes responsible for their formation. In parallel, we performed a structural mapping on satellite images, which cover the locations where the investigated outcrop occur, and we derived the attributes of the mapped structures. We performed then paleo-stress analyses of the data from both local- and regional-scale, which in turn have been related. The obtained results are consistent and suggest strike-slip kinematics. Such results are compared with areas that show similar tectonic setting on Ganymede and Europa and support the understanding of the possible local-scale setting at surface. In addition, the field data allow us to identify the structures that ease the fluid migration. The obtained results from this project aim to contribute to advance the study of icy surface tectonics and will support the preparation of planetary programs, such as JUICE mission, for dedicated observations and target areas. Acknowledgments: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 871149. The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

Introduction: In the Martian North Polar Cap, troughs are formed and enlarged by the erosive action of katabatic winds, blowing perpendicularly with respect to steep edges of the cap. Along these valleys deeper layering of the polar deposits are often exposed making it possible to study the stratigraphy of the upper part of the polar cap [1]. We focused our attention on a 140 km long and 500 m high scarp located in the North-Western edge, facing Olympia Planum, and where part of the North Polar Layered Deposits (NPLD) are exposed. NPLD deposits are finely layered and laterally continuous sequence of light and dark strata with sporadic unconformities in between, whose periodicity has been attributed to climatic and orbital variations [2]. In the polar cap, Tanaka et al. [3] has distinguished different polar units by means of surface image interpretation, hence our scarp exposes Planum Boreum 1 unit overlapped by Planum Boreum 3 unit, both composed of variable ice/dust content, but different thickness. Putzig et al. [4] identified instead seven units inside the polar cap on the basis of the pattern of radar reflections in the radargram-based stratigraphy thanks to the data provided by SHARAD. The stratigraphic sequence of our interest correlates with the upper part of the packet-inter-packet sequence of the unit G by Putzig et al. [4]. The aim of our work is to relate the composition and stratigraphy of the visible layered deposits with the subsurface radar reflectors, using the data acquired by the NASA Mars Reconnaissance Orbiter instruments. Data selection: We performed stratigraphic and geomorphologic interpretation on images of the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE); band ratios and spectral signatures on a hyperspectral cube of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM); subsurface reconstructions on radar reflectors obtained by the Shallow Radar (SHARAD). The integration of the results obtained by such a multi-score data-set underlies the possibility to join the SHARAD stratigraphy with the stratigraphic record recognisable at the surface including its compositional variability (Fig.1). Fig.1 – Data-set: MOLA DEM (a), CTX image (b), CRISM cube (c), HiRISE images (d, e) and SHARAD radargram tracks (f, g, h, i). Black rectangle in the North Polar Cap region shows the study area. Spectral analysis: Spectra for five Regions of Interest (ROIs) of about 50 pixels were acquired and are shown in Fig.2a-b. Fig.2 – (a) Regions of Interest over CRISM image detail; (b) Plot of five ROI average spectra: each colour line represents a ROI spectrum (continuum is removed). The exposed stratigraphy is composed of different amount of dry ice, water ice and basaltic dust [3]. Spectra A and B are well distinguishable, whereas the signatures of C, D and E appear similar, indicating comparable compositions. Spectrum A exhibits well developed water-ice absorption bands (1.5 and 1.95 µm), less development of same peaks might imply an increase of dry ice content. The 1 µm peak (water ice) is well visible in both A and B spectra, but less evident in C, D and E. Multiple absorptions at 1.65 and 2.06 µm, associated to CO2, are well visible in C, D and E. Other absorption bands (at 0.50, 1.02 and 2.30 µm for example) can be related to femic and aqueous alteration minerals. Spectrum A is similar to the signature of pure water ice, with less altered minerals, while C, D and E appear to be characterized by dry ice and femic minerals. Spectrum B appear to be transitional between these two end-members. Spectral indexes: Spectral indexes were produced using CRISM Analysis Toolkit (CAT) [5]. Indexes allowed us to create false colour images to highlight the presence/absence of specific minerals. Example of these are shown in Fig. 3 (see FED for the index definition). Fig.3 – Two false colour images created with spectral indexes (a) BDI1000VIS_BD15002_BD1435 representing ice compositions and (b) OLINDEX3_LCPINEX2_RBR to highlight mineral composition. Mapping and correlation to radar reflectors: Geological units were identified on CRISM and CTX data on the basis of morphology, composition, albedo and their stratigraphic relationship. Fig.4 displays the mapped units. Fig.4 – Geological map and relative units. WI-units: water-ice-rich deposits (blue), WF-unit: water ice and femic minerals deposits (light blue); DF-units: dry ice and femic minerals deposits (green); DI-units: dry-ice-rich deposits (yellow); Aeolian deposits (red); Gravitational deposits (purple). Fig.5 shows the geological units correlated with radargrams features. Variations of dielectric constant among strata are due firstly to presence of water ice in the surficial layers and dry ice in deeper ones, secondly to different amount of dust in radar units. These affect the signal reflectance: stronger if it is from water-ice layers. Additionally, high content of dust significantly decrease the radar signal, so units appear darker [4] [6]. The lines in Fig.5 represent lower contact of the geological units. Fig.5 – Correlation between geological units and radar reflectors. The colours of units are the same of geological map (vertical axis in time). Section track is shown in Fig.1. Discussion and conclusions: We provide a detailed compositional and geometrical characterization (using CRISM, HiRISE, CTX) of outcropping layered deposits of the North Polar Cap, to evaluate the potential for performing sound stratigraphic correlations with the subsurface reflectors identified in SHARAD radargrams. At a scale of single layers, compositional variations of basaltic dust content in the stratigraphic sequence were identified. This variability is visible especially in dry-ice-rich layers. Basaltic dust showed aqueous alteration, especially in water-ice-rich strata. Acknowledgments: We acknowledge support from the EU’s H2020 research and innovation program under grant agreement N° 871149 (GMAP). References: [1] Masse, M. et al. (2012) Earth and Planetary Science Letters, 317, doi: 10.1016/j.epsl.2011.11.035; [2] Byrne, S. (2009) Annual Review of Earth and Planetary Science, 37, doi: 10.1146/annurev.earth.031208.100101; [3] Tanaka, K. et al. (2008) Icarus, 196(2), doi: 10.1016/j.icarus.2008.01.021; [4] Putzig, N. et al. (2009), Icarus, 204(2), doi: 10.1016/j.icarus.2009.07.034; [5] Viviano-Beck, C. et al (2014), Journal of Geophysical Research, 119(6), doi: 10.1002/2014JE004627; [6] Lauro, S. et al. (2012), Icarus, 219(1), doi: 10.1016/j.icarus.2012.03.011.

Lava tubes, or pyroducts [1], are a peculiar type of lava caves originating from basaltic lava flows. These conduits are very efficient thermal structures that allow the lava to cover long distances before cooling down. Lava tubes, are typical features of lava fields found in volcanic-shield islands (e.g. Hawai’i, Canaries, Iceland, etc.) and intracontinental plateaus characterised by gentle slopes ( These structures are easily recognizable from the surface through the presence of skylights and roof collapses aligned in pit-chains, tracing the path of the underground conduit (Fig. 1). Analogous aligned collapses were seen on the surfaces of Mars and the Moon [2]. Thus, the great interest in studying large terrestrial lava tube systems is largely driven by their analogy with their extra-terrestrial equivalents. Figure 1: Comparison of lava tubes from different rocky bodies of the Solar System. From the left: Earth (Undara system, Australia), Mars (Arsia Mons region) and the Moon (Gruithuisen crater). The main difference between structures of different planetary bodies are due to intrinsic physical characters of the parental body and above all gravity. Indeed, a weaker gravity (as in the case of Mars and the Moon) results in higher effusion rates and, thus, larger lava flows and tubes (Fig. 1). This has led to pyroducts which are two or three orders of magnitude smaller in diameter on Earth (10 - 30 m) than on Mars (250 - 400 m) and the Moon (500 - 1100 m) [5]. Despite this different scaling, the largest lava tubes on Earth are considered to be very useful analogues to their extra-terrestrial counterparts. A clear understanding of how large pyroducts form and evolve remains elusive, even on Earth. Within this context, our work aims to identify the processes that shaped the formation of terrestrial lava tubes. Among the most studied pyroducts, the La Corona system (Lanzarote, Canary Islands, Spain) stends out for its geological context within the Canary Island Seamount Province (CISP) on which long-term and spatially focused volcanic activity developed over a poorly mobile tectonic plate. During the last 30 Ma, the absolute motion of the African plate has been nearly stationary (less than 20 mm/yr) [3]. This environment identifies the Canaries as one of the best terrestrial analogues of the Martian one-shell plate volcanism [4], and the impressive dimensions of La Corona lava tube (~9.7 km of total cave development, and a width reaching up to ~28 m for some of its sections) make it one of the most suitable lava tube for interplanetary analogies [6]. In order to understand the origin, evolution and degradation of the La Corona pyroduct, we have carried out a study of the satellite images of the northern region of Lanzarote, followed by field exploration of inner portions of the La Corona lava tube and adjacent areas. Combining terrestrial laser scanner (TLS) technology with field observations and geochemical analyses of the pre-existing lava enabled us to reconstruct the three-dimensional geometry of the lava tube system, the subsurface horizon through which it starts developing, and the volcanic series into which the pyroduct carved its path. What makes this inflated lava tube so interesting is the presence, between the flows the tube has crossed, of a red pyroclastic layer, resulting from the initial Strombolian activity of La Corona vent [7]. This weak layer of pyroclastic material played a major role in the development of the lava tube (Fig. 2), facilitating the emplacement of the inflation process and the excavation that followed [6]. By analogy, similar geological settings could be favourable for the formation of lava tubes on rocky bodies like Mars and the Moon since the volcanic sequences on such bodies can be frequently interleaved by either weak pyroclastic and regolith layers. Other influent parameters controlling erosion include slope variations of the paleo-surface (i.e., knickpoints), and the lava physical properties, both to be well investigated on terrestrial analogues to understand their role even on planetary contexts. Figure 2: Thermo-mechanical erosional stages of the lava tube in cross-sections. a) The primary effusive phase has covered the pyroclastic deposit of the initial Strombolian event; b) the inception of the tube by inflation starts exploiting the pyroclastic layer; c-d-e) progressive erosion and enlargement of the tunnel; f) post-cooling phase. On the walls are visible different layers of linings and flow ledges. The floor is covered by blocks and debris, remnants of the breaking down of the ceiling and lining walls. References [1] Coan, T. (1844). Missionary Herald. [2] Haruyama, J. et al. (2012) Trans. JAPAN Soc. Aeronaut. Sp. Sci. Aerosp. Technol. JAPAN 10. [3] Gaina, C. et al. (2013). Tectonophysics, 604, 4-25. [4] Meyzen, C. M., et al. (2015) Geol. Soc. London, Spec. Publ. 401. [5] Sauro et al. (2020) Earth-Science Rev. [6] Tomasi, I. et al. (pending) JGR – Solid Earth. [6] Carracedo, J. C. et al. (2003) Estud. Geol. 59.

