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The European Space Agency’s ANALOG-1 experiment is the culmination of 12 distinct METERON experiments carried out since 2011. These all address aspects of teleoperating a robotic asset from an orbital platform, i.e., technical implementation, user interfaces, autonomy and operations. The ANALOG-1 technology demonstration and operations concept experiment is based upon the surface mission scenario segment of the notional EL3 sample return mission. This segment focuses on the control of a lunar surface robotic asset from the Earth and from the Lunar Gateway. The experiment is taking place in two parts, with the first successfully completed from the ISS in November 2019. It assessed the effectiveness of a state-of-the-art robotic control interface to control a complex mobile robot from orbit, as well as evaluating the scientific interactions, during robotic-assisted geology exploration, between crew in orbit and scientists on the ground. Luca Parmitano operated the robot while he was on the ISS. For this experiment, a complex control station had been installed on the ISS. The experiment demonstrated the advantage of having an immersive control station and high level of robotic dexterity, with Luca finishing all his assigned and secondary geology targets ahead of time.

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

32 páginas.- 3 figuras.- 2 tablas.- 260 referencias, Nearly half a century ago, two papers postulated the likelihood of lunar lava tube caves using mathematical models. Today, armed with an array of orbiting and fly-by satellites and survey instrumentation, we have now acquired cave data across our solar system-including the identification of potential cave entrances on the Moon, Mars, and at least nine other planetary bodies. These discoveries gave rise to the study of planetary caves. To help advance this field, we leveraged the expertise of an interdisciplinary group to identify a strategy to explore caves beyond Earth. Focusing primarily on astrobiology, the cave environment, geology, robotics, instrumentation, and human exploration, our goal was to produce a framework to guide this subdiscipline through at least the next decade. To do this, we first assembled a list of 198 science and engineering questions. Then, through a series of social surveys, 114 scientists and engineers winnowed down the list to the top 53 highest priority questions. This exercise resulted in identifying emerging and crucial research areas that require robust development to ultimately support a robotic mission to a planetary cave-principally the Moon and/or Mars. With the necessary financial investment and institutional support, the research and technological development required to achieve these necessary advancements over the next decade are attainable. Subsequently, we will be positioned to robotically examine lunar caves and search for evidence of life within Martian caves; in turn, this will set the stage for human exploration and potential habitation of both the lunar and Martian subsurface., The following funding sources are recognized for supporting several of the contributing authors: Human Frontiers Science Program grant #RGY0066/2018 (for AAB), NASA Innovative Advanced Concepts Grant #80HQTR19C0034 (HJ, UYW, and WLW), and European Research Council, ERC Consolidator Grant #818602 (AGF), the Spanish Ministry of Science and Innovation (project PID2019-108672RJ-I00) and the "Ramon y Cajal" post-doctoral contract (grant #RYC2019-026885-I (AZM)), and Contract #80NM0018D0004 between the Jet Propulsion Laboratory, California Institute of Technology and the National Aeronautics and Space Administration (AA, MJM, KU, and LK).

Póster presentado en Europlanet Science Congress 2022 Granada, Spain 18-23 September 2022

