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Mars

Mars is the fourth planet from the Sun, a terrestrial world renowned as the Red Planet due to the iron oxide (rust) that gives its surface a distinctive reddish hue.^[1] Approximately half the size of Earth, with a radius of 2,106 miles (3,390 kilometers), Mars orbits at an average distance of 142 million miles (228 million kilometers), or 1.5 astronomical units, from the Sun.^[1] It features a thin atmosphere dominated by carbon dioxide (about 95%), along with traces of nitrogen and argon, which creates a hazy red sky and supports average surface temperatures ranging from 70°F (20°C) at the equator during summer to as low as -243°F (-153°C) at the poles.^[1] The planet exhibits dynamic geology, including the massive Olympus Mons, the solar system's tallest volcano at nearly three times the height of Mount Everest, and the vast Valles Marineris canyon system, stretching over 2,500 miles (4,000 kilometers).^[1] Evidence from orbital and rover missions indicates Mars once had liquid water flowing across its surface, with remnants today in the form of polar ice caps, subsurface ice, and seasonal briny flows.^[1] Mars rotates on its axis every 24.6 hours, known as a "sol," which is slightly longer than an Earth day, and its axial tilt of 25 degrees—similar to Earth's 23.4 degrees—produces seasons that last 142 to 194 sols due to its elliptical orbit.^[1] A Martian year spans 687 Earth days, during which the planet travels about 889 million miles (1.43 billion kilometers) around the Sun.^[1] Unlike Earth, Mars lacks a global magnetic field, leaving it exposed to solar radiation, and it has no rings but is orbited by two irregularly shaped moons: Phobos and Deimos, believed to be captured asteroids.^[1] Phobos, the larger of the two at about 14 miles (22 kilometers) across, orbits so close to Mars that it completes a revolution every 7.6 hours and is expected to either crash into the planet or break apart into a ring within 50 million years.^[1] Deimos, smaller at 7.5 miles (12 kilometers) in diameter, orbits farther out with a period of 30.3 hours.^[1] The surface of Mars is a cold, dusty desert marked by impact craters, ancient river valleys, and volcanic plains, with dust storms that can engulf the entire planet for months.^[1] Its thin atmosphere, with surface pressure less than 1% of Earth's, makes it inhospitable for human life without protection, though subsurface environments may harbor microbial life based on detected organic molecules and methane variations.^[1] Since the 1960s, Mars has been a primary target for space exploration, with robotic landers, orbiters, and rovers from NASA, ESA, and other agencies revealing its geological history and potential for past habitability.^[2] As of 2025, active missions like NASA's Perseverance rover and the Mars Sample Return initiative continue to investigate signs of ancient life and prepare for future human exploration.^[2]

Formation and Evolution

Origin and Early History

Mars formed approximately 4.6 billion years ago through the gravitational accretion of dust and gas particles within the protoplanetary disk that surrounded the newly formed Sun. This process involved the progressive aggregation of planetesimals in the inner solar system, where higher temperatures near the Sun limited the availability of volatile materials, resulting in predominantly rocky compositions for terrestrial planets like Mars. The planet's relatively low mass, about 10% of Earth's, is attributed to the steep radial decrease in disk density and the disruptive effects of Jupiter's early gas-driven migration, which depleted planetesimal populations in the Mars-forming region around 1.5 AU from the Sun.^[3] Following accretion, Mars underwent rapid internal differentiation into a core, mantle, and crust within the first 100 million years of solar system formation.^[4] This process likely involved a global magma ocean that crystallized, segregating a dense iron-nickel-sulfide core (with a radius of approximately 1,800 km, including a solid inner core of ~600 km discovered via seismic data as of 2025) from a silicate mantle and thin basaltic crust.^[5]^[6] Evidence for this early differentiation comes from radiometric dating of martian meteorites, such as ALH 84001, which crystallized around 4.09 billion years ago and preserves isotopic signatures (e.g., Hf-W and Nd-142 anomalies) indicating core formation between 20 and 40 million years after solar system inception.^[7]^[4] The nascent crust of Mars was profoundly shaped during the Late Heavy Bombardment, a period of intense meteoritic impacts peaking around 4.1–4.25 billion years ago.^[8] This event, linked to instabilities in the orbits of the giant planets, produced numerous large impact basins (>1,000 km in diameter) that excavated and thinned the early crust, particularly in the southern highlands, while contributing to the planet's overall volatile inventory.^[8] Approximately 80% of these basins formed within this ~150-million-year window, marking the transition from primordial accretion to more stable geological conditions.^[8]

Geological Evolution

The geological evolution of Mars is divided into three primary eras based on stratigraphic and chronological evidence: the Noachian, Hesperian, and Amazonian periods. These divisions reflect a progression from intense bombardment and aqueous activity to diminished geological dynamism, as inferred from global mapping by missions like Viking and Mars Global Surveyor. The timeline is established primarily through crater density counts, calibrated against lunar impact rates, which provide relative ages, supplemented by in situ radiometric dating from rovers. The Noachian period, spanning approximately 4.1 to 3.7 billion years ago, was marked by heavy meteoritic bombardment, widespread cratering, and evidence suggestive of extensive water-related processes, including possible standing bodies of water. Highland terrains exhibit densely cratered surfaces with degraded craters, indicating high erosion rates, potentially from rainfall or fluvial activity. Geochemical analyses by the Curiosity rover in Gale Crater have dated Noachian rocks to around 4.3 billion years using K-Ar isochron methods on mudstones, confirming early sedimentary deposition in lacustrine environments. Paleomagnetic remnants in these rocks point to an active dynamo during this era, generating a global magnetic field that protected the atmosphere. Hypotheses for a northern ocean are supported by topographic terraces and hydrated mineral signatures, though debated, suggesting transient or episodic water coverage.^[9] Transitioning to the Hesperian period (3.7 to 3.0 billion years ago), geological activity shifted toward widespread volcanism and catastrophic flooding, with reduced cratering rates signaling a decline in external bombardment. Outflow channels and chaotic terrains indicate massive water releases, possibly from subsurface aquifers or melting ice, carving features like those in the Chryse Planitia basin. Volcanic provinces, including the formation of Tharsis Montes, dominated, with lava flows dated via crater counting to this era, reflecting sustained mantle plumes. The cessation of the dynamo around 3.9 to 3.7 billion years ago, evidenced by demagnetized impact basins post-dating early craters, coincided with this transition, likely due to core cooling and loss of convection.^[10] The Amazonian period, from 3.0 billion years ago to the present, represents a phase of relative quiescence, with low rates of volcanism, erosion, and sedimentation shaping the surface. Polar layered deposits and dust mantling dominate, while sporadic volcanism continued at sites like Olympus Mons until approximately 25 million years ago, as indicated by young flow units with minimal craters. Overall planetary cooling, driven by diminishing internal heat from radioactive decay and smaller core size, led to tectonic slowdown and atmospheric thinning, reducing surface modification. Rover-based exposure age dating using cosmogenic nuclides, such as those from Curiosity, shows erosion rates as low as 0.03 meters per million years in recent terrains, underscoring the era's subdued activity.

Physical Characteristics

Internal Structure

Mars's internal structure consists of three primary layers: a metallic core, a silicate mantle, and a basaltic crust, as inferred from seismic data collected by NASA's InSight mission between 2018 and 2022, gravitational measurements, and analyses of Martian meteorites.^[11] The core is composed primarily of iron and nickel alloys, with a radius of approximately 1,830 km, making it nearly half the planet's total radius of 3,390 km. Seismic wave reflections detected by InSight indicate that the core is partially liquid, featuring a solid inner core of about 600 km radius surrounded by a molten outer layer, which contributes to its lower density compared to Earth's core.^[6]^[12] This structure likely formed during Mars's early differentiation, and its cooling has been implicated in the planet's loss of a global magnetic field billions of years ago. Overlaying the core is the mantle, a silicate-rich layer approximately 1,800 km thick, dominated by minerals like olivine and pyroxene similar to those in Earth's upper mantle. Seismic data reveal evidence of past convective currents in the mantle, which may have driven limited plate tectonics during Mars's Noachian period, influencing crustal formation and volcanism.^[13]^[14] Current models suggest the mantle is largely stagnant today, with a possible thin layer of molten silicates at its base, about 150 km thick, separating it from the core.^[13] The crust, averaging 50 km in thickness, is predominantly basaltic in composition, formed from solidified lava flows and early magmatic processes. It varies regionally, thinning to about 20-30 km in the northern lowlands and thickening to 70 km or more in the southern highlands, reflecting the planet's hemispheric dichotomy.^[15]^[16]^[17] Overall, Mars has an average density of 3.93 g/cm³, significantly lower than Earth's 5.51 g/cm³, due to its smaller size, lower iron content in the core, and thicker proportion of lighter silicates in the mantle and crust.^[18] This density profile underscores Mars's distinct evolutionary path as a smaller terrestrial planet with reduced internal heat retention.^[19]

Surface Composition and Topography

The surface of Mars is primarily covered by regolith, a fine-grained layer of unconsolidated soil and dust that consists mainly of iron-rich basaltic rocks, silicate minerals such as olivine and pyroxene, and iron oxides like hematite and magnetite.^[20]^[21] These basaltic components dominate the regolith, reflecting the planet's volcanic history, while the iron oxides, which constitute about 20 wt% Fe³⁺, impart a characteristic reddish hue through oxidation processes akin to rust formation on Earth.^[22]^[1] Hematite, in particular, is a stable iron oxide identified in surface materials, contributing to both the color and magnetic properties of the dust.^[23] Volcanic activity has been a key source of these basaltic and silicate materials throughout Mars' geological past. Topographically, Mars displays a pronounced hemispheric dichotomy, where the southern highlands—ancient terrain marked by extensive cratering—rise approximately 5–6 km above the northern lowlands, which form smoother plains infilled by later volcanic and sedimentary deposits.^[24] This elevation contrast, spanning much of the planet, results from differences in crustal thickness, with the southern crust being roughly 30 km thicker than in the north, influencing global patterns of erosion and deposition.^[25] In the polar regions, the landscape features prominent residual ice caps, primarily composed of water ice, that persist year-round atop extensive polar layered deposits consisting of alternating layers of ice and dust.^[26] These layered deposits, up to several kilometers thick, record climatic variations through their stratification, with the residual caps covering areas about 1,000 km in diameter and serving as the primary water ice reservoirs on the surface.^[27]^[28] Dust storms significantly alter the Martian surface by mobilizing fine particles through wind erosion and subsequent global deposition, which can blanket the planet in layers up to 50–100 micrometers thick during major events.^[29] These aeolian processes, driven by seasonal winds, redistribute iron oxide-rich dust, smoothing topography in some areas while eroding others, and have shaped the regolith's uniformity over time.^[30]

