The Indian Institute of Science (IISc) on 14 August 2020 said that in what could be a significant step forward in space exploration, a team of its researchers and the Indian Space Research Organisation (Isro) has developed a sustainable process for making brick-like structures on the Moon. This project began as early as on January 30, 2020.
- It exploits lunar soil, and uses bacteria and guar beans to consolidate the soil into possible load-bearing structures.
- These “space bricks” could eventually be used to assemble structures for habitation on the moon’s surface, the researchers suggest.
- It is really exciting because it brings two different fields — biology and mechanical engineering — together.
- Space exploration has grown exponentially in the last century. With Earth's resources dwindling rapidly, scientists have only intensified their efforts to inhabit the moon and possibly other planets.
- The cost of sending one pound of material to outer space is about Rs 7.5 lakh. The process developed by the IISc and Isro team uses urea — which can be sourced from human urine — and lunar soil as raw materials for construction on the moon's surface. This decreases the overall expenditure considerably.
- The process also has a lower carbon footprint because it uses guar gum instead of cement for support. This could also be exploited to make sustainable bricks on Earth, IISc said in a statement.
- Some microorganisms can produce minerals through metabolic pathways. One such bacterium, called Sporosarcina pasteurii, produces calcium carbonate crystals through a metabolic pathway called the ureolytic cycle: it uses urea and calcium to form these crystals as byproducts of the pathway.
- Living organisms have been involved in such mineral precipitation since the dawn of the Cambrian period, and modern science has now found a use for them.
- To exploit this ability, Kumar and colleagues teamed up with Isro’s Arjun Dey and I Venugopal. They first mixed the bacteria with a simulant of lunar soil, then added urea and calcium sources along with gum extracted from locally-sourced guar beans.
- The guar gum was added to increase the strength of the material by serving as a scaffold for carbonate precipitation. The final product obtained after a few days of incubation was found to possess significant strength and machinability.
- Our material could be fabricated into any freeform shape using a simple lathe. This is advantageous because this completely circumvents the need for specialised moulds – a common problem when trying to make a variety of shapes by casting.
- This capability could also be exploited to make intricate interlocking structures for construction on the moon, without the need for additional fastening mechanisms.