Introduction: Pit craters are peculiar depressions found in almost every terrestrial body of the Solar System [1]–[4]. Morphologically characterized by circular to elliptical shapes, flat rim and no ejecta blankets. Often found aligned to form a pit chain, or even coalesced with other pits. Depending on their morphology and type of alignemt (e.g. sinuous or straight in presence of faults) their origin may be attributed to either tectonic or to the collapse of a lava tube [2]. On the other hand, atypical pit craters can be found isolated with no major additional surface morphological expressions. In this work, we present a morphometric analysis of one of the atypical pit craters found on the flank of Pavonis Mons. The pit central coordinates are Lon -110.80 Lat 0.33 Data: We used a single stereo pair, ESP_033935_1805 - ESP_041900_1805, acquired by the High Resolution and Imaging Science Experiment (HiRISE) [5]and downloaded from NASA ODE-PDS [6]. Morphometric analysis: We created a high-resolution Digital Elevation Model (DEM) with a spatial resolution of 0.5 m/pixel, using a custom Jupyter Lab environment [7] to process the data with the Integrated Software for Imagers and Spectrometers (ISIS) [8] and the Ames Stereo Pipeline [9]. Finally, using QGIS v3.24, we performed the morphometric analysis, summarized in Table 1. Within QGIS, we digitised the shape of the pit, contouring the rim on the orthoimage, where is clearly recognizible the extension of the pit, as shown in Figure 1. Figure 1. In red, the polygon of the pit, designed over the orthoimage. Then we measured the semi-axis of the ellipse inscribing the shape of the pit and, finally, we used the plugin Volume Calculation Tool to compute the volume of the pit. We also computed elevation contour lines at 2 m interval. Figure 2 shows graphically the results of the analysis. Figure 2. Map of the pit, showing the elevation in blue lines. The pit seems to have two main levels of collapse, an upper level with terraces on both sides, one less developed than the other, and the floor base level. The area of the pit covers approximately 7978 m2, with a perimeter of 336 m. The edges of the enveloping hexagon have an average length of 56m. The bottom of the pit is at approx. 9525 m, while the rim has an average elevation of 9583 m, giving a height of ca. 60m. Analysis of the DEM shows two levels of collapse.The volume computation is underestimated due to the uncertainity of the left terrace. This terrace may be the results of the interpolation performed by the ASP algorithms due to the presence of hard shadows in the stereo pair. Considering that this left terrace cover almost half of the pit, we may infer that the estimated volume may be approximately double the measured volume. Further analysis, including shapes-from-shadows, may improve this result. Parameter Value Volume ~ 303.724 m3 measured, ~ 600 m3 estimated. Area 7978 m2 Perimeter 336 m Average side length ~ 56 m Average Max Elevation (RIM) ~ 9583 m Min Elevation (bottom) ~ 9525 m Maximum Depth ~ 60 m Semi-Major axis ~ 60 Semi-Minor axis ~ 90 Table 1. Summary of the parameters of the Hexagonal Pit, retreived by analysing the high-resolution DEM. As the last step, we imported the DEM as a terrain in Unreal Engine 5, to visualize it in simulated different light conditions, as shown in Figure 3. Figure 3. Pit DEM imported into Unreal Engine 5. The virtual sides of the hexagon are shown in red, while in cyan is highlighted the shadowed area in the stereo pair. Conclusion: The pit presented in this work has some unusual characteristics, its uncommon hexagonal shape, and the absence of connected secondary erosional mechanisms such as impact craters and pits could indicate the presence of structural elements that guided the rupture of the surface. Funding: 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: [1] D. Wyrick, D. A. Ferrill, A. P. Morris, S. L. Colton, and D. W. Sims, ‘Distribution, morphology, and origins of Martian pit crater chains’, J. Geophys. Res. Planets, vol. 109, no. E6, 2004, doi: 10.1029/2004JE002240. [2] F. Sauro, R. Pozzobon, M. Massironi, P. D. Berardinis, T. Santagata, and J. D. Waele, ‘Lava tubes on Earth, Moon and Mars: A review on their size and morphology revealed by comparative planetology’, Earth-Sci. Rev., vol. 209, p. 103288, 2020, doi: https://doi.org/10.1016/j.earscirev.2020.103288. [3] G. E. Cushing, ‘Mars Global Cave Candidate Catalog (MGC3)[abstract 3708]’, 2017. [4] I. S. Hong, Y. Yi, J. Yu, and J. Haruyama, ‘3D modeling of lacus mortis pit crater with presumed interior tube structure’, J. Astron. Space Sci., vol. 32, no. 2, pp. 113–120, 2015, doi: 10.5140/JASS.2015.32.2.113. [5] A. S. McEwen et al., ‘Mars Reconnaissance Orbiter’s High Resolution Imaging Science Experiment (HiRISE)’, J. Geophys. Res., vol. 112, no. E5, p. E05S02, May 2007, doi: 10.1029/2005JE002605. [6] PDS Geosciences Nodes, ‘Orbital Data Explorer - Mars Holdings’. 2021. Accessed: Nov. 10, 2020. [Online]. Available: https://ode.rsl.wustl.edu/odeholdings/Mars_holdings.html [7] G. Nodjoumi, C. Brandt, and A. P. Rossi, ‘Open-source planetary data processing environments based on jupyterhub and docker containers.’, p. 2, 2022. [8] J. Laura et al., Integrated Software for Imagers and Spectrometers. Zenodo, 2021. doi: 10.5281/zenodo.5347823. [9] R. Beyer, O. Alexandrov, and S. McMichael, NeoGeographyToolkit/StereoPipeline: NASA Ames Stereo Pipeline 2.6.1. Zenodo, 2018. doi: 10.5281/zenodo.1345235.

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.

The research conducted in recent years has revealed that processes operating at depth play an important role in the morphogenesis of stepped tablelands in Central Europe (SW Poland, N Czechia), underlain by alternating layers of sandstone and fine-grained rocks of the Upper Cretaceous age. It has been demonstrated that underground erosion significantly contributes to the in situ disintegration of the marginal parts of sandstone plateaus and mesas, thereby producing distinctive ruiniform assemblages. They comprise chaotic boulder clusters replacing the cliff-lines, joint-aligned corridors, clefts opened due to the loss of mass from beneath, as well as plazas and courtyards with negligible surface runoff. While the widespread occurrence of sandy cones at the outlets of vertical fissures and allochthonous sandy aprons on the subjacent slopes testifies well to the efficiency of underground erosion, the mechanisms of detachment of sand grains remain unknown. This research aims to elucidate which processes are making the sandstone mechanically incoherent and susceptible for mechanical erosion at depth.In older views weathering processes acting upon sandstone cliff-lines have either remained unspecified or a priori assumed to be mechanical breakdown. Yet, the presence of joint-aligned and highly disintegrated zones, often mimicking the grikes of the ‘classic’ karst terrains, as well as the widespread evidence of sandy detritus removal via subsurface drainage, allowed us to hypothesise that dissolution may be an important but neglected factor responsible for the loss of coherence of the sandstone rock mass.Sandstone samples were collected from both disintegrated and non-disintegrated sandstone cliff-lines, as well as fresh debris originating from a recent rockfall event in one of the rock cities in Czechia. Loose grains of sand, already removed from the caprock and deposited at the foot of rock walls, were investigated too. Scanning electron microscopy equipped with energy dispersive spectrometer (SEM-EDX) was used to study micromorphological changes, diagnostic of intensive chemical weathering. This was supplemented by studies using the polarizing light microscopy, i.e. study of thin sections as well as x-ray diffraction (XRD) accompanied by thermal analysis (DSC-TG) to evaluate mineralogical composition of sandstone and to assess the secondary rock porosity.The preliminary results revealed high degree of etching, mainly of syntaxial quartz overgrowths, with a number of v-shaped or irregularly shaped pits as well as large embayments. Interestingly, SEM-EDX analysis showed the presence of kaolinite, which might conform to the advanced chemical weathering of sandstone as well. It is supposed that solutional processes not only have prepared the rock for further erosional processes and the resultant development of ruiniform relief, but they also contribute to a variety of catastrophic mass movements due to the significant decrease of intact rock strength.The results presented are the first outcomes of the new Q-MESA project (no. 2020/39/D/ST10/00861) funded by the National Science Centre, Poland.

