Researchers from the Indian Space Research Organisation (ISRO) and the Indian Institute of Science (IISc) have developed a method for making bricks from Martian soil with the help of bacteria and urea. These ‘space bricks' can be used to build building-like structures on Mars, which could aid human settlement, according to a press release from IISc.
Their findings were published in PLOSOne, a peer-reviewed open-access scientific journal. The slurry was first created by mixing Martian soil with guar gum, Sporosarcina pasteurii bacteria, urea, and nickel chloride (NiCl2).
"This slurry can be poured into any shape mould, and bacteria convert the urea into calcium carbonate crystals over the course of a few days." "These crystals, in combination with biopolymers secreted by microbes, act as a cement that holds soil particles together," according to the press release.
This method makes the bricks less porous, which was a problem with previous Martian brick-making methods. "The bacteria seep deep into the pore spaces, using their own proteins to bind the particles together, decreasing porosity and resulting in stronger bricks," said Aloke Kumar, associate professor at IISc's Department of Mechanical Engineering and one of the paper's senior authors.
Koushik Viswanathan, an assistant professor in the Department of Mechanical Engineering at IISc, helped develop the slurry-casting method.
Previously, the team had used a similar method to make bricks from lunar soil. The previous method, however, could only produce cylindrical bricks, whereas the current slurry-casting method can also produce complex-shaped bricks, according to the press release.
Another issue was the composition of Martian soil, which contains a lot of iron, which makes organisms toxic. "At first, our bacteria didn't seem to grow at all. "Adding nickel chloride was a critical step in making the soil bacteria-friendly," Kumar explained.
The team is now preparing to investigate how the atmosphere on Mars interacts with the 'space bricks' due to the low gravity. According to the press release, the Martian atmosphere is a hundred times thinner than Earth's and contains over 95 percent carbon dioxide, which could have a significant impact on bacterial growth. Researchers have built a device called Mars to simulate the conditions on Mars (Martian AtmospheRe Simulator).
According to the press release, the team has also created a lab-on-a-chip device that can measure bacterial activity in microgravity. "The device is being developed with the goal of performing experiments in microgravity in the near future," said Rashmi Dikshit, a DBT-BioCARe Fellow at IISc and the study's first author, who had previously worked on the lunar bricks. The team hopes to send such devices into space with the help of ISRO to study the effects of low gravity on bacterial growth.
