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Human activities are territorialising and commodifying Mars. Areopolitically reexploring the planet is a pressing necessity as outer space actors have increasingly been operating there for several decades, intensifying thus the interaction. This paper argues that territory and resources are being made on the basis of a novel theoretical framework in the involved sub-fields of geography that it formalises, utilises, and advances: the resources-state-territory nexus and, more specifically, the resources-territory sub-nexus. The unprecedented application of a nexus thinking on areopolitics allows to analyse both sectors simultaneously. This study is informed by the Foucauldian apparatus and is grounded in the conceptual breakthroughs of object-oriented ontology. The discourses and materials, actually conceivable as objects, of the Martian endeavour are that way critically investigated to uncover the dynamics of the nexus. It results that areometrics not only creates territory but influences the creation of resources and, parallelly, that commodity frontiers not only create resources but influence the creation of territory. This interdependence is the core of the sub-nexus. Besides, the exclusive robotic mediation of the relationship with the Red Planet calls for an examination of its implications. Pointing out probe-power further brings to light the bonds between the territorial sub-elements, terrain and land, and resources through the stress it exercises on these interconnections. It also strengthens territory by creating a bridge between its constitutive sub-elements. Hence, the terrain- and land-resources bonds prove to be more substantial than the main sub-nexus, which renders the questions of territory and resources even more inseparable. [ABSTRACT FROM AUTHOR]

During the development activities of SuperCam Calibration Target, target intended for one of the two first Raman instruments to be deployed on another planetary body, our group developed a laboratory instrument that could simulate to some extent the Raman capabilities of one of such instruments and could provide data with similar quality. The use of this kind of laboratory instruments has demonstrated its utility in the evaluation of potential calibration targets or anticipating the science outcome that an instrument could provide. The present work describes our laboratory setup to support SuperCam, evaluating similarities between both instruments, despite of differences in the hardware. Evaluation of data gathered by SuperCam on Mars and the availability of one replica of SuperCam's Calibration Target allowed the comparison on the same set of targets, demonstrating how similar Signal-to-Noise Ratio (SNR) could be achieved from both instruments. The higher energy per pulse on SimulCam is compensated by a greater analytical footprint and the use of smaller collection optics. The results show how spectra obtained at representative distances of SuperCam are comparable. Operational principles are also comparable in terms of time resolution, and close in terms of spectral resolution. This similarity has allowed different science support works using SimulCam data, as well as the support to Mars detections using our setup. We provide examples of this support that will be shared with the community in different papers, as well as examples of possible operations activities that could benefit from experiments performed with SimulCam. We show how this setup can complement the two laboratory replicas in Los Alamos and Toulouse in providing support data to different experiments. [ABSTRACT FROM AUTHOR]

Identifying surface sites with significant astrobiological potential on Mars requires a comprehensive understanding of past geological processes and conditions there, including the shallow subsurface region. Numerical modelling could distinguish between regions dominated by erosion and those characterized by sediment accumulation in ancient wet environments. The target area of Jezero Crater is relatively well explored and thus is an ideal site to evaluate model calculations; however, important works are still missing on expectations related to its shallow subsurface. In this work, the best available approaches were followed, and only surface morphology was considered (supposedly formed by the last fluvial episode). The shallow subsurface became an important target recently, and this model could provide new inputs in this area. Erosion–accumulation models are suitable for terrestrial surface features, but few have been applied to Mars. This work addresses this challenge using the SIMWE (SIMulated Water Erosion) model on the Jezero Crater delta, the landing site of the Perseverance rover. For calculations, the average grain size according to the THEMIS TI data was applied to the target area. The flow depth varied between 1.89 and 34.74 m (average of 12.66 m). The water-filled channel width ranged from 35.3 to 341.42 m. A flow velocity of 0.008–11.6 m/s, a maximum erosion rate of 5.98 g/m2/h, and a deposition 4.07 g/m2/h were estimated. These calculated values are close to the range of estimations from other authors assuming precipitation of 1–20 mm/h and discharges of 60–400 m3/s. The model was able to distinguish between erosion- and accumulation-dominated areas about 1 m above Jezero Crater's delta that are not visible from above. This model helps to identify the accumulation-dominated areas with the finest grain size with good preservation capability for the shallow but invisible subsurface. [ABSTRACT FROM AUTHOR]

The three largest impact craters, the remains of which have been found on Earth to date, had diameters of about 200 km immediately after formation. The search for traces of larger impact structures continues. This paper presents the results of numerical modeling of the formation of terrestrial impact craters larger than those already found. It is shown that the inferred geothermal gradient significantly influences the initial geometry of the impact melt region, which may facilitate the search for the remains of deeply eroded ancient impact structures. [ABSTRACT FROM AUTHOR]

