Mars holds a surprisingly rich inventory of usable resources: vast deposits of water ice, an atmosphere dominated by carbon dioxide that can be split into oxygen and fuel, and a surface crust loaded with iron-bearing minerals, sulfates, and clays. None of these resources are ready to use straight out of the ground or air, but the raw materials for sustaining human life and even manufacturing are present in quantities that make a self-supporting outpost at least physically plausible. The challenge is less about whether the resources exist and more about the engineering and energy needed to extract them.
Water Ice Beneath the Surface
Water is the single most critical resource for any human presence on Mars, and the planet has far more of it than early missions suggested. Radar instruments orbiting Mars have revealed enormous subsurface ice deposits, particularly in the mid-latitudes. In western Utopia Planitia alone, orbital radar detected a reflective region spanning roughly 375,000 square kilometers, with an estimated water-ice volume of up to 14,300 cubic kilometers locked inside layered deposits about 80 to 170 meters thick.1Geophysical Research Letters. SHARAD detection and characterization of subsurface water ice deposits in Utopia Planitia, Mars To put that in perspective, that single deposit holds more water than Lake Superior.
The ice is not limited to one spot. Features called lobate debris aprons, found between roughly 30° and 50° latitude in both hemispheres, look a lot like debris-covered glaciers on Earth. Radar analysis of these features indicates they are composed of more than 80 percent water ice by volume, supporting the idea that Mars has a widespread population of buried glaciers spread across its mid-latitudes.2Icarus. Physical properties of subsurface water ice deposits in Mars’s Mid-Latitudes from the shallow radar At certain cliff faces and scarps, erosion has exposed these ice sheets directly, revealing deposits over 100 meters thick beginning just one to two meters below the surface.3PubMed. Exposed subsurface ice sheets in the Martian mid-latitudes
That shallow depth matters enormously for future missions. Ice buried under only a meter or two of regolith is within reach of drilling technology that already exists. One proposed system, called RedWater, combines coiled-tube drilling with a Rodriguez well, a technique used in Antarctica to melt subsurface ice in place and pump the resulting water to the surface through the same borehole.4Digital Commons @ Michigan Tech. RedWater: A Rodwell System to Extract Water from Martian Ice Deposits The approach avoids the need to excavate and haul frozen soil, which would demand heavier machinery.
Why Liquid Water Is Not Part of the Plan
Mars has salts that, in principle, can pull moisture from the atmosphere and form brines. But the amounts are microscopic. Even if all the water in an entire column of Martian atmosphere were absorbed by surface salts, the result would be only tens of microns of brine, far too little to flow or collect.5PubMed Central. Water on the Moon and Mars The recurring dark streaks once interpreted as salty water flows are now considered more likely to be dry granular processes, possibly lubricated by trace moisture but not actual liquid streams. For practical purposes, any usable water on Mars will come from ice or mineral extraction, not from gathering surface liquids.
Hydrated Minerals as a Water Source Near the Equator
Most of the confirmed ice deposits sit at mid to high latitudes, which creates a problem. The equatorial regions receive more solar energy and have milder temperature swings, making them otherwise attractive landing sites. But they lack the shallow ice that higher latitudes offer. One workaround is to target hydrated minerals instead. Certain magnesium sulfates and clay minerals in equatorial regolith have water locked into their crystal structure. Heating these minerals can drive out the water at moderate energy costs, and researchers have argued that a mission based on hydrated sulfates could compete with one relying on polar ice, simply because the equatorial location offers advantages in power generation and thermal management.6PubMed Central. Mineral Hydration as a Source of Accessible Water on Mars to Enable Human Missions at Equatorial Sites
The tradeoff is yield. Hydrated minerals contain a fraction of the water you would get from drilling into an ice sheet. A mission relying on mineral dehydration would need to process substantially larger volumes of soil per liter of water produced. Still, the approach opens up landing-site options that ice-only strategies cannot, and the equipment for heating soil is simpler than deep drilling rigs.