Galileo Regio is a dark terrain of Ganymede extending approximately from 180°-120° W to 0°-60° N that shows high crater density and morphotectonic structures called furrows. Such structures are kilometric-scale brittle troughs bounded by high albedo rims and a low albedo floor, and arranged with circumferential and radial setting at the regional scale [1]. Furrows are generally interpreted as the remnants of a multi-ring impact basin similar to the Valhalla basin on Callisto [2]. Galileo Regio shows two main settings of the furrows, which allow their classification into two systems: the concentric furrows of Lakhmu Fossae system, which is crosscut by the radial furrows of the Zu Fossae system [3]. In addition, Galileo Regio shows local-scale structures that rework the pristine morphology of the Lakhmu Fossae furrows. In this contribution, we investigate the furrows of Galileo Regio at both regional- and local-scale to unravel the tectonic evolution of the dark terrain. We perform a structural mapping and geostatistical analyses of the furrows in Galileo Regio, identifying their hierarchy and tectonic setting originated by regional-scale kinematics. Structure attributes such as structure length, sinuosity, azimuth, spacing within the adjacent structures, have been quantitatively characterized and allow to perform the azimuthal distribution, the Length/Spacing [5] and the paleo-stress analyses [6]. Such analyses allow to identify the structural systems and to infer the past stress fields that affected Galileo Regio (maximum and minimum horizontal stress, i.e., SHmax and Shmin, respectively). A total of four structural systems have been recognized within Galileo Regio: i) the already known Lakhmu and Zu Fossae; and ii) the Lineated system and Precursor system, proposed by this work for the first time (Fig. 1). Such systems are the result of phases of the tectonic activity that affected Galileo Regio during the geologic history of Ganymede. We identify the sequence of such phases that allow to produce an evolutionary tectonic model (Fig. 2): i) t0 represents a NW-SE extension that formed the Lineated system; ii) t1 represents the impact that originated a multi-ring basin [3, 7], i.e., the Lakhmu Fossae; iii) t2 shows the extensional activity responsible for the formation of the light terrain of Uruk Sulcus [8] and for the formation of the extensional structures of the Precursor system; iv) t3 represents the kinematics consistent with the right-lateral transpression that has affected Uruk Sulcus [4] and formed the Zu Fossae; and v) t4 presents a right-lateral strike-slip that contributes to the formation of the Precursor system. The obtained results and the presented model will be used for the scientific preparation of dedicated high-resolution observations that will be taken with the JANUS instrument [9] onboard the JUICE mission [10]. Acknowledgments: The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References: [1] Patterson, W. et al. (2010). Icarus 207,845–867; [2] McKinnon, W.B. and Melosh, H.J. (1980). Icarus 44 (2), 454–471; [3] Prockter, L.M., et al. (2000). Journal of Geophysical Research: Planets, 105(E9), 22519-22540; [4] Kersten, E., et al. (2021). Planetary and Space Science, 206, 105310; [5] Rossi, C., et al. (2018). Tectonophysics 749, 72–87; [5] Delvaux, D., and Sperner, B. (2003). Geol. Soc., London, Special Publications, 212(1), 75-100; [7] Hirata, N., et al. (2020). Icarus, 352, 113941; [8] Pappalardo, R.T., et al. (1998). Icarus, 135(1), 276-302; [9] Palumbo, P., et al. (2014). 45th LPSC Meeting. Abstract #2094; [10] Grasset, O., et al. (2013). Planetary and Space Science, 78, 1–21.

Silicon nanochannel plates (NCPs) are efficient positron to positronium converters and are employed as sources of abundant cold positronium. Characterization of the emitted positronium energy spectrum is crucial to assess the NCP performance and support their further optimization. We present here a Time-of-Flight (ToF) system optimized to measure the energy spectrum of positronium produced by NCP converters held at cryogenic temperatures. The ToF-apparatus was tested by implanting 7 keV positrons into NCPs at room temperature before performing ToF experiments using positron implantation energies of 7 and 11 keV into NCPs held at 20 K. At these conditions we succeeded in determining the energy spectrum of the positronium escaping from the nanochannels into the vacuum down to an energy of 10 meV.

Landslides are almost ubiquitous in the Solar System, with rockfall and avalanches that are observed also on other terrestrial bodies, such as the Moon (Bart, 2007; Xiao et al., 2013), Mars (Crosta et al., 2018; Lucchitta, 1987) and Mercury (Malin & Dzurisin, 1978). Landslides and mass movements have been observed also on planetary bodies characterized by extremely low gravity, as for example asteroids’ surfaces of Vesta and Ceres (Otto et al., 2013; Schmidt et al., 2017). The behaviour of mass movements on these bodies is poorly studied due to the difficulties of recreating low-gravity experimental conditions or identifying satisfactory analogues for the involved materials. In fact, the overall dimensions and morphology of the resulting deposits (area, width and length) are often the only features that can be studied and compared between different sites or planetary bodies, due to the limitations in DEMs resolution and suitable imagery. In particular, plots of the H/L ratio (drop height/runout length) provide a proxy for the average friction coefficient and have been the subject of many comparative investigations.With the aim of providing a more consistent picture of the possible outcomes of landslides and other mass movements we hereby describe a fully parametric numerical framework based on ESyS-Particle software (Abe et al., 2004; Tancredi et al., 2012), which has been specifically designed to explore the outcomes of fragmenting grain flow under different model assumptions. The framework has been designed to leverage modern distributed computing technologies to increase the number of simulations that can be executed in parallel, and to maximize the usage of already-available computing hardware. Preliminary results and the limitations are also presented and discussed.This framework will support the parametrization of numerical models for the upcoming observations of mass-movements of the future JUICE-JANUS camera observations on Jupiter Icy Moons.Acknowledgements: The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

The surface of Ganymede, which is the biggest satellite of Jupiter, shows strong tectonic deformation affecting both its geologic units, i.e., the younger light terrain and the older dark terrain. The dark terrain is characterized by low albedo, high crater density and furrows, which are morphotectonic structures formed by brittle deformation. Furrows are straight to curved fragments of troughs, with high albedo rims that bound a low albedo floor. Two systems have been recognized at the regional scale, which are the Lakhmu Fossae, whose furrow setting follows a concentric pattern resulting from a multi-ring impact basin, and the Zu Fossae, which follows a radial setting. In addition, local scale structures have been identified superimposed on the regional scale systems, leading to the reworking of the pristine structures. In this contribution, we investigate the tectonic evolution of the furrows in Galileo Regio (approximately from 180°-120° W to 0°-60° N), at both regional and local scale, with the identification of the tectonic events responsible for the deformation of this dark terrain. We performed a structural mapping and geostatistical analyses of the attributes of the mapped structures, such as the length, sinuosity, azimuth, spacing within the adjacent structures. Their quantification allows us to recognize a total of four structural systems within the area and to unravel the paleo-stress fields that have originated them. We prepared an evolutionary tectonic model of the furrow systems of Galileo Regio that shows the dynamics and the induced kinematics. We suggest that Galileo Regio underwent a sequence of tectonic phases associated with extensional and strike-slip regimes, these latter consistent with the kinematics that affected the light terrain of the adjacent Uruk Sulcus. This work advances the assumption that the dark terrain has been later affected by the same tectonics that deformed the light terrain and confirms the rejuvenation of the dark terrain towards a possible future transformation into light ones. The obtained results will be used for the scientific preparation of dedicated high-resolution observations that will be taken with the JANUS instrument onboard JUICE mission.Acknowledgments: The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

The surface of Ganymede, the largest satellite of Jupiter, consists of a strongly deformed and tectonized brittle icy crust which stands on top of a large liquid body, possibly a global subsurface ocean. In fact, by means of multiple Galileo orbital mission flybys both geophysical and structural geology measurements constrained the average icy shell thickness to be comprised between 100 and 150 km. The surface can also be divided into two main units: bright and dark terrains depending on their relative albedo, impact crated density and tectonization. Furrows and grooves represent most of the structures on Ganymede’s surface, which are essentially extensional faults, dilatant structures and strike slip faults. We hereby present a 3D geologic modelling of the region of Uruk Sulcus based on structural mapping (Rossi et al., 2020) and using techniques borrowed from oil and gas exploration.The Uruk Sulcus area is a NW-SE bright terrain of ~400 km by ~2500 km size located between 150W-180W and 30N-10S, and characterized by pervasive sets of parallel/sub-parallel grooves of 10s-to-100s km length. The most favored hypotheses relate its formation either to a purely extensional context forming a tilt-block normal faulting, or to crustal necking with creation of horsts and grabens, or to be the result of a major dextral transpression. The overall structural framework and the fault geometries (in the form of 3D meshes) was created according to existing literature and with geologic interpretation and anchored on the surface to the global DEM by Zubarev et al., (2017), and at depth to the brittle ice-subsurface ocean interface to an average value of 120 km. This ice thickness value was obtained, among other methods, also by analyzing the scaling laws ruling the spatial distribution and the length size distribution of grooves and extensional structures, which proved to be fractal. One of the implications of this fractal behavior is that the structures themselves can be interconnected forming a percolating network favoring fluid circulation and connecting the subsurface ocean with the surface (see Lucchetti et al., 2020 and references therein).By means of 3D modelling, we were able to isolate volumes of ice encompassed by major strike-slip structures of Uruk Sulcus and to exploit the scaling laws ruling the structures within such areas, in order to numerically simulate a DFN (digital fracture network) crosscutting the entire volume of ice.This way we could analyze the volume of ice crosscut by such fracture network, and to predict the locations at surface where percolation is favored. Acknowledgments: The activity has been realized under the ASI-INAF contract 2018-25-HH.0.

We provide details about the procedure employed for the three-dimensional geological modelling of the lobes of comet Churyumov-Gerasimenko (67P). The two lobes of 67P are characterized by well visible terraces and elongated cliffs that revealed a pervasive layering arranged in an onion-like fashion. None of the layers can be traced for a continuity large enough to provide a means of stratigraphic correlation. Therefore, an explicit modelling approach of the layered structure is not easily applicable. We show how a very simple modelling strategy based on implicitly-defined analytical surfaces (spheres or ellipsoids), and requiring very limited operator decision-making, can be successfully applied to produce a geological model that easily fits the available scattered attitude observations. Our formulation has the advantage of providing a small set of parameters with a precise geometrical meaning that can be compared with other parameters of the lobes (i.e. center of ellipsoids and center of mass). The presented method originates outside commercial geological modelling software packages and required devising some ad-hoc solutions for the visualization of the resulting models in comparison with observations made on OSIRIS images. Some extracts of the visualization code, helpful for applying this procedure in similar operational contexts, are also presented.

Bilobate comets—small icy bodies with two distinct lobes—are a common configuration among comets, but the factors shaping these bodies are largely unknown. Cometary nuclei, the solid centres of comets, erode by ice sublimation when they are sufficiently close to the Sun, but the importance of a comet’s internal structure on its erosion is unclear. Here we present three-dimensional analyses of images from the Rosetta mission to illuminate the process that shaped the Jupiter-family bilobate comet 67P/Churyumov–Gerasimenko over billions of years. We show that the comet’s surface and interior exhibit shear-fracture and fault networks, on spatial scales of tens to hundreds of metres. Fractures propagate up to 500 m below the surface through a mechanically homogeneous material. Through fracture network analysis and stress modelling, we show that shear deformation generates fracture networks that control mechanical surface erosion, particularly in the strongly marked neck trough of 67P/Churyumov–Gerasimenko, exposing its interior. We conclude that shear deformation shapes and structures the surface and interior of bilobate comets, particularly in the outer Solar System where water ice sublimation is negligible. The shape and internal structure of bilobate comet 67P is controlled by shear deformation inducing mechanically driven erosion along shear fracture networks, according to a 3D analysis of images from the Rosetta mission.

