AsianScientist (Apr. 30, 2025) –Lunar expeditions are becoming more than just flybys. Past lunar missions have given us insights into the lunar environment, with Chandrayaan-1 confirming the presence of water. Now, researchers are interested in longer term missions, like NASA’s Artemis programme that aims to set up a permanent habitat on the moon.
To reduce the resources needed to transport building materials from earth, astronauts would have to use what is already abundant on the moon – lunar soil.
Researchers at the Indian Institute of Science (IISc) had previously developed a bacteria-based technique to build space bricks from lunar and martian soil simulants. Now, they have developed a method to repair bricks damaged in the harsh lunar environment.
In the presence of urea and calcium, the soil bacterium Sporosarcina pasteurii produces calcium carbonate. Combined with guar gum, the calcium carbonate from the bacteria can bind lunar soil particles together to create bricks.
These bricks can be strengthened by sintering – heating them to extremely high temperatures. “It’s one of the classical ways of making bricks,” explained Aloke Kumar, associate professor at the Department of Mechanical Engineering (ME) at IISc and corresponding author of the study. “It makes bricks of very high strength, more than adequate even for regular housing.”
Sintered bricks may be strong, but bricks on the moon have to withstand far harsher conditions than on Earth. The lack of atmosphere on the moon means the temperature varies rapidly and widely, ranging from 121℃ to -133℃. “Temperature changes can be much more dramatic on the lunar surface, which can, over a period of time, have a significant effect [on building materials],” explained Koushik Viswanathan, associate professor at ME and co-author of the study. Add to that the threat of meteorites, and the bricks can become prone to fractures. “Sintered bricks are brittle. If you have a crack and it grows, the entire structure can quickly fall apart,” added Viswanathan.
Turning back to bacteria to solve this problem, the researchers induced various defects in sintered bricks, then poured in a slurry made of S. pasteurii, guar gum, lunar soil simulant, and calcium lactate. Over time, the bacteria produced calcium carbonate, filling in the cavities in the bricks, while the guar gum enhanced its binding properties.
“We were initially not sure if the bacteria would bind to the sintered brick,” said Kumar. “But we found that the bacteria can not only solidify the slurry but also adhere well to this other mass.” The process restored most of the brick’s strength, showing its potential in extending the lifespan of structures on the moon.
Apart from being useful in space, this method could also be used on Earth as a sustainable and cost-effective alternative to cement.
“One of the big questions is about the behaviour of these bacteria in extraterrestrial conditions,” said Kumar. “Will their nature change? Will they stop [producing carbonate]? Those things are still unknown.”
The team hopes to send a sample of S. pasteurii with the Gaganyaan Mission to test its behaviour in microgravity. “If that happens, to our knowledge, it will be the first experiment of its kind with this type of bacteria,” said Viswanathan.
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Source: Indian Institute of Science ; Image: Amogh Jadhav
This article can be found at Bacterial bio-cementation can repair space bricks
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