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Research about Mars

Source-linked reports with geographic coverage including Mars.

At least 19 recordsLinked to original sources
USGS2026

Subsurface water ice mapping on Mars: A probabilistic approach

Subsurface water ice deposits on Mars are an important resource for potential future human exploration. They are also an indicator of the planet’s past climate. However, the distribution of subsurface water ice in Mars’s midlatitudes is uncertain because spacecraft imagery cannot directly observe subsurface ice in most cases. Various spacecraft remote sensing instruments are sensitive to subsurface water ice, including thermal imaging spectrometers, radar sounders, and neutron spectrometers. Geomorphic analyses of images can also implicate subsurface ice. Building upon the data products from the Mars Subsurface Water Ice Mapping project, we provide a probabilistic framework to jointly interpret existing data and estimate the likelihood of subsurface water ice in the Martian midlatitudes between 60 ∘ S and 60 ∘ N with uncertainty. Broadly, we find that near-surface ice is likely present poleward of ∼45 ∘ in both the northern and southern hemispheres. However, closer to the equator, existing remote sensing data cannot uniquely constrain the presence of subsurface water ice. Our probabilistic results provide a framework for quantifying the abundance of ice on Mars, and our uncertainty estimates allow future analysis and exploration to target regions of high uncertainty.

Planetary Science Journal↗
USGS2026

Semantic segmentation of light-toned veins in multimodal ChemCam data

Since the Mars Science Laboratory landed in 2012, the ChemCam instrument aboard the rover has collected in-situ laser-induced breakdown spectroscopy (LIBS) data and context images along more than 35 km of the Gale Crater traverse, providing valuable observations including diagenetic features such as light-toned veins. These veins are of particular scientific interest because they are interpreted as indicators of past fluid circulation on Mars and provide insights into the evolution of habitability on Mars. Their identification, however, currently relies on manual visual inspection of Remote Micro Imager (RMI) images, a process that is time-consuming and sensitive to differences in human interpretation. To address this issue, in this paper we introduce a novel pixel-level labeled, multimodal dataset of ChemCam observations specifically tailored for vein detection, along with customized U-Net models to integrate both textural (RMI) and chemical (LIBS) modalities. To further ensure trustworthy scientific use, we incorporate the Learn-Then-Test (LTT) framework to provide statistical control of the false discovery rate without requiring model retraining. The experimental results demonstrate that the proposed customized U-Net models trained on the developed dataset, combined with risk-controlled prediction, increases the efficiency of pixel-level vein identification through automation and produces statistically reliable predictions for multimodal ChemCam data.

Scientific Reports↗
USGS2026

Mars as one system: Insights from the 8th international conference on Mars polar science and exploration

The 8th International Conference on Mars Polar Science and Exploration (ICMPSE) provided new insights into the complex interplay between Martian ice, climate, and atmospheric dynamics. The conference emphasized a holistic view of Mars as a system, where surface processes, subsurface ice, atmospheric dynamics, and historical climate shifts are interconnected. Research updates spanned cutting-edge remote sensing techniques and observations, terrestrial analog studies, and theoretical modeling, providing a multidimensional view of Mars' dynamic history and present-day activity. Numerous presentations highlighted the importance of understanding Mars as an integrated and dynamic system where surface and atmospheric processes interact over various timescales. This paper synthesizes unresolved questions and the major themes discussed, including mid-latitude glaciation, the evolution of the polar layered deposits (PLDs), terrestrial analog studies, climate modeling, and future mission planning. The findings contributed to refining models of Martian climate history, assessing the potential for extant life, and planning future human exploration. We also discuss the historical perspective of Mars Polar Science and new findings since the 7th conference in this series and anticipate the next four to 20 years of science on Mars related to ice, climate, and the atmosphere.