Caves on Mars are a tantalizing target for exploration, as they could harbor evidence of extinct or extant life, clues to the planet's geological history, and even potential future human habitation. However, the inherent challenges of navigating unknown and challenging terrain, coupled with limited communication capabilities, pose significant obstacles for robotic exploration in these caves. This paper presents the results of an effort to evaluate different operational concepts for a mission dedicated to exploration of caves on Mars. We conducted a series of analog exploration experiments in lava tubes on Earth, testing two hypotheses: (1) that two robots are more effective than one, and (2) that high levels of autonomy are more effective than low levels of autonomy. Our findings suggest that two robots are indeed more effective, except in low autonomy cases, where more operational resources are required. We also found that full autonomy is more efficient than low autonomy, as it enables quicker exploration and detection of targets of interest. However, the low autonomy cases benefited from the operator input to acquire higher quality data, an area of autonomy requiring further development. This paper provides insight into the design of our experiments, as well as detailing the results and implications for the design of future missions to explore caves on Mars. By shedding light on the operational concepts tested and their corresponding outcomes, we contribute to the knowledge base required to formulate optimal strategies for the realization of successful cave exploration missions on the Red Planet. [Display omitted] • We report on analog experiments for a multi-robot Martian cave exploration mission. • Full autonomy was shown to be more efficient than low autonomy (operator waypoints). • Two robots were shown to be more effective than one for scientific exploration. • Work is needed to improve autonomy for detailed scientific measurements. [ABSTRACT FROM AUTHOR]

The article explores Charles S. Peirce's taxonomy of sign classes, which aims to categorize signs based on Firstness, Secondness, and Thirdness. Scholars have proposed various solutions to organize the sixty-six classes of signs, discussing trichotomic analysis, degenerations of categories, and the application of universal categories to sign aspects. The text introduces the concept of semiostasis to explain semiosis processes, detailing phases of semiosis and cognitive capacities like perceiving/acting and comprehension/instructing. A periodic table of sign classes is presented, organizing classes into periods and phases to understand the communication of signs in semiosis, emphasizing the importance of universal semiotics and the participatory nature of minds. [Extracted from the article]

This article explores the controversy surrounding the colonization of Mars, presenting arguments from both proponents and critics. Proponents, such as Elon Musk and Robert Zubrin, argue that colonizing Mars is crucial for human survival and technological progress. However, critics like Mary-Jane Rubenstein and Deondre Smiles raise ethical concerns about the rights of microbial life, rocks, and indigenous peoples. The article also mentions the growing opposition to space colonization, calling for regulation and consideration of anti-imperialism. It emphasizes the importance of considering diverse perspectives and not underestimating the opposition to private space travel. [Extracted from the article]

The search for biosignatures on Mars has been a high priority for astrobiology. The approach to detecting putative biosignatures has largely been focused on chemical analyses targeting predominantly extinct life. However, this approach has limited the characterization of extant life, preventing differentiation between extinct and extant biosignatures. Detecting an extant martian lifeform requires approaches focused on identification of biological features. Identifying potential features of life, such as growth or reproduction, can contribute evidence necessary to identify extant biosignatures. While an unambiguous extant biosignature might not be possible with biologically focused approaches, the combined data can provide supporting evidence to attribute a biosignature to an extinct or extant lifeform in conjunction with flight tested instrumentation. With upcoming initiatives, such as the planned Mars Sample Return campaign and the Mars Life Explorer mission concept, the incorporation of extant life specific analysis is paramount for the future of Mars exploration. [ABSTRACT FROM AUTHOR]

European Space Agency's Mars Express (MEX) has been orbiting Mars for 20 years and its instruments have provided a plethora of observations of atmospheric dust and clouds. These observations have been analysed to produce many unique views of the processes leading to dust lifting and cloud formation, and a full picture of the climatologies of dust and clouds has emerged. Moreover, the orbit of MEX enables viewing the planet at many local times, giving a unique access to the diurnal variations of the atmosphere. This article provides an overview of the observations of dust and clouds on Mars by MEX, complemented by the Trace Gas Orbiter that has been accompanying MEX on orbit for some years. [ABSTRACT FROM AUTHOR]

On Earth, carbonate minerals are widely used as recorders of the geological environments in which they formed. Here, we present a method designed to retrieve the crystal chemistry of Fe‐Mg carbonate minerals using infrared remote sensing or Raman spectroscopy. We analyzed a suite of well‐characterized Fe‐Mg carbonate minerals for which Raman spectra were obtained in two different laboratories, and IR spectra were measured in reflectance and transmission from the visible range to 25‐μm. We built calibration lines for the dependence of fundamental and harmonic vibrational modes position to the Mg# (defined as Mg# = 100 × Mg/(Mg + Fe + Ca + Mn)). These calibrations should enable retrieval of Mg# based on spectroscopic observations with a typical accuracy of 10. We discuss the framework of applicability of these calibrations and apply them to a typical CRISM spectrum of carbonates from the Nilli Fossae region of Mars. Key Points: Fundamental FeMg carbonate mode position have a linear dependence to Mg# for Fe‐Mg carbonate mineralHarmonic bands at 2.3 and 2.5 also have a linear dependence of their position with Mg# for Fe‐Mg carbonate mineralsWe present calibration curves of Mg# versus fundamental and harmonic vibration position than can be used to retrieve crystal chemistry [ABSTRACT FROM AUTHOR]

The Chandler period of Mars is a new parameter determined from observational data that characterizes the properties of the planetary interior. Numerical modeling of the period of the Chandler wobble of Mars was performed for a number of internal structure models that satisfy not only geodetic data (moment of inertia, tidal Love number k2), but also data obtained during a seismic experiment in the years 2019–2022. To reconcile the theoretical and observed values of the Chandler wobble, it is necessary to take into account the inelasticity of the mantle. To take into account the viscoelastic behavior of the interior, the Andrade rheological model was used. It is demonstrated how the value of the Chandler period depends on the rheological model parameters. [ABSTRACT FROM AUTHOR]

