Human settlements in Mars may not be a distant dream

Indian researchers have developed ‘space bricks’ using soil from Mars and bacteria

Human settlements in Mars is a concept readied by countries, including India, for the future. In the context of such settlements in the offing, it would become imperative to build structures on the face of the alien planet so as to facilitate such settlements. Significant research has been pursued by a team of Indian scientists to this effect.

A team of researchers from the Indian Institute of Science (IISc) has collaborated with the Indian Space Research Organization (ISRO), to develop a sustainable method for making bricks out of Martian soil. The bricks thus made comprise the use of bacteria and urea in them.

Going by a study published in PLOS ONE, these ‘space bricks’ are capable of being deployed in the construction of building-like structures on Mars, and they in turn would help set up human settlements on the planet.

Soil from Mars, bacteria, urea, and NiCl2 make space bricks

How the researchers managed to develop the space bricks is interesting. They used a slurry created by mixing Martian soil with guar gum, a bacterium called Sporosarcina pasteurii, urea and nickel chloride (NiCl2). This slurry was then poured into moulds of different shapes and left alone for bacteria to act on them. The bacteria were found to have converted the urea into crystals of calcium carbonate, and these crystals, along with biopolymers secreted by the microbes, played to role of cement which managed to hold the soil particles together.

Research proved that reduced porosity of the bricks was achieved. The porosity factor had been a problem with other methods used to consolidate Martian soil into bricks. However, in this case, the bacteria were able to seep into the pore spaces, using their own proteins to bind the particles together. Thus reduced porosity which ensured stronger bricks was possible.

To be tested on Red Planet’s atmosphere

Though the same research team had earlier in tried this with lunar soil, they were successful only in developing cylindrical bricks. The difference in the Martian soil experiment was that the slurry-casting proved successful in making bricks of any complex shape. Koushik Viswanathan, Assistant Professor in the Department of Mechanical Engineering, IISc, whose lab works on advanced manufacturing processes, had helped in this slurry-casting endeavour. As Martian soil comprised good quantities of iron that give toxicity to organisms, addition of nickel chloride came as a critical step in making the soil hospitable to the bacteria, it has been reported.

The researchers will now look to probe the effect of Mars’ atmosphere and low gravity on the strength of the space bricks. As the atmosphere of Mars is 100 times thinner than that of the Earth and has more than 95 percent carbon dioxide, it would be important to study how it would affect bacterial growth. In view of this, the team has also built a Martian AtmospheRe Simulator (MARS, as it is called) complete with a chamber that reproduces the atmospheric conditions found on Mars in the lab. Researchers will also measure bacterial activity in micro-gravity conditions using a lab-on-a-chip device.

The IISc researchers will now take ISRO’s help to launch these devices into space in a bid to study the effect of low gravity on the bacterial growth.

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