info:eu-repo/semantics/publishedVersion

Lava caves are the result of a geological process related to the cooling of basaltic lava flows. On the Moon, this process may lead to caves several kilometers long and diameters of hundreds of meters. Access to lava tubes can be granted through skylights, a vertical pit between the lava tube and the lunar surface. This represents an outstanding opportunity for long-term missions, for future permanent human settlements, and for accessing pristine samples of lava, secondary minerals and volatiles. Given this, the ESA launched a campaign through the Open Space Innovation Platform calling for ideas that would tackle the many challenges of exploring lava pits. Five projects, including Robocrane, were selected. Solar light and direct line of sight (for communications) with the lunar surface are not available inside lava tubes. This is a problem for any robot (or swarm of robots) exploring the lava tubes. Robocrane tackles both problems by deploying an element (called the Charging head, or CH) at the bottom of the skylight by means of a crane. This CH behaves as a battery charger and a communication relay for the exploring robots. The required energy is extracted from the crane’s solar panel (on the surface) and driven to the bottom of the skylight through an electrical wire running in parallel to the crane hoisting wire. Using a crane allows the system to deal with unstable terrain around the skylight rim and protect the wires from abrasion from the rocky surface and the pit rim. The charger in the CH is wireless so that the charging process can begin as soon as any of the robots get close enough to the CH. This avoids complex and time-consuming docking operations, aggravated by the skylight floor orography. The crane infrastructure can also be used to deploy the exploring robots inside the pit, reducing their design constraints and mass budget, as the robots do not need to implement their own self-deployment system. Finally, RoboCrane includes all the sensors and actuators for remote operation from a ground station. RoboCrane has been designed in a parametric tool so it can be dynamically and rapidly adjusted to input-variable changes, such as the number of exploring robots, their electrical characteristics, and crane reach, etc., This work was supported in part by the Spanish Government under the Project MCIU-19-RTI2018-099682-A-I00 and by ESA under project CN-UE-20-ROBOCRANE.

Raponzolo is a paleo-phreatic cave explored in 2011 in the Brenta Dolomites (Trentino, Italy), at the remarkable altitude of 2,560 m a.s.l. Differently to all other caves of the area, it hosts well-cemented fine to medium sands of granitic-metamorphic composition. The composition suggests a sediment source from the Adamello and Tonale Unit, separated from the Brenta by one of the most important tectonic lineaments of the Alps (Giudicarie Line). The fine-sand sediment was sampled to determine burial time and thus a minimum age of the cave. Cosmogenic isotopes (26Al and 10Be) in quartz grains allowed to estimate a minimum burial age of 5.25 Ma based on the mean sediment transport time at the surface and infer original altitude of the catchment area. Detrital apatite fission-track (AFT) and U-Pb dating on zircons provide information on the source, both from a regional and altitude (exhumation) perspective. Two populations of detrital AFT ages center at 17 (−2.3 + 2.6) Ma and 23 (−3.3 + 3.9) Ma, whereas the main detrital zircon U-Pb age populations are younger than 40 Ma. These correspond to intrusive and metamorphic sources nowadays outcropping exclusively above 2,200–2,300 m a.s.l. in Northern Adamello and Tonale. The results point to a late Miocene erosion and infilling of the cave by allochtonous sediments, with important implications on the timing of cave speleogenesis, as well as the paleogeographical connection, tectonic evolution and uplift of different structural units of the Alps. The roundness and the well sorted size of the quartz grains suggest a fluvial or aeolian origin, possibly recycled by glacial activity related to cold events reported in high latitude areas of the world at 5.75 and 5.51 Ma. These glacial phases have never been documented before in the Alps. This information confirms that the valleys dividing these geological units were not yet deeply entrenched during the onset of the Messinian Salinity Crisis (5.6–5.5 Ma), allowing an efficient transport of sediments across major tectonic lineaments of the Alps. This study shows the potential of cave sediments to provide information not only on the age of speleogenesis but also on the paleogeography of a wide area of the Alps during the late Miocene., Frontiers in Earth Science, 9, ISSN:2296-6463

Quartz sandstone of the Sarisarinama massif in Venezuela hosts the world biggest collapse dolines in quartz-rich lithologies, with volumes up to some millions of cubic meters. Due to extremely complex logistics required to reach the massif, the genesis of these depressions and of the underlying caves has never been studied in detail. The lack of field campaigns and extended data has fostered a decade-long scientific debate on whether their origin was due to epigenic or hypogenic processes. This study integrates petrological, structural and hydrochemical observations, including analyses of silica concentration, pH, conductivity of surface and cave waters (EC), to investigate the speleogenetic processes acting underground. Petrographic and compositional analyses of the host rock (Mataui Formation) show that in the Sarisarinama region quartz sandstones are regularly characterized by clay interlayers with significant content of pyrophyllite and kaolinite and minor amount of iron hydroxides. Compared to surface waters, subsurface infiltration along vertical fractures and fault planes show enrichment in silica, higher pH and lower EC, confirming that chemical weathering is effective underground provoking intergranular silica dissolution along structural discontinuities. The weathering of the clay and iron hydroxide interlayers guides the speleogenesis, weakening specific stratigraphic levels and causing the collapse and fragmentation of the more resistant quartz sandstone strata. The initial void, created by piping of the loose sand released by quartz sandstone weathering, can migrate upwards by means of roof and wall breakdown; this chain of events eventually triggers a collapse at the surface, which generates a circular or squared sinkhole. The weathering acts mainly along the dominant fracture networks, showing a clear guidance by regional tectonics. These speleogenetic controls rule out the hypothesis of a hypogenic origin of the simas, suggesting a primary role of long-term epigenic chemical weathering and mechanical erosion guided by joints, weak clay and iron hydroxide interlayers, followed by subsequent massive collapses.

