Using bacteria to build settlements on Mars

(ORDO NEWS) — In collaboration with the Indian Space Research Organization (ISRO), a team of scientists from the Indian Institute of Science (IISc) has developed a sustainable method for making bricks from Martian soil using bacteria and urea.

These “space bricks” could be used to build building-like structures on Mars that could encourage human settlement on Mars.

The method for making these space bricks is described in a study published in the journal PLOS ONE. First, a slurry is created by mixing Martian soil with guar gum, the bacterium Sporosarcina pasteurii, urea, and nickel chloride (NiCl2).

This suspension can be poured into molds of any desired shape, and within a few days the bacteria convert the urea into calcium carbonate crystals. These crystals, along with the biopolymers released by the microbes, act as cement to hold the soil particles together.

This method has the advantage of reducing the porosity of the bricks, which has been a problem with other methods used to compact Martian soil into bricks.

“Bacteria penetrate deep into pore spaces, using their own proteins to bind particles together, reducing porosity and creating stronger bricks,” says Aloke Kumar, assistant professor of mechanical engineering at IISc, one of the authors of the paper.

The research team has previously worked on making bricks from lunar soil using a similar method. However, the previous method only produced cylindrical bricks, while the current sludge casting method produces bricks with complex shapes.

The slip casting method was developed with the help of Kushik Viswanathan, IISc Associate Professor of Mechanical Engineering, whose lab works on advanced manufacturing processes. In addition, extending the method to Martian soil proved to be a challenge.

“Martian soil contains a lot of iron, which causes toxicity to organisms. In the beginning, our bacteria didn’t grow at all. Adding nickel chloride was a key step in making the soil bacteria-friendly,” explains Kumar.

The group plans to study the effects of the Martian atmosphere and low gravity on the strength of space bricks. The Martian atmosphere is 100 times thinner than Earth’s and contains over 95% carbon dioxide, which can significantly affect bacterial growth.

The researchers built a device called MARS (Martian AtmospheRe Simulator), which consists of a camera that reproduces the atmospheric conditions that exist on Mars in the laboratory.

The team also developed a lab-on-a-chip device that is designed to measure bacterial activity in microgravity.

“The device is being developed with our intent to conduct experiments in microgravity in the near future,” explains Rashmi Dixit, DBT-BioCARe Research Fellow at IISc and first author of the study, who previously also worked on lunar bricks.

With the help of ISRO, the team plans to send such devices into space to study the effects of low gravity on bacterial growth.

“I’m very happy that many explorers around the world are thinking about colonizing other planets,” says Kumar. “It may not happen quickly, but people are actively working on it.”

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