Mars Steel
This is the first sample of a round of Mars Steel ever made. This could be turned into a threaded bolt on Mars.
The first steel that can be made on Mars has now been now been made on Earth!
Mars Steel™ is a new kind of steel designed specifically for production on Mars. The steel-making process for Mars Steel leverages Two Planet Steel’s FIC technology, robotics, and the excellent iron ore available on-planet.
Our process differs from traditional methods in crucial ways, making it the only process that can be easily adapted to use on Mars. In particular, Two Planet Steel’s Mars Steel process requires almost zero consumables and the few that are needed are readily available on Mars. This is a big deal, as it makes our process practical on Mars. In contrast, other steel-making methods require consumables that would be difficult or impossible to get on Mars. For example, the slagging agents needed to remove impurities in most iron- and steel-making furnaces are almost non-existent on that planet. Further, the “hot rolling” method for making sheet steel in a hot strip mill, is extremely water-intensive. While electric arc furnace steel-making relies on large graphite rods and refractory bricks that cannot be produced on-planet immediately.
Mars Steel can be made on Earth and Mars. As shown in the process diagrams above and below, the steps involved in making Mars Steel are nearly identical on both planets. The main difference between the two planets is the iron ore available, which we’ll discuss in a moment.
After inputting the iron ore, the first step is reduction, which we do in a low-temperature direct reduction furnace. Traditional blast furnaces consume large quantities of fossil fuels in the form of coal, a consumable that is unavailable on Mars and leads to high levels of pollution on Earth. However, these emissions will be avoided by Mars Steel on both planets by using electricity to drive the production of the reducing gases.
In a minor step, the sponge iron that results from the reduction process is ground into a powder. Most people have seen and felt this powder as the iron filings used in schools to teach about magnetics.
Most of the powder then goes through the FIC reactor. This reactor separates the iron from the impurities. On Earth, impurity removal is done with slagging, but this will be difficult on Mars. In our FIC reactor, we do not use slagging agents at all and avoid the necessity of the consumable. Instead, the iron is converted to a carbonyl iron vapor, while the residue remains in a solid state, enabling precise separation. The carbonyl iron is then turned back into iron in powder form during the decomposition step. The equipment to make Mars Steel featuring FIC is small, light, and sturdy. These are advantages for transportation via spacecraft.
The powder is then placed in a mold. Mixtures of the carbonyl iron powder and the sponge iron powder can be placed in the molds. While carbonyl iron powder is of a higher quality than the sponge iron powder, such mixing allows optimization of various steel-making issues including press-part stability (prior to sintering), part densification, and energy consumption. There are a variety of mold form options for the pressing step, each one affecting the steel’s downstream form.
FIC Reactor
The final two steps to make Mars Steel – pressing and sintering – are mature, well-understood processes. The cold isostatic press, developed in the 1950s, achieves extremely high pressure while remaining lightweight relative to alternate press types, making it practical for transportation in space. Sintering is also a long-standing technique that will actually be easier to complete on Mars than it is on Earth, thanks to the planet’s natural lack of oxygen in the atmosphere. The result is Mars Steel: a versatile material that can be used for critical infrastructure on Mars or as a premium, exclusive material for showpieces on Earth.
As mentioned earlier, the main difference between the Mars Steel process on Earth and Mars will be the iron ore. One notable example, the Pilbara chunk ore, is the best iron ore available on Earth. Almost all industrial iron ores require extra processing steps before steel-making. The Pilbara ore from Australia is of such exceptional quality that almost all the pre-processing steps aren’t needed. However, after extensive processing, some ores such as the taconite pellets from Minnesota can reach a slightly higher quality than even the Pilbara ore.
This image illustrates the average surface density of ironberries found by NASA. The area covered is approximately 1 m2.
On Mars, iron ore can be found in the Iron Region of the Meridiani Planum (IRoM) in the form of small iron spherules called ironberries. These ironberries are as high-quality as the processed Taconite pellets and easier to work with than the Pilbara ore. The false color NASA image at left shows the average surface density of loose ironberries on top of surface soils found by the rover Opportunity at IRoM. The ironberries are exceedingly easy to collect, they can be swept up from the top of these surface soils – no real mining is required. In terms of accessibility and quality ironberries are the finest raw iron ore discovered to date on any planet.
While Two Planet Steel is a for-profit company, it has an associated non-profit company called Two Planet Life. The principal objective of the non-profit is to build the infrastructure of a science station on Mars using locally made steel, electricity, and concrete. More information on Two Planet Life’s mission and work is available here.
credit: NASA/ASU
This is a mosaic image of Endurance Crater at IRoM made by Jim Bell of ASU, the lead scientist of the PanCam (Panoramic Camera) instrument on the head of NASA’s rover Opportunity. The Pancam also took the ironberry surface density image and the “background” image of Opportunity tracks at Victoria Crater.