Nakhlites (clinopyroxene-rich cumulates) and chassignites (dunites) are two types of meteorites that were emplaced onto — and subsequently ejected from— the surface of Mars together, but their petrogenetic history has been difficult to discern. We studied the primary magmatic history preserved in zoning patterns of cumulus phases from a suite of nakhlites and chassignites. Samples studied include nakhlites Northwest Africa (NWA) 11013, NWA 10645, Governador Valadares, Caleta el Cobre 022, Nakhla, Miller Range 090032, and NWA 817, as well as chassignites NWA 2737 and Chassigny. In nakhlite and chassignite olivine, phosphorous (P) preserves primary magmatic signatures, and P 2 O 5 ranges from ∼<0.01–0.21 wt %; in nakhlite pyroxene, chromium (Cr) zoning corresponds to Cr 2 O 3 abundances between ∼0.03 and 0.36 wt %. We find that nakhlite pyroxene cores uniformly formed rapidly for a time at high crustal pressures, and then slowly at near-equilibrium under lower crustal pressures. Pyroxene in the nakhlites were then stored through multiple injections of magma prior to remobilization, eruption, and final crystallization. Nakhlite olivine cores are morphologically heterogenous throughout the suite, but all record rapid initial crystallization prior to equilibrium formation, followed by resorption in changing magma compositions. Both olivine and pyroxene in the nakhlites are antecrysts, as they initially formed in a different magma than that in which they erupted. Chassignites underwent very rapid initial undercooling, and record later changes in magma conditions, resulting in thin elemental oscillatory zoning patterns in olivine grains. Together, the cumulus phases of the nakhlite and chassignite suite, combined with petrological evidence from martian shergottite meteorites, suggest that significant magmatic undercooling is the rule rather than the exception for martian magmatic systems. This may relate to the stalling of magmas within the thicker crust of Mars, fostering crystal storage with significant temperature differences between injected magmas and crystal mushes. [ABSTRACT FROM AUTHOR]

The article explores the potential benefits of inducing hibernation or torpor in humans for long-duration space travel. It discusses the hibernation abilities of the thirteen-lined ground squirrel and ongoing research into the brains of hibernating animals. The collaboration between BioServe and Fauna Bio to develop an incubator for hibernating squirrels in space is mentioned. The article also discusses the potential applications of hibernation for human spaceflight missions, including the preservation of muscle mass and mitigation of radiation effects. While there are still many unknowns and challenges, scientists are hopeful that with further research and the development of drugs and techniques, hibernation could be utilized for future missions to Mars. [Extracted from the article]

In this paper, optimal gliding trajectories are analyzed, formulating an optimal control problem to be solved computationally via nonlinear programming. A multi-objective terminal cost function that minimizes the velocity, altitude, horizontal flight path angle, and the error of a desired terminal point is formulated. The results are validated via Monte Carlo simulations, analyzing the influence of the variations in the lift-to-drag ratios in the atmospheric entry. The results show feasible solutions for minimizing the distance to the desired final point, which have significant practical implications for the controlled gliding entry of a spaceplane on Mars. In this sense, the results also show that the longitudes of the landing points do not change too much for almost all trajectories, while the latitude of these points is in the interval of about 4 degrees for the majority of the trajectories. This suggests that it is possible to implement an optimal control approach with reasonable accuracy for the controlled gliding entry of a spaceplane on Mars, even in the presence of some uncertainties regarding the aerodynamic performance of the spacecraft, such as the lift-to-drag ratio. [ABSTRACT FROM AUTHOR]

A model-based surface fluvial erosion and deposition approach was adapted to Martian conditions to forecast the potential locations for shallow subsurface sampling by the Rosalind Franklin ExoMars rover at Oxia Planum. While remote and on-site images show only the surface visible features, former fluvial-related accumulation sites might be hidden. During the fluvial activity, most accumulation-related areas are interesting with regard to clay-like sediments, which could adsorb organics effectively—such sites could be identified by modeling. By applying the SIMWE fluvial erosion/deposition model, substantial variability in accumulation and deposition-dominated areas with their specific pattern and spatial distribution could be outlined, indicating that sophisticated targeting of future sampling could use such a model-based approach. At the main valley-like feature, former water flow tracks were identified, as well as deposition-dominated locations, which are the best targets for shallow subsurface sampling. Joint evaluation of safety aspects like slope angle and loose sand dunes with scientific aspects provide the best sampling locations. Such model-based targeting is important as by using only orbital images, these locations could not be identified. [ABSTRACT FROM AUTHOR]

