Manufacturing of paving elements from lunar dust using 3D printing (laser melting process) in the laboratory
Source: BAM
A joint study by the Bundesanstalt für Materialforschung und -prüfung (BAM), Clausthal University of Technology and Aalen University of Applied Sciences, published today in the prestigious journal Springer Nature Scientific Reports, reveals fascinating prospects: With the help of innovative 3D printing technology and lunar dust, the construction of roads and landing pads on the Earth's satellite could be within reach. This opens unimagined possibilities for the construction of future lunar bases.
Lunar dust, when stirred up, poses a significant challenge to lunar missions: Due to the low gravity on Earth's satellite, it tends to float for long periods of time and can contaminate and damage machinery, devices and equipment. Permanent lunar bases therefore rely on fixed infrastructure, roads and landing pads to minimise the dust problem. At the same time, it would be extremely costly and time-consuming to transport conventional materials for road construction specifically from Earth to the Moon. It would be more advantageous to use resources already available there, such as lunar dust. It still needs to be clarified whether it can be processed into cobblestone-like elements using 3D printing.
Moon Dust as Building Material
This is where the current study comes in. The authors experimented with laser beams of different strengths and sizes (up to 100 mm diameter and 12 kilowatts of output power) to develop a robust building material from lunar dust. They used a fine-grained material (EAC-1A) which is officially qualified by the European Space Agency (ESA) as the equivalent of lunar dust.
The laser's large focal spots, up to 100 mm, allow the material to melt at high speed into solid structures covering large areas, which is essential for building roads and landing pads. During the tests, however, it turned out that when the laser tracks overlap, the enormous energy density leads to high temperature differences and stresses in the material and consequently to cracks.
The solution: The team developed triangular geometric shapes with an opening in the middle, where the laser tracks did not overlap during printing. The result: "paving stones" that interlock perfectly to create a solid surface.
Sunlight Instead of Laser
On the moon, the laser, which at over 1 tonne would be too heavy to transport to the moon, would be replaced by a highly refractive lens of several square metres. It can focus the sunlight in such a way that it can replace the intensity of the laser. Such a film-based lens (Fresnel lens) weighing less than 10 kilograms could easily be transported to the moon.
"Our results show the great potential that additive manufacturing has," says Jens Günster, project coordinator and head of the Department of Multimaterial Manufacturing Processes at BAM. "They bring us a significant step closer to building a reliable infrastructure on the moon as planned by the European Space Agency (ESA)."
The project was funded by ESA as part of the ESA Discovery Programme. In the future, further experiments on this are to be carried out with ESA and the German Aerospace Centre (DLR).