Turning Martian Air Into Oxygen and Fuel
The Martian atmosphere is about 96 percent carbon dioxide, with trace amounts of nitrogen, argon, and oxygen. At first glance, an atmosphere you cannot breathe sounds useless. But carbon dioxide is a feedstock. Split it with enough energy and you get oxygen and carbon monoxide. NASA proved this is more than theoretical when the MOXIE instrument aboard the Perseverance rover repeatedly produced small quantities of oxygen through solid oxide electrolysis of atmospheric carbon dioxide, the first demonstration of in-situ resource utilization on another planet.7PubMed Central. Mars Oxygen ISRU Experiment (MOXIE)-Preparing for human Mars exploration MOXIE’s output was modest, about enough oxygen per hour to keep one person breathing for ten minutes, but it validated the chemistry across multiple Martian seasons and atmospheric conditions.852nd International Conference on Environmental Systems. Scale Up and Coupling of the MOXIE Solid Oxide Electrolyzer for Mission-Scale Lunar and Martian Applications
Scaling MOXIE up is the next engineering challenge. A human crew would need hundreds of times more oxygen, both for breathing and as a rocket propellant oxidizer for the return trip. A scaled-up version would also feed into fuel production. The Sabatier reaction combines carbon dioxide with hydrogen to produce methane and water. If you electrolyze local water to get the hydrogen, the entire fuel cycle closes: atmospheric CO₂ plus subsurface water ice yields methane fuel and oxygen oxidizer, the same propellant combination SpaceX’s Raptor engines burn.9ECS Meeting Abstracts. Making Fuel on Mars: Methane Synthesis from Martian-Derived CO₂ and H₂O Using a Sabatier Electrolyzer Based on Proton-Conducting Ceramics Researchers have proposed space nuclear reactors that use the Martian atmosphere itself as the working medium, coupling heat-to-electricity conversion with chemical processing in a single integrated energy station.10PubMed Central. Conceptualizing in situ energy station for Mars exploration
Iron, Sulfur, and the Mineral Landscape
The rust-colored dust that gives Mars its nickname is not just decorative. Recent spectroscopic work has identified the dominant iron-bearing phase in Martian dust as ferrihydrite, a poorly crystalline iron oxide. Comparisons of orbital data, rover measurements, and lab-made mineral mixtures suggest that about 20 to 33 percent of Martian dust by weight is ferrihydrite mixed with basalt and sulfate.11Nature Communications. Detection of ferrihydrite in Martian red dust records ancient cold and wet conditions on Mars That is a strikingly high iron-mineral content, and it blankets the entire planet. Whether you could economically smelt iron from ferrihydrite under Martian conditions is an open engineering question, but the raw material is everywhere.
Sulfur is another abundant element on Mars, present at much higher surface concentrations than on Earth. The catch is that Martian sulfur exists as sulfates and sulfides, not as the elemental sulfur you would need for industrial uses like sulfur concrete.12Journal of Chemical Research. Obtaining elemental sulfur for Martian sulfur concrete Converting sulfate minerals into elemental sulfur requires chemical reduction, adding another processing step. But sulfur concrete is appealing because it does not need water to cure, unlike Portland cement, and Mars has sulfates in abundance.
The planet’s bulk composition is also notably richer in iron than Earth’s. Mars’s silicate mantle contains roughly 18 weight percent iron oxide, compared to about 8 percent for Earth’s. Its core is thought to be enriched in sulfur, meaning the mantle carries more sulfur and associated elements than our planet does. And like other rocky bodies, Mars is expected to have received a late veneer of material after its core finished forming, enriching the crust with siderophile elements like platinum, palladium, and gold.13Earth-Science Reviews. Potential strategic ore deposits on Mars: Implications for in situ resource utilization Whether any of those elements have been concentrated into ore deposits by geological processes remains unknown, but the geochemical starting conditions are favorable.
Building With Martian Regolith
Shipping construction materials from Earth is absurdly expensive per kilogram, so any long-term settlement will need to build with what is already on the ground. Martian regolith, the loose rocky soil covering the surface, turns out to be a viable construction feedstock once you process it. Heating regolith simulants (lab-made soil that mimics Mars’s composition) in a process called sintering, without any added binder, produces bricks with compressive strengths around 24 megapascals after just ten minutes. Extend the sintering time to an hour or more and the strength climbs to about 41 megapascals, comparable to standard residential concrete on Earth.14arXiv. Synthetic space bricks from lunar and martian regolith via sintering
A more creative approach blends regolith with biological material. Researchers have 3D-printed composite structures using a Mars regolith simulant mixed with spirulina, a cyanobacterium that could be grown on Mars using local CO₂ and water. The biological component acts as a binder, and a plant-based crosslinking molecule called genipin further strengthens the material.15PubMed Central. 3D printing of composites of Martian regolith simulants and cyanobacterial biomass towards sustainable material production on Mars The appeal here is self-reinforcing: the cyanobacteria consume CO₂ and produce oxygen as they grow, contributing to life support while also supplying construction feedstock. Whether the mechanical properties hold up under Martian temperature cycling and radiation is still being tested, but the concept of biologically augmented construction is one of the more inventive directions in Martian resource research.
