Characterization of ferric hydroxysulfate on Mars and implications of the geochemical environment supporting its formation.

Sulfate minerals are significant components of the martian surface and provide clues about the martian geochemical environment. One unusual Fe-sulfate phase has been intriguing Mars scientists for over a decade due to its unique spectral bands that are distinct from any known minerals and its occurrence in layered sedimentary rocks. We describe here detection of ferric hydroxysulfate (FeSOOH) and its implications for the geochemical history of Mars.

Crystal Habits as Potential Biosignatures.

Our understanding of crystalline structures within terrestrial planetary analog environments can shed light on how these features can be interpreted on rocky planets and icy moons in our solar system. The ability to distinguish biogenic and abiotic components within the mineral, crystal, and structural features allows us to inform future life detection missions, science payloads, and instrument measurement resolutions. Moreover, having these terrestrial reference measurements in a review format allows the measurement rationale to be understood in the context of mission concepts and geomicrobiological assessment of life in extreme environments.

A shallow mantle source for the Chang'e 5 lavas reveals how top-down heating prolonged lunar magmatism.

The 2-billion-year-old basalts collected by the Chang'e 5 mission are younger than any other sampled lunar igneous rock. These lavas provide critical insight into the evolution of the Moon at a time when magmatism was waning and represent a key data point for understanding how rocky bodies cool. Here, we present high-P-T experiments and phase equilibrium modeling performed on a Chang'e 5 basalt composition that show the parental magma formed in the shallow mantle, at ~75- to 130-kilometer depth.

Multi-technique characterization of iron reduction by an Antarctic : an analog system for putative Martian biosignature identification.

Microbes from terrestrial extreme environments enable testing of biosignature production in conditions relevant to astrobiological targets. Mars, which was likely more conducive to life during early warmer and wetter epochs, has inspired missions that search for signs of early life in the surficial rock record, including mineral or organic biosignatures. Microbial iron reduction is a common and ancient metabolism that may have also operated on other rocky celestial bodies.

Structural Biosignatures-A Category of Potential Biosignatures in the Life Detection Knowledge Base.

The Life Detection Knowledge Base (LDKB) is part of the Life Detection Forum suite of web tools developed for life detection mission planners. This article details the development of one of its categories of biosignatures, the category. The category includes physical attributes of objects and their spatial relationships (e.

The sediment transport mechanics driving lateral accretion in muddy meanders.

The discovery of paleo-meanders on Mars and debates about the occurrence of meandering on prevegetation early Earth have stimulated field studies of channel morphology and deposit stratigraphy in arid environments. They show that mud can provide the cohesive strength to retard outer bank erosion, enabling inner bank lateral accretion (including mud deposition) to keep pace and thus sustain meandering. The process by which mud is deposited in the lateral accretion deposits, however, is poorly known.

Positioning, navigation, and timing on the Moon and Mars with galactic cosmic rays.

The muometric wireless navigation system (MuWNS) is a technology enabling signal reception for machine controlling and communication systems underground where a radio or GPS signal would normally be lost. The penetrative power of muons in rock allows signal transmission from the surface down to 1.5-2.

Lunar dichotomy in surface water storage of impact glass beads.

Water is the one of most precious resources for planetary utilisation. Lunar nearside impact glass beads (IGBs) have been demonstrated to contain abundant solar wind-derived water (SW-HO); however, little is known about its farside counterpart. Here, we report the water abundances and hydrogen isotope compositions and their distribution in farside IGBs collected by the Chang'e-6 mission to investigate the role of IGBs in the lunar surface water cycle.

Carbonates identified by the Curiosity rover indicate a carbon cycle operated on ancient Mars.

Ancient Mars had surface liquid water and a dense carbon dioxide (CO)-rich atmosphere. Such an atmosphere would interact with crustal rocks, potentially leaving a mineralogical record of its presence. We analyzed the composition of an 89-meter stratigraphic section of Gale crater, Mars, using data collected by the Curiosity rover.

Water abundance in the lunar farside mantle.

The water contents of the lunar interior record important clues for understanding the formation and subsequent thermochemical evolution of the Moon. The Chang'e-6 (CE6) mission returned samples from the South Pole-Aitken impact basin of the lunar farside, providing an opportunity to study the water contents of the farside mantle. Here we report the water abundances and hydrogen isotope compositions of apatite and melt inclusions from CE6 mare basalt, derived from partial melting of the lunar mantle.

Humidity Enhancement in Dry Permafrost: The Effects of Temperature Cycles on Habitability.

The search for life in the solar system often focuses on water and on environments where habitable conditions exist, persistently or occasionally. In this search, dry permafrost (ice-free frozen soil) has received minimal attention. It was previously proposed that within martian dry permafrost the water activity (, an essential property for habitability) could be enhanced by diurnal thermal cycles and water desorption from soil grains, but the details remain unexplored.

Biological, Equilibrium and Photochemical Signatures of C, N and S Isotopes in the Early Earth and Exoplanet Atmospheres.