Magnetic and Orbital Properties

Magnetic Field

Mars lacks an active global magnetic field today, as there is no dynamo operating in its core to generate one. The planet's dynamo is believed to have ceased approximately 4 billion years ago, likely due to the cooling of its molten core, which halted the convective motions necessary for sustaining such a field.^[31]^[32] Instead, Mars possesses strong localized crustal remanent magnetism, remnants of its ancient global field that were "frozen" into the rocks as they cooled in the presence of the early dynamo. These magnetic anomalies are particularly intense in the southern highlands, where magnetized crustal materials create patchy fields that indicate a vigorous dynamo operated during the Noachian period, over 3.7 billion years ago. The Mars Global Surveyor spacecraft first detected these features in 1999 during its aerobraking phase, mapping vector magnetic fields that revealed concentrations south of the hemispheric dichotomy boundary.^[33]^[34] Measurements from Mars Global Surveyor at altitudes of approximately 400 km indicate that these crustal fields reach strengths of 100 to 1,500 nanotesla (nT) in localized patches, corresponding to surface strengths up to ~20,000 nT, far weaker than Earth's global field of 30,000 to 60,000 nT but still significant for a non-dynamo planet.^[35]^[33]^[36] These remnant fields interact with the solar wind, forming mini-magnetospheres that partially shield the surface but cannot protect the planet globally. The MAVEN mission, ongoing as of 2025, has further characterized these interactions, confirming localized protection but insufficient global shielding against atmospheric loss. The absence of a strong, overarching field has allowed the solar wind to strip away much of Mars' atmosphere over billions of years, contributing to its current thin, arid conditions.^[37]^[38]^[39]

Orbit and Rotation

Mars orbits the Sun in an elliptical path with a semi-major axis of 1.524 astronomical units (AU), placing its average distance from the Sun at approximately 228 million kilometers. The orbit's eccentricity of 0.0934 results in a significant variation in distance, ranging from about 1.38 AU at perihelion to 1.67 AU at aphelion, a roughly 20% fluctuation that influences the intensity of solar radiation received by the planet. This orbital period, known as a Martian year, lasts 687 Earth days, or 668.59 Martian sols.^[1] The planet rotates on its axis once every 24.6 hours in a sidereal day, closely resembling Earth's 23.9-hour rotation period.^[1] Mars' axial tilt of 25.2 degrees relative to its orbital plane is similar to Earth's 23.4-degree tilt, driving the formation of seasons through varying sunlight exposure across latitudes.^[40] This tilt, combined with the elliptical orbit, causes Martian seasons to differ in length: in the northern hemisphere, for example, spring lasts about 194 sols, summer 178 sols, autumn 142 sols, and winter 154 sols.^[1] Over longer timescales, Mars experiences precession of its spin axis and variations in obliquity due to gravitational interactions within the solar system. The precession cycle, during which the spin axis completes one full rotation relative to the orbital plane, spans approximately 170,000 years.^[41] Obliquity oscillates with periods around 120,000 years, ranging from nearly 0° to as high as 60° over millions of years in chaotic variations, which can redistribute polar ice caps and contribute to climate variability.^[42] Relative to Earth, Mars has a synodic period of 780 days, the time between successive oppositions when the two planets align on opposite sides of the Sun, occurring roughly every two years and facilitating optimal observation and mission opportunities.^[43]

Atmosphere and Climate

Atmospheric Composition

The atmosphere of Mars is dominated by carbon dioxide, which constitutes approximately 95.3% of its volume by percentage, followed by nitrogen at 2.7% and argon at 1.6%, with trace amounts of oxygen (about 0.13%) and water vapor (typically less than 0.03%).^[44] These proportions were precisely measured by the Viking landers in the 1970s and confirmed by subsequent missions such as Curiosity, which reported similar values including 2.6% molecular nitrogen.^[45] The presence of carbon dioxide leads to seasonal condensation, forming frost caps at the poles during winter, where CO₂ freezes out of the atmosphere, temporarily altering local compositions by depleting CO₂ levels.^[46] Surface atmospheric pressure on Mars averages 6.1 millibars, equivalent to about 0.6% of Earth's sea-level pressure, making it a tenuous envelope that provides minimal protection from solar radiation.^[47] This pressure varies seasonally by up to 25%, primarily due to the sublimation and deposition of carbon dioxide ice on the polar caps, which releases or absorbs significant volumes of gas and causes global pressure fluctuations observable by orbiting spacecraft.^[48] Diurnal variations add further modulation, with daily cycles of around 10% driven by temperature changes and thermal tides.^[48] The Martian atmosphere originated largely from volcanic outgassing during the planet's early history, when extensive volcanism released carbon dioxide, nitrogen, and other volatiles from the mantle into the atmosphere.^[49] Over billions of years, significant atmospheric loss occurred through interactions with the solar wind, which stripped away lighter gases like hydrogen and oxygen due to the absence of a global magnetic field, as well as through impact erosion from meteorites that ejected atmospheric particles into space. Additionally, analyses by NASA's Curiosity rover, as of April 2025, indicate that much of the ancient CO₂ atmosphere was incorporated into carbonate minerals such as siderite on the surface, contributing to its thinning.^[50] These processes have resulted in the current depleted state, with isotopic enrichments in heavier elements like argon-38 indicating preferential loss of lighter isotopes.^[51] Vertically, the atmosphere features a troposphere extending up to about 40 km, where convective mixing dominates and temperature decreases with altitude at an average lapse rate of approximately 5 K/km in a clear CO₂-dominated environment. Above this layer lies the stratosphere, where temperatures stabilize or increase due to radiative heating from dust and ozone traces, though the overall scale height remains small owing to the low gravity and pressure.^[52] This structure influences the distribution of minor constituents, with water vapor concentrated in the lower troposphere.

Climate Patterns and Weather

Mars experiences distinct seasons due to its 25-degree axial tilt, similar to Earth, but each season lasts nearly twice as long—ranging from about 146 to 199 Earth days (142 to 194 sols)—because a Martian year spans 687 Earth days. The planet's highly eccentric orbit, with an eccentricity of 0.093, results in significant hemispheric asymmetry: the southern hemisphere's summer occurs near perihelion, when Mars is about 20% closer to the Sun, leading to warmer conditions and peak solar insolation up to 44% higher than during northern summer.^[1]^[53] This eccentricity amplifies seasonal contrasts, with southern summers reaching surface temperatures up to 30 K higher than their northern counterparts. Surface temperatures on Mars vary dramatically by latitude and time of day, reflecting its thin atmosphere and low thermal inertia. The global average surface temperature is approximately -60°C, with equatorial regions averaging around -60°C during the day but dropping sharply at night, while polar regions can reach -125°C in winter. Diurnal temperature swings are extreme, often exceeding 100 K, due to the rapid radiative cooling in the CO₂-dominated atmosphere that provides minimal insulation.^[1]^[54] Global dust storms, a hallmark of Martian weather, typically erupt every 3 Martian years (about 5–6 Earth years) during southern spring or summer, driven by regional temperature contrasts and strong winds exceeding 100 km/h. These storms can engulf the planet, lifting fine iron oxide particles into the atmosphere to altitudes of 50–60 km, which absorb sunlight and raise air temperatures by 20–50 K globally, with local increases up to 40 K in the southern hemisphere.^[55]^[56] The 2018 storm, for instance, encircled the planet and persisted for months, altering atmospheric circulation and temporarily warming the surface by an average of 0.9 K worldwide.^[56] Evidence from orbital imagery and spectroscopic analysis indicates that during the Hesperian period (approximately 3.7 to 3.0 billion years ago), Mars underwent a warmer and wetter climate phase, as inferred from extensive dendritic valley networks in the southern highlands that resemble terrestrial fluvial systems formed by precipitation and runoff.^[57] These networks, concentrated in Noachian-Hesperian terrains, suggest episodic rainfall and surface stability for at least 500 million years into the late Hesperian, contrasting with the arid conditions that followed.^[58]^[59] Since 2014, NASA's MAVEN orbiter has provided direct measurements of Mars' ongoing atmospheric loss, revealing that solar wind erosion strips away atoms at a rate of about 100 grams per second, with oxygen comprising a significant fraction through processes like photochemical escape and ion pickup.^[60]^[61] These observations quantify the gradual thinning of the atmosphere, linking current escape dynamics to the planet's long-term climate evolution. Water vapor, though trace at less than 0.03% of the atmosphere, interacts with these processes by dissociating into hydrogen and oxygen, contributing to the measured loss rates.^[61]

Surface Features

Volcanic Landforms

The Tharsis region represents the most prominent volcanic province on Mars, characterized by massive shield volcanoes formed through prolonged hotspot activity that produced basaltic lava flows over billions of years.^[62] This region hosts Olympus Mons, the largest volcano in the Solar System, standing approximately 22-26 km high with a base diameter exceeding 600 km, surrounded by a basal scarp 2-10 km tall and extensive aureole deposits from gravitational spreading.^[62] Adjacent to it lie the Tharsis Montes—Arsia Mons (up to 20 km high, 400-700 km base), Pavonis Mons (14-18 km high, 460 km base), and Ascraeus Mons (18-25 km high, 435 km base)—aligned along a northeast-southwest trend, each featuring large summit calderas and radial lava fans indicative of effusive eruptions from a stationary mantle plume.^[62]^[63] In contrast, Elysium Planitia forms a smaller volcanic province northeast of Tharsis, dominated by low-relief shield volcanoes and widespread lava flows rather than towering edifices.^[62] Key features include Elysium Mons (16 km high, 415 km base), along with smaller domes and cones 0.7-1.5 km across, interpreted as products of hotspot-driven basaltic volcanism with possible interactions involving ground ice or pyroclastics.^[62] Lava flows here extend across the plains, forming broad, fluid deposits that contrast with the more centralized builds in Tharsis, and include ridges 10-40 km long linked to volcanic vents.^[62] Volcanic activity across these provinces peaked during the Hesperian period (approximately 3.7-3.0 billion years ago), with constructional phases extending into the Amazonian, but crater counting reveals possible recent eruptions as young as less than 2 million years ago on some flows in Tharsis and Elysium.^[64] For instance, certain lava units in Elysium Planitia yield ages of 0.5-2.5 million years based on impact crater densities analyzed from high-resolution images.^[65] These timelines, derived from Hartmann-Neukum isochrons applied to CTX imagery, indicate episodic rather than continuous activity, with Tharsis showing older summit builds (up to 200 million years) but younger flank flows.^[66] Lava tube networks are inferred throughout Tharsis and Elysium from sinuous ridges, collapse chains, and pit craters aligned along flow paths, suggesting efficient subsurface transport of basaltic magma during eruptions.^[62] These features, often 10-40 km long and associated with low-slope flanks, mirror terrestrial analogs like those on Hawaii and indicate tube systems that could span tens to hundreds of kilometers, preserving volatiles and providing insights into past flow dynamics.^[67]^[68]

