NEW DELHI: In what could be an important step forward space exploration, a team of researchers from the Indian Institute of Science (IISc) en Indian Space Research Organization (Isro) has a sustainable process for making brick-like structures on the moon.
It exploits moon soil and uses bacteria and guar gum to consolidate the soil into potentially viable structures, an IISc said in a statement. These “space bricks” could eventually be used to collect structures for living on the moon’s surface, the researchers suggest. ‘It’s really exciting because it brings two different fields – biology and mechanical engineering – together, ”says Aloke Kumar, Assistant Professor in the Department of Mechanical Engineering, IISc, one of the authors of two recently published studies.
The cost of shipping one pound of material to outer space is about Rs 7.5 lakh. The process developed by IISc and Isro team uses urea – which can be obtained from human urine – and lunar soil as raw materials for accumulation on the surface of the moon. This significantly reduces the total expenditure. The process also has a lower carbon footprint because it uses guar gum instead of cement for support. This could also be used to make durable bricks on Earth.
Some microorganisms can produce minerals through metabolic pathways. One such bacterium, called Sporosarcina pasteurii, produces calcium carbonate crystals via a metabolic pathway called the ureolytic cycle: it uses urea and calcium to form these crystals as by-products of the pathway. “Living organisms have been involved in such mineral deposits since the beginning of the Cambrian period, and modern science has now found a use for them,” says Kumar.
To harness this power, Kumar and colleagues at IISc have partnered with Isro scientists Arjun Dey and I Venugopal. They first mixed the bacteria with a lime-based simulator. Then they added the required urea and calcium sources along with gum that was extracted from locally sourced guarabon bones. The guar gum was added to increase the strength of the material by serving as a scaffolding for precipitation of carbonate. The final product obtained after a few days of incubation was found to have significant strength and machinability.
“Our material could be made in any freeform form with a simple lathe. This is beneficial because it embraces the need for specialized molds – a common problem when trying to create a variety of shapes by casting. This capability could also be used to create complex interlocking structures for construction on the moon, without the need for additional fastening mechanisms, ”explains Koushik Viswanathan, assistant professor in the Department of Mechanical Engineering, IISc, another author.
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