This review reports Curiosity’s scientific results and operational status during mission years 9–12 on Mars, covering August 2020–August 2024.

Major scientific findings

• Organic molecules: SAM’s first thermochemolysis experiment detected more than 20 aromatic and cyclic organic compounds—including benzene, toluene, naphthalene derivatives, sulfur-bearing organics, and ester/carboxylic-acid-related compounds—in clay-rich rocks of Glen Torridon. These findings strengthen the evidence that ancient lake and lake-margin sediments preserved organic matter for billions of years.
• Clay-to-sulfate transition: Curiosity directly investigated the orbital clay-sulfate transition on Mount Sharp. The transition corresponds to a broad environmental change from predominantly lacustrine and river/shoreline settings to increasingly arid, aeolian environments. The shift toward aridity was not uniform: wet-dry cycles, fluctuating groundwater, and intermittent surface water continued.
• Mg sulfate-bearing unit: CheMin identified magnesium sulfate minerals, including the first detection on Mars of starkeyite—a polyhydrated Mg sulfate—and also detected kieserite, a monohydrated Mg sulfate. These minerals likely formed through brine concentration and later dehydration. The unit is dominated by wind-deposited sediments, although some intervals preserve evidence of shallow water and lakes.
• Ancient ice-free lake: Wave ripples in the Amapari Marker Band indicate that an ice-free lake existed during the early Hesperian period, despite the generally arid conditions recorded by surrounding strata.
• Carbonates and climate: Many sulfate-unit samples are enriched in siderite, an iron carbonate, at levels consistent with chemical sedimentation. This may represent a substantial portion of Mars’ previously “missing” carbonate and suggests atmospheric CO₂ sequestration into minerals.
• Gediz Vallis: The canyon and associated alluvial deposits record numerous later fluvial and debris-flow events, occurring after Mount Sharp’s older strata had been deposited, lithified, and eroded. Bright clasts in the canyon were identified as native elemental sulfur, the first such detection on Mars.
• Atmosphere and radiation: Curiosity continued long-term monitoring of dust, winds, clouds, atmospheric composition, and radiation. It observed high-altitude noctilucent and iridescent clouds and completed radiation measurements spanning an entire solar cycle, including the mission’s largest measured dose rate during a May 2024 solar particle event.

Mission performance

During years 9–12, Curiosity:

• Traveled 9.1 km and climbed approximately 450 m.
• Reached a total traverse distance of 32.4 km and elevation gain of about 850 m.
• Drilled and analyzed 15 samples, bringing the mission total to 48.
• Conducted 1,083 ChemCam target analyses and 605 APXS analyses.

Rover and instrument status

All ten scientific instruments continued to return valuable data, although with important limitations:

• ChemCam: Laser operations were restricted after degradation of its high-voltage subsystem.
• Left Mastcam: A filter wheel failure eliminated narrow-band multispectral imaging through that camera.
• DAN: Its active neutron generator failed, but passive neutron measurements remain available.
• SAM: One gas-chromatograph column became obstructed; another column is being used instead.
• CheMin: Remaining sample-cell capacity is limited because several cells are clogged, though procedural changes have extended their usability.
• The rover also continues to cope with wheel wear, degraded computer redundancy, aging brakes, and declining MMRTG power.

Future plans

The mission planned to investigate:

1. A regional “boxwork” ridge network thought to record ancient groundwater flow.
2. Higher portions of the Mg sulfate-bearing unit.
3. A major unconformity and overlying yardang-forming unit, potentially recording a significant climatic or depositional hiatus.

Overall, the review concludes that Curiosity remains scientifically productive and capable of addressing major questions about Mars’ ancient habitability, climate evolution, water history, organic preservation, and subsurface fluid activity despite substantial aging and resource constraints.

The InSight lander, which has been on the Martian surface since 2018, has been tasked with studying the planet’s interior. Equipped with a suite of instruments, including a seismometer and a heat probe, InSight has gathered pivotal data that allowed researchers to reconstruct the subsurface geology. The study, led by scientists including Xiao and Carrasco, takes a significant leap in interpreting seismic waves to reveal structures previously hidden beneath the Martian regolith.

Drilling down into the data, the research highlights that these fluvial sediments found beneath the surface could offer vital clues about the ancient Martian environment. Analysis of seismic data, in particular, provided insights into how these sediments were deposited and subsequently altered over time. The implications suggest that water once flowed freely across the Martian landscape, potentially creating habitable environments for microbial life.