Ganymede’s dark terrain represents the older geologic unit of the satellite, subsequently crosscut by swaths belonging to the younger light terrain. Compared to the light terrain, the dark terrain shows low albedo, higher crater density and morphotectonic structures called furrows. These structures are radial or circumferential fragments of troughs bounded by high albedo rims and a low albedo floor, generally thought being the remnants of a multi-ring impact basin similar to the Valhalla or Asgard basins on Callisto [1, 2]. In particular, in Galileo Regio and Marius Regio, the furrow systems show a concentric pattern centered at around 20° S 180° W, which is the assumed location of the crater formed by an impactor of 50-150 km in radius [3, 4]. Many furrows have been preserved until the present day in their pristine form, while some of them have acted as zones of weakness re-used by subsequent tectonic deformation. For this reason, they show a more complex morphology and are likely considered as precursors of light grooved terrain formation. In this contribution, we perform a structural mapping at the regional scale of the furrows in Galileo Regio, identifying their hierarchy and tectonic setting originated by the regional scale kinematics. Our mapping reveals that transpression, already recognized in the adjacent Uruk Sulcus area [5], affects the dark terrain of Galileo Regio, too. We mapped the structures in Galileo Regio (Fig. 1) by considering their spatial distribution and crosscutting relationships. In addition, we mapped the local-scale fractures that have tectonically modified remnants of furrows by leaving a deformation zone with higher albedo with respect to the surrounding dark material. These fractures show geometries and features associated with the Riedel shear, and synthetic and antithetic structures that form in strike-slip regimes [6]. The NE-SW and NW-SE trending structures that crosscut the concentric furrow systems occur from Uruk Sulcus to approximately 60° N and have been recognized as conjugate (Fig. 2). Hence, the setting of the mapped furrows and their associated structures allows identifying the (paleo)stress field that has affected this dark terrain. We infer that Galileo Regio has been characterized by regional kinematics consistent with the right-lateral transpression that has affected Uruk Sulcus. It is possible to recognize a ≈ NE-SW trending maximum horizontal stress (σh max) responsible for a shortening associated with strike-slip in the area that extends from 180°-120° W to 0°-60° N. Therefore, we can assume that the dark terrain has been deformed by the same tectonic processes that have formed the light grooved terrain of Uruk Sulcus. This work confirms the key role that transpression has played in the leading hemisphere of Ganymede and the reactivation (and possibly the inversion) of the furrows in Galileo Regio, which have followed a deformation history beginning from an impact origin to a tectonic remodeling. Further geo-statistical analysis will be performed to support this reconstruction. Obtained results from this study will be used for the scientific preparation of dedicated high-resolution observations that will be taken with the JANUS instrument [7] onboard JUICE mission [8]. Acknowledgements: The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References: [1] McKinnon, W.B., Melosh, H.J., 1980. Evolution of planetary lithospheres: evidence from multiringed structures on Ganymede and Callisto. Icarus 44 (2), 454–471. https://doi.org/10.1016/0019-1035(80)90037-8. [2] Prockter, L. M., Figueredo, P. H., Pappalardo, R. T., Head, J. W., & Collins, G. C. (2000). Geology and mapping of dark terrain on Ganymede and implications for grooved terrain formation. Journal of Geophysical Research: Planets, 105(E9), 22519-22540. [3] Prockter, L.M., Collins, G.C., Murchie, S.L., Schenk, P.M., Pappalardo, R.T., 2002. Ganymede furrow systems as strain markers: implications for evolution and resurfacing processes. In: 33rd Lunar and Planetary Science Conference, Abstract #1272. Lunar and Planetary Institute, Houston. [4] Hirata, N., Suetsugu, R., & Ohtsuki, K. (2020). A global system of furrows on Ganymede indicative of their creation in a single impact event. Icarus, 352, 113941. [5] Rossi, C., Cianfarra, P., Salvini, F., Mitri, G., Massé, M., 2018. Evidence of transpressional tectonics on the Uruk Sulcus region, Ganymede. Tectonophysics 749, 72–87. https://doi.org/10.1016/j.tecto.2018.10.026 [6] Fossen, H. (2010). Structural geology. Cambridge, UK: Cambridge University Press. [7] Palumbo, P. et al. 2014. JANUS: The Visible Camera Onboard the ESA JUICE Mission to the Jovian System. 45th LPSC Meeting. Abstract #2094. [8] Grasset, O., Dougherty, M. K., Coustenis, A., Bunce, E. J., Erd, C., Titov, D., et al. (2013). JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system. Planetary and Space Science, 78, 1–21.

The surface of Ganymede has first been observed by the Voyager missions in 1970’s highlighting the presence of a deeply tectonized environment. Galileo Mission in 1996 imaged the Jovian satellites also providing at high-resolution images at targeted places during its flybys. Ganymede's crust is mainly composed of a brittle ice overlying a subsurface ocean, whose depth was constrained to be ~100-150 km [1]. The surface of Ganymede can be subdivided into dark and bright terrains depending on their crater density, differences in albedo and surface morphology. The latter is driven mainly by tectonization, characterized by presence of furrows and grooves. These structures represent the brittle deformation of the icy shell. We focus on the bright terrain located in the region of Uruk sulcus, a NW-SE terrain ~400 km wide and ~2500 km long located between 150W -180W and 30N-10 S strongly deformed by sets of parallel/sub-parallel (often evenly-spaced) grooves both at a regional and local scale. The presence of such structures in light terrains is hypothesized to be determined by tilt-block normal faulting [2], by crustal necking similar to mid ocean ridges [3], or by major dextral transpression, as in the case of Uruk sulcus [4]. It has been demonstrated that such structures show a fractal spatial clustering, and represent a preferential pathway for fluid from the ~100-150 km-deep ocean [1]. We are testing different 3D geomodelling approaches hence deriving more information on both the volume of the fractured brittle ice crust and the most favored location of actual percolation. Nowadays 3D geomodelling is approaching the planetary geology framework, as testified by the outcomes of the PLANMAP Horizon 2020 project [5, 6, 7, 8, 9]. With information either derived from direct surface observations and measurements and/or also constrained by geologic interpretation, it is possible to derive a 3D geomodel of the subsurface that represents specific geologic properties or geometries. We built a preliminary Uruk sulcus model geometry using the global DEM [10] as an initial, low-resolution surface textured with the controlled global mosaic from DLR of Voyager 1, 2 and Galileo images at an average resolution of 359 m/pixel. This served as an upper surface boundary to project the structural mapping from Rossi et al., (2020) and also as an anchor point to reconstruct the major Uruk sulcus structures. As a lower model boundary, the icy crust is constrained at depth by the ocean-ice interface. We used the depth value calculated using the fractal clustering analysis in [1] related to Uruk sulcus. We were able to reconstruct a preliminary qualitative model of the fault geometries for GUS1 (Grooves of Uruk Sulcus 1) system deformation ([4] as a large-scale structural framework. As a first test we focused on a smaller region in the sigmoidal area named S2 and containing the GUS3 (see white square in figure 1b). We extracted a voxel-based volume of icy crust comprised between the surface, the lower ocean-ice interface bounded by the major fault lines delimiting GUS3. At this location a major set of high-angle extensional structures at NE-SW arranged in a right-stepping en-echelon geometry are present, together with other two lower in number grooves families with NW-SE and NS orientations. With this voxel-based volume and knowing the scaling laws of the size distributions of these feature and their azimuths, it is possible to simulate a DFN (Digital Fracture Network) for each of the fractures’ families (fig. 2a). With the DFN it is possible to infer possible high-connectivity locations in the fractured ice volumes and their location at the surface (figure 2b). Further quantitative analysis work on the DFN and the volume of ice will allow to simulate the movement along the major structures backwards and forward in time in order and to capture the strain in the ice volume by incorporating its rheological parameters, and also test the transpression vs necking approach. The 3D geomodelling approach appears as a promising tool not only for scientific analysis but also to identify interesting target of future JUICE observation, where resurfacing or deep fluid expulsions could be more favored. Figure 1: a) The structural map by[4] with the families of grooves (GUS). In b) the 3D geometric reconstruction of the larger GUS1 structures. This analysis is focused in the white box Figure 2: In a) the modelled DFN with the three families of major structures and in b) voxel-based volume showing areas at higher connectivity. Acknowledgements: The activity has been realized under the ASI-INAF contract 2018-25-HH.0. References: [3] Pizzi, A., Domenica, A.D., Komatsu, G., Cofano, A., Mitri, G., Bruzzone, L., 2017. Spreading vs. Rifting as modes of extensional tectonics on the globally expanded Ganymede. Icarus 288, 148–159. https://doi.org/10.1016/j.icarus.2017.01.034 [4] Rossi, C., Cianfarra, P., Salvini, F., Mitri, G., Massé, M., 2018. Evidence of transpressional tectonics on the Uruk Sulcus region, Ganymede. Tectonophysics 749, 72–87. https://doi.org/10.1016/j.tecto.2018.10.026 [1] Lucchetti, A., Rossi, C., Mazzarini, F., Pajola, M., Pozzobon, R., Massironi, M., Cremonese, G., 2021. Equatorial grooves distribution on Ganymede: Length and self-similar clustering analysis. Planetary and Space Science 195, 105140. https://doi.org/10.1016/j.pss.2020.105140 [2] Pappalardo, R.T., et al., 1998. Grooved Terrain on Ganymede: First Results from Galileo High-Resolution Imaging. Icarus 135, 276–302. https://doi.org/10.1006/icar.1998.5966 [7] Pozzobon, R., Penasa, L., De Toffoli, B., Rossi, A. P., & Massironi, M. (2020). 3D geo-models based on multiple datasets on Mars (implicit or explicit modelling) (Public D6.1; Planmap Deliverable). [8] Penasa, L., Pozzobon R., Rossi, A. P., Massironi, M., (2020), 3D geo-models based on multiple datasets on the Moon (implicit or explicit modelling) (Public D6.2; Planmap Deliverable). [9] Pozzobon, R., Penasa, L., Massironi, M., Ferrari, S., (2021) 3D geo-models based on multiple datasets on Mercury (explicit modelling) (Public D6.3; Planmap Deliverable). [6] Massironi, M., Rossi, A. P., and the PLANMAP Consortium, PLANMAP Final report 2021 [5] Massironi, M. et al., 2018. Towards integrated geological maps and 3D geo-models of planetary surfaces: the H2020 PLANetary MAPping project, in: EGU General Assembly Conference Abstracts, EGU General Assembly Conference Abstracts. p. 18106. [10] Zubarev, A., Nadezhdina, I., Brusnikin, E., Giese, B., Oberst, J., 2017. A search for Ganymede stereo images and 3D mapping opportunities. Planetary and Space Science 146, 40–54. https://doi.org/10.1016/j.pss.2017.07.021