The unambiguous detection of biosignatures in exoplanet atmospheres is a primary objective for astrobiologists and exoplanet astronomers. The primary methodology is the observation of combinations of gases considered unlikely to coexist in an atmosphere or individual gases considered to be highly biogenic. Earth-like examples of the former include CH and O, and the latter includes dimethyl sulfide (DMS).

Enhancing Lagrangian particle tracking using objective Eulerian coherent structures.

Forecasting the drift of floating particles in the ocean is crucial for pollution control but it is often hindered by uncertainties in surface velocity fields and numerical particle initialization, leading to significant trajectory errors. This study addresses these challenges by integrating Objective Eulerian Coherent Structures (OECS) into Lagrangian particle-transport simulations. OECS identify hyperbolic regions in ocean flows that redirect trajectories, thereby enabling a more accurate depiction of particle trajectories.

Elliptical ejecta of asteroid Dimorphos is due to its surface curvature.

Kinetic deflection is a planetary defense technique delivering spacecraft momentum to a small body to deviate its course from Earth. The deflection efficiency depends on the impactor and target. Among them, the contribution of global curvature was poorly understood.

Informing Planetary Protection Policies for the Future Exploration of Ceres: State of Understanding after the Dawn Mission.

We review the current state of understanding of Ceres as it relates to planetary protection policy for future landed missions, including for sample return, to the dwarf planet. The Dawn mission found Ceres to be an intriguing target for a mission, with evidence for the presence of regional, possibly extensive liquid at depth, and local expressions of recent and potentially ongoing activity. The Dawn mission also found a high abundance of carbon in the regolith, interpreted as a mix of carbonates and amorphous carbon, as well as locally high concentrations of organic matter.

Wave ripples formed in ancient, ice-free lakes in Gale crater, Mars.

Symmetrical wave ripples identified with NASA's Curiosity rover in ancient lake deposits at Gale crater provide a key paleoclimate constraint for early Mars: At the time of ripple formation, climate conditions must have supported ice-free liquid water on the surface of Mars. These features are the most definitive examples of wave ripples on another planet. The ripples occur in two stratigraphic intervals within the orbitally defined Layered Sulfate Unit: a thin but laterally extensive unit at the base of the Amapari member of the Mirador formation, and a sandstone lens within the Contigo member of the Mirador formation.

Evolving glacier patterns in the Chenab River Basin (1993-2021): Drivers and environmental implications.

Glaciers of Jammu and Kashmir are retreating faster than those in the broader northwestern Himalayas, yet some glaciers in the Chenab River basin display signs of periodic advancement and mass gain (2005-2007). These features, such as coalescing lobate structures and blocked meltwater streams, raise intriguing questions about localized glacier dynamics. While global concerns over climate change and glacier retreat persist, the lack of detailed evidence regarding glacier advance in this region warrants further investigation.

Dormancy in the origin, evolution and persistence of life on Earth.

Life has existed on Earth for most of the planet's history, yet major gaps and unresolved questions remain about how it first arose and persisted. Early Earth posed numerous challenges for life, including harsh and fluctuating environments. Today, many organisms cope with such conditions by entering a reversible state of reduced metabolic activity, a phenomenon known as dormancy.

Mapping of Western Valles Marineris Light-Toned Layered Deposits and Newly Classified Rim Deposits.

Layered deposits are found on the plateaus surrounding the western portion of Valles Marineris, mantling the chasmata rims. These rim deposits exhibit intricate layering and are described as light-toned layered deposits (LLDs) in previous studies. Light-toned layered deposits are thought to be composed of pyroclastic ash that was emplaced during volcanic eruptions and later chemically altered.

Two distinct populations of dark comets delineated by orbits and sizes.

Small bodies are capable of delivering essential prerequisites for the development of life, such as volatiles and organics, to the terrestrial planets. For example, empirical evidence suggests that water was delivered to the Earth by hydrated planetesimals from distant regions of the Solar System. Recently, several morphologically inactive near-Earth objects were reported to experience significant nongravitational accelerations inconsistent with radiation-based effects, and possibly explained by volatile-driven outgassing.

The Europa Imaging System (EIS) Investigation.

The Europa Imaging System (EIS) consists of a Narrow-Angle Camera (NAC) and a Wide-Angle Camera (WAC) that are designed to work together to address high-priority science objectives regarding Europa's geology, composition, and the nature of its ice shell. EIS accommodates variable geometry and illumination during rapid, low-altitude flybys with both framing and pushbroom imaging capability using rapid-readout, 8-megapixel (4k × 2k) detectors. Color observations are acquired using pushbroom imaging with up to six broadband filters.

Automated Mineralogy Analysis of the Apollo 17 73002 Continuous Core Thin Sections Using QEMSCAN Mapping Techniques.

The Apollo 17 73001/73002 double drive tube, collected at the base of the South Massif in the Taurus-Littrow Valley, was opened in 2019 as part of the Apollo Next Generation Sample Analysis program (ANGSA). A series of continuous thin sections were prepared capturing the full length of the upper portion of the double drive tube (73002). The aim of this study was to use Quantitative Evaluation of Minerals by SCANing electron microscopy (QEMSCAN), to search for clasts of non-lunar meteoritic origin and to analyze the mineralogy and textures within the core.