Crucially, the study indicates that these sediments are not just randomly distributed; they reveal patterns consistent with past river channels and floodplains. This finding suggests that there were periods in Mars’ history when liquid water was abundant, which could have played a significant role in shaping the planet’s geological features. The identification of such fluvial features deep beneath the surface opens new avenues for understanding Mars’ climatic history and its potential capacity to support life.

Moreover, the research emphasizes the importance of using advanced geophysical techniques, including wave propagation analysis, to glean information about the Martian crust. By examining how seismic waves travel through different materials, scientists can infer the composition and structure of subsurface layers. This methodology has proven instrumental in revealing the complexity of Mars’ geology.

The implications of these findings extend beyond academic interest; they offer a roadmap for future exploration missions to Mars. Understanding the location and nature of these subsurface sediments may help inform landing site selection for future missions, ultimately enhancing our chances of discovering signs of past life. Scientists are particularly interested in examining these sedimentary environments closer, as they are prime candidates for harboring biosignatures.

Additionally, the presence of subsurface water ice, possibly associated with these sediments, poses significant questions about the current availability of water resources on Mars. Water is a critical element for any future human exploration missions, making the identification of accessible water sources a top priority for researchers. The knowledge gleaned from this study could inform technologies and strategies for resource utilization on Mars.

As researchers continue to analyze the findings from the InSight lander, there is hope that further investigations can reveal more about Mars’ enigmatic past. Each revelation is a piece of the puzzle that could illuminate the history of water on Mars and its potential to support life forms. Scientists bridge a connection between geological processes observed on Earth and the similar, yet distinct, processes that have shaped Mars.

A key takeaway from this research is the confirmation that Mars was once a much wetter planet than we see today. This realization is exhilarating, as it reshapes our understanding of the Red Planet’s climate and raises the possibility that life could have existed in its ancient rivers and lakes. The sensational nature of these discoveries captures the imagination and drives further inquiries into Mars’ potential for life—past, present, or future.

Furthermore, the techniques employed in this study serve as a model for how we approach extraterrestrial geology. The interdisciplinary collaboration between seismologists, geologists, and planetary scientists highlights the necessity of combining expertise to tackle complex scientific questions. This collaborative spirit fosters an environment where innovation thrives, enabling researchers to develop new methods and technologies for future missions.

As the world eagerly follows the ongoing discoveries related to Mars, this research underscores the importance of sustained investment in planetary exploration. The need for continued funding and resources becomes increasingly apparent, especially as we aim to expand our understanding of not just Mars, but other celestial bodies within our solar system. The study by Xiao and colleagues is a testament to what we can achieve through perseverance and dedication to science.

In conclusion, the research detailing the subsurface fluvial sediments beneath InSight on Mars marks a significant milestone in planetary science. It propels us closer to answering critical questions about our neighboring planet’s history and the ongoing search for extraterrestrial life. As we gather more pieces of this complex cosmic puzzle, the scientific community remains fervently optimistic about the possibilities that lie ahead on Mars.

This remarkable study not only enhances our comprehension of Mars’ geological features but also ignites excitement for ongoing explorations that promise to reshape our understanding of the universe itself. Each discovery beckons the scientific community, helping us to unravel the mysteries of the cosmos. As we stand on the brink of new discoveries, the quest for knowledge about Mars continues, revealing potential past environments where life could have thrived.

Subject of Research: Subsurface fluvial sediments beneath InSight on Mars

Article Title: Subsurface fluvial sediments beneath InSight on Mars from geophysical constraints

Article References:

Xiao, W., Carrasco, S., Xu, Z. et al. Subsurface fluvial sediments beneath InSight on Mars from geophysical constraints. Commun Earth Environ 6, 784 (2025). https://doi.org/10.1038/s43247-025-02777-1

Image Credits: AI Generated

DOI: 10.1038/s43247-025-02777-1

Keywords: Mars, InSight lander, geophysical techniques, subsurface sediments, planetary exploration, ancient water, geological history

Previous models focused primarily on hydrogen’s pivotal role in the Martian atmosphere. Early findings suggested that hydrogen, when combined with carbon dioxide, could catalyze greenhouse warming episodes. However, this hydrogen has a limited lifespan in the atmosphere, presenting complications in sustaining long-term warmth. The research team, led by Danica Adams, a NASA Sagan Postdoctoral Fellow, employed advanced photochemical modeling techniques to meticulously unveil the nuances of the atmospheric interactions on Mars in its early history, particularly the relationship between hydrogen and other gaseous components.

