Researchers at the Indian Institute of Science (IISc) joined hands with the Indian Space Research Organisation (ISRO) and have developed "space bricks" that can be utilised to make building-like structures on planet Mars and can help with human settlement on the planet.
A press release put out by the Bengaluru-based research university stated that these bricks are made from Martian soil along with bacteria and urea and the method that is used to make these space bricks has already been outlined in a study published by PLOS One journal.
“A slurry is first created by mixing Martian soil with guar gum, a bacterium called Sporosarcina pasteurii, urea and nickel chloride (NiCl2). This slurry can be poured into moulds of any desired shape and over a few days, the bacteria convert the urea into crystals of calcium carbonate. These crystals, along with biopolymers secreted by the microbes, act as cement holding the soil particles together,” the release from IISc stated.
As per researchers, this method provides an advantage — reduced porosity of the bricks. This has been an obstacle when it comes to using other methods to make bricks from Martian soil. “The bacteria seep deep into the pore spaces, using their own proteins to bind the particles together, decreasing porosity and leading to stronger bricks,” says Aloke Kumar, Associate Professor in the Department of Mechanical Engineering at IISc, one of the senior authors of the paper.
Previously, the research team had put their brains together to use lunar soil to make bricks while putting to work a similar method. However, the method used could only give cylindrical bricks, while the current slurry-casting method is also capable of producing complex-shaped bricks. The slurry-casting method was developed with the help of Koushik Viswanathan, Assistant Professor in the Department of Mechanical Engineering, IISc, whose lab works on advanced manufacturing processes. The release also stated that extending the method to Martian soil wasn't without its challenges.
“Martian soil contains a lot of iron, which causes toxicity to organisms. In the beginning, our bacteria did not grow at all. Adding nickel chloride was the key step in making the soil hospitable to the bacteria,” explains Kumar.
The team has had the chance to test the strength of these bricks against the effect of the Red Planet's atmosphere and low gravity. The atmosphere on Mars is not only 100 times thinner, but also contains 95 per cent carbon dioxide, which has a significant effect on the growth of bacteria. MARS (Martian AtmospheRe Simulator) is the device that the researchers have come up with and it consists of a chamber that produces, in a lab, the same atmospheric conditions that are found on Mars.
The team has also developed a lab-on-a-chip device that aims to measure bacterial activity in microgravity conditions. “The device is being developed keeping in mind our intention to perform experiments in microgravity conditions in the near future,” explains Rashmi Dikshit, a DBT-BioCARe Fellow at IISc and first author of the study, who had also previously worked on lunar bricks. With the help of ISRO, the team has plans of sending such devices into space, so that they can further study the effect of low gravity on bacterial growth.
“I'm so excited that many researchers across the world are thinking about colonising other planets,” says Kumar. “It may not happen quickly, but people are actively working on it.”