2 páginas.- 1 figura.- 16 referencias, To the Editor — 2021 is the International Year of Caves and Karst. To honour this occasion, we wish to emphasize the vast potential embodied in planetary subsurfaces. While researchers have pondered the possibility of extraterrestrial caves for more than 50 years, we have now entered the incipient phase of planetary caves exploration....

Research on planetary caves requires cross-planetary-body investigations spanning multiple disciplines, including geology, climatology, astrobiology, robotics, human exploration and operations. The community determined that a roadmap was needed to establish a common framework for planetary cave research. This white paper is our initial conception

The orthoquartzite Imawarì Yeuta cave hosts exceptional silica speleothems and represents a unique model system to study the geomicrobiology associated to silica amorphization processes under aphotic and stable physical–chemical conditions. In this study, three consecutive evolution steps in the formation of a peculiar blackish coralloid silica speleothem were studied using a combination of morphological, mineralogical/elemental and microbiological analyses. Microbial communities were characterized using Illumina sequencing of 16S rRNA gene and clone library analysis of carbon monoxide dehydrogenase (coxL) and hydrogenase (hypD) genes involved in atmospheric trace gases utilization. The first stage of the silica amorphization process was dominated by members of a still undescribed microbial lineage belonging to the Ktedonobacterales order, probably involved in the pioneering colonization of quartzitic environments. Actinobacteria of the Pseudonocardiaceae and Acidothermaceae families dominated the intermediate amorphous silica speleothem and the final coralloid silica speleothem, respectively. The atmospheric trace gases oxidizers mostly corresponded to the main bacterial taxa present in each speleothem stage. These results provide novel understanding of the microbial community structure accompanying amorphization processes and of coxL and hypD gene expression possibly driving atmospheric trace gases metabolism in dark oligotrophic caves.

Caves remain among the most challenging exploration frontiers on planet Earth. They are difficult to access, present a range of unique and unusual environmental characteristics, and can only be mapped through direct human exploration. These challenges and several environmental factors specific to caves mean that speleology shares several analogies with space missions. For humans, cave exploration imposes isolation, confinement, minimal privacy, technical challenges, limited equipment and supplies, a sense of disconnect from the surface and regular life, a lack of diurnal cycles, and the constant presence of risk. As many of the same challenges are imposed on humans during space exploration, in 2005 the European Space Agency (ESA) began examining the possibility of using natural cave systems as a platform for astronaut training. These efforts resulted in a new ESA training programme named CAVES ( C ooperative A dventure for V aluing and E xercising human behaviour and performance S kills) being launched in 2011, involving astronauts from partner space agencies. The primary objective of this training is to enhance astronaut individual and team performance and behavioural competencies by exposing them to the challenges of a real mission into an unknown and dangerous environment. To achieve this, the course's training activities are based around a real scientific and technological programme focused on cave science. Many aspects of the location and course content have been designed by a team of behavioural experts, scientists, trainers, operations engineers and speleologists with the support of caving organizations and schools. CAVES training events leverage cave exploration to create situations that are analogues to spaceflight in terms of safety protocols, perception and management of risk, crew composition and role assignments, group living, isolation, and confinement. In addition, these courses provide an opportunity for astronauts to experience spaceflight-like or relevant operations, science, equipment testing, and exploration, in preparation for future planetary endeavours. The scientific, exploration and equipment testing aspects of the course are real (not simulated). This ensures that these activities provide benefits to the speleological and scientific communities, whilst guaranteeing the realism of these activities for training purposes. During six editions of CAVES, from 2011 to 2019, 34 astronauts from 6 different space agencies (ESA, NASA, JAXA, ROSCOSMOS, CSA and CNSA) have taken part in the training. The CAVES training programme has been recognized by all participant astronauts and, in particular, by those who have travelled to space, as one of the best space analogue training opportunities available on Earth. The learning outcomes are applicable to both current and future orbital missions, as well as surface and subsurface missions to other planetary bodies.

Machine Learning (ML) has found several applications in spectroscopy, including being used to recognise minerals and estimate elemental composition. In this work, we present novel methods for automatic mineral identification based on combining data from different spectroscopic methods. We evaluate combining data from three spectroscopic methods: vibrational Raman scattering, reflective Visible-Near Infrared (VNIR), and Laser-Induced Breakdown Spectroscopy (LIBS). These methods were paired into Raman + VNIR, Raman + LIBS and VNIR + LIBS, and different methods of data fusion applied to each pair to classify minerals. The methods presented here are shown to outperform the use of a single data source by a significant margin. Additionally, we present a Deep Learning algorithm for mineral classification from Raman spectra that outperforms previous state-of-the-art methods. Our approach was tested on various open access experimental Raman (RRUFF) and VNIR (USGS, Relab, ECOSTRESS), as well as synthetic LIBS NIST spectral libraries. Our cross-validation tests show that multi-method spectroscopy paired with ML paves the way towards rapid and accurate characterization of rocks and minerals., 11 pages