Impact Craters and Basins

Impact craters and basins on Mars are primary surface features resulting from hypervelocity collisions with asteroids and comets throughout the planet's history. The distribution of these features is uneven, with a higher density observed in the southern highlands, which date to the Noachian period approximately 3.7 to 4.1 billion years ago, reflecting an ancient, heavily bombarded crust nearly saturated with craters in the 32- to 128-km size range.^[69] In contrast, the northern lowlands exhibit a lower crater density due to extensive resurfacing processes that have buried or erased many older impacts, making the highlands appear older relative to the smoother plains.^[70] Among the most prominent basins is Hellas Planitia, the largest well-preserved impact basin on Mars, measuring approximately 2,300 km in diameter and reaching depths of up to 7 km below the planetary datum, formed during the Early Noachian epoch around 4 billion years ago.^[71]^[72] This massive structure dominates the southern hemisphere and serves as a key example of the scale of early bombardment events that shaped the Martian crust.^[73] Impact craters on Mars vary in morphology based on size and target properties. Simple craters, typically smaller than 7 km in diameter, form bowl-shaped depressions with raised rims and minimal internal structure.^[74] Larger complex craters, exceeding this simple-to-complex transition diameter of about 7 km, feature central peaks, terraced walls, and more extensive ejecta, resulting from greater structural rebound during formation.^[74] Additionally, secondary craters arise from the ballistic re-impact of ejecta material expelled from primary craters, often forming chains or clusters radiating outward. Due to Mars' thin atmosphere and low erosion rates from wind, water, or volcanism compared to Earth, many craters exhibit remarkable preservation, allowing ejecta blankets—layered sheets of debris surrounding the rim—to remain intact and reveal details of the impact process.^[76] Fresh or young craters further display prominent rays, bright linear streaks of fine ejecta that extend hundreds of kilometers, highlighting the planet's minimal degradational environment.^[77] These well-preserved features provide critical evidence for surface processes and are used to estimate relative ages through crater density counts.^[78]

Tectonic and Fault Structures

Mars exhibits a variety of tectonic and fault structures that reveal its geological evolution, including extensive rift systems, evidence of ancient crustal movements, and signs of planetary contraction. Unlike Earth, Mars lacks active plate tectonics today, but its surface features suggest a dynamic past influenced by internal heat loss and volcanic loading. These structures primarily formed during the Noachian and Hesperian periods, with some younger activity persisting into the Amazonian epoch. The Valles Marineris is the most prominent tectonic feature on Mars, a vast canyon system extending approximately 4,000 kilometers along the equator, with widths up to 600 kilometers and depths reaching 7 kilometers in places.^[79] This network of interconnected chasmata formed primarily through extensional tectonics, where crustal stretching and faulting occurred in response to the uplift of the nearby Tharsis volcanic province around 3.5 billion years ago.^[80] The stretching created grabens and normal faults, with subsequent erosion and mass wasting enlarging the canyons over time.^[81] Remnant crustal magnetism provides key evidence for ancient plate-like tectonics on Mars, particularly linear magnetic stripes observed in the southern highlands that resemble those at Earth's mid-ocean ridges.^[82] These stripes, detected by the Mars Global Surveyor spacecraft, indicate periodic reversals of a global magnetic field during the Noachian epoch (approximately 4.1 to 3.7 billion years ago), when seafloor spreading may have imprinted alternating polarities on the crust as it cooled.^[83] Additionally, anomalous magnetic patterns near the Isidis impact basin suggest possible subduction zones, where older oceanic-like crust was recycled into the mantle, supporting models of early plate tectonics before the dynamo ceased around 4 billion years ago.^[83] Cerberus Fossae represents a younger system of graben faults in the Elysium Planitia region, southeast of the Elysium Mons volcanic complex, formed by extensional stresses from the uplift of the Elysium bulge.^[84] These linear fractures, up to 1,000 kilometers long and several kilometers wide, developed as magmatic dikes intruded the crust during Late Amazonian times, approximately 100 million to 2 million years ago, and are associated with brief volcanic episodes.^[85] The faults briefly interacted with volcanic regions, channeling magma and possibly triggering flood events. Global contraction of Mars, driven by core and mantle cooling, is evidenced by lobate scarps and wrinkle ridges scattered across the planet, particularly in the southern highlands and northern plains. These compressional features, formed by thrust faulting, indicate a cumulative radial shrinkage of 1 to 2 kilometers since the Hesperian period. Analysis of over 100 such scarps shows they accommodate strains of about 0.1% to 0.2%, consistent with thermal models of gradual planetary cooling without ongoing plate tectonics.

Subsurface Features

Subsurface features on Mars encompass a variety of potential underground voids and cavities, including lava tubes, pit craters, and possible impact-related structures, which have been inferred primarily from high-resolution orbital imagery such as that from the High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter. These features are often linked to the planet's volcanic history, providing insights into past geological processes and offering potential sites for future exploration due to their protective qualities against surface hazards. Detection relies on identifying "skylights"—surface openings that reveal underlying voids—allowing scientists to estimate subsurface dimensions and morphologies without direct access. Lava tubes, elongated subsurface tunnels formed by flowing molten lava that cools and hardens around a central channel, are prominent in the Tharsis and Elysium volcanic provinces. HiRISE imagery has revealed skylights associated with these tubes, indicating widths estimated at 100 to 1,000 meters or more, significantly larger than terrestrial analogs due to Mars' lower gravity and prolonged eruption durations. For instance, in the Tharsis region near the Tharsis Montes volcanoes, including Arsia Mons, multiple skylight clusters suggest extensive tube networks spanning tens of kilometers, while similar features in Elysium, around Elysium Mons, point to comparable scales. These structures originate from volcanic activity, where buoyant lava flows created insulated pathways beneath the surface.^[68]^[86] Possible impact-induced caves may exist within fractured zones of crater walls, where the immense energy of meteorite collisions generates subsurface voids through shock fracturing and material displacement. Such features are hypothesized in various impact basins, where simulations of crater formation reveal significant porosity and faulting that could harbor cave-like cavities. Pit craters, distinct non-impact depressions formed by the collapse of subsurface material often tied to volcanic or tectonic weakening, are evident in regions like Arsia Mons. HiRISE observations show these pits reaching depths of up to 100 meters, with diameters typically 100 to 300 meters, appearing as steep-walled holes without raised rims. In Arsia Mons, chains of such pits align with underlying rilles, suggesting connections to drained magma chambers or weakened crust from past eruptions.^[87] The exploration potential of these subsurface features is substantial for future human missions, as they could provide natural shielding from cosmic and solar radiation, reducing exposure by up to three orders of magnitude compared to the surface. Lava tubes and pit craters, in particular, offer stable, enclosed environments suitable for habitats, potentially accommodating large volumes while protecting against micrometeorites and extreme temperature fluctuations. Studies emphasize their role in enabling sustainable outposts by leveraging existing geology for radiation attenuation.^[88]^[89]

Hydrology and Resources

Evidence of Past Liquid Water

Geological evidence for past liquid water on Mars includes extensive fluvial landforms that indicate sustained surface flow during the Noachian and Hesperian periods, approximately 4.1 to 3.0 billion years ago.^[90] These features suggest a wetter climate early in Martian history, with water carving channels and valleys through erosion and sediment transport.^[91] Outflow channels, such as those surrounding Chryse Planitia, represent massive, episodic floods that released vast volumes of water, likely from subsurface aquifers or chaotic terrain collapses during the Hesperian epoch.^[91] These channels, including Kasei Valles and Ares Vallis, exhibit widths up to hundreds of kilometers and depths of kilometers, with streamlined islands and depositional bars indicative of high-velocity flows exceeding 10 meters per second.^[92] In contrast, valley networks like Nanedi Vallis in Xanthe Terra display dendritic branching patterns resembling terrestrial river systems, formed over extended periods through precipitation-driven runoff in the Noachian era.^[93] These networks, spanning thousands of kilometers in the southern highlands, imply prolonged hydrological activity rather than single catastrophic events.^[94] Mineralogical data from orbital spectrometers further confirm aqueous alteration processes. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter identified hydrated phyllosilicates, such as smectites and kaolinite, in Mawrth Vallis, pointing to low-temperature water-rock interactions in ancient lake beds or soils during the Noachian period.^[95] These clays, exposed in layered outcrops up to 200 meters thick, formed through leaching and precipitation in neutral to alkaline environments. In Gale Crater, CRISM spectra revealed sulfate minerals like gypsum and jarosite in stratified deposits, evidencing acidic, evaporative conditions in a long-lived lake system during the Hesperian. Deltaic sediments provide direct evidence of persistent standing bodies of water. In Jezero Crater, the Perseverance rover confirmed a well-preserved fan-shaped delta at the crater's western margin, composed of alternating lake and river deposits that accumulated over at least 5 to 10 million years around 3.5 billion years ago.^[96] These layered sediments, including mudstones and sandstones, record fluctuating water levels and sediment input from an inlet valley, sustaining a lake that filled much of the 49-kilometer-wide crater.^[96] The hypothesis of a vast northern ocean integrates these observations, proposing that the low-lying northern plains (Vastitas Borealis) hosted a sea covering about one-third of the planet's surface around 4 billion years ago. Supported by the global distribution of deltas draining into the northern lowlands and shoreline-like features, this ocean likely formed from outflow channel floods and persisted episodically into the Hesperian, with a volume equivalent to a global layer over 100 meters deep. Tsunami deposits and sediment patterns in the region corroborate marine conditions during this era.^[97] In 2025, the Zhurong rover identified subsurface structures in Utopia Planitia consistent with ancient coastal deposits, further supporting the existence of this ocean.^[98]

