Astronaut urine could be a key concrete ingredient on the moon

A key challenge in building colonies on the moon is that it's incredibly expensive to transport construction materials to space from Earth. That's why researchers are exploring how moon bases could be mostly constructed from raw materials already there. A team of scientists working with the European Space Agency (ESA) are exploring how urine could be a key ingredient in lunar concrete. A 3D printer could then form the "mud" into structural components. From FEYCT - Spanish Foundation For Science And Technology:

Scientists from Norway, Spain, the Netherlands and Italy, in cooperation with ESA, have conducted several experiments to verify the potential of urine urea as a plasticizer, an additive that can be incorporated into concrete to soften the initial mixture and make it more pliable before it hardens. Details are published in the Journal of Cleaner Production.

"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," explains one of the authors, Ramón Pamies, a professor at the Polytechnic University of Cartagena (Murcia), where various analyses of the samples have been carried out using X-ray diffraction.

"But moreover," he adds, "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."

Using a material developed by ESA, which is similar to moon regolith, together with urea and various plasticizers, the researchers, using a 3D printer, have manufactured various 'mud' cylinders and compared the results.

image: ESA, Foster and Partners