BENGALURU: A space brick that researchers at the Indian Institute of Science (IISc) and Indian Space Research Organisation (ISRO) came up with for future moon habitats might just show a breakthrough in the construction sector back on Earth.
After years of research, the team has begun developing bricks from the Lunar Soil Simulant (LSS) which ISRO provided. This is supposed to be an accurate replica of the soil available on Moon. Considering that Moon and Earth may have similar types of sand, the technology could have implications for eco-friendly constructions, said Aloke Kumar, Assistant Professor, Mechanical Engineering, IISc.
Team looking to subject Space Brick to microgravity
Kumar and his team have made the moon sand stronger for construction, by infusing bio-mineralisation or bio-cementation bacteria into it. The bacteria builds a cocoon of calcium carbonate layers around it and dies. The sand and the calcium carbonate are bound together by biopolymers (protien plus other things) that ooze out of the bacteria.
Since the bacteria splits into two before dying, the process of bio-mineralisation in unending. The only way to stop the runaway process is to stop giving them food – Carbon and urea and other things, said Aloke. The fact that urea can be used to convert the bacteria into calcium carbonate, which can be used for construction, might just be a goldmine for waste management, he added.The team is also looking to subject their product to microgravity (or gravity close to zero) tests for potential human habitation on Moon for long durations, and to protect instruments for micro-meterorite impact.
At present, the whole process of conversion of bacteria to calcium carbonate, to make the brick, takes about 10-21 days, much like the process of turning milk into curds, and the team is still optimising various parameters, said Aloke. For similar constructions on the Moon, the European Space Agency (ESA) has come up with project URBAN, where they work with 3D printing of the structures. NASA also is experimenting with concrete in microgravity in space.
What makes it ecofriendly?
While cement/concrete making is an industrial process which is carbon-intensive, and many materials are artificially manufactured in the laboratory, it has a net carbon dioxide emission and hence carbon footprint is net positive. When the brick itself is growing naturally using a bacteria that is natural to the planet, carbon footprint is negative. As per NASA data, the natural process can sequester (cut down) carbon by 10%, said Kumar. The team is also looking at using multispecies colony in this process of conversion of bacteria into calcium carbonate to eliminate the production of ammonia.