Adams’ research delves deep into the dynamics of the early Martian atmosphere. Through simulations that mimic atmospheric chemical processes, which have proven essential in contemporary studies of air pollution, the team analyzed how various gases interacted over geological timescales. This approach provided insights into how hydrogen, in tandem with other gases, influenced the planet’s climate, potentially creating conditions conducive to liquid water formation.

This study represents a significant shift in understanding Mars’ climatic history. Historian Robin Wordsworth, a prominent figure in environmental science at Harvard, emphasizes the idea that while early Mars may feel like a distant memory, it can be reconstructed convincingly by adopting the right scientific inquiries. By integrating atmospheric chemistry with climate models, the research not only clarifies the potential climates of ancient Mars but also offers insights into its capacity for supporting life.

The simulations addressed specific geological periods: the Noachian and Hesperian epochs, which spanned from roughly 4 to 3 billion years ago. During this time, Mars experienced distinct warm intervals lasting thousands to millions of years, suggesting a dynamic interplay of environmental conditions. These findings are underscored by terrestrial analogs that display similar geological features and implicate past hydrological systems.

As Adams’ research progressed, it pointed toward episodic warm spells characterized by crustal hydration, a process where water from the surface infiltrated the Martian crust. This influx of water was believed to generate hydrogen gas, which gradually accumulated in the atmosphere over immense timescales. The ability of this model to mirror Mars’ geological features bolsters the hypothesis of significant climatic variations in the ancient past, aligning science closer to the vibrant planet depicted in old Mars exploration narratives.

Weather patterns on early Mars appear to have been anything but stable, with dramatic fluctuations marking the climatic landscape. An intriguing aspect of this research focuses on the role of carbon dioxide within the Martian atmosphere. Ultraviolet radiation from the Sun would continuously convert CO2 into carbon monoxide (CO). During warmer periods, the recycling of CO back into CO2 would help maintain a greenhouse effect, reinforcing warm conditions. Conversely, prolonged cooler intervals hindered this recycling, allowing CO to accumulate and leading to significant reductions in atmospheric oxygen levels.

Adams articulated the fluctuating chemical states of the atmosphere and emphasized the organismal implications of these transitions. The study offers crucial timeframes for the alternation between these warm and cold climates, demonstrating a systematic approach to understand how such climatic events could challenge the prospects for prebiotic chemistry, a fundamental prelude to the emergence of life on Mars.

The implications of these findings extend beyond theoretical realms. The researchers are investigating isotope modeling techniques to uncover concrete evidence of these climatic alternations directly from Martian rocks. This ambitious undertaking aims to comprehend the geological record within the context of the forthcoming Mars Sample Return mission. Given the spacecraft’s planned return of Mars’ surface materials to Earth, these insights could unlock the door to validating theoretical models and furthering our understanding of extraterrestrial life’s origins.

In the larger context of planetary science, Mars offers a unique case study due to its lack of tectonic shift which characterizes Earth. This stability has preserved geological features in their ancient form, offering a window into the planet’s evolution and making Mars a fascinating subject of study for scientists looking to understand planetary climate dynamics.

As the research team continues this multifaceted analysis, it’s evident that Mars, once a thriving planet with flowing waters and lakes, poses essential questions about planetary processes in our solar system. The innovative approaches taken by Adams and her fellow researchers shed new light on the complexities of Mars’ climatic journey and the resilience of life in varying conditions, potentially steering future research towards new horizons in astrobiology.

While many questions remain regarding the specific conditions that allowed Mars to harbor liquid water and the plausible existence of life, our continued exploration of Mars and its features promises to hold answers that could redefine our understanding of habitability on other worlds. As scientists pursue these questions with increasing sophistication, each finding may serve as a stepping stone towards elucidating the grand story of Mars’ ancient environments.

With the subsequent Mars Sample Return mission on the horizon, this research positions itself not just as an exercise in theoretical modeling but as a significant contribution to the foundational questions about the potential for life beyond our doorstep. The synthesis of atmospheric chemistry and climate modeling presented in this study not only enhances our understanding of Mars but invites us to consider the implications for similar celestial bodies in our universe.

Through the collaborative efforts of scientists undertaking this fascinating exploration, the history of our neighboring planet emerges more clearly. There lies great excitement in the intersection of chemical modeling, geology, and planetary science which together narrate the story of Mars’ evolution – a story that continues to capture the imagination and drive the exploration of humankind into the stars above.

Subject of Research: Mars’ ancient climate and the potential for liquid water.
Article Title: Understanding Ancient Mars: The Role of Hydrogen and Climate Dynamics in a Liquid Water Past.
News Publication Date: 15-Jan-2025
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