Icarus↗
USGS2026

Amazonian mass balance history of Martian ice reservoirs: Current knowledge and uncertainties

A major part of the history of the Amazonian period on Mars is the movement of water ice between near-surface reservoirs across the planet. This work assesses the ages and volumes of different parts of the Martian water ice inventory over the last ∼1 Gyr, to reconstruct the time history of ice reservoirs to the extent that it is currently known and determine whether they provide a mass-balanced history. We find that the available constraints do not provide a mass-balanced history over the last 1 Gyr: published age and volume estimates for past ice are unable to account for the former location of most ice known to exist today. Possible explanations for this may include: (i) observational uncertainties on reported ages and volumes; (ii) longer-term past presence of the Polar Layered Deposits than indicated by reported age estimates; (iii) peak paleo-volumes of mid-latitude glaciers or other extant deposits much larger than their present-day state; (iv) large past volumes of equatorial or mid-latitude ice; (v) missing H 2 O reservoirs that are not well known enough to be included in an inventory at present, such as a large abundance of adsorbed water; and (vi) secular increase of the near-surface ice inventory over the last 1 Gyr. These are not mutually exclusive, but shortcomings exist for each. Determination of a more accurate mass balance history will provide insights into the major events of the Amazonian period.

Icarus↗
USGS2026

Mars sample return campaign: Biological risk and a proposed sample safety assessment protocol

Returning surface samples from Mars to Earth has been a major planetary science objective, with the potential for the detection of microbiological life and the possibility of improving our understanding of the origins of life. The National Aeronautics and Space Administration and the European Space Agency assembled a team to assess the level of risk that returned samples could contain potential biohazards. The team was chartered with optimizing previous sample safety assessment strategies, defining what constitutes a biological hazard, developing a protocol to test for biohazards, and establishing a statistical framework to determine if samples may be safe for release from a high-containment facility. This report presents the biological context for a proposed three-step protocol for testing returned samples, including how to determine if microorganisms are present, and if they could be (or were recently) alive.

Applied and Environmental Microbiology↗
USGS2025

Advancing current understanding of Martian impact-generated hydrothermal systems through novel coupled modeling: Insights from Gale, Jezero, and other craters

Impact-generated hydrothermal systems are considered potentially habitable environments on Mars, Earth, and other planetary bodies for microbial life. However, there is an ongoing debate regarding what geological features on Mars provide definitive evidence for such systems. Although earlier studies have modeled hydrothermal processes in Martian craters, they often lacked integration with shock physics hydrocodes to constrain initial impact conditions. The importance of this two-code coupling was demonstrated by successfully replicating alteration signatures in the Earth's Haughton impact structure. In this study, we use a similar two-code approach, combining the iSALE hydrocode with the HYDROTHERM hydrothermal model to simulate the full evolution of impact-generated hydrothermal systems. We apply this method to craters the size of Jezero (∼50 km) and Gale (∼154 km) in diameter. Although Jezero's interior is largely buried, our results align with hypothesized hydrothermal vents and alteration minerals near central uplifts in similarly sized exposed craters, such as Toro and Auki. Furthermore, our models correspond to alteration patterns observed by the Curiosity in the lower layers of Mount Sharp, which may represent remnants of impact-driven hydrothermal activity. A key finding is that these systems may persist much longer than previously estimated. Our simulations suggest that a Jezero-sized system could remain habitable for thermophiles for approximately 720,000 years, whereas a Gale-sized system could persist for nearly 2 million years. Additionally, simulations under unsaturated crustal conditions reveal that air-dominated near-surface layers can suppress vertical fluid flow, enabling deep subsurface alteration without producing detectable mineral signatures at the surface.

Journal of Geophysical Research - Planets↗
USGS2025

Planning considerations related to contamination control for the return and analysis of Martian samples

The joint National Aeronautics and Space Administration and European Space Agency Mars Sample Return (MSR) Campaign is a proposed multi-mission effort to bring selected geological samples from Mars to Earth for the purpose of scientific investigation. Significant parts of these investigations could be affected by Earth-sourced contamination that is either misinterpreted as having a martian origin or that masks a martian signal. The Mars 2020 Perseverance rover implemented strict contamination control requirements to limit contamination of the samples during sample collection. Contamination control and contamination knowledge requirements have not yet been established for the samples after they arrive on Earth. The MSR Sample Receiving Facility (SRF) Contamination Panel (SCP) was tasked with defining the terrestrial biological, organic, and inorganic contamination limits for martian samples during their residence inside the SRF. To reach our recommendations, the SCP studied (i) the previously proposed limits and rationale of the Organic Contamination Panel, (ii) cleanliness levels achieved for sampling hardware by the M2020 mission, (iii) recent improvements in analytical technology and detection limits, (iv) updated information regarding the organic content of martian samples ( e.g. , from the Sample Analysis at Mars instrument on the Curiosity rover and laboratory analyses of martian meteorites), and (v) information about the composition and geologic context of samples being collected by the Perseverance rover for return to Earth.

