Slope streaks are prevalent and intriguing dark albedo surface features on contemporary Mars. Slope streaks are readily observed in the equatorial and subequatorial dusty regolith regions with low thermal inertia. They gradually fade over decadal timescales. The proposed mechanisms for their formation vary widely based on several physicochemical and geomorphological explanations. The scientific community is divided in proposing both dry and wet mechanisms for the formation of slope streaks. Here we perform a systematic evaluation of the literature for these wet and dry mechanisms. We discuss the probable constraints on the various proposed mechanisms and provide perspectives on the plausible process driving global‐scale slope streak formation on contemporary Mars. Although per our understanding, a thorough consideration of the global distribution of slope streaks, their morphology and topography, flow characteristics, physicochemical and atmospheric coincidences, and terrestrial analogies weighs more in favor of several wet mechanisms, we acknowledge that such wet mechanisms cannot explain all the reported morphological and terrain variations of slope streaks. Thus, we suggest that explanations considering both dry and wet processes can more holistically describe all the observed morphological variations among slope streaks. We further acknowledge the constraints on the resolutions of remote sensing data and on our understanding of the Martian mineralogy, climate, and atmosphere and recommend continuous investigations in this direction using future remote sensing acquisitions and simulations. In this regard, finding more wet and dry terrestrial analogs for Martian slope streaks and studying them at high spatiotemporal resolutions can greatly improve our understanding.

The study of past and future climatic variations in the Hindu Kush–Himalayan (HKH) region is a well-documented topic of scientific research. Recent studies have highlighted the significantly higher rates of warming in the HKH region compared to the global average. The HKH region has the largest reserves of glacial ice outside the poles. These glaciers are predominantly known to be sensitive indicators of changing regional and global climate. The large geographical extent, high elevation and perennial inclemency in weather conditions project remote sensing as the only viable option to study glacial characteristics periodically on a regional scale. The present chapter starts with a review of significant studies to assess the extent of climate change in the HKH. Climate-sensitive glacial markers which can be studied using remote sensing are identified. The chapter focuses on the key markers such as changes in glacier extents, glacier facies and supraglacial debris, and mass balance and thickness. The chapter examines these markers separately with respect to changing climate through recent remote sensing-based studies. It provides an overview of recent studies which deal with regional scale glaciological monitoring and assessment. The conclusive section of the chapter suggests the future role of remote sensing applications in studying these markers of climate change. The chapter uses recent studies to highlight key aspects that should be kept in perspective while undertaking remotely sensed glacial assessments.

utside of established RSL regions and further prompt the inclusion of a new geographical region within the RSL candidate group. Our inferences on the RSL candidates are based on several morphological and geophysical evidences and analogies: (i) the dimensions of the RSL candidates are consistent with confirmed mid-latitude RSL; (ii) albedo and thermal inertia values are comparable to those of other mid-latitude RSL sites; and (iii) features are found in a summer season image and on the steep and warmest slopes. These results denote the plausible presence of transient liquid brines close to the previously proposed landing ellipse of the ExoMars rover, rendering this site particularly relevant to the search of life. Further investigations of Mawrth Vallis carried out at higher spatial and temporal resolutions are needed to identify more of such features at local scales to maximize the scientific return from the future Mars rovers, to prevent probable biological contamination during rover operations, to evade damage to rover components as brines can be highly corrosive, and to quantify the ability of the regolith at mid-latitudes to capture atmospheric water which is relevant for in-situ-resource utilization.

