Astronauts may have to pee more often as they build infrastructures on the Moon in the future. Researchers have proposed mixing their urine to strengthen the materials for lunar bases.
The team working with the European Space Agency (ESA) found that the urea in the human pee could serve as a plasticizer in the concrete. The finding is expected to help reduce logistical challenges in sending or making construction materials to the Moon.
Researchers estimate that transporting just 0.45 kg of material from Earth to space would cost up to $10,000. That is why ESA and other space agencies have been seeking ways to use raw materials on the Moon’s surface and other things already in space for the lunar project.
Construction materials may also come from astronauts themselves. The researcher team, composed of experts from Norway, Spain, the Netherlands and Italy, found the compound urea in the urine can be converted into an additive that can be mixed with concrete.
The study, published in the Journal of Cleaner Production, shows that the urine-based material could help soften the mixture and make it more pliable before it turns into concrete.
“With this study we have seen that a waste product, such as the urine of the personnel who occupy the moon bases, could also be used,” Ramón Pamies, study author and a professor at the Polytechnic University of Cartagena in Spain, said in a statement. “The two main components of this body fluid are water and urea, a molecule that allows the hydrogen bonds to be broken and, therefore, reduces the viscosities of many aqueous mixtures.”
Pamies and his colleagues used a 3D printer in Norway to test how the urine would work with Moon-like materials from ESA to produce plasticizers. The team was able to create “mud” cylinders and found the final products with urea can support heavy weights.
The material also remained stable in shape and could resist heat at 80°C. The researchers plan to mass produce the construction materials made with urea using 3D printing technology.
However, they noted more tests are required to produce the best building material for the Moon bases.
“We have not yet investigated how the urea would be extracted from the urine, as we are assessing whether this would really be necessary, because perhaps its other components could also be used to form the geopolymer concrete,” Anna-Lena Kjøniksen, researcher from the Østfold University College in Norway, said. “The actual water in the urine could be used for the mixture, together with that which can be obtained on the Moon, or a combination of both.”