The Perchlorate Problem
Not every resource on Mars is friendly. The soil is laced with perchlorates, chlorine-containing salts that are toxic to humans, disrupt thyroid function, and would contaminate any crops grown in raw regolith. Perchlorates have been detected at every landing site that has tested for them, at concentrations well above what would be acceptable for agriculture or habitation on Earth.
Removing perchlorates before using Martian soil for farming or habitat construction is not optional. Several biological remediation strategies have been explored, including phytoremediation (using plants to absorb or break down the salts) and microbial remediation (using perchlorate-reducing bacteria).16New Space. Potential Biological Remediation Strategies for Removing Perchlorate from Martian Regolith Both approaches work on Earth, where perchlorate contamination from rocket fuel manufacturing and other industrial sources is a known problem. Adapting them to Mars adds complications: lower gravity, intense radiation, and the need to operate inside pressurized greenhouses. But the underlying biology is well understood, and perchlorate-reducing microbes are metabolically simple organisms that could potentially be shipped to Mars as freeze-dried cultures.
Perchlorates have a silver lining, too. They are powerful oxidizers, and in principle could be processed into components for solid rocket propellants or used in chemical oxygen generators. A resource that is simultaneously a hazard and a potential product is a recurring theme on Mars.
Methane Clathrates and What They Tell Us
Occasional methane detections in the Martian atmosphere have been one of the more tantalizing puzzles in planetary science. One possible source is methane clathrates, cage-like structures where methane molecules are trapped inside ice crystals. Lab experiments simulating Martian conditions found that the sulfate salts and clay minerals abundant in places like Gale Crater can speed the initial formation of clathrates but ultimately reduce the total amount that crystallizes. The salts pull water away from the clathrate structure, and water bound tightly to clay surfaces is unavailable for cage formation.17The Planetary Science Journal. CH₄-clathrates in Clay Minerals and Sulfate Brines: Application to Gale Crater on Mars This means that even where the mineral conditions seem right, clathrate deposits may be smaller than hoped. As a methane resource, clathrates on Mars remain speculative.
Who Gets to Mine Mars
Identifying resources is one thing. Deciding who can extract them is another. The 1967 Outer Space Treaty, which every major spacefaring nation has signed, declares that no country can claim sovereignty over a celestial body. It does not explicitly address commercial mining, which was not on anyone’s radar in the 1960s. The treaty does require that any space activities by private companies must be authorized and continuously supervised by their home nation, placing governments in a regulatory role even for commercial ventures.18Acta Astronautica. Space resource activities and the evolution of international space law
The United States passed the Commercial Space Launch Competitiveness Act in 2015, asserting that U.S. citizens can own resources they extract from space. Luxembourg followed with similar legislation. But neither law has been tested in practice, and the broader international community has not agreed on a unified framework. Some legal scholars argue the Outer Space Treaty permits extraction for use but not territorial claims over deposits. Others see a gap in the law that could lead to disputes once extraction becomes technically feasible. Economic modeling of commercial water-ice mining on Mars has explored profitability under various scenarios, treating parameters like colony location and market demand as variables, but the legal foundation underneath any such business remains unresolved.19Acta Astronautica. Mars Colony in situ resource utilization: An integrated architecture and economics model
The Energy Bottleneck
Every resource-extraction process described above requires energy, and lots of it. Splitting CO₂ into oxygen, melting subsurface ice, heating sulfate minerals to release water, sintering regolith into bricks, and running Sabatier reactors all demand power on a scale that solar panels alone may struggle to provide, especially during Martian dust storms that can darken the sky for weeks. The Perseverance rover’s MOXIE experiments ran on the rover’s nuclear power source, hinting at the likely path forward. Fission reactors sized for a surface outpost, producing tens to hundreds of kilowatts, are the most commonly proposed solution. Coupling a nuclear thermal source with chemical conversion of the atmosphere into fuel and oxygen has been modeled as a single integrated system, where the reactor both powers the habitat and drives the chemistry that produces propellant and breathable air.10PubMed Central. Conceptualizing in situ energy station for Mars exploration
Solar is not useless, though. Mars receives roughly 40 percent of the solar energy Earth does, and at equatorial sites during clear conditions, solar arrays can contribute meaningfully. A hybrid approach, nuclear for baseload and solar for supplemental power during calm weather, is what most mission architectures assume. The energy question is ultimately what determines whether Martian resources are accessible or just theoretically present. Ice in the ground means nothing if you cannot power a drill and a heater.