Magma ocean crystallization models that track fO2 evolution can reproduce the D/H ratios of both the Earth and Mars without the need for exogenous processes. Fractional crystallization leads to compositional evolution of the bulk oxide components. Recent work suggests that metal‐saturated magma oceans may contain near‐present‐day Fe3+ concentrations. We model the fractional crystallization of Earth and Mars, including Fe2+ and Fe3+ as separate components. We calculate Fe3+ partition coefficients for lower mantle minerals and compare the results of fractional crystallization for both Earth and Mars. We calculate oxygen fugacity (fO2) at the surface as the systems evolve and compare them to constraints on the fO2 of the last magma ocean atmosphere from D/H ratios, both with and without metal saturation. For Earth, we find that Fe3+ likely behaves incompatibly in the lower mantle in order to match the D/H constraint for whole mantle models, but shallow magma ocean models also provide reasonable matches. Disproportionation in whole mantle magma oceans likely overpredicts the amount of Fe3+ and metal that form or require subsequent reduction to return to present‐day values. For Mars, we cannot match the D/H constraints on last fO2 unless the magma ocean begins with <50% of the predicted Fe3+, but better match the present day mantle redox. We show that Fe3+ partitioning has a measurable effect on magma ocean redox, and that it evolves throughout the magma ocean's lifetime. We highlight the need for additional experimental constraints on ferric iron mineral/melt partitioning and more thermodynamic data for the Fe‐disproportionation reaction. Plain Language Summary: During the formation of planets such as Earth and Mars, many undergo a stage in which their rocky mantles are almost fully molten, called a magma ocean. The crystallization of different minerals as the magma ocean cools leads to changes in the composition of the melt. The melt maintains contact with the atmosphere throughout this stage, so changes in the melt's composition, especially the availability of oxygen, can lead to changes in the atmosphere's composition. In this paper, we use a model that looks at how the melt's composition changes, with a special focus on how different types (or species) of iron (Fe2+, Fe3+) behave as minerals form. We tested different depths of the magma oceans and initial compositions. For Earth, shallow magma ocean models produce results that agree with information that we have about the composition of the last atmosphere in contact with the magma ocean better than whole mantle models. For Mars, all of the models produce similar results but predict too much Fe3+ formation to be successful in recreating the last atmosphere, but match present‐day Mars relatively well. Key Points: We model mineral/melt partitioning during magma ocean crystallization using new Fe3+ partition coefficients for lower mantle mineralsWe calculate oxygen fugacity (fO2) of outgassing at the surface for Earth and Mars magma oceans and match to constraints from planetary D/HFor Earth, fractionated shallow magma ocean models (<1,000 km) match constraints, but Mars must start Fe3+‐depleted to match constraints [ABSTRACT FROM AUTHOR]

The northern inlet channel to Jezero crater (Sava Vallis) terminates in a fan‐shaped depositional feature, part of which blends into the separate well‐known western fan delta that is the field site for the Mars 2020 mission's Perseverance rover. Jezero's northern fan potentially represents either a second fan delta within the crater or a distal portion of the western fan. To constrain the fluvial and sedimentological history of Jezero and place the rover's in situ observations in proper geologic context, we photogeologically map the northern fan deposits at a larger mapping scale than previous studies, using ground‐based imaging from the Perseverance rover for context. Fifteen map units are identified using HiRISE‐based interpretations of geologic characteristics and inferred processes as well as crosscutting relative age relationships. Mapped units are also defined based on orbital data from CRISM and THEMIS to assess their compositional signatures. We interpret the northern fan deposits as older than the uppermost blocky unit in the western fan delta, suggesting that they were deposited contemporaneously with or prior to the deposition of the western fan, and under similar climate conditions. The eastern portion of the northern fan deposits shows evidence of fluvial deposition from Sava Vallis, while part of its western side could represent a distal part of the western fan delta. We synthesize our interpretations to present scenarios for the deposition of the northern and western fans, which can help constrain the history of both watersheds and place it into context within the broader Isidis basin region. Plain Language Summary: The Mars 2020 Perseverance rover has primarily focused on using its scientific instruments to study the delta along Jezero crater's western margin. But there are fan‐shaped features that appear to originate from both the crater's western and northern channels ‐ Neretva Vallis and Sava Vallis, respectively. In this project, we compile orbital images, spectroscopy data sets, and images taken by the rover's Mastcam‐Z instrument to investigate whether the northern fan originated from the northern channel or is an outlying part of the western delta. Based on these observations and the geologic map created using them, we show that the northern fan deposits are older than the uppermost unit mapped in the western delta. We also demonstrate how the western portion of the northern fan deposits could be an outer part of the western delta, while the eastern portion may preserve material from Sava Vallis. We show that some units across the northern and western fans are the same or similar, making this work useful as the rover's mission continues. Finally, we present scenarios that could lead to what we see in Jezero today, helping us to understand the potential history of this area and the relationship between the northern and western watersheds. Key Points: Deposition of Jezero crater's northern fan predates that of its western fan blocky material—the western delta's uppermost surficial unitThe northern fan shows evidence of deposition from Sava Vallis, but part of its western region could be a distal part of the western deltaThe stratigraphic and depositional hypotheses presented provide context for the Mars 2020 mission and help constrain the history of both watersheds [ABSTRACT FROM AUTHOR]

The results of numerical modeling of the values of the Chandler wobble period of Mars have been presented for a set of internal structure models that satisfy all currently available observable data: geodetic (average radius, mass, moment of inertia, tidal Love number k2) and crustal thickness and core radius values obtained from seismic data processing. Andrade rheology was used to take into account inelasticity when calculating model values of the tidal Love number k2 and the Chandler wobble period. It has been shown how the model values of the Love number k2 and the Chandler period depend on the Andrade rheological parameter and the adopted viscosity distribution. [ABSTRACT FROM AUTHOR]