Astrobiology↗
USGS2025

Sample Science Traceability Matrix (SSTM) for Perseverance’s Mars sample return collection

The Mars Sample Return (MSR) Campaign aims to retrieve a set of carefully selected and documented samples collected by NASA’s Perseverance rover in and around Jezero Crater on Mars and deliver this set to Earth for comprehensive laboratory analyses. To emphasize the immense scientific return of this unique collection, this work presents a Sample Science Traceability Matrix (SSTM), a systematic framework that aligns each sample with the MSR campaign’s defined science objectives, subobjectives, and critical research questions. The SSTM explicitly connects prioritized goals—including geologic history, astrobiology, planetary evolution, and human exploration science—to each of the individual samples gathered in and around Jezero Crater on Mars. This matrix offers a structured, quantitative method to assess each sample’s capacity to address key scientific questions, while highlighting synergies across the sample suite and showcasing the overall value of the collection. The SSTM provides a valuable tool for guiding future sample analyses and identifying the most impactful samples that could be collected in the future to complete the set collected by the Mars 2020 mission. It also supports the next phase of Mars sample science and informs strategies for future Mars exploration missions.

Astrobiology↗
USGS2025

Exploring Martian geothermal and liquid water potential with basin modeling

Assessing the potential for geothermal energy and liquid water presence in the Martian subsurface is crucial for future exploration and habitability studies. In this work, we employed comprehensive finite element model simulations adapted specifically for Martian conditions to estimate subsurface temperatures and the potential for liquid water at depth within Martian crater basins. Rock and fluid property values for basin fill were carefully adjusted to match Martian gravity, radiogenic heat generation, and compositional characteristics derived from rover analyses, Martian meteorite samples, and orbital spectroscopy data. Multiple modeling scenarios were explored to systematically evaluate end-member cases across critical variables such as heat flow, lithological composition, and average surface temperature. Sensitivity testing revealed that heat flow and average annual surface temperatures are the most important variables. Results were used in calculations based on a database of Martian craters to estimate the temperature of crater fill at depth. Our model results indicate significant potential for sustained liquid water in the subsurface within sedimentary deposits across a range of crater sizes and latitudes. They further suggest that viable geothermal reservoirs likely exist and are potentially accessible for future Martian missions seeking energy sources or exploring astrobiological hypotheses. This study provides a methodological framework for geothermal and hydrological assessments for the subsurface of Mars, contributing to ongoing planetary exploration strategies.

Conference Paper↗
USGS2025

Properties of new flows indicate that Martian gullies form via CO2 frost-fluidization processes

Martian gully landforms are widely seen as evidence of liquid water, often attributed to snowmelt during high-obliquity periods within the last few million years. However, widespread present-day flows within existing gullies are caused by CO 2 frost, presenting an alternative formation mechanism. Entrained frost vapourizes to fluidize flows, allowing them to behave similarly to wet debris flows on Earth. The slopes where present-day flows erode and deposit provide insights into the landforms that many such flows could create. The shallowest slopes eroded by the flows are similar to slopes at existing channel mouths, and the most mobile flows reach final slopes similar to the outer reaches of existing gully aprons. This is consistent with formation of gullies entirely by CO 2 frost-driven flows, assuming their intensity and frequency varies in space and time. Geologically recent snowmelt cannot be ruled out, but is not required to explain the observed gully morphology.