Rembrandt is a 715 km-diameter basin on Mercury centered at 32.89°S latitude and 87.86°E longitude. This crater constitutes a remarkable example of the stratigraphic variability on Mercury. The uppermost smooth plains of volcanic origin, which are temporally unrelated to the impact event, have been distinguished by the surrounding smooth plains utilizing spectral information. The basin is crosscut by a prominent NE-SW thrust system more than 1000 km long, named Enterprise Rupes (Ferrari et al., 2015; Galluzzi et al., 2015; Semenzato et al., 2020), attributed mainly to crustal shortening induced by global contraction (see Semenzato et al., 2020 and references therein). This consists of a set of lobate scarps and wrinkle ridges with inverse to transpressional kinematics (Massironi et al., 2015). The aim of this work, as part of the PLANMAP Horizon 2020 project, is to use all the available information on the site to provide a comprehensive 3D model of both the structural setting and the thicknesses of the main units of the Rembrandt basin infilling using explicit modeling approach. The principle of three-dimensional explicit modelling relies on the creation of 3D surfaces based on geologic observations and constraints. While implicit modelling and its effectiveness rely on the amount of available data both on the surface and the subsurface to provide a mathematical solution that satisfies all the constraints, the explicit geological modelling implies a more extended geologic interpretation based on the available data which is subject to the operator’s experience and is essentially based on the construction of several interpreted cross-sections to be then interpolated generating mesh surfaces. The advantage is that such type of geologic modelling can be applied in areas with scarcity of data, especially related to subsurface constraints. In the case of the Rembrandt basin, we mainly based our reconstruction on the geo-stratigraphic map and geologic cross-section from Semenzato et al. (2020). Additional constraints, regarding fault kinematics and fault plane geometry, were provided by Galluzzi et al. (2015) and Crane (2020). As a basemap, we used the MESSENGER MDIS global mosaic at 166 m/pixel together with the MDIS global DEM (665 m/pixel), both of them available in the USGS repositories, with the same Lambert Conformal Conic (LCC) projection of the geo-stratigraphic map. In Rembrandt basin two different infillings - the YIP (Young Interior smooth Plains) and OIP (Older Interior smooth Plains) units - overlay the IT (para-autochtonous intracrater plains) base unit. The thickness of these units was estimated with several methods in Semenzato et al., (2020), among which the presence of impact craters excavating and exposing the inner basin stratigraphy. We used such craters for the construction of the interpreted cross-sections in complement to the one by Semenzato et al., (2020). These were subdivided into two intersecting sub-parallel sets. The interpreted subsurface horizons were used for mesh interpolation together with the geologic contacts between the different units on the surface creating meshes representin ghte top of the YIP, OIP and IT basin infilling units. The volume between them was then calculated. The structural modelling was carried out using the structural mapping from Semenzato et al., (2020) and Ferrari et al., (2015). The faults’ vergence and their angles were extracted both thanks to the illumination conditions on the image mosaic and topography, to the measurements provided by Galluzzi et al., (2015) on displaced impact craters and to the work by Crane (2020) and Massironi et al., (2015). This way we were able to model the Enterprise rupes thrust geometry, its splays and backthrusts as well as contractional lobate scarps and extensional radial features within the basin infilling units. Although requiring a certain degree of assumptions especially on planetary bodies, the 3D geomodelling proves to be a useful tool in order to check surface interpretations that might change once set into 3D environment and refine volume calculations and 3D shape of geologic units. Follow up investigations will focus on forward and backwards modeling work on the activity of the Enterprise Rupes system. Figure 1: in a) the mesh construction for the main Enterprise rupes structure, constrained with surface mapped lineaments and anchored on the geologic cross-section. In b) the tetrahedral volumetric mesh representing the two events of Rembrandt basin infilling. In c) the structural and stratigraphic geomodel of Rembrandt basin (https://skfb.ly/6ZqtI). Acknowlegements: This research was supported by the European Union’s Horizon 2020 under grant agreement No 776276‐PLANMAP. References: Crane, K., 2020. Structural interpretation of thrust fault-related landforms on Mercury using Earth analogue fault models. Geomorphology 369, 107366. https://doi.org/10.1016/j.geomorph.2020.107366 Ferrari, S., Massironi, M., Marchi, S., Byrne, P. K., Klimczak, C., Martellato, E., & Cremonese, G. (2015). Age relationships of the Rembrandt basin and Enterprise Rupes, Mercury. Geological Society, London, Special Publications, 401(1), 159–172. https://doi.org/10.1144/SP401.20 Galluzzi, V., Di Achille, G., Ferranti, L., Popa, C., & Palumbo, P. (2015). Faulted craters as indicators for thrust motions on Mercury. Geological Society, London, Special Publications, 401(1), 313–325. https://doi.org/10.1144/SP401.17 Massironi, M., Di Achille, G., Rothery, D. A., Galluzzi, V., Giacomini, L., Ferrari, S., Zusi, M., Cremonese, G., & Palumbo, P. (2015). Lateral ramps and strike-slip kinematics on Mercury. Geological Society, London, Special Publications, 401(1), 269–290. https://doi.org/10.1144/SP401.16 Semenzato, A., Massironi, M., Ferrari, S., Galluzzi, V., Rothery, D. A., Pegg, D. L., Pozzobon, R., & Marchi, S. (2020). An Integrated Geologic Map of the Rembrandt Basin, on Mercury, as a Starting Point for Stratigraphic Analysis. Remote Sensing, 12(19), 3213. https://doi.org/10.3390/rs12193213

Mounds are positive relief features that can be ascribed to a variety of phenomena; they can be related to monogenic edifices due to spring or mud volcanism, rootless cones on top of lava flows, pingos and so on. In the case of sedimentary or spring case of mud extrusion, these mounds can be widespread regionally and/or contained in large complex craters, often in populations of several hundreds or thousands . Previous work on detection of such mounds in the Mars Arabia Terra involved exploiting morphometric parameters and mapping them onto Digital Terrain Models . In this work, we take a step further and develop more general methods to automatically detect them without explicitly defining the topographical features. We achieve this by using a generative framework trained in an adversarial fashion to produce realistic mappings with only a small number of training samples. Further, we introduce a terrain simulator based on this framework that learns the terrain simulation parameters, and allows us to induce domain specific knowledge automatically into the network. Our key results indicate that learning latent representations based on simulations can offer improvements in detection accuracy, while making it more robust to changing terrain scenarios.

The objective of this work is to present a new Free and Open-Source Software (FOSS) to read and convert to multiple data formats data acquired by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express (MEX) orbiting Mars since 2005.MARSIS is an orbital synthetic aperture radar sounder that operates with dual-frequency between 1.3 and 5.5 MHz and wavelengths between 230 and 55 m for subsurface sounding. The Experiment Data Record (EDR) and Reduced Data Record (RDR) datasets are available for download on public access platforms such as the Planetary Science Archive fo ESA and the PDS-NASA Orbital Data Explorer (ODE).These datasets have been widely used for different research, focused to study the subsurface of the red planet up to a depth of a few kilometres, and especially for studying ice caps and looking for subsurface ice and water deposits, producing relevant results. (Lauro et al., 2020; Orosei et al., 2020)The Python tool presented here is capable of reading common data types used to distribute MARSIS dataset and then converting into multiple data formats. Users can interactively configure data source, destination, pre-processing and type of outputs among:Geopackages: for GIS software, is a single self-contained file containing a layer in which are stored all parameters for each file processed. Numpy array dump: for fast reading and analysis of original data for both frequencies. PNG images: for fast inspections, created for each frequency, and saved. Image pre-processing filters, such as image-denoising, standardization and normalization, can be selected by user. SEG-Y: for analysing data with seismic interpretation and processing software, see e.g. OpendTect, consist of a SEG-Y file for each frequency. SEG-Y capability is the most relevant feature, since is not present in any of other FOSS tool and give to researchers the possibility to visualize radargrams in advanced software, specific for seismic interpretation and analysis, making it possible to interpret the data in a fully three-dimensional environment.This tool, available on zenodo (Nodjoumi, 2021), has been developed completely in Python 3, relying only on open-source libraries, compatible with principal operating systems and with parallel processing capabilities, granting easy scalability and usability across a wide range of computing machines. It is also highly customizable since it can be expanded adding processing steps before export or new types of output. An additional module to ingest data directly into PostgreSQL/PostGIS and a module to interact directly with ACT-REACT interface of data platforms are under development.Acknowledgments:This study is within the Europlanet 2024 RI, and it has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149. References:Lauro, S. E. et al. (2020) ‘Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data’, doi: 10.1038/s41550-020-1200-6.Nodjoumi, G. (2021) 'MARSIS-xDR-READER', doi: 10.5281/zenodo.4436199Orosei, R. et al. (2020) ‘The global search for liquid water on mars from orbit: Current and future perspectives’, doi: 10.3390/life10080120.

Antihydrogen atoms with K or sub-K temperature are a powerful tool to precisely probe the validity of fundamental physics laws and the design of highly sensitive experiments needs antihydrogen with controllable and well defined conditions. We present here experimental results on the production of antihydrogen in a pulsed mode in which the time when 90% of the atoms are produced is known with an uncertainty of ~250 ns. The pulsed source is generated by the charge-exchange reaction between Rydberg positronium atoms—produced via the injection of a pulsed positron beam into a nanochanneled Si target, and excited by laser pulses—and antiprotons, trapped, cooled and manipulated in electromagnetic traps. The pulsed production enables the control of the antihydrogen temperature, the tunability of the Rydberg states, their de-excitation by pulsed lasers and the manipulation through electric field gradients. The production of pulsed antihydrogen is a major landmark in the AE $$\bar{g}$$ IS experiment to perform direct measurements of the validity of the Weak Equivalence Principle for antimatter. Antihydrogen atoms are a unique type of antimatter that can be used to probe small violations of fundamental laws of physics. The authors present experimental results obtained with the AEgIS project at CERN for the production of antihydrogen atoms (Hbar) via charge exchange with laser excited positronium that allow for precise timing of Hbar production.

We monitor the seasonal erosion and accretion of dust deposits in the Imhotep, Hatmehit, and Ma’at regions of comet 67P/Churyumov–Gerasimenko with OSIRIS Narrow Angle Camera images. The vertical accuracy of such measurements is 0.2 m and the spatial scale of the images we used is lower than 0.60 m pixel−1. We calculate the height of 21 boulders by applying a tool that allows to measure the shadow length of a boulder projected on the surrounding dust deposit, assuming that any height variation is not due to boulder intrinsic change. Any boulder height variation provides a direct measurement about the thickness variation of the surrounding dust layer due to the occurring erosion and/or accretion. The analysis concerns the period from 2014 August, inbound to perihelion, to 2016 September, outbound. We measured the erosion in the Ma’at region of 0.6 ± 0.2 m from 2014 September 12 to December 2, and an erosion of 0.4 ± 0.3 m from 2014 December 3 to 2015 February 15. Then, we measured a dust deposition of 0.7 ± 0.3 m during the following perihelion phase, until 2016 May–September. This result confirms the link between the erosion of the Southern hemisphere and the fallout in the northern regions. The Imhotep and Hatmehit regions are characterized by a negligible erosion during the inbound orbit, consistent with pebble-made nucleus models predicting no erosion when the temperature of the nucleus surface is Ts < 205 K.

