More than 50 years have passed since humans first landed on the moon. But moon exploration did not stop there, as humanity is planning to return to the lunar surface soon with NASA's upcoming Artemis mission.

The space agency has repeatedly pointed out that the return on the lunar surface will be "to stay" and build a lunar base for humanity. To do that, humans need to be resourceful and creative.

A suggestion came from a group of scientists saying that astronauts can use their urine in an effort to find sustainable solutions in building future colonies on the moon. In collaboration with the European Space Agency, the team published a study in the Journal of Cleaner Production elaborating their suggestion.

This new suggestion is just one of many equally creative ideas to build colonies in space. Some other ideas also include building mushroom houses on the lunar surface and the origami-inspired habitat to reduce the amount of resources astronauts need to bring with them on their journey to the moon.

Lunar Concrete Made from Urine

Last Friday, the European Space Agency announced that the main organic compound of urine known as urea could become a useful ingredient in making concrete to build on the moon. They said that urea would make the mixture for a "lunar concrete" more malleable before it turns into its sturdy form.

Using only materials available on site for a moon base or other construction would reduce the need to launch supplies from Earth, according to the researchers.

One of the study author, Ramón Pamies, a professor at the Polytechnic University of Cartagena, Murcia, said that with their research, they have seen that a waste product, such as the urine of an astronaut who occupies the bases could be used.

In making the lunar concrete, urine is mixed with lunar regolith, the layer of rocky material that covers the bedrock of the moon. Since urea has the ability to break down hydrogen bonds, it can reduce the viscosity of the regolith mixture which makes it moldable before it hardens.

Lesser Materials are Needed to Transport from Earth to Moon

Using urine would result in a reduced need to find other resources on the moon such as water, or the need to carry other resources from Earth to the moon. Transporting 0.45 kilograms of supplies from Earth would approximately cost $10,000, which makes transporting the entire construction material less than ideal.

The team tested this new method by using a material similar to lunar regolith and mixed it with urea to make different concrete cylinders using a 3D printer.

The researchers are not yet sure whether urea needs to be extracted from the urine or urine can be used as it is for the concrete mixture. One of its researchers, Anna-Lena Kjøniksen, from the University of Norway, said that actual water from the urine could be used or the water obtained from the moon, or it can be both. Previous studies suggest that ancient deposit of ice can be found in the dark craters of the moon's southern and northern poles.