Current Ice Deposits and Potential Resources

Mars's polar regions host significant deposits of water ice, primarily concentrated in the northern and southern caps. The northern polar cap, Planum Boreum, extends approximately 1,000 kilometers in diameter during the Martian summer and is composed mainly of water ice, covered by a thin seasonal layer of carbon dioxide (CO₂) ice that sublimates in warmer months.^[99] Beneath this, layered deposits of water ice reach thicknesses of up to 2 kilometers, preserving records of past climate variations. In contrast, the southern polar cap, Planum Australe, measures about 350 kilometers across and features a more complex structure of alternating layers of water ice and dust, overlain by a permanent veneer of CO₂ ice approximately 8 meters thick.^[99] These caps together hold an estimated volume of water ice equivalent to a global ocean several meters deep if melted.^[100] Beyond the poles, subsurface water ice is widespread in Mars's mid-latitudes, detected through ground-penetrating radar observations from orbiters like the Mars Reconnaissance Orbiter's SHARAD instrument. In regions such as Utopia Planitia, radar data reveal extensive glacier-like ice deposits buried beneath 1 to 10 meters of dry regolith, with purities exceeding 90% in some areas.^[101] One prominent deposit in Utopia Planitia spans over 12,000 square kilometers and contains approximately 5,200 cubic kilometers of ice—comparable in volume to Lake Superior on Earth—making it a prime candidate for resource extraction due to its accessibility and shallow burial depth.^[102] Recent in situ measurements by China's Zhurong rover in Utopia Planitia further confirm high ice contents of 55% to 85% by volume in the shallow subsurface, highlighting the prevalence of these frozen reservoirs across vast plains.^[103] Recurring slope lineae (RSL)—dark, linear streaks that form and lengthen on steep slopes during warmer periods—have been observed by the High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter. A 2025 study concludes these features likely result from dry granular flows, such as dust avalanches triggered by wind or impacts, rather than liquid water.^[104] The Phoenix Mars Lander, which operated in 2008 near the northern plains, directly confirmed perchlorate salts comprising 0.4% to 0.6% of the soil by mass and exposed a subsurface water ice layer at depths of 5 to 18 centimeters, with the overlying soil exhibiting up to 20-30% ice content upon thermal analysis. These findings underscore the role of salts in the Martian soil, though direct evidence of widespread liquid water remains elusive. The abundance of water ice positions Mars as a key target for in-situ resource utilization (ISRU), enabling the production of vital supplies for future missions. Extracted water can undergo electrolysis to yield oxygen for breathing and propulsion, as well as hydrogen for combining with atmospheric CO₂ to produce methane fuel via the Sabatier process.^[105] Accessible deposits, particularly in mid-latitude glaciers and polar margins, are estimated to contain 10 to 100 billion tons of water ice suitable for mining with current technologies, sufficient to support propellant production for multiple crewed vehicles.^[106] NASA's MOXIE experiment on the Perseverance rover has already demonstrated oxygen production from CO₂, paving the way for integrated ISRU systems that could reduce mission masses by up to 60% through local resource harvesting. Atmospheric water vapor, though minor, contributes seasonally to these resources via adsorption into the regolith.

Moons

Phobos

Phobos is the larger and inner moon of Mars, exhibiting an irregular, elongated shape with dimensions of approximately 27 by 22 by 18 kilometers, giving it a mean diameter of about 22 kilometers. It orbits Mars at a mean distance of 9,377 kilometers from the planet's center, completing a full revolution every 7 hours and 39 minutes—faster than Mars' own rotation period. This proximity results in Phobos appearing to rise in the west and set in the east from Martian latitudes where it is visible, and it is tidally locked, always presenting the same hemisphere toward the planet.^[107]^[108]^[109] Phobos possesses a notably low mean density of 1.87 g/cm³, indicative of a highly porous interior, possibly a rubble-pile aggregate with significant voids comprising up to 30% of its volume. Its composition is inferred to resemble carbonaceous chondrites, rich in carbon and low in density, based on spectral analyses from spacecraft like Mars Express. The surface is densely pockmarked by craters, reflecting its ancient, heavily bombarded history; the most distinctive feature is Stickney Crater, an enormous impact scar spanning 9.5 kilometers across—one of the largest relative to its host body in the solar system—and nearly spanning the moon's width on its leading face.^[110]^[111]^[112] The formation of Phobos is a subject of ongoing debate, primarily between the captured asteroid hypothesis—positing it was snared from the main asteroid belt early in the solar system's history—and the impact ejecta model, suggesting it coalesced from debris flung out by a giant collision on Mars. Evidence favoring the latter includes its low density and orbital alignment, which argue against the structural integrity expected of a captured body, though both theories remain viable pending direct sampling. JAXA's Martian Moons eXploration (MMX) mission, planned for launch in 2026, will address this by landing on Phobos to collect surface regolith and return it to Earth by 2031 for detailed analysis of its mineralogy and isotopes.^[112]^[113]^[114] Due to gravitational tidal forces from Mars, Phobos' orbit decays at a rate of roughly 1.8 centimeters per year, inexorably drawing it closer to the planet. Models predict that within 30 to 50 million years, it will cross Mars' Roche limit, where tidal stresses will tear it apart, potentially creating a transient ring system of debris fragments.^[115]^[112]

Deimos

Deimos is the smaller and outer of Mars' two moons, orbiting at a mean distance of 23,460 km from the planet's center with a sidereal period of approximately 30.3 hours. It measures about 12 km in mean diameter, making it one of the smallest known moons in the Solar System, and maintains synchronous rotation, always presenting the same face to Mars due to tidal locking. Its low bulk density of approximately 1.48 g/cm³ suggests a porous, rubble-pile structure composed primarily of carbonaceous chondrite-like material, with significant void space. The surface of Deimos appears unusually smooth compared to other airless bodies, likely blanketed by a thick layer of fine regolith that obscures underlying geological structures and erodes smaller craters over time. Only a few prominent craters are visible, including the 1.9-km-wide Voltaire and the 1-km-wide Swift, both located on the moon's leading hemisphere; these features indicate a relatively low impact flux, possibly due to Deimos' position farther from the asteroid belt.^[117]^[118] The regolith cover, estimated to be tens of meters thick in places, may result from impacts that eject material from Mars or Deimos itself, contributing to the moon's dark, reddish albedo of about 0.07. Deimos' origin is thought to be similar to that of its companion moon, likely as a captured asteroid from the outer Main Belt perturbed into Martian orbit by gravitational interactions, though its greater distance from Mars has resulted in less tidal evolution and surface modification. This hypothesis is supported by its spectral similarity to C- or D-type asteroids and low density, consistent with primitive, volatile-rich compositions. Deimos shares orbital resonances with the inner moon, completing one orbit for every four of the latter, stabilizing their configurations over billions of years.^[119] Observationally, Deimos was first imaged in detail during the Viking Orbiter missions in 1977, which revealed its smooth terrain at resolutions down to 100 meters per pixel.^[120] Higher-resolution images from the Mars Reconnaissance Orbiter's HiRISE instrument in 2009 provided color-enhanced views exposing subtle spectral variations and confirming the paucity of craters. Due to its negligible gravity—escape velocity under 10 m/s—Deimos has been proposed as an accessible landing target for future missions, serving as a low-risk precursor to Mars surface operations with easier ascent and sample return.^[121]

Exploration History

Pre-Telescopic and Early Observations

Human observations of Mars date back to ancient civilizations, where the planet's reddish hue and erratic motion across the sky prompted both astronomical records and mythological associations. Babylonian astronomers recorded detailed positions of Mars as early as the MUL.APIN texts around 1200 BCE, using these observations to develop predictive models for planetary paths, including step-function approximations of Mars' variable speed.^[122] In Greek mythology, Mars was linked to the god Ares, depicted as whirling a "fiery sphere" among the planets, symbolizing the god's warlike and destructive nature in works like the Homeric Hymn to Ares.^[123] Similarly, ancient Chinese astronomers noted Mars' oppositions and retrograde motions before the Zhou dynasty (circa 1045 BCE), interpreting its lingering in constellations like Xin as omens of disaster, rebellion, or imperial downfall, as documented in texts such as the Records of the Grand Historian.^[124] The advent of the telescope marked a turning point in Mars observations, beginning with Galileo Galilei in 1610, who provided the first telescopic views of the planet, noting its disk-like appearance and slight phases similar to Venus, confirming its status as a world orbiting the Sun.^[125] These early efforts revealed Mars' near-full phase near opposition but lacked surface detail due to limited optical power. In the 17th and 18th centuries, astronomers refined these views with improved instruments. Giovanni Domenico Cassini, observing from Bologna in 1666, sketched Mars in its gibbous phase, depicting dark surface markings and bright patches suggestive of polar regions, while estimating the planet's rotation period at approximately 24 hours and 40 minutes.^[126] William Herschel, using his reflecting telescopes, measured Mars' rotation more precisely around 1781 at about 24 hours and 23 minutes during opposition observations, also noting bright polar spots interpreted as ice caps.^[127] By the 19th century, observations grew more systematic, enabling the first maps of Martian features. In 1840, Wilhelm Beer and Johann Heinrich von Mädler produced the earliest detailed chart of Mars' surface, identifying albedo variations like dark regions and establishing a coordinate system based on fixed markings.^[128] Angelo Secchi advanced this in 1858 with colored drawings from the Vatican Observatory, clearly delineating polar caps as bright, icy formations and prominent dark areas such as Syrtis Major, which he likened to terrestrial canals, fostering speculation about the planet's habitability.^[129]