This study presents a global database of pitted cones on Mars. This database was created using an active deep-learning approach based on a global mosaic of Mars Context Camera (CTX) images, followed by extensive manual verification. The global database contains 250,547 pitted cones along with their central coordinates and diameters. 94.2% of the pitted cones have diameters ranging from 100 m to 1 km. Most of them are in the northern lowlands, while some are scattered in the southern highlands. Systematic evaluation of the extracted pitted cones is performed in Isidis Planitia, Acidalia Planitia, and Cerberus Palus on Mars. The results reveal that the precision ranges from 79.2% to 85.6%, and the recall rate ranges from 62.4% to 87.7%, indicating a varying among regions but satisfactory performance. Manual digitizing evaluation indicates that over 94.1% of manual labels by different annotators have a differentiation rate of 10%, showing promising precision and consistency. This global database can facilitate further research on the origin and evolution of pitted cones on Mars. [ABSTRACT FROM AUTHOR]

One-third of Mars' surface has shallow-buried H2O, but it is currently too cold for use by life. Proposals to warm Mars using greenhouse gases require a large mass of ingredients that are rare on Mars' surface. However, we show here that artificial aerosols made from materials that are readily available at Mars--for example, conductive nanorods that are ~9 micrometers long--could warm Mars >5 × 103 time smore effectively than the best gases. Such nanoparticles forward-scatter sunlight and efficiently block upwelling thermal infrared. Like the natural dust of Mars, they are swept high into Mars' atmosphere, allowing delivery from the near-surface. For a 10-year particle lifetime, two climate models indicate that sustained release at 30 liters per second would globally warm Mars by >30 kelvin and start to melt the ice. Therefore, if nanoparticles can be made at scale on (or delivered to) Mars, then the barrier to warming of Mars appears to be less high than previously thought. [ABSTRACT FROM AUTHOR]

Understanding the longevity of Mars's dynamo is key to interpreting the planet's atmospheric loss history and the properties of its deep interior. Satellite data showing magnetic lows above many large impact basins formed 4.1-3.7 billion years ago (Ga) have been interpreted as evidence that Mars's dynamo terminated before 4.1 Ga—at least 0.4 Gy before intense late Noachian/early Hesperian hydrological activity. However, evidence for a longer-lived, reversing dynamo from young volcanics and the Martian meteorite ALH 84001 supports an alternative interpretation of Mars's apparently demagnetized basins. To understand how a reversing dynamo would affect basin fields, here we model the cooling and magnetization of 200-2200 km diameter impact basins under a range of Earth-like reversal frequencies. We find that magnetic reversals efficiently reduce field strengths above large basins. In particular, if the magnetic properties of the Martian mantle are similar to most Martian meteorites and late remagnetization of the near surface is widespread, >90% of large (> 800 km diameter) basins would appear demagnetized at spacecraft altitudes. This ultimately implies that Mars's apparently demagnetized basins do not require an early dynamo cessation. A long-lived and reversing dynamo, unlike alternative scenarios, satisfies all available constraints on Mars's magnetic history. Weak magnetic fields above Mars's large impact basins are often interpreted as a signature of the dynamo's early cessation. Here, the authors demonstrate that these weakly magnetic basins may instead have formed in a long-lived but reversing dynamo. [ABSTRACT FROM AUTHOR]

Soil being a naturally formed material, the prediction and analysis of anchor uplift capacity incorporating the inherent variabilities in the soil properties is essential. This paper presents a probabilistic analysis of horizontal strip anchors in spatially varying soil using the multivariate adaptive regression splines (MARS) as a prediction model. The use of MARS in spatially varying soils is proposed, and its advantage over the conventional expensive Monte Carlo simulations is reported in this paper. The soil cohesion and friction angle have been modeled as lognormal random fields, and the influence of the spatially distributed soil properties on the anchor uplift capacity is assessed in the current study. Furthermore, a comparison between the deterministic and reliability-based design methodologies is presented, and their implications on the design of foundation are discussed. The results indicate that the code-specified factor of safety (FOS) value of 1.5 does not fulfill the target probability of failure ( P f ) values recommended in probabilistic design. A minimum FOS = 2 is required to satisfy the P f ≤ 0.001 criteria, which is usually recommended for the design of foundations. [ABSTRACT FROM AUTHOR]

Chide et al. [J. Acoust. Soc. Am. 155, 420–435 (2024)] provide a first attempt to infer the spectrum of temperature fluctuations on Mars from experimental data on the variances of travel-time and log-amplitude fluctuations recorded by the microphone on board the Perseverance rover. However, the theoretical formulations that were used to interpret the travel-time data have limitations. In addition to explaining those issues, this article also outlines approaches for predicting statistical characteristics of acoustic signals in the Martian atmosphere. In particular, the experimentally observed dependence of the travel-time variance on the propagation range can be attributed to ground-blocking of buoyantly produced turbulent velocity fluctuations and the non-Markov character of phase fluctuations. [ABSTRACT FROM AUTHOR]

Recent seismological studies of the Martian core revealed its relatively low density, suggesting the presence of large amounts of light elements including oxygen and carbon in addition to sulfur. In order to reveal crystallizing solids in the light-element-rich core of Mars, we performed high-pressure melting experiments on Fe-S-O-C alloys at 26–49 GPa using a laser-heated diamond-anvil cell. The liquidus phase relations in the Fe-S-O-C system were determined based on textural and chemical characterizations of recovered samples. The results show that Fe-S-O-C liquids crystallize FeO or Fe 3 C in the presence of small amounts of O or C in liquids. Accordingly the liquidus fields of Fe 3 S and Fe 2 S are small, and the quaternary eutectic point is found to be close to the Fe-Fe 3 S binary eutectic point. Under Martian core conditions, S-rich liquids have low liquidus temperatures to crystallize FeO or Fe 3 C compared to S-poor liquids. The pressure dependence of liquidus temperatures suggests that crystallization of Mars' core starts at the center upon cooling. According to the FeO-Fe 3 C cotectic surfaces and their liquidus temperatures, an FeO and/or Fe 3 C inner core is predicted unless the Martian core remains entirely liquid. [ABSTRACT FROM AUTHOR]