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

Future human missions to the surface of the Moon and Mars will involve scientific exploration requiring new support tools to enable rapid and high quality science decision-making. Here, we describe the PANGAEA (Planetary ANalogue Geological and Astrobiological Exercise for Astronauts) Mineralogical Database developed by ESA (European Space Agency): a catalog of petrographic and spectroscopic information on all currently known minerals identified on the Moon, Mars, and associated with meteorites. The catalog also includes minerals found in the analog field sites used for ESA's geology and astrobiology training course PANGAEA, to broaden the database coverage. The Mineralogical Database is composed of the Summary Catalog of Planetary Analog Minerals and of the Spectral Archive and is freely available in the public repository of ESA PANGAEA. The Summary Catalog provides essential descriptive information for each mineral, including name (based on the International Mineralogical Association recommendation), chemical formula, mineral group, surface abundance on planetary bodies, geological significance in the context of planetary exploration, number of collected VNIR and Raman spectra, likelihood of detection using different spectral methods, and bibliographic references evidencing their detection in extraterrestrial or terrestrial analog environments. The Spectral Archive provides a standard library for planetary in-situ human and robotic exploration covering Visual-Near-Infrared reflective (VNIR) and Raman spectroscopy (Raman). To populate this library, we collected VNIR and Raman spectra for mineral entries in the Summary Catalog from open-access archives and analyzed them to select the ones with the best spectral features. We also supplemented this collection with our own bespoke measurements. Additionally, we compiled the chemical compositions for all the minerals based on their empirical formula, to allow identification using the measured abundances provided by LIBS and XRF analytical instruments. When integrated into an operational support system like ESA's Electronic Fieldbook (EFB) system, the Mineralogical Database can be used as a real-time and autonomous decision support tool for sampling operations on the Moon, Mars and during astronaut geological field training. It provides both robust spectral libraries to support mineral identification from instrument outputs, and relevant contextualized information on detected minerals.

Meghalaya (NWIndia) is one of the regions in theworldwith highest recorded rainfalls. Because of these peculiar climatic conditions and intense solutional weathering, karstic caves are widely reported in the numerous limestone areas of this part of India. Likewise, the extremely high rainfall and the tropical monsoon climate have fostered the formation of several caves in silicate-rich lithologies. The most important of these caves is Krem Puri, over 25.5 km long, characterized by a fracture-controlled labyrinth forming a bi-dimensional maze with mostly phreatic morphologies and some recent, still active, vadose entrenchments. A detailed petrographic study of the host rocks has shownthis cave to be formed along a set of quartzarenite, hybrid arenite and calcarenite layers in a mostly siliciclastic sedimentary succession. XRF elemental analysis of the different rock strata guiding the speleogenesis confirms that the early stage of cave development is confined mainly in the calcium carbonaterich layers. Geochemical analyses carried out on water flowing in the cave (drips, streams) have shown that carbonate dissolution is the dominant chemical weathering process contributing to Krem Puri water solutes, whereas the dissolution of quartz, feldspars and clays play only a secondary role in rock weathering. The morphology of the cave points to a lithology-guided dissolution of the carbonate-rich layers and piping of the residual quartz sand in phreatic conditions, when the surface river network was not yet evolved and the water table was at the level of or higher than the cave. This phreatic speleogenetic phase predates the start of river network entrenchment (that started not earlier 5 Ma ago, and probably accelerated around 3.5 Ma), which deactivated the karst maze. With a lowdenudation rate of 0.15mm/yr, this active phreatic cave level,which currently lies beneath a more or less 120 m overburden, was originally covered by a sedimentary sequence at least 1–2kmthick. After its decoupling fromthe underground drainage system, denudation slowly brought the surface close to the maze system gradually introducing infiltration of vadose waters into the conduits. This caused the formation of the vadose entrenchments probably b100 ka ago, and carbonate speleothem deposition in the cave.