Robotic Missions and Landings

The exploration of Mars through robotic missions began in the mid-20th century, marking a pivotal era in planetary science by providing the first detailed data on the planet's surface, atmosphere, and geology. NASA's Mariner 4, launched on November 28, 1964, conducted the inaugural successful flyby on July 14, 1965, capturing 21 black-and-white images that revealed a cratered, barren landscape and a thin carbon dioxide atmosphere, fundamentally altering perceptions of Mars as a potentially habitable world.^[130] Subsequent flybys by Mariner 6 and 7 in 1969 expanded this view, returning over 200 images and spectroscopic data that confirmed the absence of significant water vapor and mapped atmospheric features like south polar clouds.^[131] The Viking program represented a major leap, achieving the first successful landings on Mars in 1976. Viking 1 touched down on July 20 in the Chryse Planitia region, transmitting the initial color photographs from the surface and conducting soil analysis that detected organic compounds, though life detection experiments yielded inconclusive results.^[130] Viking 2 followed on September 3 in Utopia Planitia, providing complementary data on weather patterns and surface composition over several years of operation, with the orbiters surveying global topography and atmospheric dynamics until contact was lost in the early 1980s. Advancements in the late 1990s introduced mobility to Mars exploration. The Mars Pathfinder mission, launched in 1996, successfully landed Sojourner—the first wheeled rover—on July 4, 1997, in Ares Vallis, where it analyzed rocks and soil for 83 sols (Martian days) using alpha proton X-ray spectroscopy, demonstrating technologies for future autonomous navigation.^[130] Building on this, NASA's Mars Exploration Rovers Spirit and Opportunity arrived in 2004; Spirit operated until 2010 after traversing 7.73 kilometers in Gusev Crater, while Opportunity endured until 2018, covering 45.16 kilometers in Meridiani Planum and uncovering evidence of ancient liquid water through mineralogical analysis of hematite spherules and evaporites.^[132] The 21st century saw increasingly sophisticated rovers probing Mars' habitability. Curiosity, launched in 2011, landed in Gale Crater on August 6, 2012, and has since traveled more than 35 kilometers (22 miles) as of 2025, employing a suite of instruments including the Sample Analysis at Mars (SAM) lab to detect organic molecules and confirm a past lake environment conducive to microbial life. Perseverance, arriving in Jezero Crater on February 18, 2021, focuses on astrobiology by collecting 27 rock core samples (plus regolith and air samples) for future return to Earth via the Mars Sample Return mission as of 2025, while its Ingenuity helicopter achieved the first powered flight on another planet in 2021. In September 2025, analysis revealed potential biosignatures in a sample collected in 2024 from 'Cheyava Falls' rock.^[133] International collaboration has diversified Mars exploration. The European Space Agency's Mars Express, launched in 2003 and entering orbit on December 25, 2003, has imaged over 95% of the surface at resolutions up to 20 meters per pixel, identifying hydrated minerals like clays that suggest ancient aqueous activity.^[134] China's Tianwen-1 mission, launched in July 2020, achieved a historic trifecta in 2021 with orbital insertion, landing in Utopia Planitia on May 14, and deployment of the Zhurong rover, which traversed approximately 2 kilometers over its operational period, investigating subsurface structures and potential water ice via ground-penetrating radar before entering hibernation.^[135] The United Arab Emirates' Hope orbiter, launched in July 2020 and arriving on February 9, 2021, studies daily and seasonal atmospheric dynamics from its unique elliptical orbit, contributing global climate data that complements other missions' findings.^[136] Recent missions have targeted specialized scientific objectives. NASA's MAVEN orbiter, launched in 2013 and operational since September 2014, measures the escape of atmospheric gases to explain Mars' water loss over billions of years, revealing that solar wind has stripped away significant portions of the once-thicker atmosphere. The InSight lander, touching down on November 26, 2018, in Elysium Planitia, deployed a seismometer that detected over 1,300 marsquakes until mission end in December 2022, providing insights into the planet's internal structure and core size. ESA's ExoMars Trace Gas Orbiter, launched in 2016, maps trace gases like methane with high precision since 2018, aiding searches for geological or biological sources despite the Schiaparelli lander's crash during its 2016 demonstration.^[134] NASA's ESCAPADE mission, launched on November 13, 2025, consists of two small spacecraft to investigate Mars' magnetosphere and solar wind interactions, with arrival planned for 2027.^[137] These robotic endeavors have collectively transformed our understanding of Mars' geological evolution and potential for past life, with ongoing operations continuing to relay data as of 2025.

Crewed Mission Concepts

Crewed missions to Mars represent the next frontier in human space exploration, building on decades of robotic reconnaissance to enable sustainable human presence on the Red Planet. These concepts involve complex architectures for transit, landing, surface operations, and return, leveraging advancements in propulsion, life support, and in-situ resource utilization (ISRU). As of 2025, major space agencies and private entities have outlined timelines targeting the 2030s, though technical, financial, and logistical hurdles persist.^[138] NASA's Artemis-to-Mars architecture aims for crewed Mars missions in the 2030s, utilizing the Space Launch System (SLS) and Orion spacecraft to transport astronauts to Mars orbit, where they would rendezvous with a human landing system for surface descent. The agency envisions Orion serving as a crew transport vehicle for deep-space transit, with commercial partners providing landers capable of supporting extended surface stays of up to 30 days initially. This phased approach draws from lunar Artemis missions to test technologies like habitat modules and radiation shielding, with Mars orbital missions potentially occurring by the mid-2030s.^[139]^[138] SpaceX's Starship system forms the core of Elon Musk's vision for rapid Mars colonization, with plans for uncrewed missions launching in 2026 to demonstrate entry, descent, and landing technologies during the next Earth-Mars transfer window. These precursor flights will test ISRU for producing propellant from Martian resources, such as water ice and atmospheric CO2, to enable return trips without Earth-sourced fuel. Crewed missions are targeted for 2028-2030, involving fleets of Starships to ferry up to 100 passengers per flight, establishing initial outposts with goals of self-sustaining habitats by the 2040s.^[140]^[141] Internationally, the European Space Agency (ESA) contributes to crewed Mars preparation through the Mars Sample Return (MSR) mission, a collaborative effort with NASA delayed to the 2030s due to cost overruns and redesign needs, with sample retrieval now projected for 2035-2039 as of 2025. This robotic precursor will inform human landing sites and resource extraction techniques, while ESA explores contributions to future crewed elements like ascent vehicles. Meanwhile, China's National Space Administration (CNSA) has outlined ambitions for a crewed Mars mission by 2033, focusing on orbital rendezvous and surface exploration using heavy-lift launchers like the Long March 10, as part of a broader planetary roadmap emphasizing ISRU and long-duration habitats.^[142]^[143]^[144] Key challenges for these missions include cosmic radiation exposure, estimated at 1 sievert (Sv) for a round-trip journey, which exceeds NASA's career limits and increases cancer risk, necessitating advanced shielding like water walls or polyethylene barriers. Prolonged microgravity during the 6-9 month transit can cause muscle atrophy, bone loss, and cardiovascular issues, mitigated through exercise regimens and potential artificial gravity via rotating habitats. Psychological isolation from Earth, compounded by communication delays up to 24 minutes, poses risks of crew stress and requires robust selection and support protocols. Mission opportunities are constrained by Hohmann transfer windows, which align Earth and Mars orbits every 26 months for efficient fuel use, limiting launch cadence and demanding precise synchronization.^[145]^[146]^[147]

Astrobiology and Habitability

Potential for Life

During the Noachian era, approximately 4.1 to 3.7 billion years ago, Mars exhibited conditions conducive to habitability, including widespread liquid water that carved valley networks and filled ancient lakes and basins.^[49] Volcanic activity during this period supplied energy through hydrothermal systems and chemical disequilibria, potentially supporting microbial metabolism via redox reactions involving minerals and gases.^[148] Organic compounds essential for life were likely delivered to the surface by meteorites and micrometeorites, providing carbon-based building blocks that could have accumulated in sedimentary environments.^[149] In the present epoch, Mars' surface is largely inhospitable due to intense ionizing radiation from cosmic rays and solar particles, which penetrates the thin atmosphere and sterilizes shallow subsurface layers over geological timescales, limiting potential microbial refuges to depths greater than 2 meters.^[150] However, subsurface aquifers or transient brines formed by deliquescence of salts could offer protected niches where liquid water persists at temperatures around -60°C, a threshold tolerable for Earth extremophiles in frozen or desiccated states. Key habitability factors include episodic water availability from subsurface ice melting or atmospheric humidity, nutrient sources such as reduced metals and organics, and energy from chemical gradients like those between perchlorates—toxic oxidants that disrupt cellular processes but potentially usable as electron acceptors by specialized microbes—and ferrous iron in minerals.^[151]^[152] Earth analogues for these Martian niches include microbial communities in the hyperarid Atacama Desert, where endolithic bacteria endure extreme desiccation, high UV exposure, and perchlorate-rich soils by exploiting thin moisture films and mineral protections.^[153] Similarly, Antarctic Dry Valleys host psychrophilic and halotolerant extremophiles in permafrost and ephemeral brines, demonstrating survival strategies against cold temperatures, low water activity, and oxidative stress that mirror potential subsurface conditions on Mars.^[154]

Ongoing Searches and Biosignatures

Ongoing searches for biosignatures on Mars focus on instruments aboard rovers that detect organic compounds, minerals indicative of past water activity, and atmospheric gases potentially linked to biological or geological processes. The Chemistry and Mineralogy (CheMin) instrument on NASA's Curiosity rover uses X-ray diffraction and fluorescence to identify and quantify minerals in powdered rock and soil samples, providing insights into environments that could have supported life by revealing clay minerals and sulfates associated with ancient aqueous conditions.^[155] Complementing CheMin, the Sample Analysis at Mars (SAM) suite on Curiosity employs gas chromatography-mass spectrometry to separate and identify organic molecules released from heated samples, enabling the detection of volatile compounds that could serve as biosignatures.^[156] On NASA's Perseverance rover, the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument utilizes deep-ultraviolet Raman and fluorescence spectroscopy to map organic molecules and minerals on rock surfaces, targeting sites in Jezero Crater for potential signs of ancient microbial life.^[157] While the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) on Perseverance demonstrates oxygen production from atmospheric CO2 to support future human exploration, SHERLOC's organic detection capabilities directly advance astrobiological investigations.^[158] Key findings from these instruments include the detection of chlorinated organic molecules, such as chlorobenzene, which were first identified in data from the Viking landers' gas chromatograph-mass spectrometers in 1976 at levels of 0.08–1.0 parts per billion, and later confirmed by Curiosity's SAM in 2014 at concentrations between 150 and 300 parts per billion, suggesting the presence of complex organics despite Martian oxidative conditions.^[159]^[160] Additionally, Curiosity has observed transient spikes in atmospheric methane, with a notable plume reaching about 21 parts per billion in 2019, potentially indicating geological or biological sources, while ESA's Trace Gas Orbiter (TGO), part of the ExoMars program, has mapped seasonal methane variations but detected no widespread plumes, constraining possible release mechanisms to localized events.^[161]^[162] In September 2025, NASA announced that a rock sample collected by Perseverance in July 2024 from Jezero Crater, nicknamed “Cheyava Falls,” contains features interpreted as a potential biosignature, including leopard-like spots suggestive of ancient microbial activity.^[133] To enable more detailed Earth-based analysis, Perseverance has been caching rock and regolith samples since 2021, collecting 30 tubes as of November 2025 from diverse sites in Jezero Crater, including sedimentary rocks rich in organics and minerals, for potential return via the Mars Sample Return mission, a collaborative NASA-ESA effort planned to retrieve and analyze them for unambiguous biosignatures.^[163] Future missions will extend these searches, with ESA's Rosalind Franklin rover, scheduled for launch in 2028, equipped to drill up to 2 meters into the Martian subsurface—far deeper than previous rovers—to access preserved organics and analyze them in situ with advanced instruments like the Mars Organic Molecule Analyzer, targeting Oxia Planum for ancient habitable environments.^[164] For comparative astrobiology, NASA's Dragonfly mission to Titan, launching in 2028 and arriving in 2034, will investigate prebiotic chemical processes on the organic-rich moon, providing context for understanding potential biosignature formation pathways relevant to early Mars.^[165]