Auto-semantic segmentation is important for robots on unstructured and dynamic environments like planets where ambient conditions cannot be controlled and the scale is larger than that found indoors. Current learning-based methods have achieved breathtaking improvements on this topic. For onboard applications, however, all those methods still suffer from huge computational costs and are difficult to deploy on edge devices. In this paper, unlike previous transformer-based SOTA approaches that heavily relied on complex design, we proposed Light4Mars, a lightweight model with minimal computational complexity while maintaining high segmenting accuracy. We designed a lightweight squeeze window transformer module that focuses on window-scale feature extraction and is more effective in learning global and local contextual information. The aggregated local attention decoder is utilized to fuse semantic information at different scales, especially for unstructured scenes. Since there are few all-terrain datasets for semantic segmentation of unstructured scenes like Mars, we built a synthetic dataset SynMars-TW, referencing images collected by the ZhuRong rover on the Tianwen-1 mission and the Curiosity rover. Extensive experiments on SynMars-TW and the real Mars dataset, MarsScapes show that our approach achieves state-of-the-art performance with favorable computational simplicity. To the best of our knowledge, the proposed Light4Mars-T network is the first segmentation model for Mars image segmentation with parameters lower than 0.1M. Code and datasets are available at https://github.com/CVIR-Lab/Light4Mars. [ABSTRACT FROM AUTHOR]

High temporal resolution of measurements of the magnetic field and plasma of Mars is provided by observations on the Mars Atmosphere and Volatile Evolution (MAVEN; Jakosky et al., 2015) satellite, making it possible to analyze thin layers of the plasma envelope of Mars. This paper describes the magnetic structure associated with the daytime Martian magnetopause. It was shown that the solar wind passing through the shock wave on the dayside of Mars does not directly interact with the Martian ionosphere. A layer of plasma and magnetic field 200–300 km thick forms the daytime magnetosphere, which is the region between the magnetosheath and the ionosphere (Vaisberg and Shuvalov, 2020). There are two types of daytime magnetosphere: (1) the more common type of magnetosphere consists of heated and accelerated O+ ions and , located between the ionosphere and the flowing hot stream of Mars; (2) another type of daytime magnetosphere consists of accelerated O+ ions and in the magnetosheath, where they form a continuing accelerated beam, forming a plume. Between the magnetosheath and the magnetosphere there is a magnetic structure that rotates, almost without changing its size. This structure is located in the second part of the np/(np + nh) transition from ~1 to ~10–2. The transition between the magnetosheath and magnetosphere occurs smoothly, both in energy density and in ion composition, with a decrease in the proton flux and an increase in the heavy ion flux. [ABSTRACT FROM AUTHOR]

Mars has nearly ideal conditions for CO2 dissociation by glow discharge plasmas. The directly generation of O2 and CO on Mars was considered to be feasible and practical for in situ resource utilization of Martian atmosphere to get respirable O2 and fuel. In this paper, we conduct several experiments under simulated Martian conditions to investigate the process and how the key parameters effect the generation of O2 and CO in CO2 glow discharge reactions. The yields of new products (i.e., O2 and CO) under various gas discharge work parameters (i.e., discharge power, frequency, voltage, gap between the discharge plane electrodes and gas pressure) were systematically investigated. The reaction mechanism and reaction path of CO2 glow discharge has been discussed. In our study the max yield of O2 by CO2 discharge dissociation was got about 21.8 g/h at 168 W which is very close to that of NASA MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) at the same power. Our results showed the great potentiality of glow discharge for the practicable technology of O2 and CO generation for in-situ resource utilization on Mars. [ABSTRACT FROM AUTHOR]

• The current state of research on Martian ISRU-based binder systems is shown and summarized. • The recommended research directions for Martian ISRU-based binders are described. • Future studies while being subjected to the simulated harsh Martian environment are recommended. The harsh environmental conditions on Mars require building materials that are highly resilient. The cost of transporting binder ingredients for construction materials to Mars is very high. In-situ resource utilisation (ISRU) of Martian resources can help minimise the transportation costs. This review discusses the proposed direction of future investigations to achieve high resiliency and minimal cost for Martian ISRU-based binders. The Martian ISRU-based binders can be bio-based, magnesium-based, polymer-based, geopolymer-based, metal-based or sulphur-based. The review focuses strictly on studies related to the investigation of binder systems produced by utilising simulated in-situ Martian resources. It is divided into sections based on the characteristics of the binder system. Important properties that are investigated include rheological properties, mechanical properties, radiation-shielding properties, and abrasion resistance. The recommended research directions for each Martian ISRU-based binder and other future works related to the key properties are described at the end of this manuscript. This review provides an overview of the potential directions of future research and strongly advocates for additional studies that simulate the behaviour of potential Martian ISRU-based binder systems for use in construction applications in the harsh environment of Mars. [ABSTRACT FROM AUTHOR]