In this work, we aim to characterize the dust motion in the inner coma of comet 67P/Churyumov-Gerasimenko to provide constraints for theoretical 3D coma models. The OSIRIS camera on-board the Rosetta mission was able for the first time to acquire images of single dust particles from inside the cometary coma, very close to the nucleus. We analyse a large number of particles, performing a significant statistic of their behaviour during the post-perihelion period, when the spacecraft covered distances from the nucleus ranging between 80 and 400 km. We describe the particle trajectories, investigating their orientation and finding highly radial motion with respect to the nucleus. Then, from the particle brightness profiles, we derive a particle rotational frequency of ν < 3.6 Hz, revealing that they are slow rotators and do not undergo fragmentation. We use scattering models to compare the observed spectral radiance of the particles with the simulated ones in order to estimate their size, finding values that range from millimetres up to centimetres. The statistics performed in this paper provide useful parameters to constrain the cometary coma dynamical models. © 2021 The Author(s)., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung in Gottingen, Germany; CISAS-University of Padova, Italy; the Laboratoire d'Astrophysique de Marseille, France; the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain; the Research and Scientic Support Department of the European Space Agency, Noordwijk, The Netherlands; the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain; the Universidad Politechnica de Madrid, Spain; the Department of Physics and Astronomy of Uppsala University, Sweden; and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universit at Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. GIADA was built by a consortium led by the Univ. Napoli Parthenope INAF-Oss. Astr. Capodimonte, in collaboration with the Inst. de Astrofisica de Andalucia, Selex-ES, FI and SENER. GIADA was managed and operated at INAF-IAPS. GIADA was funded and managed by the Agenzia Spaziale Italiana, IT, with the support of the Spanish Ministry of Education and Science MEC, ES. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission. This research has been supported by the Italian Space Agency (ASI) within the ASI-INAF agreements I/032/05/0, I/024/12/0, and ASI 2020-4-HH.0. Fernando Moreno acknowledges financial support from the Spanish plan National de Astrofisica y Astronomia LEONIDAS project RTI2018-095330-B-100, project P18-RT-1854 from Junta de Andalucia, and the Centro de Excelencia Severo Ochoa Program under grant SEV-2017-0709. Elisa Frattin acknowledges funding from Italian Ministry of Education, University and Research (MIUR) through the `Dipartimenti di eccellenza' project Science of the Universe.

Among the variety of earth analogues, what surely stand out are lava tubes. A lava tube is a type of lava cave formed by a low-viscosity lava flow that can develop 1) forming a continuous and hard crust, which forms a roof above the still flowing lava stream (over-crusting), or 2) slipping between pre-existing lava flows (inflation). The resulting structure constitutes among the most efficient thermal structures on Earth, because of their capacity of thermal insulation isolated lava flows can travel over long distances across lava fields. Lava tubes, which on Earth are typical features of lava fields encountered in intracontinental plateaus and volcanic-shield islands (slopes Indeed, in the last decade, high-resolution orbital images on planetary bodies like Mars and the Moon offer the possibility of studying the morphology of these structures, detecting them from the recurrent collapses in the pyroduct’s roof, that shows the presence and the path of the pyroduct itself. The pit chains show characteristics similar to those on Earth: elongated with minor axis representing the width of the tube and with major axis along the flow direction. The differences in gravity between Earth and the other planetary bodies and its concurrent influence on the effusion rates result in a significant difference in lava tube dimensions, indeed, terrestrial pyroducts tend to generally have a smaller width (10–30 m) than those on Mars (250–400 m) and the Moon (500–1100 m) [3]. In the post-cooling phases, lava tubes are characterized by a near-constant inner temperature and, on other planetary bodies, they might offer natural protection against micrometeorites and solar and cosmic radiations making them ideal locations for future planetary explorations. Within this framework, studying the largest lava tubes on Earth is of interest as they could represent the best planetary analogues. In order to employ lava tubes as locations for future explorations, it is important to understand exactly how they form and develop not only during the active phase (flow-phase) but also and more importantly during the post-cooling phase. Alongside the NW African continental margin (Morocco), is located the Canary Island Seamount Province (CISP), a magmatic province generated by the extremely slow transit (~8–10 mm/yr) of the African plate over a hotspot during more than the last 133 Ma [5] and hence represents both long-term and spatially focused volcanic activity over a poorly mobile tectonic plate. For this reason, it constitutes one of the best terrestrial analogues of the Martian one-shell plate volcanism [6]. In the NE region of Lanzarote (Canary Islands) stands La Corona lava tube system that, with its 7.6 km length and an average width of 30 m [4], is one of the largest volcanic cave complexes on Earth. Therefore, the occurrence of volcanism on an almost stationary plate and the impressive dimensions of La Corona lava tube make it one of the most suitable lava tubes for interplanetary analogies. Different field surveys were conducted over the last two years in order to explore its three-dimensional geometry using 3D laser-scan. These data allowed to place constraints on the tube origin (inflation process rather than over-crusting), the involvement of thermal erosional processes (inferred from characteristic morphologies) and to identify a weak pyroclastic level within the tube which might have favoured the inflated tube inception. Also, the presence of an important amount of secondary mineralisation inside the tube has been very significant in understanding the evolution of the pyroduct in the cooling and post-cooling phases. These secondary mineralisation (mainly sulphates) show an interesting contribution from the Aeolian and marine environment in the latest evolutionary stages of this lava tube. Studying this exceptional example of terrestrial lava tube will allow to improve our understanding of the formation and evolutional processes giving rise to analogue features on other planetary bodies of the Solar System. [1] Haruyama, J. et al. (2012) Trans. JAPAN Soc. Aeronaut. Sp. Sci. Aerosp. Technol. JAPAN 10 [2] Tettamanti C. (2019) Analysis of skylights and lava tubes on Mars, Department of Physics and Astronomy “Galileo Galilei", Univerisy of Padova (Italy) [3] Sauro, F., et al. (2018) 49th Lunar Planet. Sci. Conf. 2018 [4] Carracedo, J. C. et al. (2003) Estud. Geol. 59 [5] van den Bogaard, P. (2013). Sci. Rep. 3 [6] Meyzen, C. M., et al. (2015) Geol. Soc. London, Spec. Publ. 401

Pit chains commonly occur along a bounding fault, allowing to infer a genetic relationship between grabens and pits. In this work we propose a comprehensive model for the formation of pit chains , the complex sequence of rift system and troughs in Noctis Labyrinthus. Like other previous authors, we confirm that a volcano-tectonic activity is the main process controlling the generation of such interesting and intricate structures in the studied area. We analyzed the geometrical properties and the maximum displacement as a function of fault length and cumulative frequency of fault length distribution for 499 mapped faults, which reveal the host lithology of the faults and the arrangement of rocks in of the crust and the lithosphere. We finally suggest a model where a relative sequence of events responsible for the formation and development of the scalloped network of troughs in Noctis Labyrinthus (Mège et al.,2003).In this model, the magma propagates from depth to the surface by exploiting a network of interconnected fractures, and as a consequence, this magma inflation generates the formation of dike-induced grabens and pit chain on the surface. Introduction Noctis Labyrinthus is one of the enigmatic area in the surface of Mars.This area is made up by a complex inter-connected network of canyons and branched extensional faults and grabens Fig.1.These particular features of unknown origin, make Noctis Labyrinthus an interesting target to understand the possible factors that control the formation of these complex grid of troughs and infer the possible fault system evolution. We performed a detailed qualitative and quantitative study of these faults system through the study of their geometrical properties and surface morphology in order to understand their mechanical evolution and variations over different scales of length, the mechanisms of growth and the related stress field. We measured the maximum displacement as a function of faults length. The Dmax/L diagram provides slightly different results according to the fault type, since this ratio change from normal, thrust, and strike slip faults, so it provides information about the possible nature of the faults in the selected area (Seog Kim et al., 2005). The cumulative frequency plot Fig.3 was used to infer the scaling law of the fault system and faults growth, determine the lithology of the faulted rocks, the arrangement of materials in the subsurface and also the vertical confinement of faults vs. penetration of the brittle crust (Sornette.,2009; Torabi and Berg., 2011;Sornette et al., 1993; Cowie et al., 1991). Fig.1.Surface interconnection between faults and pit chains, which follow a linear trend. Faults sizes and colors are labeled on the graph. 1. Data and methods In our work, as a basemap, we used two orthoimages H3210_0000 and H3221_0000 from High Resolution Stereo Camera (HRSC) on board Mars Express, bearing a resolution of 12.5 m/pixel and for the surface topography, we utilized an individual Digital Elevation Model (DEM) from Mars Orbiter Laser Altimeter (MOLA) on board Mars Global Surveyor, with resolution of ~460 m/pixel. With these data sets, we made all morphometric measurements required for characterizing the faults and the grabens systems, analyzing faults distribution using rose diagrams, measuring faults lengths and the maximum vertical displacement of faults population and carry out a DMax Vs. L diagram and a cumulative frequency plot by input data in Origin software. Afterward, we studied the relationship of those fractures in terms of the formation and evolution of Pit chains and troughs. 2. Discussion and Conclusion Noctis Labyrinhus is a framework of intricate rifts systems and branched faults, that have coalesced together to form an interconnected topography characterized by large troughs and canyons, driven by an invariant extensional stress field. Fault grow and develop at the same way but at different scales (Schultz et al., 2000; Turabi and Berg., 2011). Crustal-Scale linkage in localized faulting zone is responsible for the formation of rift segment border by a pre-existing fracture (Soliva and Schultz., 2008). So far, only a few locations on Mars, where the DMax/L relationship has been measured. In our work, the nonlinear distribution in the Fig.2 might be explained by the presence of small size fractures, with different depths, which could be one of reasons that affect the large distribution of measurements in the Displacement-Length diagram (Turabi and Berg., 2011), or alternatively, it could be linked to the brittle crust thickness that control the displacement and the length of faults as in the terrestrial analogues faults systems (Soliva and Schultz., 2008; Schultz and Fossen.,2002; Soliva et al., 2005; Comie., 1998). Fig.2. DMax /L diagram of faults studied in this work, shows a large scattering of values. The different DMax /L limits are plotted in various lines with different colors. Topographic offsets was measured along single MOLA tracks. The cumulative frequency Vs. Length of fault population values grows in exponential fit Fig.3 of size distribution, mainly reflecting the presence of layered sequence of massive basalt (R.Soliva and R.Schultz., 2008). Fig.3.The cumulative size distribution of the fault length population with Exponential and Power Law fits. On the diagram, the Exponential function fits the most with the main trend. Furthermore,We classified pit chains as a morphological features of volcanic collapse generated by pressure drop above dikes (Mège and Masson., 1996; Liu and wilson., 1998; Scott et al., 2000; Mège and Masson., 1996; Wilson and Head., 2002; Ernst et al., 2001; Mège et al.,2003).Dikes play an important role to connect the surface to the magmatic source. The magma chamber at depth continuously generate flow that will be transported later to the upper levels through the dikes (Mège et al.,2003). This procedure will produce a stress in the dike tip, followed by deflation causing the collapsing of the surface, where there is a graben already formed. This sequence of events is responsible for the generation of the pit chain.We are suggesting a model based on a coupled physical processes of an early extension, visible on the surface by a forked grid of faults and grabens and a magma plumbing. Acknowledgements This research has been supported by European Union’s Horizon 2020 under grant agreement N° 776276-PLANMAP.