Cultural and Scientific Impact

In Mythology and Literature

In ancient Roman mythology, Mars was revered as the god of war, second in importance only to Jupiter within the pantheon, and identified with the Greek deity Ares, though adapted to embody Rome's martial prowess and protection of the state.^[166] The planet Mars received its name from this god due to its distinctive reddish hue, which ancient observers associated with blood and the ferocity of battle, evoking the imagery of warfare central to Mars's domain.^[167] This connection extended to the calendar, where the third month, March, and the day known as dies Martis—Latin for "day of Mars"—honored the deity, with the latter evolving into the English "Tuesday" through Germanic interpretations equating Mars with the war god Tiw.^[168] In astrology, Mars holds rulership over the zodiac signs Aries and Scorpio, symbolizing raw energy, initiative, and assertiveness that often manifest as themes of aggression, conflict, and unyielding drive.^[169] This planetary influence is traditionally viewed as a malefic force, igniting passions that can propel action but also provoke strife, with its position in a natal chart interpreted to reveal an individual's approach to competition and willpower, drawing from ancient Hellenistic texts that linked Mars to battlelust and civil discord.^[170] Such associations underscore Mars's enduring role in astrological lore as a catalyst for both constructive ambition and destructive impulses. Mars's portrayal in literature gained prominence in the 19th century amid growing astronomical interest, exemplified by French astronomer Camille Flammarion's La Planète Mars et ses conditions d'habitabilité (1892), a seminal work compiling centuries of observations to hypothesize the planet's potential for life and its canals as evidence of an advanced civilization.^[171] This speculative tradition culminated in H.G. Wells's The War of the Worlds (1898), a groundbreaking science fiction novel depicting a hostile Martian invasion of Earth by desperate inhabitants fleeing their dying world, which captured public fears of imperial conquest reversed and popularized the trope of extraterrestrial aggression.^[172] Entering the early 20th century, Edgar Rice Burroughs's Barsoom series, beginning with A Princess of Mars (serialized 1912), romanticized Mars as a arid, resource-scarce planet on the brink of extinction, where heroic Earthling John Carter navigates ancient ruins and warring species, blending adventure with visions of a fading red world.^[173]

Modern Depictions and Influence

In contemporary science fiction, Mars is frequently portrayed as a frontier for human colonization and survival, reflecting advancements in real-world space exploration. Andy Weir's novel The Martian (2011), adapted into a 2015 film directed by Ridley Scott, depicts an astronaut's solitary struggle to survive on the harsh Martian surface using scientific ingenuity, emphasizing themes of resilience and human adaptability.^[174] This work draws on actual NASA data to ground its narrative in plausible engineering challenges, such as growing food in Martian soil and generating water from rocket fuel.^[174] Kim Stanley Robinson's Mars Trilogy (1992–1996), comprising Red Mars, Green Mars, and Blue Mars, explores the ethical, political, and ecological implications of terraforming the planet over two centuries, portraying Mars as a canvas for societal transformation.^[174] These novels highlight conflicts between corporate exploitation and environmental stewardship, influencing discussions on sustainable space settlement.^[174] Earlier influences persist in modern retellings, such as Ray Bradbury's The Martian Chronicles (1950), which continues to inspire adaptations and analyses of Mars as a symbol of lost civilizations and human hubris.^[175] Television series like The Expanse (2015–2022) present a colonized Mars as a militarized society with domed habitats and advanced technology, drawing from orbital mechanics and planetary science to depict interplanetary tensions.^[174] This portrayal underscores Mars' role in geopolitical narratives, where the planet serves as a strategic outpost in a solar system-spanning economy.^[174] In film, satirical takes like Mars Attacks! (1996) parody invasion tropes with grotesque aliens, critiquing Cold War-era fears while evolving into memes in digital culture.^[174] Artistic representations of Mars have shifted toward introspective and critical lenses in recent decades. Illustrator Michael Whelan's 1989 cover for The Martian Chronicles captures the planet's eerie desolation through surreal landscapes, blending scientific accuracy with imaginative dread.^[175] Contemporary exhibits, such as the Scottsdale Museum of Contemporary Art's "Life on Mars" (2025), feature works by artists like Erika Lynne Hanson and Steven J. Yazzie, using textiles, ceramics, and video to evoke Indigenous connections to land and challenge the feasibility of Mars colonization by reframing it through Earth's environmental crises.^[176] These pieces employ Martian-like desert imagery to promote appreciation of terrestrial ecosystems.^[176] The cultural influence of these depictions extends to public engagement with space exploration. Visions of Mars in media have historically inspired figures like rocket pioneer Robert Goddard and astronomer Carl Sagan, fostering support for NASA missions such as Viking (1976) and Phoenix (2008).^[175] Modern proponents, including SpaceX CEO Elon Musk, echo science fiction by advocating for human settlement, as articulated in his 2015 interviews and 2024 plans for domed habitats and sustainable reproduction on Mars.^[177] This narrative drives societal interest, evidenced by global participation in projects like the 2007 Visions of Mars DVD, which carried 250,000 messages to future settlers aboard the Phoenix lander.^[175] Overall, Mars' portrayal in popular culture amplifies scientific curiosity and ethical debates on humanity's expansion beyond Earth.^[177]

