Future lunar expectations may be made more from materials found on the moon
Future astronauts can make lunar buildings from moon dust and urinate.
That’s the suggestion of chemist Anna-Lena Kjøniksen and her colleagues, who made cement from urea – a major component of urine – and artificial lunar soil.
When people stay on other planets or on the moon for a long time, they have to envelop the light, also because Earth’s transmission equipment is expensive. NASA estimates that each pound of matter placed in orbit costs around $ 10,000.
Using local resources can reduce costs. Researchers suggest using lunar soil to make concrete or cement for 3D printed apartments for astronauts (SN: 2/21/13). However, most cement recipes require a lot of water, which is scarce and extremely heavy on the moon, to hunt in space (SN: 4/15/19).
Around the world, adding a chemical called a superplasticizer to a cement mix reduces water requirements by preventing a drier mix from becoming too crumbly while still remaining flexible enough to be used in a 3D printer. But most superplasticizers are organic compounds, which are also lacking in the moon, says Kjøniksen of Østfold University College in Halden, Norway.
He then hit him. “I thought about what’s in the moon? If you add people, what can you use?” He says. Maybe human waste can help.
Kjøniksen used urea to thicken the plastic mixes. Urea breaks the hydrogen bonds between molecules, reduces friction, and allows molecules to slide into each other more easily. He had never heard of anyone using it on cement, “but I thought it was worth a try.”
A powder of silicon dioxide and aluminum oxide – a substitute for moon dust – are the main ingredients in Kjøniksen cement. Its chemical content is similar to that of fly ash, the main component of common cement mixes, but with larger and more crystalline grains. The team combined this powder with powdered urea, purchased from a chemical company that was not pure from actual urine, with water to make the cement. Compared to the other two superplasticizers used in construction around the world, “urea works very well,” says Kjøniksen.
The mixture retained its shape under light weight and withstood temperature changes. Entering the cement through a pipe and placing several layers on top of each other using a 3D printer resulted in a small, solid wall, the team reported in the Journal of Cleaner Production on February 20.
Kjøniksen plans to test the cement at higher temperatures and in a vacuum room that mimics the absence of the moon’s atmosphere. The next step is to measure the wall to a more realistic size. He also wants to determine whether future astronauts will need to clean their urine or if they can use acid directly in the cement.
In real life, making urea cement is probably more complicated than just urinating into a bucket, says European Space Agency scientist Belinda Rich, who was not involved in the study. this but collaborates with Kjøniksen and his colleagues on follow-up experiments. However, in general, making cement with urea in the moon can be handy, he says.
“It was like such a stupid idea,” Rich said. “But here we are – it works.”