While the idea of building houses on the moon was once confined to the realm of science fiction, NASA hopes it could become a reality in the near future.
Now, scientists have revealed a rather unusual building material for lunar bases – astronauts’ urine.
A new study by researchers from the Polytechnic University of Cartagena has indicated that urea – a chemical found in urine – could be used as a plasticiser in the concrete of structures on the moon.
Using urea as a material could solve the problem of having to transport building materials from Earth to the moon, according to the researchers.
Professor Ramon Pamies, an author of the study, said: “To make the geopolymer concrete that will be used on the moon, the idea is to use what is there: regolith (loose material from the moon’s surface) and the water from the ice present in some areas.
“But moreover, 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.
“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.”
In the study, the researchers tested using urea as a plasticiser to build mud cylinders. The cylinders were heated to 80°C, before their resistance was tested.
While the results are early, they indicate that urea from urine could serve as a reliable plasticiser in the future.
Anna-Lena Kjøniksen, one of the researchers on the study, said: “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.
“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.”