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Mantle convection controls the observed lateral variations in ...
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[17]
InSight Constraints on the Global Character of the Martian Crust
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EARLY CRUSTAL EVOLUTION OF MARS1 - Annual Reviews
May 19, 2005 · The bulk of the ∼50-km-thick Martian crust formed at ∼4.5 Gyr BP, perhaps from a magma ocean. This crust is probably a basaltic andesite or andesite.
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Mars's Crustal and Volcanic Structure Explained by Southern Giant ...
Mar 16, 2024 · Mars features a crustal dichotomy, with its southern hemisphere covered by a thicker basaltic crust than its northern hemisphere.
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Mars compared to Earth - Phys.org
Dec 7, 2015 · However, Earth's density is higher than that of Mars – 5.514 g/cm3 compared to 3.93 g/cm3 (or 0.71 Earths) – which indicates that Mars' core ...
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A Geophysical Perspective on the Bulk Composition of Mars
Nov 14, 2017 · Bulk silicate mantle composition is abbreviated BSM. Bulk Mars ... thickness), we performed a number of mantle convection simulations.<|separator|>
[22]
[PDF] chemical, mineralogical, and physical properties of martian dust and ...
Basaltic soil and dust on Mars have a composition similar to the average crustal composition [9]; howev- er, soil and dust have enrichments in S and Cl (Table ...
[23]
Silicate mineralogy of martian meteorites - ScienceDirect
The focus of this review is on the major silicate minerals (plagioclase, olivine, and pyroxene) found in martian meteorites. These three phases also most likely ...
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[PDF] Mineralogy and evolution of the surface of Mars: A review - HAL
Indeed, the Martian regolith contains about 20 wt% Fe3+. (Bell III et al., 2000; Foley et al., 2003; Rieder et al., 1997) mostly under the form of iron oxides ...
[25]
[PDF] Chapter 15: Iron Mineralogy and Aqueous Alteration on Mars from ...
Magnetite is identified as the strongly magnetic component in martian soil. Jarosite (in the Burns outcrop at Meridiani Planum) and goethite (in Clovis Class ...
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Constraints on the Origin of the Martian Dichotomy From Southern ...
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A hybrid origin of the Martian crustal dichotomy - ResearchGate
The Martian crustal dichotomy is the stark ∼5 km difference in surface elevation and ∼26 km difference in crustal thickness between the northern lowlands ...
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The Residual Polar Caps of Mars - NASA Technical Reports Server
Aug 1, 2000 · The Martian polar regions have been known to have thick layered sequences (presumed to consist of silicates and ice), CO2 seasonal frost, ...
[29]
Mars' Atmosphere, Weather, and Frozen Volatiles - CRISM
The polar deposits left after disappearance of the seasonal cap polar cap each year – the "residual cap" and underlying "polar layered deposits" – are made ...
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North Polar Ice Cap - Mars Education - Arizona State University
On top of the polar layered deposits lies the residual ice cap, made of water ice and about 1,000 km (600 mi) wide. It has a volume about half that of the ...
[31]
Quantitative analysis of the Martian atmospheric dust cycle
The analysis of the dust sedimentation cycle suggests that the annual cycle might produce a dust layer of about 50–100 μm on the surface of some particular ...
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[PDF] Dust Storms on Mars - NASA Technical Reports Server (NTRS)
From Earth-based observations and numerous spacecraft missions, it is apparent that aeolian processes have played all important role in altering the surface of ...
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[PDF] The Inner Solar System's Habitability Through Time
In contrast, neither Venus nor Mars have an active dynamo creating a measurable magnetic field. Mars' magnetic dynamo stopped about 4.1 Gyr ago (Morschhauser et.
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Magnetic Strips Preserve Record of Ancient Mars - NASA Science
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[PDF] PDF - Mars Global Surveyor Magnetic Field Investigation
The majority of the crustal magnetic sources lie south of the dichotomy boundary on the. 30 APRIL 1999 VOL 284 SCIENCE www.sciencemag.org. Page 4. ancient ...
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[PDF] a global map of mars' crustal magnetic field based on electron ...
Introduction: One of the great surprises of the. Mars Global Surveyor mission was the discovery of intensely magnetized crust [1, 2]. Magnetic sources on.
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Why is only half of Mars magnetized? - The Planetary Society
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NASA's MAVEN Makes First Observation of Atmospheric Sputtering ...
May 28, 2025 · Early on in Mars' history, the atmosphere of the Red Planet lost its magnetic field, and its atmosphere became directly exposed to the solar ...
[39]
[PDF] Exploring Mars' Climate History - NASA
Nov 11, 2013 · Today, only local magnetic fields remain. As the magnetic field turned off, the solar wind began stripping Mars of more of its atmosphere. Over ...<|control11|><|separator|>
[40]
None
Nothing is retrieved...<|control11|><|separator|>
[41]
Mars precession rate determined from radiometric tracking of the ...
It takes approximately 170,000 years for the spin axis to rotate once about the normal to the orbit plane, while nutations of the rotation axis occur on a ...
[42]
Large-Scale Variations in the Obliquity of Mars - Science
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[PDF] Interplanetary Mission Design Handbook:
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Life on Mars: Past, Present, and Future
... atmosphere with CO2 and N2, and potential for preservation of evidence of life. Composition of the Martian atmosphere is 95.3% Carbon dioxide, 2.7% Nitrogen ...
[45]
With Mars Methane Mystery Unsolved, Curiosity Serves Scientists a ...
Nov 12, 2019 · The results SAM spit out confirmed the makeup of the Martian atmosphere at the surface: 95% by volume of carbon dioxide (CO2), 2.6% molecular ...
[46]
The Five Most Abundant Gases in the Martian Atmosphere
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[47]
[PDF] Activity 5—At a Glance - Mars
This fact is significant in our study of Mars because the atmospheric pressure at the Martian surface hovers just above 6.1 millibars. Any water that might ...Missing: average | Show results with:average
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Pressure Cycles on Mars | NASA Jet Propulsion Laboratory (JPL)
Nov 15, 2012 · The curves also show a strong daily variation in pressure of around 10 percent, with a peak near 7 a.m. on Mars and a minimum near 4 p.m. This ...
[49]
[PDF] The Climate of Early Mars - NASA Technical Reports Server (NTRS)
Multiple lines of geologic evidence now point to an episodically warm surface during the late Noachian and early Hesperian periods 3–4 Ga. The low solar flux ...
[50]
[PDF] THE EVOLUTION OF THE MARTIAN ATMOSPHERE
Pepin compared the abundances of noble gases, nitrogen, and carbon dioxide trapped in glassy phases of the EETA 79001 shergottite with the composition of the ...Missing: exact | Show results with:exact
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[PDF] New Tropospheric Range Corrections With - IPN Progress Report
y temperature lapse rate surface altitude. Taltitude where temperature becomes constant with altitude tropo outer edge of troposphere (about 40 km). JPL ...
[52]
NASA Mars Orbiters Reveal Seasonal Dust Storm Pattern
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[53]
Temperature of the Martian Surface
May 6, 1999 · The coldest temperatures (shown in purple) are -120C and the warmest temperatures (white) are -65C. The pattern of nighttime temperature in the ...
[54]
[PDF] The Mars Global Dust Storm of 2018
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Surface Warming During the 2018/Mars Year 34 Global Dust Storm
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[56]
NASA-Funded Study Extends Period When Mars Could Have ...
Feb 2, 2022 · The new work extends the potentially habitable period on Mars by about 500 million years, into the late Hesperian age. “Discerning the climate ...Missing: era | Show results with:era
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Branching geometry of valley networks on Mars and Earth ... - Science
Jun 27, 2018 · Most valley networks on Mars are thought to have been formed in a rather short epoch during the Late Noachian and Early Hesperian (42, 43). Lake ...
[58]
Late Noachian to Hesperian climate change on Mars: Evidence of ...
Jun 24, 2010 · Our results support the hypothesis of rapid climate change at the end of the Noachian period. However, geologic relationships between the crater ...
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NASA Mission Reveals Speed of Solar Wind Stripping Martian ...
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Photochemical escape of oxygen from Mars: First results from ...
Feb 21, 2017 · Photochemical escape rates range from 1.0 to 6.0 × 1025 s−1 for equinox solar minimum conditions and from 4.0 to 22.0 × 1025 s−1 for equinox ...
[61]
[PDF] Atlas of Volcanic Landforms on Mars - USGS Publications Warehouse
Olympus Mons, largest known volcano in the Solar System, is about 26 km high, more than 600 km across at base, and surrounded by a well- defined scarp as much ...
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Small Volcanic Vents of the Tharsis Volcanic Province, Mars
Feb 3, 2021 · Olympus Mons has a majority of nearby vents that are oriented within 30° of radial (57 of 103 vents), as does Ascraeus Mons (69 of 110 vents), ...
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[PDF] The volcanic history of Mars - Stuart Robbins
We have used our CTX-based crater counts to construct a time- line for the last volcanic activity from each major volcano's calde- ras (Figs. 14 and 15, and ...
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Evidence for geologically recent explosive volcanism in Elysium ...
Sep 1, 2021 · We present evidence for a fine-grained unit that is atypical of aeolian deposits in the region and may be the youngest volcanic deposit yet documented on Mars.
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[PDF] Timeline of Martian Volcanism - PSRD
May 27, 2011 · Arecent study of Martian volcanism presents a timeline of the last major eruptions from 20 large volcanoes, based on the relative ages of ...
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Distribution and Morphology of Lava Tube Systems on the Western ...
Jun 3, 2022 · This study uses imaging and topographic data sets acquired from spacecrafts orbiting Mars to study the western flank of the Martian volcano Alba Mons.
[67]
Lava tubes on Earth, Moon and Mars: A review on their size and ...
Sinuous collapse chains and skylights in lunar and Martian volcanic regions have often been interpreted as collapsed lava tubes (also known as pyroducts).
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Distribution of Early, Middle, and Late Noachian cratered surfaces in ...
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[69]
Relative Ages of the Highlands, Lowlands, and Transition Zone ...
Jan 1, 2005 · We find the overall Highland crater population in this area is slightly older than the Lowlands, consistent with previous global studies, but ...
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Hellas Planitia - Gazetteer of Planetary Nomenclature
Diameter, 2299.16 km. Center Latitude, -42.43 °. Center Longitude, 70.50 °. WKT ... The Gazetteer of Planetary Nomenclature website is maintained by the USGS ...
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Hellas Planitia - NASA
May 10, 2010 · With a diameter of about 1,400 miles and a depth reaching the lowest elevations on Mars, Hellas is one of the largest impact craters in the ...
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Geologic Map of Part of the Western Hellas Planitia, Mars
Hellas Planitia, the deepest tract on Mars, is a broad depression lying within the high-rimmed, approximately 2,300-km-wide Hellas impact basin.Missing: diameter | Show results with:diameter
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A new global database of Mars impact craters ≥1 km: 2. Global ...
Jun 5, 2012 · With detailed topographic data for the largest crater database to-date, we analyzed crater depth-to-diameter ratios for simple and complex ...
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Crater Ejecta and Chains of Secondary Impacts - NASA Science
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[PDF] AT A GLANCE - Mars
The Martian surface contains thousands of impact craters because, unlike Earth, Mars has a stable crust, low erosion rate, and no active sources of lava. So, ...
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Well‐preserved low thermal inertia ejecta deposits surrounding ...
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Investigating Mars: Ius Chasma - NASA Science
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Magnetic Stripes Preserve Record of Ancient Mars
Apr 29, 1999 · Scientists using the spacecraft's magnetometer have discovered banded patterns of magnetic fields on the Martian surface.
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Tectonic implications of Mars crustal magnetism - PNAS
Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization.
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[PDF] elysium region 25/210 g, 1992 map 1-2147
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Magmatic dikes and megafloods: a protracted history of interactions ...
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[PDF] MARTIAN LAVA TUBES AS POTENTIAL WATER
Two main volcanic regions can be identified: Tharsis and Elysium. These immense, elevated structures are thousands of kilometers in diameter and cover about ...
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Impact generated porosity in Gale crater and implications for the ...
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Thermal anomalies on pit craters and sinuous rilles of Arsia Mons ...
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(PDF) The role of caves and other subsurface habitats in the future ...
Jun 7, 2016 · It is expected that the radiation doses within caves can be three orders of magnitude lower than on the Martian surface. Furthermore, several ...
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[PDF] origin of the valley networks on mars: a hydrological perspective
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Evidence of an oceanic impact and megatsunami sedimentation in ...
Dec 1, 2022 · The circum-Chryse outflow channels are considered to be the primary source of Mars' Late Hesperian northern ocean. These outflow channels ...
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Climate models used to explain formation of Mars valley networks
Oct 12, 2015 · The river channel on Earth looks darker because it is filled with water, whereas Nanedi Vallis has been dry for billions of years. Credit ...
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[PDF] N92-i0778
Noachian. Period could have ceased, resulting in no further valley-network formation. Alternatively or in addition, valley-network formation by hydrothermal.
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Characterization of phyllosilicates observed in the central Mawrth ...
Nov 26, 2009 · Mawrth Vallis contains one of the largest exposures of phyllosilicates on Mars. Nontronite, montmorillonite, kaolinite, and hydrated silica ...
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Perseverance rover reveals an ancient delta-lake system ... - Science
Oct 7, 2021 · The Perseverance rover landed in Jezero crater, Mars, in February 2021. Earlier orbital images showed that the crater contains an ancient river delta.
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Tsunami waves extensively resurfaced the shorelines of an early ...
May 19, 2016 · It has been proposed that ~3.4 billion years ago an ocean fed by enormous catastrophic floods covered most of the Martian northern lowlands.
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north and south polar cap - Mars Education
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Large asymmetric polar scarps on Planum Australe, Mars
For instance, the volumes of both Planum Australe and Planum Boreum (respectively ∼1.6 × 106 km3 and ∼1.1 × 106 km3) are of the same order as that of the ...
