A team of researchers from the Indian Institute of Science (IISc) and ISRO have developed a scalable technique to make “space bricks” for Mars using Martian Simulant Soil (MSS). These bricks can eventually be used for habitation on that planet.
According to media reports, a team led by Aloke Kumar, Associate Professor at IISc’s mechanical engineering department, demonstrated that by using Microbial Induced Calcite Precipitation (MICP) under right conditions, certain bacteria can precipitate calcium carbonate, which can create bricks using MSS.
Besides Kumar, the team consists of Rashmi Dikshit, Nitin Gupta and Koushik Viswanathan from IISc, and Arjun Dey from ISRO’s UR Rao Satellite Centre. The five were also part of the team that developed “space bricks” for moon by using lunar simulant soil (LSS) in February 2018.
In their latest findings published in PLOS One, the team has reported the creation of bricks using both LSS and MSS.
Bacteria are very versatile organisms and certain species are capable of bio-mineralisation, a process by which living organisms produce minerals to harden or stiffen existing tissues, which was used to make these bricks.
The team used one specific bacterium, Sporosarcina pasteurii, which was introduced into simulant soil and hardened, said a Times of India report. Under ideal conditions, the MSS, which is in powder form, would slowly turns into a brick, within 15-20 days of introducing the bacteria.
Similar to the process of manufacturing LSS bricks, the team used guar gum, a naturally occurring polymer, as an additive to add strength to the bricks from MSS. Extracted from guar beans, guar gum has thickening and stabilising properties useful in food, feed, and industrial applications.
While the team had learnt most of what was needed to make bricks using MSS from their earlier project, there were challenges it had to overcome, said the ToI report. For one, the bacterium used is soil bacteria on earth. Martian soil has a lot of iron, which makes it difficult for microbes to flourish.
Some of these issues the team faced were pointed out by a paper published in the International Journal of Astrobiology by Hitesh G Changela and others, according to Kumar.
The paper said that one limitation may be the various salts that are known to inhibit or prevent microbial metabolism, including perchlorates and chaotropic salts, sulphate salts, and those that create multiple stresses and poly extreme conditions.
Besides this, from the time they developed the lunar brick, the team has been able to shift to a scalable casting-based manufacturing method which, apart from enabling production of multiple bricks simultaneously, also provides flexibility to produce a range of shapes, including hollow structures, according to Viswanathan.