Private US lander Blue Ghost captured high-definition images of a lunar sunset. To cut costs, instead of carrying material from Earth, astronauts would need to use the abundantly available lunar soil, or ‘regolith’ – a complex mixture of broken minerals and rocks – to build structures on site.
Researchers at the Indian Institute of Science (IISc.) have developed a bacteria-based technique to repair bricks that can be used to build lunar habitats, if they get damaged in the moon’s harsh environment.
According to IISc., future lunar expeditions are no longer planned as just flyby missions. NASA’s Artemis programme, for example, seeks to set up a permanent habitat on the moon.
To cut costs, instead of carrying material from Earth, astronauts would need to use the abundantly available lunar soil, or ‘regolith’ – a complex mixture of broken minerals and rocks – to build structures on site.
A few years ago, researchers at the Department of Mechanical Engineering (ME), IISc., developed a technique that uses a soil bacterium called sporosarcina pasteurii to build bricks out of lunar and Martian soil simulants.
Calcium carbonate crystals
The bacterium converts urea and calcium into calcium carbonate crystals that, along with guar gum, glue the soil particles together to create brick-like materials. This process is an eco-friendly and low-cost alternative to using cement.
Subsequently, the team also explored sintering – heating a compacted mixture of soil simulant and a polymer called polyvinyl alcohol to very high temperatures – to create much stronger bricks.
“It’s one of the classical ways of making bricks. It makes bricks of very high strength, more than adequate even for regular housing,” said Aloke Kumar, Associate Professor in the Department of ME and corresponding author of the study.
IISc said that though sintering is an easily scalable process, as multiple bricks can be made at once in a furnace, the lunar surface is extremely harsh (temperatures can swing from 121°C to -133°C in a single day), and it is constantly bombarded by solar winds and meteorites.
This can cause cracks in these bricks, weakening structures built using them.
Temperature changes
“Temperature changes can be much more dramatic on the lunar surface, which can, over a period of time, have a significant effect. Sintered bricks are brittle. If you have a crack and it grows, the entire structure can quickly fall apart,” said co-author Koushik Viswanathan, Associate Professor.
To solve this problem, the team once again turned to bacteria. In a new study, they created different types of artificial defects in sintered bricks and poured a slurry made from sporosarcina pasteurii, guar gum, and lunar soil simulant into them.
“We were initially not sure if the bacteria would bind to the sintered brick. But we found that the bacteria can not only solidify the slurry, but also adhere well to this other mass,” Prof. Kumar said.
Tolerance to high temperatures
The reinforced bricks were able to withstand temperatures ranging from 100°C to 175°C. The team is currently working on a proposal to dispatch a sample of sporosarcina pasteurii into space as part of the Gaganyaan mission, to test its growth and behaviour under microgravity.
Published – April 01, 2025 05:09 pm IST
