The European Space Agency said Friday that human urine could one day become a useful ingredient in making concrete to build on the moon.
The agency said researchers in a recent study it sponsored found that urea, the main organic compound in urine, would make the mixture for a “lunar concrete” more malleable before it hardens into its sturdy final form.
It noted that using only materials available on site for a moon base or other construction would reduce the need to launch supplies from Earth.
The main ingredient in “lunar concrete” would be a powdery soil found on the moon’s surface known as lunar regolith. ESA said urea, which can break hydrogen bonds and reduce the viscosity of fluid mixtures, would limit the amount of water necessary in the recipe.
“Thanks to future lunar inhabitants, the 1.5 liters (3.2 pints) of liquid waste a person generates each day could become a promising by-product for space exploration,” it said in a statement.
On Earth, urea is used as an industrial fertilizer and a raw material by chemical and medical companies.
“The hope is that astronaut urine could be essentially used as it is on a future lunar base, with minor adjustments to the water content,” study co-author Marlies Arnhof said in the ESA statement. “This is very practical, and avoids the need to further complicate the sophisticated water recycling systems in space.”
Earlier, Scientists from Norway, Spain, the Netherlands and Italy, in cooperation with ESA, had 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.
"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," explained Ramon Pamies, a professor at the Polytechnic University of Cartagena (Murcia).
Transporting about 0.45 kg from the Earth to space costs about $10,000, that means that building a complete module on our satellite in this way would be very expensive.
This is the reason why space agencies are thinking of using raw materials from the moon's surface, or even those that astronauts themselves can provide, such as their urine.
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.
The scientists stress the need for further testing to find the best building material for the moon bases, where it can be mass-produced using 3D printers.
(With inputs from Assosciated Press.)