Settling on Mars presents a major difficulty: building habitats. Indeed, transporting cement from Earth would prove too costly and laborious. Fortunately, scientists may have found a surprising solution by betting on resources already available on the red planet.
A bacterium named
Sporosarcina pasteurii, found in Earth's soils, could be valuable. It produces urea which, when reacting with calcium, forms calcium carbonate crystals. Mixed with guar gum, these crystals bind regolith particles, the dust of Mars, to create a brick-like material.
With this in mind, the goal is to use local resources, an approach called in-situ resource utilization. This would significantly reduce the amount of materials to be transported from Earth. Shubhanshu Shukla, an ISRO astronaut, indicates that this method would enable longer missions on the Red Planet. The aim is to make Martian colonies autonomous and economical.
To test this lead, researchers use Martian regolith simulants. However, these simulants often omit perchlorate, a toxic compound present on Mars. By carefully adding it, the team examined its impact on the bacterium. The results reveal that perchlorate, although harmful, positively influences the production of construction materials.
Against all expectations, perchlorate, despite the stress it imposes on bacterial cells, strengthens the produced material. Swati Dubey, a microbiologist, observed that this is due to the formation of an extracellular matrix. This matrix creates micro-bridges between the bacteria and the crystals, improving the particle-binding process, known as biocementation.
These micro-bridges could help bacteria repair their damaged cells and better unite the regolith particles. The next step is to test this process in a carbon dioxide-rich atmosphere, similar to that of Mars. This will make it possible to see how the bacterium adapts to the planet's real conditions.
Aloke Kumar from the Indian Institute of Science mentions the importance of understanding how terrestrial organisms react to the Martian environment. This research, published in
PLOS One, opens promising avenues for future space colonization by exploiting resources available on-site.