The European Space Agency’s Rosetta mission was designed to orbit and land on the Jupiter-family comet 67P/Churyumov-Gerasimenko (hereafter 67P) for the first time. To investigate the nucleus, the Optical, Spectroscopic, and Infrared Remote Imaging System [1] was designed. The OSIRIS instrument consisted of two cameras operating from near ultraviolet to near infrared wavelengths. The Wide-Angle Camera (WAC) imaged the dust and the gas surrounding the nucleus with a spatial scale of 10.1 m/pixel at 100 km from the surface. The Narrow-Angle Camera (NAC) investigated the comet nucleus and its surface topography with a spatial scale of 1.86 m/pixel at the same distance. The surface of comet 67P immediately appeared geologically complex, with a large variety of terrains and geological features [2]. In addition, the OSIRIS observations revealed a dichotomy in appearance between the two hemispheres. In particular, the northern regions are almost fully covered by dust [2, 3]. On the contrary, in the equatorial regions, consolidated and coarse terrains seem to have replaced the dust on the surface [4]. This dichotomy is linked to the insolation and subsequent erosion of the surface [5]. The dust cover in the northern regions is the result of transport mechanisms of particles from the southern hemisphere during the southern summer [5, 6]. The strong insolation and the water ice content in the south could erode the surface up to 20 m [5] at the perihelion. Method and results By applying the method developed by Cambianica et al. (2020) [6], we monitored the erosion and accretion of dust deposits of the Imhotep, Hatmehit, and Ma’at regions (Fig. 1) with a vertical accuracy of 0.4 m. The tool is based on the measurement of the shadow length projected by a boulder on the surrounding pebbles deposit. In Fig. 2 an example of the height measurement is shown. After assuming that the position of the boulder did not change during the observational period [7], any height variations provide an indication of how the thickness of the surrounding dust layer is varying in time through erosion and accretion phenomena. We measured the height of three populations of boulders, and the analysis covers the period from August 2014, inbound the perihelion, to September 2016, outbound. Our results show that equatorial regions remain almost inactive before perihelion, contrarily to the Ma’at region which shows erosion during the inbound orbit, and a subsequent dust deposit during the perihelion cometary activity. These results are in line with those found for the Hapi region [6], for which an erosion of the dust deposit of about 1.7 m during the inbound orbit and a fallout of 96% during perihelion cometary activity were measured [6]. Comparing our results with those obtained for the Hapi region, we confirm that the amount of the erosion in the southern hemisphere may be linked with the transport mechanism of the eroded material, and then to its fallout on the nucleus, justifying the presence of coarse terrain only in the southern hemisphere. Fig. 1. OSIRIS NAC images showing the analyzed boulder populations located in the Imhotep (A), Hatmehit (B), and Ma’at (C) regions of 67P respectively. The first image of this set (A) was taken on 23 November 2014, at a distance of 30.1 km and a scale of 0.57 m/px. Image B was taken on 23 July 2016 at a distance of 10.22 km and has a scale of 0.19 m/px, while the last one (C) was taken on 13 September 2014 at a distance of 30.1 km and a scale of 0.56 m/px. White circles indicate the measured boulders. Fig. 2. (a) NAC view of the Ma’at region. This image was acquired in 2014. (b) Close-up of a boulder and of its shadow. The green line represents the projection of the Sun illumination direction. (c) Boulder section. The y-axis is oriented as the normal to the average plane around the peak of the shadow. The x-axis is obtained by projecting the green line in panel b on this average plane; the x-axis origin coincides with the peak of the shadow. Acknowledgements OSIRIS was built by a consortium of the Max-Planck-Institut für Sonnensystemforschung, in Göttingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d’Astrophysique de Marseille, France, the Instituto de Astrofísica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut für Datentechnik und Kommunikationsnetze der Technischen Universität Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC and ESTEC for their work in support of the Rosetta mission. References [1] Keller, H. U., Barbieri, et al. (2007). Osiris, the scientific camera system onboard Rosetta. Space Science Reviews, 128(1-4):433–506. [2] Thomas, N., Sierks, H., et al. (2015). The morphological diversity of comet 67P/Churyumov-Gerasimenko. Science, 347(6220):aaa0440 [3] El-Maarry, M. R., Thomas, et al. (2015). Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/Osiris images. Astronomy & Astrophysics, 583:A26. [4] Keller, H. U., Mottola, S., et al. (2017). Seasonal mass transfer on the nucleus of comet 67P/Chuyumov–Gerasimenko. Monthly Notices of the Royal Astronomical Society, 469(Suppl_2):S357–S371. [5] Keller, H. U., Mottola, et al. (2015). Insolation, erosion, and morphology of comet 67P/Churyumov-Gerasimenko. Astronomy & Astrophysics, 583:A34. [6] Cambianica, P., Fulle, M., Cremonese, et al., (2020). Time evolution of dust deposits in the Hapi region of comet 67P/Churyumov-Gerasimenko.\ Astronomy and Astrophysics 636, A91. [7] Cambianica, P., Naletto, G., Cremonese, G. et al. 2019. Quantitative analysis of isolated boulder fields on comet 67P/Churyumov-Gerasimenko.\ Astronomy and Astrophysics 630, A15.

The processes leading to the formation of planetary systems leave behind a significant mass of small bodies - up to 35 Earth masses depending on the model [1] - orbiting at large heliocentric distance, and observed around 20% of Sun-like stars [2]. It is established that those bodies play an important role in the migration of gas giants away from their stars and may be necessary for life to develop on the smaller planets. Yet, the conditions within these primitive populations are not well understood, especially their collisional environment. In the last decade, space missions have brought fascinating new data which challenge our concepts of impacts in the Early Solar System. The mission Rosetta at comet 67P, for instance, has revealed a complex cometary world where collisions, from small to catastrophic, played a significant role. Recent work [3,4] suggests that the topography of cometary nuclei and potential layering are shaped by processes which are primarily ancient. Current erosion does not appear sufficient to create features such as deep pits and tall cliffs over the lifetime of a comet in the Inner Solar System. Could they be due to impacts ? Or early activity in the Centaur phase ? On a larger scale, dynamical simulations argue that objects like the Jupiter Family Comets may have been totally disrupted by catastrophic collisions. While models show that the high porosity and volatile content of cometary nuclei would survive such impacts, it is not clear whether the deeper structural features like layers can be preserved. From the same data set, different authors come to different conclusions with respect to collisions in the early outer planetary system (summarized in [5]). Furthermore, different modeling approaches [6,7,8] lead to distinct results. Overall, there is quite some confusion as to how to interpret the cratering record on very porous, icy objects, in the Outer Solar System. This is further complicated by the fact that we may not be able to properly recognize impact features on such bodies. Here we report on the results obtained by the OCEOSS (Outcome of Collisions in the Early Outer Solar System) ISSI group. The concept of this working group is to bring together experts on collisions and cometary morphology. Over the last few years, modelers have developed new numerical simulations to account for cometary-like material. In parallel, thanks to the Rosetta and New Horizon missions, small bodies morphologists have a much better understanding of the type of landform that can exist on comets, and new measurements of the material physical properties. Our group investigates how morphological features observed today on comets and KBOs could relate to the early collisional environment, beyond the typical crater counting studies. We will summarize our results along three main topics: Large scale collisions, small scale collisions, and populations. We find that the outcome of merger collisions, such as the one which may have created comet 67P or KBO Arrokoth can be very different depending on the internal structure of the bodies. If layers are already present before the collision, the impact may lead to shedding and creation of cliffs/terraces resembling what we see on comets. More energetic impacts would lead to catastrophic disruption, although the fragments may come back together by gravitational interaction, leading to cometary rubble piles. Recent work on this process for asteroids shows that this could lead to the high porosity and potential density variation we observe across bilobate-comets. On a local scale, we simulated a km size projectile impacting a 30km KBO, which is the expected order of magnitude for creating features such as the largest crater observed on Arrokoth [9]. We find a large diversity of depth-to-diameter ratio (d/D) for craters, depending on the impact and material parameters. We caution against the simple asteroid-like approximation d/D=10 for all cases [10], as it can lead to erroneous interpretation of the projectile population when extrapolating from crater shapes only. We will discuss what our models mean for the interpretation of current spacecraft data, and how this work can support future missions to comets/KBOs, like ESA's Comet Interceptor [11]. References: [1] Tsiganis et al., Origin of the orbital architecture of the giant planets of the Solar System, Nature 2005 [2] Wyatt, M., Extrasolar Kuiper belts, in book The Trans-Neptunian Solar System, 2019 [3] Vincent et al, Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography, MNRAS 2017 [4] Birch et al, Geomorphology of comet 67P/Churyumov-Gerasimenko, MNRAS 2017 [5] Weissmann et al, Origin and Evolution of Cometary Nuclei, SSR 2020 [6] de Niem et al, Low velocity collisions of porous planetesimals in the early solar system. Icarus 2018 [7] Jutzi et al, Formation of bi-lobed shapes by sub-catastrophic collisions. A late origin of comet 67P's structure, A&A 2017 [8] Schwarz et al, Catastrophic disruptions as the origin of bilobate comets, Nature Astronomy 2018 [9] Spencer et al, The geology and geophysics of Kuiper Belt object (486958) Arrokoth, Science 2020 [10] Bottke et al, Interpreting the Cratering History of Bennu, Ryugu, and Other Spacecraft-Explored Asteroids, EPSC 2019 [11] Snodgrass, C. & Jones, G., The European Space Agency's Comet Interceptor lies in wait, Nature Communications 2019 Acknowledgements The OCEOSS team thanks the International Space Science Institute (ISSI Bern), which made this collaboration possible.

Observations of comet nuclei indicate that the main constituent is a mix of ice and refractory materials characterized by high porosity (70–75%) and low bulk strength (10 −4 –10 −6 MPa); however, the nature and physical properties of these materials remain largely unknown. By combining surface inspection of comet 67P/Churyumov–Gerasimenko and three-dimensional (3D) modeling of the independent concentric sets of layers that make up the structure of its two lobes, we provide clues about the large-scale rheological behavior of the nucleus and the kinematics of the impact that originated it. Large folds in the layered structure indicate that the merging of the two cometesimals involved reciprocal motion with dextral strike–slip kinematics that bent the layers in the contact area without obliterating them. Widespread long cracks and the evidence of relevant mass loss in absence of large density variations within the comet’s body testify that large-scale deformation occurred in a brittle-plastic regime and was accommodated through folding and fracturing. Comparison of refined 3D geologic models of the lobes with triaxial ellipsoids that suitably represent the overall layers arrangement reveals characteristics that are consistent with an impact between two roughly ellipsoidal cometesimals that produced large-scale axial compression and transversal elongation. The observed features imply global transfer of impact-related shortening into transversal strain. These elements delineate a model for the global rheology of cometesimals that could be possible evoking a prominent bonding action of ice and, to a minor extent, organics.

