How bacteria could help build and maintain cities on the moon

If all goes to plan, scientists may someday begin building outposts on the moon — and some experts believe that these outposts could be constructed with bricks made out of lunar regolith. And now, a new study based on lunar regolith simulant experiments suggests that if these moon-dust bricks crack, bacteria could be used to seal them back up.

Using as many local lunar resources as possible to construct a base on the moon is essential to keep costs down; launching large masses of material from Earth to the moon is very expensive. Thus, making bricks out of lunar regolith has long been mooted as a potential solution. Many teams around the world, including researchers at the Indian Institute of Science (IISc), have been experimenting making these kinds of bricks with lunar regolith simulants.

Regolith, for context, refers to the loose dust and rocks covering the surface of the moon. Actual samples of lunar regolith are rare and precious, and therefore simulants, which aim to replicate different types of regolith, are used for experiments instead. Previously, the IISc researchers found a way of using a terrestrial soil bacterium called Sporosarcina pasteurii to make bricks out of regolith simulant. The bacteria are able to convert urea — which the bacteria produce as waste — and calcium into calcium carbonate crystals. When mixed with guar gum that is extracted from guar beans, these crystals are able to bind regolith particles together to form bricks.