covers the Moon – Lunarcrete is an umbrella term for ‘concrete made on the Moon’. As the US and China race to establish long-term lunar settlements, scientists are searching for suitable building materials to protect people from dangerous radiation and drastic temperature fluctuations. Lunarcrete is a promising candidate: Instead of sand and gravel, it uses lunar regolith, the gray soil that covers the Moon, as its main aggregate.

One challenge, however, is the binder: While portland cement uses a lot of water on Earth, water is a precious resource on the Moon. So researchers are looking for alternatives that reduce or eliminate the need for water. An alternative is to send some cement (or some other binder) from Earth and mix it with the regolith using minimal water and cure inside sealed habitats.

The second is sulfur lunarcrete, where scientists melt sulfur, mix it with regolith, and cool it to solidify. Sulfur can work like cement without water but it softens when heated too much. A third idea is to heat the regolith with microwaves or concentrated sunlight so that the grains partially melt and fuse together, forming bricks.

Recently, researchers at Louisiana State University led by Arup Bhattacharya simulated a dome-shaped lunar habitat with Chandracrete walls. When they exposed it to temperatures ranging from 120 C to -130 C, they found that the walls could preserve the inside temperature at 22 C.

Walls made of two layers of Lunarcrete with a layer of empty space in between were also found to be excellent insulators.