Geophysical Research Letters↗
USGS2025

Geologic map of MTM −15032 and −20032 quadrangles, western Ladon basin, Mars

Our mapping efforts focused on the geomorphic terrains and geologic units contained within Mars Transverse Mercator (MTM) −15032 and −20032 quadrangles. These two quadrangles are located along the west side of Ladon basin and span lat −12.5° N. to −22.5° N. and long 325° E. to 330° E. The western part of Ladon basin and its bounding basin ring structures to the west preserved features that help to understand the long history of drainage across the Margaritifer Terra region of Mars. Our geologic map provides new insight into the extent of aqueous activity across western Ladon basin and the adjoining highlands, which includes the northern part of Ladon Valles, Arda Valles, numerous small valleys in the western highlands, and light-toned layered deposits associated with these fluvial features. The Mars Odyssey Thermal Emission Imaging System (THEMIS) infrared (IR) daytime mosaic (100 meters per pixel) was used as the primary base map. We constructed the geologic map of western Ladon basin at 1:1,000,000 scale. We identified 20 geologic units in the map area, which we divided into the following groups: crater units; volcanic units; chaotic units; basin fill units; crater, valley, and channel units; and plateau and highlands units. We observed the following sequence of events: (1) formation of Ladon and Holden impact basins in the middle Noachian, producing a mountainous unit; (2) landscape degradation and infilling during the Late Noachian to Late Hesperian forming terra units; (3) formation of Ladon Valles in the Late Noachian to Early Hesperian by catastrophic flooding, producing channel units; (4) accumulation of sediments in the Late Noachian to Early Amazonian, forming basin fill units; (5) formation of a smooth crater fill unit during the Early to Late Hesperian; (6) deposition during the Late Hesperian to Early Amazonian, creating light-toned layered units within Ladon Valles, Ladon basin, and other smaller valley networks along the western uplands, as well as formation of a light-toned unit along some crater floors; (7) formation a of chaotic unit in the Early to Middle Amazonian, formation of alluvial fans in the Early Amazonian, and eruption of a volcanic unit in the Middle Amazonian; and (8) formation of craters throughout the geologic history of the map region.

Scientific Investigations Map↗
USGS2025

Refined mapping of subsurface water ice on Mars to support future missions

Mars has an extensive yet poorly understood cryosphere. Nevertheless, both direct and indirect evidence indicates extensive buried ice across the midlatitudes, including locations where it is presently unstable. While much progress has been made in exploring the processes responsible for ice deposition and preservation during recent climatic fluctuations, a global assessment of the multiple ice reservoirs remains elusive. Motivated by science and the need to find suitable human landing sites, the Mars Subsurface Water Ice Mapping (SWIM) project has developed techniques to map out buried ice. Through integration of all appropriate orbital data sets, the SWIM project produces ∼3 km pixel −1 ice consistency maps over depth ranges of 0–1 m, 1–5 m, and >5 m. In concert with other studies, prior SWIM phases have recognized the uncertainty in our understanding of the geographic and vertical distribution of ice, especially between depths of 1 m and 10 m, creating a push for new ice-prospecting orbital missions, such as the International Mars Ice Mapper mission concept. Here we document the latest SWIM phase, which provides notional targeting maps of the lowest-latitude ice for future missions via a significant improvement in the geomorphic component of our work. The new mapping incorporates both an enhancement in our mapping of geomorphic features and surveys of thermal contraction crack polygons. Our results demonstrate the highly variable nature of the spatial distribution of the shallowest ground ice, with the most equatorward excursions occurring below 30° latitude N/S, locations thought to be out of equilibrium with the current climate.

The Planetary Science Journal↗
USGS2025

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. In both locations, the ripples have an average wavelength of ~4.5 centimeters. Internal laminae and ripple morphology show an architecture common in wave-influenced environments where wind-generated surface gravity waves mobilize bottom sediment in oscillatory flows. Their presence suggests formation in a shallow-water (<2 meters) setting that was open to the atmosphere, which requires atmospheric conditions that allow stable surface water.

