Lunar Regolith as Ore: Mare Ilmenite and Highland Anorthosite

Published June 14, 2026

People talk about lunar mining like someone needs to strike a lucky vein. Wrong. The ore body is the dirt under your boots. Terrestrial mining wastes its budget on the front half: drill, blast, crush, grind, dry, sort, and pray the chemistry works. On the Moon, micrometeorites ran that front half for free over four billion years.

The Moon's edge isn't exotic richness. Its surface is already pulverized, bone dry, and far easier to read than weathered Earth rock. Lunar industry doesn't start with prospectors hunting a bonanza. It starts by treating the surface as pre-milled feed.

The first paying customer isn't buying rare metals. It's the site operator building an outpost that needs oxygen, landing pads, berms, shielding, glass, and repair stock. Before exporting to orbit, the Moon replaces its own bulky imports.

That's why regolith matters: the rock is already half-processed.

On Earth, the First Bill Is for Breaking Rock

Mining analysts routinely skip how brutal the first step is.

Suppose you want to extract metal from rock. Before chemistry even begins, you spend a fortune making that rock smaller. Crushing and grinding aren't decorative. On Earth, comminution can eat a quarter to half of total processing energy. Heavy machinery must crush and grind solid rock down to fine particles, chewing through steel wear parts while running continuous dust handling and water management just to turn "there is mineral in this rock" into "this material is fine enough to separate."

The Moon skipped that step. Billions of years of impact bombardment pounded the crust into granular feed. It isn't gentle—regolith is abrasive, sharp, and electrostatic—but mechanically, it's already sitting at the grind size Earth mills spend millions to reach.

That beats ore grade alone. On Earth, high grade means hauling less waste rock. On the Moon, the prize is preparation: feed sitting on the surface, pre-fragmented, without needing a heavy multi-megawatt grinding circuit.

When every kilogram of machinery must be landed, powered, and maintained in vacuum, eliminating the grinding circuit is pure survival math. At the scale of an initial demonstration, skipping that circuit keeps landed payload within what a lander can deliver; at the scale of an expanding outpost, it frees electrical power and eliminates replacement steel wear parts.

The Moon Paid the Grinding Bill

The High Ground, Chapter 3: Regolith Is the Deposit

Soil returned from the Apollo 16 landing site, in the lunar highlands, is 27.18 percent aluminum oxide by weight and 8.09 percent calcium oxide. Soil from the Apollo 11 site on Mare Tranquillitatis, one of the basalt plains called maria, is about 10 percent aluminum oxide. Iron runs the other way. The highland soil holds 5.18 percent iron oxide, and the Tranquillitatis soil holds about 17 percent. Both are mostly silica, 45.09 percent in the highland sample and about 42 percent in the mare sample, with magnesium oxide at 7.32 percent and about 9 percent.

Those two analyses are why the research behind The High Ground treats the Moon's surface as more than one ore. Regolith is the loose layer of broken rock and fine grains that covers the Moon, and the research sorts it into three provinces. The highlands are anorthosite, built mostly of a mineral called plagioclase, and they are the feed for aluminum and calcium. The maria are basalt that carries ilmenite, a mineral made of iron oxide and titanium dioxide, and they are the feed for oxygen and iron. The third province, called KREEP, holds rare earth elements. The report that measures them puts lunar rare earth levels far below the grades of rare earth ore mined on Earth, so KREEP is a possible side stream for use in the space between Earth and the Moon, not a cargo worth shipping home.

The median grain of lunar regolith is about 45 to 100 micrometers across. On Earth, crushing and grinding rock down to a size that a separator can handle takes 25 to 50 percent of the energy spent processing ore. The research says lunar regolith at its natural grain size can go straight into electrostatic and magnetic separators, machines that sort grains by electric charge and by magnetism, with no grinding mill in front of them.

Oxygen is the product that shows whether this feed works. The route the research leans on is hydrogen reduction of ilmenite: the soil is heated with hydrogen gas, and the hydrogen strips oxygen out of the iron oxide in the mineral. Of the minerals in that report, ilmenite gives the most oxygen this way, about 10.5 percent of its weight, all of it from the iron oxide it contains. Mare regolith is only 5 to 15 percent ilmenite by weight, so raw soil fed straight into the reactor gives up about 1 to 3 percent of its weight as oxygen. Most of the soil that goes into the reactor is not ilmenite, and it gets heated anyway.

For a feed that is 10 percent ilmenite, the research puts the energy cost at 24.3 ± 5.8 kilowatt-hours for each kilogram of liquid oxygen, and most of that energy goes into heating the soil.

Two other routes get oxygen out of regolith, and each pays a different penalty. Carbothermal reduction uses carbon to pull the oxygen out. It runs hotter than hydrogen reduction and takes more of the oxygen out of the soil. Molten regolith electrolysis melts the soil and drives the oxygen out with electric current, and it needs no chemical brought up from Earth to do it.

Engineers grade how close a technology is to working hardware with a technology readiness level, or TRL, where a higher number means it has been tested in conditions closer to the real ones. In the research, carbothermal reduction stands at TRL 6, hydrogen reduction of ilmenite at TRL 5, and molten regolith electrolysis at TRL 4 to 5. The carbothermal rating rests on a 2024 Sierra Space thermal vacuum test, which produced more than 20 grams of oxygen per kilowatt-hour and above 20 percent oxygen by weight.

Because heating is the largest share of the bill, and most of the raw mare soil is not ilmenite, the energy goes furthest when the ilmenite is concentrated before anything is heated. Concentrating an ore before processing it is called beneficiation. In the vacuum electrostatic separation results the research reports, integrated processing under full vacuum raised the ilmenite content about threefold, with ilmenite recovery of 31.93 percent by weight in that result. A threefold enrichment means each kilogram that goes into the hydrogen reactor carries about three times as much ilmenite as the soil did when it was dug. The separator sits in front of the hydrogen reactor, and the share of ilmenite it passes along sets how much of the reactor's heat goes into soil that holds no ilmenite.

Hydrogen reduction leaves iron behind. The research reports that iron at above 98 percent purity, with less than 2 percent oxide by weight and no sulfur, and counts 30 to 37 kilograms of iron in each tonne of high-titanium regolith. Titanium dioxide is left behind too. Turning it into titanium metal stands at TRL 2 to 3, so for now the titanium dioxide is a stockpile kept for a later process, not an immediate product.

The oxides decide where a plant goes. One report groups the high-titanium ground into categories and names Oceanus Procellarum and Mare Tranquillitatis as the two largest deposits in its category A. That category covers 732,477 square kilometers in total, with regolith averaging 4.4 meters thick. The Chang'e-5 mission returned 1,731 grams from Oceanus Procellarum in December 2020, and the sample from the northern part of that plain measures 5 percent titanium dioxide and 22.5 percent iron oxide by weight.

The map behind those choices has a hole in it. The six Apollo sample sites sit inside a region about 600 kilometers across, roughly 0.1 percent of the Moon's surface. The research says the regolith around the south pole is poorly characterized, and it gives no oxide table for it.

A plant built on these findings can tell highland soil from mare soil, sort its ilmenite before it heats anything, and stack its titanium dioxide until a metal process is ready. Raw mare soil still gives up only 1 to 3 percent of its weight as oxygen, and every tonne of it has to be dug, carried, and sorted first, at sites chosen from samples taken at six Apollo landings and one Chang'e-5 return. Moving that much soil, and building with it, is where The High Ground goes next. Open Chapter 4, Built from Dust.