Aeolian processes are believed to play a major role in the landscape evolution of Mars. Investigations on Martian aeolian landforms such as ripples, transverse aeolian ridges (TARs), and dunes, and aeolian sediment flux measurements are important to enhance our understanding of past and present wind regimes, the ongoing dust cycle, landscape evolution, and geochemistry. These aeolian bedforms are often comprised of loose sand and sharply undulating topography and thus pose a threat to mobility and maneuvers of Mars rovers. Here we present a first-hand account of the distribution, morphologies, and morphometrics of TARs in Oxia Planum, the recently selected ExoMars 2020 Rover landing site. The gridded mapping was performed for contiguous stretches of TARs within all the landing ellipses using 57 sub-meter high resolution imaging science experiment (HiRISE) scenes. We also provide the morphological descriptions for all types of TARs present within the landing ellipses. We use HiRISE digital terrain models (DTMs) along with the images to derive morphometric information for TARs in Oxia Planum. In general, the average areal TAR coverage was found to be 5.4% (±4.9% standard deviation), increasing from west to east within the landing ellipses. We report the average TAR morphometrics in the form of crest–ridge width (131.1 ± 106.2 m), down-wind TAR length (17.6 ± 10.1 m), wavelength (37.3 ± 11.6 m), plan view aspect ratio (7.1 ± 2.3), inter-bedform spacing (2.1 ± 1.1), slope (10.6° ± 6.1°), predominant orientations (NE-SW and E-W), and height (1.2 ± 0.8 m). While simple TARs are predominant, we report other TAR morphologies such as forked TAR, wavy TAR with associated smaller secondary ripples, barchan-like TAR, networked TAR, and mini-TARs from the region. Our results can help in planning the rover traverses in terms of both safe passage and scientific returns favoring aeolian research, particularly improving our understanding of TARs.

The changing climate is affecting the melting process of glacier ice and snow in Himalaya and may influence the hydro-geochemistry of the glacial meltwater. This paper represents the ionic composition of discharge from Bilare Banga glacier by carrying out hydro-geochemical analysis of water samples of melting season of 2017. The pH and EC were measured on-site in field, and others parameters were examined in the laboratory. The abundance of the ions observed in meltwater has been arranged in decreasing order for cations as Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ and for anions as HCO₃⁻ > SO₄²⁻ > Cl⁻ > NO₃⁻, respectively. Analysis suggests that the meltwater is mostly dominated by Ca²⁺ and HCO₃⁻. It has been observed that the ionic concentration HCO₃⁻ is dominant and Cl⁻ is the least in the catchment. Piper plot analysis suggests that the chemical composition of the glacier discharge not only has natural origin but also has some anthropogenic input. Hydro-geochemical heterogeneity reflected the carbonate-dominated features (Ca²⁺–HCO₃⁻) in the catchment. The carbonate weathering was found as the regulatory factor to control the chemistry of the glacial meltwater due to the high enrichment ratio of (Ca²⁺ + Mg²⁺) against TZ⁺ and (Na⁺ + K⁺). In statistical approach, PCA analysis suggests that geogenic weathering dynamics in the catchment is associated with carbonate-dominant lithology.

We describe the development of a robust, self-sustainable, versatile environmental monitoring station, the S3ME2, with a multitude of sensors capable of operating in extreme environments (from cold arid sub-arctic regions to hot deserts and high-altitude mountain terrains), providing realtime quality data of critical climate and geophysical parameters for a wide field of research such as pressure, surface and subsurface temperature and humidity, magnetic field and seismic activity. The dedicated communication modem utilizes IoT technology and can deliver this data from remote regions. The S3ME2 has been designed as a low-cost instrument to facilitate the production of multiple units. During the pilot phase, it has demonstrated continuous operability for up to 6 months, including survival during extremely cold, snowy, and low insolation, and low wind periods in the Sub-Arctic region. With its robust design, S3ME2 exploits the use of renewable sources of energy such as solar and wind power to power the system. The S3ME2 has also been designed from a modular point of view with commercial off the shelf components (COTS) and open source hardware, considering long term operability of the station. The sensor modules can be easily added, replaced, or upgraded such that a stable functioning of the system is guaranteed.

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, testing 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.

The rise in temperature is already evident in Himalaya with rate of increase varying seasonally and spatially. Changes in precipitation are also evident with no clear trend. Several studies in different parts of Himalayas suggest that the glaciers are retreating in general with few exceptions as response to changes in temperature and precipitation. The stream flow in river basins in Indian Himalayan region (IHR) is already showing changes in studies undertaken in the last few decades. Use of glacio-hydrological models gives opportunity to estimate stream flow in glaciated river basins and understand the changes. The present study deals with estimation of discharge in Shaune Garang Basin, Himachal Pradesh using a glacio-hydrological model based on degree day factors. The model was used to estimate long term average of melt season discharge (1985-2007) in the basin. The modelled discharge shows good correlation with measured discharge for simulation period except for first year of comparison.