Science Advances↗
USGS2025

Ageing of organic materials at the surface of Mars: A Raman study aboard Perseverance

The Perseverance rover is exploring Jezero crater on Mars, one of its goals being to collect samples to be returned to Earth to search for organic remains of ancient Martian life. However, the organic content of these rocks has likely suffered from the radiation environment on the surface of Mars to an extent yet to be quantified. For the first time, a 1000 sols long ageing experiment was conducted at the surface of Mars, i.e. under actual Martian conditions, relying on the 100 % organic Ertalyte target carried by Perseverance. White at landing, the Ertalyte target has turned brown with time, while its Raman signal changed, with a modification of the background (its maximum has shifted from 1500 to 2000 cm −1 ) and a reduction of the contribution of the Raman signal of Ertalyte (by a factor of 5 over the first 500 sols). Given the intrinsic resistance of the Ertalyte to UV exposure, which is not anticipated for most Martian organic materials, these results suggest that exposure at the surface of Mars will make the detection of Martian organic molecules challenging.

Geochemical Perspectives Letters↗
USGS2024

How, when and where current mass flows in Martian gullies are driven by CO2 sublimation

Martian gullies resemble water-carved gullies on Earth, yet their present-day activity cannot be explained by water-driven processes. The sublimation of CO 2 has been proposed as an alternative driver for sediment transport, but how this mechanism works remains unknown. Here we combine laboratory experiments of CO 2 -driven granular flows under Martian atmospheric pressure with 1D climate simulation modelling to unravel how, where, and when CO 2 can drive present-day gully activity. Our work shows that sublimation of CO 2 ice, under Martian atmospheric conditions can fluidize sediment and creates morphologies similar to those observed on Mars. Furthermore, the modelled climatic and topographic boundary conditions for this process, align with present-day gully activity. These results have implications for the influence of water versus CO 2 -driven processes in gully formation and for the interpretation of gully landforms on other planets, as their existence is no longer definitive proof for flowing liquids.

Communications Earth and Environment↗
USGS2024

Polar science results from Mars Reconnaissance Orbiter: Multiwavelength, multiyear insights

Mars Reconnaissance Orbiter (MRO), with its arrival in 2006 and nearly continuous operation since, has provided data for the study of martian polar processes spanning nine Mars years. Mars' polar deposits have long been thought to preserve records of past climates, potentially readable like terrestrial ice cores. However, unraveling millions of years of history in the ice depends on understanding Mars' current and recent-past climate, including the interactions of atmospheric and surface processes . MRO has allowed for revolutionary discoveries, long-term monitoring of ongoing processes, and multiple complementary datasets to address the question of how the polar ice deposits reflect climatological changes. In part, MRO has been able to do this from its variety of instrumentation simultaneously observing interannual changes in geomorphology of the surface in up to ∼25 cm/pixel detail, repeatable processes and changes in the atmosphere, and surface composition, as well as investigating signs of past changes recorded in the icy polar layered deposits. In this paper, we summarize the contribution of MRO to our current understanding of Mars polar science, and in particular how MRO's long-duration mission has improved our understanding of the fundamental volatile cycles on Mars.

Icarus↗
USGS2024

The High-Resolution Imaging Science Experiment (HiRISE) in the MRO extended science phases (2009–2023)

The Mars Reconnaissance Orbiter has been orbiting Mars since 2006 and has acquired >80,000 HiRISE images with sub-meter resolution, contributing to over 2000 peer-reviewed publications, and has provided the data needed to enable safe surface landings in key locations by several rovers or landers. This paper describes the changes to science planning, data processing, and analysis tools since the initial Primary Science Phase in 2006–2008. These changes affect the data used or requested by the community and how they should interpret the data. There have been a variety of complications to the dataset over the years, such as gaps in monitoring due to spacecraft and instrument issues and special events like the arrival of new landers or rovers on Mars or global dust storms. The HiRISE optics have performed well except for a period when temperature uniformity was perturbed, reducing the resolution of some images. The focal plane system now has 12 rather than 14 operational detectors. The first failure (2011) was a unit at the edge of the swath width , reducing image width by 10% rather than creating a gap. The recent (2023) failure was in the middle of the swath. An unusual problem with the analog-to-digital conversion of the signal (resulting in erroneous data) has worsened over time; mitigation steps so far have preserved full-resolution imaging over all functional detectors. Soon, full-resolution imaging will be narrowed to a subset of the detectors and there will be more 2 × 2 binned data. We describe lessons received for future very high-resolution orbital imaging. We continue to invite all interested people to suggest HiRISE targets on Mars via HiWish, and to explore the easy-to-use publicly available images.

Icarus↗