Sinuous collapse chains and skylights in Lunar and Martian volcanic regions have often been interpreted as collapsed lava tubes (also known as pyroducts, [1]). This hypothesis has fostered a forty years debate among planetary geologists trying to define if analogue volcano-speleogenetic processes acting on Earth could have created similar subsurface linear voids in extra-terrestrial volcanoes. On Earth lava tubes are well known thanks to speleological exploration and mapping in several shield volcanoes, with examples showing different genetic processes (inflation and overcrusting [1, 2, 3]) and morphometric characters. On the Moon subsurface cavities have been inferred from several skylights in maria smooth plains [4], and corroborated using gravimetry and radar sounder [5, 6] while on Mars several deep skylights have been identified on lava flows with striking similarities with terrestrial cases [7]. Nonetheless, a clear understanding of the potential morphologies and dimensions of martian and lunar lava tubes remains elusive. Although it is still impossible to gather direct information on the interior of martian and lunar lava tube candidates, scientists have the possibility to investigate their surface expression through the analysis of collapses and skylight morphology, morphometry and their arrangement, and compare these findings with terrestrial analogues. In this work we performed a morphological and morphometric comparison with lava tube candidate collapse chains on Mars and the Moon. By comparing literature and speleological data from terrestrial analogues and measuring lunar and martian collapse chains on satellite images and digital terrain models (DTMs), this review sheds light on tube size, depth from surface, eccentricity and several other morphometric parameters among the three different planetary bodies. The dataset here presented indicates that martian and lunar tubes are 1 to 3 orders of magnitude more voluminous than on Earth and suggests that the same processes of inflation and overcrusting were active on Mars, while deep inflation and thermal entrenchment was the predominant mechanism of emplacement on the Moon. Even with these outstanding dimensions (with total volumes exceeding 1 billion of m3), lunar tubes remain well within the roof stability threshold. The analysis shows that aside of collapses triggered by impacts/tectonics, most of the lunar tubes could be intact, making the Moon an extraordinary target for subsurface exploration and potential settlement in the wide protected and stable environments of lava tubes. References [1] Kempe, S., 2019. Volcanic rock caves, Encyclopedia of Caves (Third edition). Academic Press, pp. 1118-1127 [2] Calvari, S. and Pinkerton, H., 1999. Lava tube morphology on Etna and evidence for lava flow emplacement mechanisms. Journal of Volcanology and Geothermal Research, 90(3-4): 263-280. [3] Sauro, F., Pozzobon, R., Santagata, T., Tomasi, I., Tonello, M., Martínez-Frías, J., Smets, L.M.J., Gómez, G.D.S. and Massironi, M., 2019. Volcanic Caves of Lanzarote: A Natural Laboratory for Understanding Volcano-Speleogenetic Processes and Planetary Caves, Lanzarote and Chinijo Islands Geopark: From Earth to Space. Springer, pp. 125-142. [4] Haruyama, J., Morota, T., Kobayashi, S., Sawai, S., Lucey, P.G., Shirao, M. and Nishino, M.N., 2012. Lunar holes and lava tubes as resources for lunar science and exploration, Moon. Springer, pp. 139-163. [5] Chappaz, L., Sood, R., Melosh, H.J., Howell, K.C., Blair, D.M., Milbury, C. and Zuber, M.T., 2017. Evidence of large empty lava tubes on the Moon using GRAIL gravity. Geophysical Research Letters, 44(1): 105-112 [6] Kaku, T., Haruyama, J., Miyake, W., Kumamoto, A., Ishiyama, K., Nishibori, T., Yamamoto, K., Crites, S.T., Michikami, T. and Yokota, Y., 2017. Detection of intact lava tubes at marius hills on the moon by selene (kaguya) lunar radar sounder. Geophysical Research Letters, 44(20). [7] Cushing, G.E., 2012. Candidate cave entrances on Mars. Journal of Cave and Karst Studies, 74(1): 33-47

Chemical mobility of crystalline and amorphous SiO2 plays a fundamental role in several geochemical and biological processes, with silicate minerals being the most abundant components of the Earth’s crust. Although the oldest evidences of life on Earth are fossilized in microcrystalline silica deposits, little is known about the functional role that bacteria can exert on silica mobility at non-thermal and neutral pH conditions. Here, a microbial influence on silica mobilization event occurring in the Earth’s largest orthoquartzite cave is described. Transition from the pristine orthoquartzite to amorphous silica opaline precipitates in the form of stromatolite-like structures is documented through mineralogical, microscopic and geochemical analyses showing an increase of metals and other bioessential elements accompanied by permineralized bacterial cells and ultrastructures. Illumina sequencing of the 16S rRNA gene describes the bacterial diversity characterizing the consecutive amorphization steps to provide clues on the biogeochemical factors playing a role in the silica solubilization and precipitation processes. These results show that both quartz weathering and silica mobility are affected by chemotrophic bacterial communities, providing insights for the understanding of the silica cycle in the subsurface.

Quartz is considered one of the less soluble minerals of the Earth's crust, and thus hardly affected by chemical weathering. Despite this, for more than forty years, it is clear that the formation of caves and peculiar solutional weathering dominated landforms in quartz-rich lithologies is common and shares several similarities to the well-known karstic ones in carbonate rocks. In the last thirty years great strides have been made in furthering our knowledge of the distribution of these forms around the world, and the geochemical processes involved. These studies have clearly shown that solutional weathering is a fundamental process, acting through intergranular dissolution of quartz increasing the rock porosity and decreasing the rock strength to erosion. This process has been described in the concepts of ‘arenization’ and ‘phantomization’ and the widespread evidences of the fundamental role of quartz solution in landform genesis has even developed to the extent of several geomorphologists reassessing the definition of the term ‘karst’, and its application to these peculiar lithologies. Nonetheless the process is complicated by several factors, related both to environmental conditions (water chemistry and availability) as well as to the compositional and textural characters of the lithology (presence of clays, iron hydroxides, carbonate cement, etc.). All these aspects have to be taken carefully in consideration in order to understand if solution is a dominant or accessory process in the landscape evolution. In this review the state of knowledge on the relevant chemical processes, weathering mechanisms, and speleogenesisk involved in the surface and underground karstification, and clear examples of quartz solution and solutional landforms from different world locations, are outlined and discussed.

none 4 no Terrestrial laser scanning (TLS) is increasingly used in geomorphology for the study of medium- to small scale landforms. A light weight, compact and portable TLS device has been used in the Grotta A Cave (Mt. Lessini, N Italy) to make a detailed 3D model of the underground environment. A total of 16 scans were used to survey the about 150 m long cave in b6 h. The 3D model of the cave walls makes it possible to carry out morphometric measurements on the different cave environments. The TLS data allowed us to calculate cave volumes and distinguish cupola, phreatic conduit and basalt dike volumes. Wall roughness analysis also allowed recognising smaller- scale morphologies such as megascallops, differential corrosion forms and mineral crusts. These observations have enabled us to discern between different karstification processes and speleogenetic phases, highlighting the importance of condensation-corrosion on the cave passage enlargement in a quantitative way. open Fabbri, Stefano; Sauro, Francesco; Sant'Agata, Tommaso; De Waele, Jo Fabbri, Stefano; Sauro, Francesco; Sant'Agata, Tommaso; De Waele, Jo

