In 2024, NASA plans to fly to the moon again but this requires a special surface on the lunar base. To build it, only two things are actually needed, but they are quite unusual: urine and moon dust. This blog article shows how 3D printing turns it into building blocks for a moon base.
Astronaut urine and moon dust as a potential 3D printing material for a moon base? Yeah, you read that right! Researchers from Norway’s Østfold University College found out that these materials are capable to withstand enormous weights while retaining its structure when used to form samples in a 3D printer. They even survive repeated freeze-thaw cycles without breaking. But let’s take a closer look at the habitat moon first.
Life on a Celestial Body
The next NASA team on the moon is going to land at the lunar South Pole. Unfortunately, it is not possible to simply settle on the lunar surface and they can’t take many materials with them to build a station because the transportation from Earth into the Outer Space poses many challenges. The transport of three apples into space, which weigh about 450g, for example, costs about 10,000 dollars. A reasonable solution is therefore to build a lunar station that can be constructed with materials that exist on the moon itself.
Furthermore the astronauts need a safe habitat to protect them from extreme temperature fluctuations from negative nine degrees Fahrenheit to negative 313 degrees Fahrenheit. Besides, they must be shielded from the impact of micrometeorites and radiation.
The expedition is part of NASA’s Artemis program with the goal to find and use resources on the moon to allow long-term exploration. NASA administrator Jim Bridenstine explains that Artemis aims for a permanent presence on and around the moon, unlike the Apollo program. However, as already explained, this project requires materials found on the moon and those that the astronauts already have with them.
Concrete Mixed out of Moon Dust and Human Urine
A new study published on February 20, 2020 in the Journal of Cleaner Production investigated the potential for using moon dust – also known as regolith – in combination with human urea to create building blocks that can be printed with a 3D printer.
“[In our work] we are utilizing lunar regolith, a.k.a. moon dust, in combination with sodium hydroxide and water, to make geopolymer concrete […] that [does] not utilize ordinary cement. It is desirable to use this on the moon since it is horrendously expensive to bring anything up from Earth. Since water is in limited supply on the moon, we need to add something to reduce the amount of water we need to gain good flow-properties for 3D-printing building structures.”
Urea is an abundant source useful for breaking hydrogen bonds. Thanks to these properties, it can help to reduce the viscosity of the moon dust concrete, making it softer and more pliable before it has fully cured. The structure of the material is therefore very suitable for 3D printing.
In the next step Kjøniksen and her team will test if they can use the material’s ability for 3D printing in a vacuum and the concrete’s ability to stop irradiation.
“If we manage to develop a geopolymer concrete that can be 3D-printed in a vacuum and still give the desired mechanical and radiation shielding properties, we hope they will test it in space in the future,”