ESA’s PAVER project aimed to create paved surfaces on the lunar surface using melted lunar regolith. They conducted ground-based tests using a carbon dioxide laser and are planning to use a Fresnel lens on the Moon to focus sunlight. The successful use of lasers to melt simulated lunar dust is a significant development in addressing the challenges posed by lunar dust in future missions.
The construction of roads on the lunar surface is essential for astronauts who will likely be driving rather than walking during their missions. Lunar dust is fine, abrasive, and sticky, leading to equipment damage and spacesuit corrosion. For example, the Apollo 17 lunar rover overheated when its rear fender was lost and replaced with a lunar map, covered in kicked-up dust. The Soviet Lunokod 2 rover experienced a similar fate, dying from overheating after its radiator became covered in dust.
To prevent the accumulation of lunar dust, it is necessary to pave active areas on the Moon, including roads and landing pads. The idea of melting sand to create roads was originally proposed in 1933. ESA’s PAVER project, led by Germany’s BAM Institute for Materials Testing in collaboration with Aalen University, LIQUIFER Systems Group, and the University of Claustal in Austria and Germany, investigated the feasibility of building lunar roads using a similar approach. The project received support from the Institute for Space Materials Physics of the German Aerospace Center (DLR).
The PAVER consortium utilized a 12-kilowatt carbon dioxide laser to melt simulated lunar dust and create a glassy solid surface that can serve as a paved surface on the Moon. They achieved spot sizes of 5 to 10 cm in their trials. By utilizing a 4.5 cm diameter laser beam, they developed a strategy to produce a triangular hollow-centered geometry of about 20 cm in diameter. This approach allowed them to create solid surfaces over large areas of lunar soil suitable for roads or landing pads.
The project’s materials engineer, Advenit Makaya, explained that the current laser used in their experiment functions as a light source instead of lunar sunlight. To achieve equivalent melting on the lunar surface, the laser light would be focused using a Fresnel lens with a diameter of several meters.
The PAVER consortium’s methodology involved trial and error to determine the optimal laser beam size and geometry. They found that larger spot sizes were easier to work with, as heating on a millimeter scale produced challenging agglomeration due to surface tension. With their approach, they were able to create a stable layer of molten regolith, which could be better controlled. The resulting material is glassy and brittle but can withstand primarily downward compressive forces, potentially being repaired if needed.
The research team discovered that reheating a cooled track could cause cracks, leading them to minimize crossover in the geometry. The depth of a single melt layer achieved was approximately 1.8 cm. Depending on the required loads, the constructed structures and roads could consist of multiple layers.
The PAVER consortium estimated that a 100 square meter landing pad with a 2 cm thick high-density material could be constructed in 115 days using their approach.
The PAVER project originated from a call for ideas conducted by ESA’s Basic Activities Discovery Division through the Open Space Innovation Platform (OSIP). Out of 69 submissions, 23 ideas were implemented, including the PAVER project. The project has opened up promising avenues for future research in extraterrestrial manufacturing and construction.
Overall, the successful use of lasers to melt lunar dust represents a significant advancement towards the construction of roads and landing pads on the lunar surface, addressing the challenges posed by lunar dust in future lunar missions.
Source: scitechdaily.com