Geologic mapping is a key element of planetary exploration for mission planning, orbital and rover reconnaissance, and target selection for in-situ analysis and sample return, as well as for understanding the formation and evolution of planetary surfaces. The PLANMAP project (http://www.planmap.eu) aims at produce high-level, standardized geological maps of the Moon, Mars, and Mercury (Massironi M. et al., 2018). The project is integrating different types of data as images, spectral-cubes, chemical data, Digital Terrain Models and three-dimensional geological models to produce geological maps suitable to planetary exploration at different levels. The process results in rich datasets composed by a variety of datatypes encapsulated in open standards and released to the community as freely accessible packages (https://maps.planmap.eu).To accomplish the complexity of deploying PLANMAP packages, considering reliability and automation as key components of a data release workflow, we arranged a data management framework respecting the FAIR (findable, accessible, interoperable, and reusable) guidelines. Geographic data are stored and served by a multi-layered Web-GIS allowing easy information discovery. Particular attention has been paid in designing the user interface and in the definition of the underlying data structure. Different data query services are also provided to properly address different user needs (Luzzi E. et al., 2020). PLANMAP’s datasets can be downloaded in the form of fully contained packages (https://data.planmap.eu) fulfilling a specifically designed standard. Once a data package is ready for publication, validation and summary information extraction take place and the results are published together within the packages.We will here present an overview of the PLANMAP’s deployed data system, and the technical solutions that were adopted with the final goal of improving the quality standards of planetary geological maps.References:- Luzzi E. et al., 2020, “Tectono-magmatic, Sedimentary and Hydrothermal History of Arsinoes and Pyrrhae Chaos, Mars.”, EarthArXiv, doi:10.31223/osf.io/td297- Massironi M. et al., 2018, “Towards integrated geological maps and 3D geo-models of planetary surfaces: the H2020 PLANetary MAPping project”, EGU General Assembly 2018

Geological maps have been historically a central part of the geological knowledge acquisition process: they are used to summarize all the relevant information of a site of interest and they provide the cornerstone for decision making, scientific discovery and three-dimensional geological modeling. Depending on the scope of the geological survey the cartography can depict different types of content: whether lithostratigrapy, chronostratigrapy, morphology, or other criteria are considered, the building blocks of a geological map is the geological unit, as the base element used to subdivide a region into geologically homogeneous patches of terrain. Digitized maps are normally represented within GIS software as polygonal layers. A common approach for mapping has been to directly draw polygons representing the different units on the map: although this approach appears the simplest one, it poses several issues in terms of topological consistency of resulting maps, especially when it comes to updating existing cartography. Furthermore, from a purely information science standpoint this representation, although useful for visualization, is inherently redundant, defining the same boundary geometry two times for each polygonal couples in contact. Editing polygonal layers is inherently problematic because vertex and edge correspondence between polygons in contact must be enforced by the operator. Although most GIS software implements appropriate tools (for editing and for topology validation) which can help in achieving error-free polygonal layers, the burden of using them is left to the operator and it is not enforced by the data format itself. A better solution for generating topologically-consistent geological maps consists in tracing the contacts separating the units, and then transforming them into polygonal layers (by using what is often known as a “polygonize” operation) for map finalization (see Figure 1). Figure 1: Generation of a consistent polygonal layer by polygonize operation, this can be performed by any GIS and is suggested as a good practice in geological map generation. A line layer is used for tracing the contacts between the different units and a point layer is also needed to define attributes for the polygons. This approach is also more similar to the geological reasoning that is performed when mapping, especially when remotely -sensed imagery is used (as in planetary mapping): the operator tries to identify the boundaries between different terrains rather than directly defining the area covered by the units themselves. This strategy hasve the clear benefit of making editing the map easier but, even when employed by the operator, the original layers (contact lines and points) are rarely or never distributed to the public, making it impossible to apply this method when updating already existing maps. In order to solve this problem we implemented a python module and a QGIS plugin called Mappy which is mostly based on already-existent modules as numpy (Oliphant 2006), geopandas (Jordahl et al. 2019), and topojson (Bostock 2017). Mappy implements the backwards transformation of the polygonize operation decomposing a polygonal layer into boundary lines and a point layer that contains the attributes of the original polygonal layer (the forward transform is also implemented). The input polygonal layer is first transformed into a topology-aware representation via topojson: first the intersection points are detected and then the polygons boundaries are split at those points, creating a list of arcs: each representing an unique portion of a contact line (Figure 2). Topojson representation can also account for rounding errors in the nodes coordinates and makes it possible to also consistently apply line-simplification methods (e.g. to reduce the number of nodes) while maintaining the original topology. Figure 2: The inverse operation of a "polygonize" operation as performed by mappy. a) the input polygonal layers with attributes; b) the topojson representation as list of arcs (each polygon is then just a list of arcs in the right order); c) the arcs are aggregated to create a representation more suitable for geological editing; d) point are positioned in the visual center of each polygon and the attributes are then transferred. Although being topologically sound, the topojson format of a polygonal layer is not the best suited representation for editing geological maps: given each line is split at the intersection points (Figure 2b) a contact might be split in a number of segments (i.e. when a contact separates one unit from several others) making it more difficult to edit the contact of a specific unit. For this reason, Mappy further processes the lines to aggregate several continuous arcs into a single polylines (Figure 2c). For each polygon an indicator point is then automatically computed to be in its visual center and the original attributes of the polygons are transferred to it. The points are placed by using the “polylabel” method provided by shapely module (Gillies and others 2007). The described approach has been then implemented in a standalone module that is also accessible from a QGIS plugin enabling easy transformation of any existing map into a line and points representations and vice-versa, therefore simplifying the process of editing and topology checking of existent geological maps. Acknowledgments: This research was supported by European Union’s Horizon 2020 under grant agreement No 776276- PLANMAP. References: Bostock, Mike, 2017 TopoJSON. URL: https://github.com/topojson/topojson-specification. Gillies, Sean, and others, 2007 Shapely: Manipulation and Analysis of Geometric Objects. toblerity.org. https://github.com/Toblerity/Shapely. Jordahl, Kelsey, Joris Van Den Bossche, Jacob Wasserman, et al., 2019 Geopandas/Geopandas: V0.4.1. Zenodo. https://zenodo.org/record/2585849, accessed June 29, 2020. Oliphant, Travis, 2006 NumPy: A Guide to NumPy. https://www.numpy.org/.

Aims. We provide a measurement of the seasonal evolution of the dust deposit erosion and accretion in the Hapi region of comet 67P/Churyumov-Gerasimenko with a vertical accuracy of 0.2-0.9 m. Methods. We used OSIRIS Narrow Angle Camera images with a spatial scale of lower than 1.30 m px-1 and developed a tool to monitor the time evolution of 22 boulder heights with respect to the surrounding dust deposit. The tool is based on the measurement of the shadow length projected by the boulder on the surrounding pebble deposit. Assuming the position of the boulders does not change during the observational period, boulder height variations provide an indication of how the thickness of the surrounding dust layer varies over time through erosion and accretion phenomena. Results. We measured an erosion of the dust deposit of 1.7 ± 0.2 m during the inbound orbit until 12 December, 2014. This value nearly balances the fallout from the southern hemisphere during perihelion cometary activity. During the perihelion phase, the dust deposit then increased by 1.4 ± 0.8 m. This is interpreted as a direct measurement of the fallout thickness. By comparing the erosion rate and dust volume loss rate at the Hapi region measured in the coma, the fallout represents ~96% in volume of the ejecta. The amount of the eroded pristine material from the southern hemisphere, together with its subsequent transport and fallout on the nucleus, led us to discuss the pristine water ice abundance in comet 67P. We determine that the refractory-to-ice mass ratio ranges from 6 to 110 in the perihelion-eroded pristine nucleus, providing a pristine ice mass fraction of (8 ± 7)% in mass. © 2020 ESO., OSIRIS was built by a consortium of the Max-Planck Institut fur Sonnensystemforschung, in Guttingen, Germany, CISAS University of Padova, Italy, the Laboratoire de Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC and ESTEC for their work in support of the Rosetta mission. We made use of Arcgis 10.3.1 software together with the Matlab, Java, and ImageJ software to perform our analysis. I.T. acknowledges the support from project GINOP-2.3.2-15-2016-00003 "Cosmic effects and hazards".

International audience; In this work we present a hybrid detection method providing simultaneous imaging and timing information suitable for fully monitoring positronium (Ps) formation, its laser excitation, and its spatial propagation for the first trials of pulsed antihydrogen ($\bar{H}$) production through a charge-exchange reaction with trapped antiprotons ($\bar{p}$). This combined method, based on the synchronous acquisition of an EJ-200 scintillation detector and a microchannel plate (MCP) detector with a dual readout (phosphor screen image and electrical pick-up signal), allows all relevant events in the experiment to be accurately determined in time while allowing high resolution images of e$^{+}$ from Ps laser photodissociations to be acquired. The timing calibration process of the two detectors discussed in details as well as the future perspectives opened by this method.

We characterized the pulsed Rydberg-positronium production inside the Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AE$\overline{\textrm{g}}$IS) apparatus in view of antihydrogen formation by means of a charge exchange reaction between cold antiprotons and slow Rydberg-positronium atoms. Velocity measurements on the positronium along two axes in a cryogenic environment (≈10K) and in 1T magnetic field were performed. The velocimetry was done by microchannel-plate (MCP) imaging of a photoionized positronium previously excited to the $n$=3 state. One direction of velocity was measured via Doppler scan of this $n$=3 line, another direction perpendicular to the former by delaying the exciting laser pulses in a time-of-flight measurement. Self-ionization in the magnetic field due to the motional Stark effect was also quantified by using the same MCP-imaging technique for Rydberg positronium with an effective principal quantum number $n_\textrm{eff}$ ranging between 14 and 22. We conclude with a discussion about the optimization of our experimental parameters for creating Rydberg positronium in preparation for an efficient pulsed production of antihydrogen. We characterized the pulsed Rydberg-positronium production inside the AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) apparatus in view of antihydrogen formation by means of a charge exchange reaction between cold antiprotons and slow Rydberg-positronium atoms. Velocity measurements on positronium along two axes in a cryogenic environment (10K) and in 1T magnetic field were performed. The velocimetry was done by MCP-imaging of photoionized positronium previously excited to the $n=3$ state. One direction of velocity was measured via Doppler-scan of this $n=3$-line, another direction perpendicular to the former by delaying the exciting laser pulses in a time-of-flight measurement. Self-ionization in the magnetic field due to motional Stark effect was also quantified by using the same MCP-imaging technique for Rydberg positronium with an effective principal quantum number $n_{eff}$ ranging between 14 and 22. We conclude with a discussion about the optimization of our experimental parameters for creating Rydberg-positronium in preparation for an efficient pulsed production of antihydrogen.

From the experimental point of view, very little is known about the gravitational interaction between matter and antimatter. In particular, the Weak Equivalence Principle, which is of paramount importance for the General Relativity, has not yet been directly probed with antimatter. The main goal of the AEgIS experiment at CERN is to perform a direct measurement of the gravitational force on antimatter. The idea is to measure the vertical displacement of a beam of cold antihydrogen atoms, traveling in the gravitational field of the Earth, by the means of a moiré deflectometer. An overview of the physics goals of the experiment, of its apparatus and of the first results is presented.