Over the past 15 years several expeditions by French, American and especially Italian cavers have unveiled over 50 caves in the Cordillera de la Sal (Atacama Desert, Northern Chile). Many of these caves contain a variety of speleothems and minerals, some of which have rarely been observed within karst systems. Most of the secondary deposits in these caves are composed of halite, but also other halide, carbonate, sulphate, nitrate, phosphate, and silicate minerals have been found. Among the sixteen cave mineral species recognized, atacamite, darapskite, blödite, leonite, anhydrite, and especially antarcticite are worth mentioning. In one of the samples an unknown Ca-Sr-bearing chloride mineral has also been discovered, but it has not been possible to carry out detailed mineralogical analyses. These often-rare minerals have formed in this region due to the very extreme hyperarid and salt-rich environment. This research reports the mineralogical results and proposes the genetical mechanisms leading to the formation of antarcticite, powdery anhydrite, and the paragenesis of the halite-darapskite-blödite. This study also shows that Atacama caves may be excellent analogues to study weathering processes and subsurface secondary minerals in hyperarid and hypersaline environments on Mars.

The deep subsurface of other planetary bodies is of special interest for robotic and human exploration. The subsurface provides access to planetary interior processes, thus yielding insights into planetary formation and evolution. On Mars, the subsurface might harbour the most habitable conditions. In the context of human exploration, the subsurface can provide refugia for habitation from extreme surface conditions. We describe the fifth Mine Analogue Research (MINAR 5) programme at 1 km depth in the Boulby Mine, UK in collaboration with Spaceward Bound NASA and the Kalam Centre, India, to test instruments and methods for the robotic and human exploration of deep environments on the Moon and Mars. The geological context in Permian evaporites provides an analogue to evaporitic materials on other planetary bodies such as Mars. A wide range of sample acquisition instruments (NASA drills, Small Planetary Impulse Tool (SPLIT) robotic hammer, universal sampling bags), analytical instruments (Raman spectroscopy, Close-Up Imager, Minion DNA sequencing technology, methane stable isotope analysis, biomolecule and metabolic life detection instruments) and environmental monitoring equipment (passive air particle sampler, particle detectors and environmental monitoring equipment) was deployed in an integrated campaign. Investigations included studying the geochemical signatures of chloride and sulphate evaporitic minerals, testingAnalog researchastrobiologyMarssubsurfacetechnology methods for life detection and planetary protection around human-tended operations, and investigations on the radiation environment of the deep subsurface. The MINAR analogue activity occurs in an active mine, showing how the development of space exploration technology can be used to contribute to addressing immediate Earth-based challenges. During the campaign, in collaboration with European Space Agency (ESA), MINAR was used for astronaut familiarization with future exploration tools and techniques. The campaign was used to develop primary and secondary school and primary to secondary transition curriculum materials on-site during the campaign which was focused on a classroom extra vehicular activity simulation., We thank the Science and Technology Facilities Council (STFC) for their support of the Boulby Underground Science Facility in which MINAR5wasconducted. Knowledge gainedin the execution of STFC grant, ST/M001261/1, was used to advance objectives in MINAR 5. We thankCleveland Potash and ICL for their generous in-kind and logistics supportto MINAR and the underground science facility with which MINAR is made possible.Boris Laurent is funded by a Leverhulme Trust Research Project Grant, RPG-2016-071. SPLIT Research and Developmenthas been fundedby three research grants (UKSA CREST and STFC’s Follow on Fund) between 2013 and 2017, with support in 2018 by CREST to realise a TRL 5 flight type prototype instrument.Jon Telling (gas analysis development) is funded in part by UK Space Agency grant ST/R001421/

A hybrid numerical, finite differences and semi-analytical/empirical model has been developed to evaluate the spatial and time scale of chemical weathering along a fracture in quartz sandstones. The model is based on the diffusion transport occurring from the bedrock mass toward the fracture walls driven by the SiO2 concentration gradient between water in the bedrock pores (high silica content) and water flowing in the fracture (low silica content). Because of molecular diffusion, intergranular water becomes undersaturated with respect to silica. This promotes dissolution of quartz at grain boundaries and results in a porosity profile decreasing from the fracture walls toward the rock interior. Bedrock individual grains are released and gradually removed by the water flowing into the fracture when a critical value of porosity is reached (Grain Release Threshold, GRT): this process drastically increases the fracture enlargement rate. The model outcomes establish a minimum time of 90 ka to reach the GRT. This time is independent of length, aperture and dip of the fracture, but is controlled by parameters such as the initial fracture aperture, water temperature, quartz grain size, and initial bedrock porosity. It is attested that the water flowing in the fracture remains undersaturated with respect to silica over very long timescales (in the order of 105 years) and over very long flow paths. In turn, this suggests that the extremely slow reaction between quartz and water is the key-factor for the formation of subterranean karst-like features in quartz sandstone, otherwise silica saturation would be reached after short distances and deep weathering in this lithology would be prevented. Finally, the model outcomes were compared to field data from the Gran Sabana caves (Venezuela) and other quartz sandstone weathering landforms elsewhere, showing that dissolution/diffusion in the rock matrix is a reliable mechanism for the formation of these peculiar karst-like features.

