If humanity ever makes it to constructing the first permanent buildings on Mars, they will likely need bricks made from Martian regolith—but the construction material may also require blood and other bodily fluids from astronauts themselves.
The explorers tasked with establishing a permanent Martian base will also need to pack strategically. Space will be at a premium aboard the rocket that takes them to Earth’s neighbor, and the mission’s cost and fuel requirements increase in tandem with the amount of cargo. Because of this, the earliest crews will need to rely on the resources around them—which is mostly a lot of rocks and dirt. A millenia-old strategy, however, may help them make the most of other readily available additives.
Ancient Roman concrete is known for its excellent resiliency, strength, and even self-healing properties. But masons often used other key ingredients in the brickmaking: blood and urine. Knowing this, a research team from Iran’s Kharazmi University recently mixed and tested multiple potential building materials using various combinations of sediment found on Mars, as well as other easily obtainable components.
[Related: Inside the project to bring ‘self-healing’ Roman concrete to American shorelines.]
“Ancient Romans utilized organic additives, including animal blood, primarily to improve the durability and workability of their mortar,” they wrote in a subsequent study published in the journal, Acta Astronautica. “Although it is a bit strange, blood can be utilized to create strong concrete or bricks for onsite construction on Mars.”
Depending on the region of the planet, Martian soil contains the right chemical composition for multiple types of concrete. After compiling geological data collected by past Mars landers and orbiters, the team identified 11 potential concrete options for future astronauts. These included geopolymer and magnesium silica mixtures. They then created simulated building material samples using a 3D printer, stress tested them, and recorded the results.
According to the team, a sulfur-based concrete will likely be the most reliable initial material for buildings on Mars. But researchers also suggest that another, more outlandish contender could be AstroCrete, a modern form of Roman concrete that contains additional, human-sourced ingredients.
“The production process is simple. Aggregates (Martian regolith) bind together through contact with human serum albumin (HAS), a protein found in blood plasma,” they write.
The team theorizes that a single astronaut could produce enough HAS to make the amount of AstroCrete necessary to construct a single-occupancy dwelling in about 72 weeks. To increase the AstroCrete’s compressive strength and plasticity while also lowering its brittleness, the study authors offer another possible additive—urea extracted from sweat, tears, and urine. An additional major benefit of AstroCrete is that it requires no water to mix, which is especially useful given the planet’s almost entirely arid conditions.
Researchers stressed that mission engineers and astronauts will need to consider much more than just sulfur-based concrete or AstroCrete when planning a base on Mars. Numerous other challenges, such as the planet’s exposure to ultraviolet radiation, deadly climate, low gravity, and lack of water may all prevent humans from permanently living there. Success, the authors explain, therefore “hinges upon the development of low-cost and practical solutions,” including “onsite construction utilizing in-situ resources emerges as the most promising approach.” Resources that may include the blood, sweat, and tears of the first Martian visitors.
