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.
  1. It exploits lunar soil, and uses bacteria and guar beans to consolidate the soil into possible load-bearing structures
  2. These “space bricks” could eventually be used to assemble structures for habitation on the moon’s surface, the researchers suggest.
  3. It is really exciting because it brings two different fieldsbiology and mechanical engineering — together.
  4. 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.
  5. 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. 
  6. 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.
  7. 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. 
  8. 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.
  9. 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
  10. 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.
  11. 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. 
  12. This capability could also be exploited to make intricate interlocking structures for construction on the moon, without the need for additional fastening mechanisms.