NASA and the Department of Defense are planning for a mission to Mars in the 2030s-2040s using nuclear thermal propulsion (NTP). NTP uses a nuclear reactor to heat flowing hydrogen and create thrust. A serious concern for crewed and uncrewed missions to Mars is the loss of reactor control. The reactor startup and initial rocket impulse are initiated in cislunar or near-earth orbital regions; therefore, radio communications between ground control and the NTP engine should occur in real time. However, radio communications can take more than 20 min, depending on planet positions, to reachMars orbiters fromground control. To address this delay, local autonomous controls are implemented onboard the NTP engine to ensure acceptable operation. However, autonomous controls have not been demonstrated or implemented in research or power reactor contexts because of safety and reliability concerns. To enable autonomous controls development, demonstration, and validation, Oak Ridge National Laboratory has created a nonnuclear hardware-in-the-loop test bed. Sensors throughout the test bed relay system status and hardware response to the user control algorithm, including measurements of temperature, flow, pressure of a loop, control drum position, and drum speed. This paper discusses the development of this facility and user accessibility. [ABSTRACT FROM AUTHOR]

Measurements of Ar and N2 densities at 160–250 km altitude from the Mars Atmosphere and Volatile Evolution (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) during February 2015–February 2023 are analyzed to provide a comprehensive analysis of their diurnal‐ and zonal‐mean (DZM) structures, and ZM (solar‐synchronous) diurnal (DW1) and semidiurnal (SW2) tides. After applying a solar flux trend correction, multi‐year binning and averaging with respect to longitude, local solar time (LST), latitude and Ls at each height results in the first full global picture of these components of the ZM thermosphere for a single climatological Mars year. The following new observational insights into Mars thermosphere are obtained: The DZM N2 latitude versus Ls (latvsLs) structures contain a prominent latitudinally‐symmetric annual component (∼±25%–35%) due to the eccentricity of Mars orbit around the Sun, and an antisymmetric component (∼±30%–45%) below about 190 km that is seasonally‐symmetric and thus consistent with the tilt of Mars rotation axis. Aperiodic deviations from these symmetries increase with height and are tentatively attributed to dissipation of waves originating in the lower atmosphere. DW1 and SW2 maximize around 200–220 km altitude, suggesting existence of an unknown dissipation mechanism at higher altitudes. The DZM, DW1 and SW2 components of Ar generally exceed those of N2 by factors of 1.4–2.5. The scale heights of Ar and N2 between 205 and 245 km are also employed to derive DZM exosphere temperatures, which reflect aperiodic ∼±15K deviations from the annual‐mean in the latvsLs frame. Key Points: DZM of N2 and Ar densities (160–250 km) at Mars contain periodic latitude‐Ls variabilities due to Mars eccentric orbit and its axial tiltAperiodic latitude‐Ls variabilities in DZM N2 and Ar are potentially attributable to dissipation of waves from the lower atmosphereDZM exosphere temperatures derived from N2 and Ar scale heights (205–245 km) are aperiodic in the latitude‐Ls frame and are of order ±15K [ABSTRACT FROM AUTHOR]

Chloride deposits are markers for early Mars' aqueous past, with important implications for our understanding of the martian climate and habitability. The Colour and Stereo Surface Imaging System (CaSSIS) onboard ESA's Trace Gas Orbiter provides high-resolution color-infrared images, enabling a planet-wide search for (small) potentially chloride-bearing deposits. Here, we use a neural network to map potentially chloride-bearing deposits in CaSSIS images over a significant fraction of the planet. We identify 965 chloride deposit candidates with diameters ranging from <300 to >3000 m, including previously unknown deposits, 136 (~14%) of which are located in the highlands north of the equator, up to ~36°N. Northern chloride candidates tend to be smaller than in the south and are predominantly located in small-scale topographic depressions in low-albedo Noachian and Hesperian highland terranes. Our new dataset augments existing chloride deposit maps, informs current and future imaging campaigns, and enables future modelling work towards a better understanding of the distribution of near-surface water in Mars' distant past. [ABSTRACT FROM AUTHOR]

We introduce a novel analytical model of the growth of barchan dunes in terms of their two flanks, from which we derive expressions for the size‐dependence of the bilateral asymmetry of these bedforms in three cases where different mechanisms dominate the growth process. Analysis of the morphology of barchans on Mars and Earth suggest that there may exist two distinct attractor states for the asymmetry distribution. By comparing our analytical results with the observations, we show that the growth of barchan dunes appears to be dominated by processes, which are proportional to the basal area or volume of the bedforms, rather than being linear to their width as is typically assumed. We propose hypotheses explaining area‐dominated growth as a result of variable wind regimes and volume‐dominated growth from collisions. These predictions appear to be in line with the available data for the terrestrial swarms and barchan‐like submarine bedforms and offer the potential of predicting patterns in inaccessible wind regimes from data on the morphology of the dunes. [ABSTRACT FROM AUTHOR]