The volcanic island of Lanzarote hosts an impressive variety of cavities formed by different volcanic processes. The presence of well preserved lava fields belonging to historic eruptions and more ancient and weathered quaternary and pliocene terrains and the association with an arid climate provide the unique opportunity of studying volcanic caves at different stages of evolution on the same volcanic island. The different mechanisms of lava tube emplacement can be observed in great detail, from the most recent pyroducts of different sizes formed during the Timanfaya eruption (1730–1736) to the exceptionally voluminous conduits of the Corona volcano, formed during the Last Glacial Maximum and partially submerged by the sea level upraise during the Holocene. In addition, other type of cavities, like explosive and geyser vents, “hornitos” and sinkholes in pyroclastic deposits offer the opportunity to extend the study to other important volcano-speleogenetic processes in different settings. All these cavities are easily accessible and present a variety of morphological, mineralogical, biological and microbiological significances, allowing for a wide range of multidisciplinary studies. The countless analogies with lava tube collapses and other potential volcanic cave features detected on the Moon and Mars also provide an unprecedented research ground that offers hints to solve some open issues in the interpretation of still unresolved planetary cavities. These characteristics make the Lanzarote and Chinijo Islands UNESCO Global Geopark an exceptional case where the protection and scientific outreach has been extended to the volcanic subsurface. In this chapter we offer a review of the current knowledge and existing scientific studies on the volcanic caves of Lanzarote and we discuss future researches and protection issues that need to be addressed in order to fully include this geoheritage in strategic plans of environmental protection.

Scientific exploration will play an important role in future human missions to the Moon and Mars. Extra-Vehicular Activities (EVA) on the surface of these objects will be supported by a host of technologies driving operations and data collection. In order to enhance the scientific return of each EVA and utilise expertise located on Earth, it is necessary to record, index and store all the scientific information collected on a planetary surface, and rapidly distribute it amongst the relevant mission support personnel in a structured way. How this information is stored and shared amongst mission support elements will make a significant difference to the feedback that can be provided to EVA teams before, during, and after exploratory EVAs. The Electronic Fieldbook (EFB) is an innovative information system, developed by the European Space Agency (ESA) in the context of their astronaut field training courses and test campaigns, composed of deployable hardware and software designed to fulfil this role. The system uses peer-to-peer networking and mesh protocols to provide disruption tolerant data transmission, as well as information harmonisation and sharing among all system users. Its software stack is platform agnostic, and the system is able to interface with external instruments and tools to gather and centralise data. A combination of commercial off the shelf and custom hardware currently supports the EFB network and interfaces. Users can collect scientific data and document sampling procedures through attaching images, instrument readings, written and audio notes, and other metadata, and have it automatically distributed to all authorised users across its network. Through this system, the EFB enables real-time situational awareness to all science instructors and simulated mission support positions, such as mission control, science backrooms, and Intra-Vehicular crew. The EFB has been developed in the context of the CAVES and PANGAEA astronaut training programmes developed by ESA and is targeting deployment in future lunar and Martian human exploration missions.

Summary In situ measurements of discharge, pH, electric conductivity (EC), temperature, and SiO2 content have been carried out during five expeditions in the last 20 years on the summit plateaus, inside caves and along the rivers of the surrounding lowlands of three tepui massifs in Venezuela (Auyan, Roraima, and Chimanta). Additionally, detailed chemical analyses were performed on waters sampled in a newly discovered extensive quartz-sandstone cave system on the Auyan Tepui. Rock samples of the quartz-sandstone bedrock from different locations have been analysed to obtain their chemical composition with a wavelength dispersive X-ray fluorescence spectrometer. These data show that the majority of silica present in surface and subsurface water comes from dissolution of quartz and only in minor amount from hydrolysis of other silicate minerals. Probably the presence of a hardened crust of iron hydroxides limits the dissolution of silica on the top surface of tepuis. Dissolution in the subsurface, instead, is more significant and causes, in the long term, the “arenisation” of the quartz-sandstone and its subsequent removal by mechanical erosion. On the other hand, waters flowing on the arkosic rock outcropping on the lowland below the tepuis obtain their high dissolved silica content mainly from hydrolysis of silicates. The morphological evolution of these table mountains appears thus to be controlled mainly by the underground weathering of the quartz-sandstone, with the opening of deep fractures (grietas) and the collapse of large underground horizontal cave systems. Scarp retreat, instead, seems to be related to the higher weathering rate of the more arkosic formations underlying the quartz-sandstones.

This paper presents new results of the application of passive seismic surveys for the stratigraphic investigation of planetary volcanic analogues. We tested HVSR (Horizontal-to-Vertical Spectral Ratio) surveys that seem particularly suitable for planetary subsurface exploration. In order to exploit the potential of these surveys in stratigraphic applications, HVSR surveys were undertaken at the Tinguaton volcanic region (Lanzarote, Canary Islands). Seismic noise measurements were collected during the PANGAEA-X 2018 testing campaign which formed part of the European Space Agency's (ESA) astronaut training program. Single-station, free-field seismic noise data were collected along two orthogonal profiles, one crossing the Tinguaton volcano, the other passing alongside the Tinguaton caldera. Seismic stratigraphic sections obtained from the shear wave velocity constrained inversion of the main H/V peaks provided the main impedance contrasts between layers and a bulk estimate of the shear wave velocity in the layers. Contour maps of the HVSR patterns were used to recognize and identify the main volcanic units, such as scoria deposits and different basaltic lava flows, geological structures, such as a regional fault related to the volcanic vent source, and morphological characteristics, such as the Tinguaton caldera. This study also identified several pitfalls that may limit the accuracy of such investigations. These include the multilayer setting of scoria deposits and, partly, of underlying basalts, as well as the presence of very thin horizons or a very gradual increase in shear wave velocity. Our study also shows the topographic effect due to the volcano's sharp topography along crater rim is significant and results in severe artifacts in the data. From our work, it is clear that HVSR method is an effective method to support the investigation of planetary volcanic terrains on the Moon and Mars with similarly volcanic complex geological settings, even where horizontal layering and the isotropic site response are not fully verified.