International audience; A main scientific goal of the experiment is the direct measurement of the Earth’s local gravitational acceleration g on antihydrogen. The Weak Equivalence Principle is a foundation of General Relativity. It has been extensively tested with ordinary matter but very little is known about the gravitational interaction between matter and antimatter. Antihydrogen is produced in via resonant charge-exchange reaction between cold Rydberg-excited positronium and cooled down antiprotons. The achievements for the development of a pulsed cold antihydrogen source are presented. Large number of antiprotons, necessary for a significant production rate of antihydrogen, are captured, accumulated, compressed and cooled over an extended period of time. Positronium (Ps) is formed through e$^{+}$-Ps conversion in a silica porous target at 10 K temperature in a reflection geometry inside the main apparatus. The so-formed Ps cloud is then laser-excited to Rydberg levels, for the first time in a 1 T magnetic field. Consequently, a detailed characterization of the Ps source for antihydrogen production in magnetic field needed to be performed. Several detection techniques are extensively used to monitor antiproton and positron manipulations in the formation process of antihydrogen inside the main apparatus. Positronium detection techniques underwent extensive improvements in sensitivity during the last antiproton run. At the same time, major efforts to improve integrate and commission the detectors sensitive to antihydrogen production took place.

We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1 T superconducting magnet of the AEgIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4K and are read out by silicon photomultipliers (MPPCs) at near room temperature. FACT provides the antiproton/antihydrogen annihilation position information with a few ns timing resolution. We present the hardware and software developments which led to the successful operation of the detector for antihydrogen detection and the results of an antiproton-loss based efficiency assessment. The main background to the antihydrogen signal is that of the positrons impinging onto the positronium conversion target and creating a large amount of gamma rays which produce a sizeable signal in the MPPCs shortly before the antihydrogen signal is expected. We detail the characterization of this background signal and its impact on the antihydrogen detection efficiency. We present the commissioning of the Fast Annihilation Cryogenic Tracker detector (FACT), installed around the antihydrogen production trap inside the 1 T superconducting magnet of the AEḡIS experiment. FACT is designed to detect pions originating from the annihilation of antiprotons. Its 794 scintillating fibers operate at 4 K and are read out by silicon photomultipliers (MPPCs) at near room temperature. FACT provides the antiproton/antihydrogen annihilation position information with a few ns timing resolution. We present the hardware and software developments which led to the successful operation of the detector for antihydrogen detection and the results of an antiproton-loss based efficiency assessment. The main background to the antihydrogen signal is that of the positrons impinging onto the positronium conversion target and creating a large amount of gamma rays which produce a sizeable signal in the MPPCs shortly before the antihydrogen signal is expected. We detail the characterization of this background signal and its impact on the antihydrogen detection efficiency.

We investigate experimentally the possibility of enhancing the production of 2S3 positronium atoms by driving the 1S3–3P3 and 3P3–2S3 transitions, overcoming the natural branching ratio limitation of spontaneous decay from 3P3 to 2S3. The decay of 3P3 positronium atoms toward the 2S3 level has been efficiently stimulated by a 1312.2 nm broadband IR laser pulse. The dependence of the stimulating transition efficiency on the intensity of the IR pulse has been measured to find the optimal enhancement conditions. A maximum relative increase of ×(3.1±1.0) in the 2S3 production efficiency, with respect to the case in which only spontaneous decay is present, was obtained.

This correction provides updated acknowledgements: This work was supported by Istituto Nazionale di Fisica Nucleare; the Swiss National Science Foundation Ambizione Grant (No. 154833); a Deutsche Forschungsgemeinschaft research grant; an excellence initiative of Heidelberg University; Marie Sklodowska-Curie Innovative Training Network Fellowship of the European Commission’s Horizon 2020 Programme (No. 721559 AVA); European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement ANGRAM No 748826; European Research Council under the European Union’s Seventh Framework Program FP7/2007-2013 (Grants Nos. 291242 and 277762); Austrian Ministry for Science, Research, and Economy; Research Council of Norway; Bergen Research Foundation; John Templeton Foundation; Ministry of Education and Science of the Russian Federation and Russian Academy of Sciences; and the European Social Fund within the framework of realizing the project, in support of intersectoral mobility and quality enhancement of research teams at Czech Technical University in Prague (Grant No. CZ.1.07/2.3.00/30.0034).

Between August 2014 and September 2016, the ESA space mission Rosetta escorted comet 67P/Churyumov-Gerasimenko (67P) during its perihelion passage. The onboard OSIRIS Narrow Angle Camera (NAC) acquired high-resolution multispectral images of the cometary surface. These datasets allowed a characterization of the spectrophotometric variegation of the layering of the large lobe, correlated with the layer structural elevation. Aims. We perform a spectrophotometric characterization of the outcropping stratification of the small lobe of 67P as a function of its structural elevation, and consequently, a spectrophotometric comparison of the layered outcrops of the two lobes. Methods. We selected two sequences of post-perihelion OSIRIS NAC images (similar to 2.4 au outbound to the Sun), from which we built up two multispectral images, framing an extended geological section of the onion-like stratification of the small lobe. Then we classified the consolidated areas of the outcropping and the relative coarse deposits that were identified in the multispectral data with a two-class maximum likelihood method. For this, we defined the classes as a function of the structural elevation of the surface. Results. As a result, we identified a brightness variegation of the surface reflectance that is correlated with the structural elevation. The outer class, which is located at higher elevations, appears darker than the inner class. This fits previously obtained results for the large lobe. The reflectance values of the nucleus of 67P tend to decrease with increasing structural elevation. Conclusions. The observed spectrophotometric variegation can be due to a different texture as well as to a different content of volatiles and refractories. We suggest that the outer outcrops appear darker because they have been exposed longer, and the inner outcrops appear brighter because the surface has been more effectively rejuvenated. We interpret this variegation as the result of an evolutionary process.© ESO 2019, We are grateful to Andrea Longobardo for suggestions and corrections that improved our paper. OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS - University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.

International audience; In this work, we show recent measurements of $2^{3}S$ long-lived positronium production via spontaneous decay from the 3 3P level. The possibility to tune the velocity of the $2^{3}S$ positronium, excited following this scheme, is presented. In the light of these results, we discuss the use of the $3^{3}P$→ $2^{3}S$ transition to realize a monochromatic pulsed $2^{3}S$ positronium beam with low angular divergence. Preliminary tests of $2^{3}S$ beam production are presented. The possibility to overcome the natural $3^{3}P$ → $2^{3}S$ branching ratio via stimulated emission, and thus increasing the intensity of the $2^{3}S$ source, is also shown. A position-sensitive detector for a pulsed beam of positronium, with spatial resolution of ≈ 90 $\mu m$, is finally described in view of its possible application for the spatial characterization of the $2^{3}S$ beam

Oral Presentation -2nd Planetary Mapping and Virtual Observatory Workshop 1-3 July 2019, Domaine de St. Paul, Saint-Rémy-lès-Chevreuse, France

Geologic mapping key to many elements of planetary exploration, ranging from mission planning, orbital and rover reconnaissance, the reconstruction of local to global planetary geologic histoties and multi-scale characterisation and selection of landing sites and sample analyses. PLANMAP aims at producing geologic maps with the widest possible range of underlying data sources, including imagery, topography, hyperspectral, and geophysical data, as well as direct or indirect three-dimensional information, in order to produce surface and subsurface geologic models of planetary surfaces at local and regional scales, both from orbital and lander/rover platforms. Mapping products at various level of maturity and development are available on the Planmap data portal as both files, web-accessible maps and OGC endpoints for both desktop and programmatic access onhttps://data.planmap.eu/andhttps://maps.planmap.eu/. Planmpap code and utilities are going to be available onhttps://github.com/planmap-eu. Acknowledgements: Planmap receives funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 776276.

International audience; In this contribution, the system of the external plastic scintillator slabs of the AEgIS experiment is presented. These slabs, surrounding the superconducting magnet and operating at room temperature, are read out by photomultiplier tubes (PMTs) that are calibrated and equalised to be exploited as a whole detector with useful segmentation and redundancy to effectively detect single antiparticle annihilations. In particular, thanks to periodically recurring calibrations with cosmic rays and to a detailed study of the system in different operational conditions, including extensive Monte Carlo (MC) simulations, these scintillators can be used to identify antiproton annihilations over the constant background represented by cosmic rays and over the strongly time-dependent background due to positrons/positronium annihilations. By means of the sampling and digitization of the analog signal produced by each phototube and the consequent analysis of the amplitude of the recorded events, the energy released by the particle in the scintillator slab can be estimated consistently and with good accuracy. As a consequence, we are able to identify an amplitude range where positrons/positronium annihilations can be univocally excluded. This prerequisite allows us to exploit the array of external plastic scintillators for antihydrogen annihilations tagging.

By using the Rosetta/OSIRIS-NAC data set taken in 2014 August, we focus on the neck region, called Hapi, located on 67P Churyumov-Gerasimenko's Northern hemisphere. The gravitational potential and slopes of Hapi, coupled with the geological unit identification and the boulder size-frequency distributions, support the interpretation that both taluses and gravitational accumulation deposits observable on Hapi are the result of multiple cliff collapses that occurred at different times. By contrast, the fine-particle deposits observable in the central part of the study area are made of aggregates coming from the Southern hemisphere and deposited during each perihelion passage. Both the consolidated terrains on the western part of Hapi, as well as the centrally aligned ridge made of boulder-like features, suggest that Hapi is in structural continuity with the onion-like structure of the main lobe of 67P. Despite the dusty blanket observable on Hapi, its terrains are characterized by water-ice-rich components that, once repeatedly and rapidly illuminated, sublimate, hence resulting in the strong jet activity observed in 2014 August.© 2019 The Author(s)., The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.

Positronium in the $2^3S$ metastable state exhibits a low electrical polarizability and a long lifetime (1140 ns) making it a promising candidate for interferometry experiments with a neutral matter-antimatter system. In the present work, $2^3S$ positronium is produced - in absence of electric field - via spontaneous radiative decay from the $3^3P$ level populated with a 205nm UV laser pulse. Thanks to the short temporal length of the pulse, 1.5 ns full-width at half maximum, different velocity populations of a positronium cloud emitted from a nanochannelled positron/positronium converter were selected by delaying the excitation pulse with respect to the production instant. $ 2^3S $ positronium atoms with velocity tuned between $ 7 \cdot 10^4 $ m/s and $ 10 \cdot 10^4 $ m/s were thus produced. Depending on the selected velocity, a $2^3S$ production effciency ranging from $\sim 0.8 \%$ to $\sim 1.7%$, with respect to the total amount of emitted positronium, was obtained. The observed results give a branching ratio for the $3^3P$-$2^3S$ spontaneous decay of $(9.7 \pm 2.7) \% $. The present velocity selection technique could allow to produce an almost monochromatic beam of $\sim 1 \cdot 10^3 $ $2^3S$ atoms with a velocity spread $ < 10^4 $ m/s and an angular divergence of $\sim$ 50 mrad.

Nanochanneled silicon targets with high positron/positronium (Ps) conversion rate and efficient Ps cooling were produced. Morphological parameters of the nanochannels, such as their diameter and length, were adjusted to get a large fraction of thermalized Ps at room temperature being emitted into vacuum. Ps cooling measurements were conducted combining single-shot positron annihilation lifetime spectroscopy and Doppler spectroscopy of the 13S → 23P transition. 2γ–3γ annihilation ratio measurements were also performed to estimate the positron/Ps conversion efficiency. In a converter with nanochannel diameter of 7–10 nm and depth of 3.89 μm, ∼28% of implanted positrons with an energy of 3.3 keV was found to be emitted as Ps with a transverse kinetic energy of 11 ± 2 meV. The reduction of the nanochannels depth to 1.13 μm, without changing the nanochannel diameter, was found to result in a less efficient cooling, highlighting the presence of Ps reflection from the bottom end of nanochannels.