Barchans are eolian dunes of crescent shape found on Earth, Mars and other celestial bodies. Among the different types of barchan‐barchan interaction, there is one, known as chasing, in which the dunes remain close but without touching each other. In this paper, we investigate the origins of this barchan‐barchan dune repulsion by carrying out grain‐scale numerical computations in which a pair of granular heaps is deformed by the fluid flow into barchan dunes that interact with each other. In our simulations, data such as position, velocity and resultant force are computed for each individual particle at each time step, allowing us to measure details of both the fluid and grains that explain the repulsion. We show the trajectories of grains, time‐average resultant forces, and mass balances for each dune, and that the downstream barchan shrinks faster than the upstream one, keeping, thus, a relatively high velocity although in the wake of the upstream barchan. In its turn, this fast shrinkage is caused by the flow disturbance, which induces higher erosion on the downstream barchan and its circumvention by grains leaving the upstream dune. Our results help explaining the mechanisms behind the distribution of barchans in dune fields found on Earth and Mars. Plain Language Summary: Barchans are crescent‐shaped wind‐formed dunes that grow when the wind is roughly unidirectional and the amount of sand is limited (typically, over a non‐erodible ground). They are found in dune fields on Earth and Mars, where barchan dunes interact with each other, forming different field patterns. One first question that arises is why, in some cases, two nearby barchans do not touch each other. Is there a repulsion mechanism? In this paper, we investigate the barchan‐barchan dune repulsion by carrying out numerical computations of the motion of the fluid and each grain forming a pair of barchans. The outputs are detailed measurements of both fluid and grains, such as trajectories, forces, and mass balances, and they show that the downstream barchan shrinks faster than the upstream one. The results also show that the faster shrinkage is due to the fluid flow disturbance caused by the upstream barchan: the fluid impacts the downstream dune, increasing its erosion at the same time that it entrains further downstream part of grains coming from the upstream dune. As a result, the downstream barchan moves at the same pace or faster than the upstream dune, though receiving grains from the latter (which only loses grains). Key Points: We investigate numerically both the fluid flow and motion of grains for understanding the mechanisms behind barchan‐barchan dune repulsionWe measure the flow rate of grains and show that there is, indeed, greater erosion on the downstream barchanThe disturbed flow impacting the downstream barchan induces higher erosion (of its grains) and low accumulation (of upstream grains) [ABSTRACT FROM AUTHOR]

Here we present water vapor vertical profiles observed with the ExoMars Trace Gas Orbiter/Nadir and Occultation for MArs Discovery instrument during the perihelion and Southern summer solstice season (LS = 240°–300°) in three consecutive Martian Years 34, 35, and 36. We show the detailed latitudinal distribution of H2O at tangent altitudes from 10 to 120 km, revealing a vertical plume at 60°S–50°S injecting H2O upward, reaching abundance of about 50 ppmv at 100 km. We have observed this event repeatedly in the three Martian years analyzed, appearing at LS = 260°–280° and showing inter‐annual variations in the magnitude and timing due to long term effects of the Martian Year 34 Global Dust Storm. We provide a rough estimate of projected hydrogen escape of 3.2 × 109 cm−2 s−1 associated to these plumes, adding further evidence of the key role played by the perihelion season in the long term evolution of the planet's climate. Plain Language Summary: Studying the vertical distribution of the Martian atmosphere is crucial to understand what happened to the water presumably present in larger abundance on ancient Mars. We have analyzed the vertical profiles of three Martian Years during the Southern summer, revealing a strong vertical transport of water vapor to the upper atmosphere. This seasonal phenomenon seems to be repeated annually, although with variations in the location and time of the year. Our estimation of the associated upward hydrogen flux represents an important loss which could have contributed to the escape of water to space for at least the period in which Mars had its present orbital inclination. Key Points: Latitudinal distributions of water vapor up to 120 km are analyzed in detail using Nadir and Occultation for MArs Discovery (NOMAD) observations with an improved retrieval schemeWater vapor injection during the perihelion localized around 50°–60°S in three consecutive Martian yearsMartian year 34 Global Dust Storm may have affected the driving mechanisms of the plume, delaying its appearance and reducing its magnitude [ABSTRACT FROM AUTHOR]

HiRISE images and digital elevation models (DEMs) of outcrops in candidate Martian glaciovolcanoes provide more detailed evidence for glaciovolcanic processes than has previously been available for Mars. A group of ridges in the Pavonis Mons fan‐shaped glacial deposit features pervasive layering, evidence for local collapse and slumping, and steeper faces in the direction of paleoglacier flow inferred from other features in the deposit. After comparison with terrestrial analogs, we conclude that these ridges are excellent candidates for tephra‐dominated tindar, formed in phreatomagmatic subglacial eruptions. The englacial meltwater lakes required for a phreatomagmatic origin represent a rare example of voluminous surface water bodies in the Late Amazonian of Mars. Plain Language Summary: Steep‐sided landforms in glacial deposits next to volcanoes are good places to look for evidence that lava and ice interacted. We studied high‐resolution images of a steep‐sided ridge in a glacial deposit on the Pavonis Mons volcano on Mars, and used two of the images to make a 3‐D model of the ridge. The distinctly layered beds of rock that make up the ridge, the depressions in nearby ridges, the evidence that part of the ridge collapsed while it was being built, and the way the slope of the ridge changes with location are very similar to landforms on Earth called "tephra‐dominated tindar". This suggests that the Martian ridge formed in a long‐lived body of liquid water, which have been very uncommon on Mars for the past few hundred million years. Key Points: A steep‐sided ridge in the Pavonis Mons glacial deposits comprises a fractured lower unit overlain by layers dipping away from the crestIts steepness and layering are similar to effusion‐dominated tuyas and tephra‐dominated tindar. Morphology and context favor the latterThis implies substantial ice melting and that liquid water remained to interact with the growing edifice, unusual for late Amazonian Mars [ABSTRACT FROM AUTHOR]