A sophisticated technology could provide the planned lunar bases with solid foundations, shows a proof-of-concept study. Moon dust can therefore be transformed into paving stones using concentrated light, which could be used to build roads and landing sites. In their experiments, the scientists used a laser and simulated lunar dust. On the moon, however, focused sunlight could burn the components into the regolith, according to the future vision.
The first step was successful over 50 years ago - projects are now being worked on for the permanent presence of humans on the moon: the construction of bases on the Earth's satellite is planned. However, there are huge challenges to be overcome during implementation. The material on the lunar surface poses a major problem. It is characterized by a fine-grained substance - the so-called regolith. This moon dust can be easily stirred up and then floats above the surface for a long time due to the low gravity. It can then settle on machines, devices and equipment and thereby damage them. In order to limit the dust problem, permanent infrastructure, roads and landing pads must be built for permanent lunar bases.
Use existing resources
However, transporting building materials from Earth to the moon would be extremely complex and expensive. That's why scientists are currently researching various ways to use resources that already exist on the moon. The team from the “PAVER” project, funded by the European Space Agency (ESA), is exploring whether the problematic moon dust itself can be turned into building material. The vision is to use concentrated sunlight on the moon as a heat source to melt regolith into a solid that can be used to create building components.
In their laboratory experiments, the scientists used a laser that developed power similar to that of a “sunlight magnifying glass” on the moon. They then used the beam to treat test material whose composition corresponds to that of lunar regolith: In addition to a number of other compounds, this substance consists largely of the glass base material silicon dioxide.
Successfully “sizzled” into the dust
It turned out that a 4.5 centimeter wide laser focal spot made it possible to generate temperatures of over 1000 degrees Celsius, which caused the material to melt. This allowed a trace of glass-like material to be melted into the dusty test surfaces at a rate of five millimeters per minute. The hard substance reaches a thickness of around two centimeters. This made it possible to produce flat units. However, it has been shown that certain shapes can lead to tension in the material and consequently to cracks. The cheapest version turned out to be a rounded triangular shape with a small one
Opening in the middle. These approximately 25 centimeters wide tiles can then be used interlocking to build solid surfaces, the scientists say.
As they explain, it seems quite unproblematic to replace the laser used for the experiments - which weighs over a ton - with a "slim" solar concept on the moon. Accordingly, it would be possible to concentrate the strong solar radiation using a film-based lens system to such an extent that a sufficiently hot focal spot could be created. Such a 2.4 square meter Fresnel lens would weigh less than ten kilograms and could therefore be easily transported to the moon, say the researchers.
The promising results of the proof-of-concept study will now lead to further investigations in collaboration with ESA and the German Aerospace Center (DLR). Finally, project coordinator Jens Günster from the Federal Institute for Materials Research and Testing in Berlin says: “Our results show the great potential of the process. “They bring us a significant step closer to building a reliable infrastructure on the moon, as the European Space Agency (ESA) is planning,” said the scientist.
Source: Federal Institute for Materials Research and Testing, specialist article: Scientific Reports, doi: 10.1038/s41598-023-42008-1