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SHARAD detection and characterization of subsurface water ice ...
Sep 15, 2016 · Morphological analyses of Utopia Planitia, Mars, have led to the hypothesis that the region contains a substantial amount of near-surface ...
[101]
Mars Ice Deposit Holds as Much Water as Lake Superior
Nov 22, 2016 · Scientists examined part of Mars' Utopia Planitia region, in the mid-northern latitudes, with the orbiter's ground-penetrating Shallow Radar ( ...
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Layered subsurface in Utopia Basin of Mars revealed by Zhurong ...
Sep 26, 2022 · Here we report an in situ ground-penetrating radar survey of Martian subsurface structure in a southern marginal area of Utopia Planitia conducted by the ...
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NASA Confirms Evidence That Liquid Water Flows on Today's Mars
Sep 28, 2015 · These downhill flows, known as recurring slope lineae (RSL), often have been described as possibly related to liquid water. The new findings ...
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[PDF] Current NASA Plans For Mars In Situ Resource Utilization
Feb 20, 2018 · ▫ Mars ISRU Testbeds (late '90s early '00s):. – LMA/JSC Sabatier/Water Electrolysis: 0.02 kg/hr O2; 0.01 kg/hr CH4. – KSC RWGS/Water ...
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[PDF] Mars Water In-Situ Resource Utilization (ISRU) Planning (M-WIP ...
Apr 22, 2016 · This scoping analysis is intended to provide guidance regarding a number of complex and inter- related issues involving the potential use of ...
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Phobos - NASA Science
Nov 3, 2024 · Phobos is the larger of Mars' two moons and is 17 x 14 x 11 miles (27 by 22 by 18 kilometers) in diameter. It orbits Mars three times a day.Missing: density | Show results with:density
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[PDF] N94- 25688
10 km in diameter. Phobos is in a low, almost circular orbit about Mars, with the semi-major axis equal to 9378 km and the eccentricity of the orbit only 0.015.
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[PDF] Trajectory Design for the Phobos and Deimos & Mars Environment ...
greater than 45 degrees in true anomaly of Phobos' orbit. Given Phobos' rotation property of being tidally locked with Mars, the trajectory design varies ...
[109]
Martian moon probably pretty porous - Science News
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[PDF] T-J1r 1 ;
The probable low density, water-rich carbonaceous chondrite composition of Phobos. (and Deimos?) suggests that they may have formed in the asteroid belt and ...
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Martian moons: Phobos - ESA Science & Technology
The dominant feature on Phobos is a relatively large impact crater (diameter about 9.5 km), named Stickney, which was the maiden name of Asaph Hall's wife.
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Martian Moons eXploration - JAXA
The current schedule has a launch date in JFY 2026, followed by Martian orbit insertion in JFY 2027 and the spacecraft will return to Earth in JFY 2031.Mission · Science · Gallery · International Collaboration
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Mars' Moon Phobos is Slowly Falling Apart - NASA
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Deimos - NASA Science
Nov 3, 2024 · Deimos is the smaller of Mars' two moons. It's 9 by 7 by 6.8 miles in size (15 by 12 by 11 kilometers). Deimos orbits Mars every 30 hours.Missing: characteristics | Show results with:characteristics
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Deimos! | NASA Jet Propulsion Laboratory (JPL)
Aug 11, 2006 · The two craters, Voltaire and Swift, are presently the only craters with names on all of Deimos. Author Jonathan Swift, in his 1726 Gulliver's ...
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Mars Moons: Facts - NASA Science
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Viking imaging of Phobos and Deimos: An overview of the primary ...
Sep 30, 1977 · The Viking primary mission (June 20 to November 15, 1976) yielded approximately 50 images of Phobos and Deimos. These pictures completed the ...
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[PDF] Strategic Implications of Phobos as a Staging Point for Mars Surface ...
ellipsoids and are tidally locked with Mars, keeping one face toward the planet. Since Phobos is at a location of very strong tidal forces (inside Roche's ...Missing: distance | Show results with:distance
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The Earliest Astronomers: A Brief Overview of Babylonian Astronomy
Sep 18, 2023 · These plots show Mars' speed at different points on its 360-degree path across the sky for 4 different measurable quantities for Mars. The ...
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ARES - Greek God of War & Battlelust (Roman Mars)
The Romans identified their god Mars with the Greek Ares. Source: Dictionary of Greek and Roman Biography and Mythology. CLASSICAL LITERATURE QUOTES. HYMNS TO ...
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Sky Signal | The World of Chinese
Aug 12, 2020 · Ancient Chinese saw Mars as a signal of disaster, chaos, and punishment, especially when it moved backward or stayed at the Xin constellation.
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Meet Our Solar System: Mars - Space Center Houston
Mar 8, 2022 · ... first person to see Mars through a telescope was astronomer Galileo Galilei. He took the first accurate observations of the planet in 1610.
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The Geography of Mars Class - Long Beach - CSULB
Nov 15, 2014 · He drew Mars in gibbous phase, again with the black pill in the center. ... left many sketches of his observations of Mars in 1666. These ...
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This Month in Physics History | American Physical Society
His first major discoveries were that Mars and Jupiter exhibit axial rotation. But on March 13, 1781, while scanning the skies with a 7-inch reflecting ...
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What Mars Maps Got Right (and Wrong) Through Time
Oct 19, 2016 · From the first map of Mars in 1831 to a new gravity map released in March, cartography has shaped how we understand the red planet.
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Mars: A history of false impressions - NBC News
Sep 26, 2005 · 1858: Angelo Secchi, a Jesuit monk, draws Mars and calls Syrtis Major the "Atlantic Canal." He later writes that he was persuaded by the ...
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25 Years of Continuous Robotic Mars Exploration - NASA
Sep 13, 2022 · The first successful Mars mission, Mariner 4, surprised many scientists when, during its flyby on July 14, 1965, it returned 22 black-and-white ...
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50 Years of Mars Exploration - NASA Science
Aug 20, 2015 · NASA's Mars exploration began with Mariner 4 in 1965, with 15 robotic missions since, and human missions planned for the 2030s. Curiosity is ...
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Mars Exploration Rovers: Spirit and Opportunity - NASA Science
NASA's Spirit and Opportunity rovers were identical twin robots who helped rewrite our understanding of the early history of Mars.Sunset on Mars · Rover Basics · Martian Dust Devil · Highlights
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Robotic Exploration of Mars - Missions to Mars
The orbiter operated until 25 July 1978; the lander operated on the surface from 3 September 1976 to 11 April 1980. The Viking orbiters and landers returned ...
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Tianwen-1 mission marks 1st year on Mars
May 16, 2022 · Since landing, Zhurong has continued moving southward and transmitted data back to Earth. It has completed explorations of the Martian surface, ...
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Emirates Mars Mission - Hope Probe
Oct 27, 2025 · The first Arab and Islamic probe to Mars, a project named “Hope Probe”. This makes the UAE one of only nine countries working to explore Mars.
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Artemis - NASA
With NASA's Artemis campaign, we are exploring the Moon for scientific discovery, technology advancement, and to learn how to live and work on another world.Artemis II · Artemis III · Artemis I mission · Artemis Partners
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NASA Shares Progress Toward Early Artemis Moon Missions with ...
Jan 9, 2024 · NASA will now target September 2025 for Artemis II, the first crewed Artemis mission around the Moon, and September 2026 for Artemis III.
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Mission: Mars - SpaceX
SpaceX is planning to launch the first Starships to Mars in 2026. These first vehicles will gather critical data on entry and landing, serving as the ...
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SpaceX Starship Mars mission update 2025
May 30, 2025 · Here are slides from Elon Musk's latest update of SpaceX's Starship Mars mission architecture presented on May 29, 2025.
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NASA announces new path options for Mars Sample Return mission
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Radiation Exposure Comparisons with Mars Trip Calculation
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Beating 1 Sievert: Optimal Radiation Shielding of Astronauts on a ...
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Hohmann transfer orbit diagram | The Planetary Society
... Mars is at the same position in its orbit. Earth and Mars align properly for a Hohmann transfer once every 26 months. Myron Kayton. Original diagram found ...
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[PDF] Exploring Mars for Evidence of Habitable Environments and Life
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NASA's Curiosity Takes Inventory of Key Life Ingredient on Mars
Jun 27, 2022 · Besides liquid water and organic carbon, Gale crater had other conditions conducive to life, such as chemical energy sources, low acidity, and ...
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Survivability of the lichen Xanthoria parietina in simulated Martian ...
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[PDF] Perchlorate on Mars - NASA
Whether brines are habitable depends on the relative abundance of liquid H2O and the panoply of salts therein. BIO: Ben Clark became involved in space ...
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Astrobiology Field Sites
Atacama Desert, Chile The Atacama is the driest non-polar desert in the world and is a suitable analog for ancient Mars.
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[PDF] Extremophiles and Human Space Exploration
Atacama Desert (Chile), McMurdo Dry. Valleys (Antarctica). ~60% relative humidity. Extremophiles**. Factor. Class. Defining Growth Condition. Example Organisms.
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[PDF] Mars Science Laboratory - CheMin Instrument - NASA
CheMin is a mineralogy instrument using X-ray diffraction and fluorescence to identify and quantify minerals in rocks and soil, measuring bulk composition.
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Sample Analysis at Mars (SAM) - NASA
SAM's instrument suite consists of a Gas Chromatograph (GC), a Quadrupole Mass Spectrometer (QMS), and a Tunable Laser Spectrometer (TLS), as well as systems ...
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Perseverance Science Instruments
Perseverance's science instruments are state-of-the-art tools designed to acquire information about Martian geology, atmosphere, environmental conditions, and ...
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NASA's Oxygen-Generating Experiment MOXIE Completes Mars ...
Sep 6, 2023 · Since Perseverance landed on Mars in 2021, MOXIE has generated a total of 122 grams of oxygen – about what a small dog breathes in 10 hours. At ...
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Identification of Chlorobenzene in the Viking Gas Chromatograph ...
Jun 20, 2018 · We found evidence for the presence of chlorobenzene in Viking Lander 2 (VL-2) data at levels corresponding to 0.08–1.0 ppb (relative to sample mass).
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How NASA Curiosity Instrument Made First Detection of Organic ...
Dec 16, 2014 · SAM also detected and identified the compounds using its Gas Chromatograph Mass Spectrometer (GCMS) mode. In this mode, volatiles are separated ...
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Curiosity's Mars Methane Mystery Continues - NASA
about 21 parts per ...
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First results from the ExoMars Trace Gas Orbiter - ESA
Apr 10, 2019 · More recently, Mars Express observed a methane spike one day after one of Curiosity's highest-level readings. TGO's search for methane on Mars.
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Mars Rock Samples - NASA Science
As part of its search for signs of ancient life on Mars, Perseverance is the first rover to bring a sample caching system to the Red Planet that will package ...
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Mar 30, 2025 · Rosalind Franklin will be the first rover to drill to a depth of up to two metres below the martian surface, acquiring samples buried ...
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This revolutionary mission concept includes the capability to explore diverse locations to look for prebiotic chemical processes common on both Titan and Earth.
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Mars | Roman Mythology, Symbols & Powers - Britannica
Sep 19, 2025 · It is clear that by historical times he had developed into a god of war; in Roman literature he was protector of Rome, a nation proud in war.
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Mars is Named After... - Universe Today
Jun 4, 2008 · Mars is named after the Roman god of war. Many believe that ancient peoples associated Mars with bloodshed and war because of its red color. ...
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Explainer: the gods behind the days of the week - The Conversation
Jan 1, 2018 · The Roman weekday 'dies Veneris' was named after the planet Venus, which in turn took its name from Venus, goddess of love.
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Mars in Astrology - ASTROGRAPH
Rulership: Aries and Scorpio Detriment: Libra and Taurus Keyword: Desire. Mars is the fourth planet from the Sun, and is named after the Roman God of War.
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Mars, War, Anger, and Violence - Michael J. Morris
Mar 6, 2022 · War, violence, and anger are some of the oldest significations of Mars in astrology, in sources such as Teucer of Babylon, Vettius Valens, and ...
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La Planète Mars et ses Conditions d'Habitabilité - Nature
IN this very handsome volume the author brings together every available observation and piece of information that can be gathered from published and unpublished ...Missing: summary | Show results with:summary
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The War of the Worlds (novel) | Summary, Analysis, & Characters
Oct 28, 2025 · The War of the Worlds chronicles the events of a Martian invasion as experienced by an unidentified male narrator and his brother. The story ...
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The Barsoom Series by Edgar Rice Burroughs | Research Starters
Spanning eleven novels, the series begins with "A Princess of Mars," where John Carter, an Earthman, finds himself transported to Mars after a series of ...
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Mars, as seen from Earth: The red planet in pop culture
May 7, 2021 · In Hinduism, it's a representation of Mangal, a force of strength, violence and anger. In Chinese and Arabian mythology, it represents fire.
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Visions of Mars: Then and Now | The Planetary Society
A collection of scientific and science-fiction texts about Mars, depictions of Mars in art, and messages to future settlers of Mars.
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Artists contemplate life on Mars in Scottsdale museum exhibition
Sep 11, 2025 · It's the final weekend for Scottsdale Museum of Contemporary Art's "Life on Mars" exhibit, which contemplates the red planet.Missing: depictions 2020-2025
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The Long History of Life on Mars | The New Yorker
Aug 29, 2025 · ... popular culture started to become more unified, Mars—and Martians—became a meme, popping up everywhere from advertisements to vaudeville.