Past Innovations in Martian Bricks
IISc has been at the forefront of developing brick-like materials from simulated lunar and Martian soil for years. Earlier research, detailed in 2022,
involved a sophisticated mix of simulated Martian regolith, guar gum, nickel chloride, urea, and the bacterium Sporosarcina pasteurii. This groundbreaking method improved upon an even earlier technique that could only produce cylindrical bricks from lunar soil. The newer process harnessed the bacteria's ability to consume urea, producing crystals that act as a natural cement. These biopolymers secreted by the microbes also helped to bind the soil particles, significantly reducing the porosity of the resulting material. To overcome the challenges posed by the high iron content in Martian soil, which initially inhibited bacterial growth, nickel chloride was incorporated. This additive was crucial for ensuring robust bacterial activity, a key component in the cementation process.
Leveraging Martian Perchlorate
The latest breakthrough from IISc centers on the surprising utility of perchlorate, a chemical naturally present in Martian soil but considered toxic and flammable. In their recent experiments, researchers introduced perchlorate into the brick-making mixture, alongside guar gum and nickel chloride. They observed that the bacteria, when subjected to the stress of perchlorate, responded by secreting an "extracellular matrix." This matrix proved instrumental, forming chemical bridges between individual bacterial cells and precipitate minerals. Contrary to initial expectations, the perchlorate, when integrated into the brick composition with these specific ingredients, actually facilitated the process. Dr. Shubhanshu Shukla, a former astronaut involved in the research, highlighted the potential for future studies to assess these effects in environments with high CO2 concentrations, aiming to better replicate Martian atmospheric conditions.
Sustainable Construction Applications
The implications of this research extend beyond extraterrestrial construction, offering a sustainable and less carbon-intensive building strategy applicable on both Mars and Earth. On the Red Planet, these bio-bricks could be essential for constructing critical infrastructure such as roads, launch pads, and landing zones for rovers and landers. Such structures would provide stable surfaces, preventing vehicles from toppling over on the uneven Martian terrain. As Shubhanshu Shukla emphasized, the core principle is maximizing "in situ resource utilization." This means leveraging materials already present at the destination, drastically reducing the need to transport heavy building supplies from Earth. By constructing habitats and infrastructure on-site, missions can become more feasible and allow for longer, more sustained exploration and operations over time.
