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10-16-2023

Astronauts will melt lunar dust to build roads on the moon

More than walking its surface, humans are working towards living on the moon. This daunting task will require construction of roads and landing pads on the moon, which the likes of the Toyota Baby Lunar Cruiser can use. Interestingly, scientists recently discovered that we could melt the lunar soil to create these roads.

Lunar dust is a problem

One of the biggest challenges of lunar exploration in the Apollo era was the clogging of equipment and erosion of spacesuits by dust. The Apollo 17 lunar rover barely survived after almost overheating because dust almost covered it completely. 

A more brutal fate befell the Lunokod 2 when it overheated and failed because its radiator was utterly covered in dust. But we may now be able to prevent these issues with the discovery of a way to create roadworthy surfaces.

Roads on the moon

In a recent ESA project, researchers melted lunar dust into a more solid substance that could be used to build roads on the moon. Lunar dust, or lunar soil, is a fine, powdery substance covering the moon. It forms when meteoroids impact the moon’s surface, adopting a texture similar to the talcum powder.

The researchers employed a 12-kilowatt carbon dioxide laser to heat a powder that substitutes lunar dust. This powder contains pyroxene, olivine, and plagioclase.

Melting lunar soil

The experts observed that the dust compacted at 1200°C, forming a black glassy surface. The compression strength of the compacted structure was close to that of a concrete slab that could serve as a moon road surface.

In 1993, experts proposed the idea of melting sand to build roadways on Earth. This lunar project is believed to have spawned from that original Earth-road concept, attempting to replicate the same road building process, this time on the moon.

Advenit Makaya, a materials engineer and an ESA scientist on the team, said: “The resulting material is glasslike and brittle but will mainly be subject to downward compression forces. Even if it breaks, we can still go on using it, repairing it as necessary.”

Modifications are still needed

The researchers understand that bringing a laser to the moon is impossible. However, they believe the lunar sunlight can serve as the light source for the experiment.

“In practice, we would not bring a carbon dioxide laser on the moon. Instead, this current laser is serving as a light source for our experiments to take the place of lunar sunlight, which could be concentrated using a Fresnel lens a couple of meters across to produce equivalent melting on the surface of the moon,” said Makaya.

Melt layers for moon roads

The team observed a risk of cracking if the cooled track is reheated. Considering that one melt layer is about 1.8 cm deep, moon roads and other structures could be composed of many layers, depending on the forces of the load.

“Such high depth of melting to produce massive structures can only be reached by large laser spots,” explained Jens Günster, the head of BAM’s Multimaterial Manufacturing Processes Division.

The team believes it might be possible to construct a two-centimeter thick, 100 square meter landing pad in about 115 days.

The research, called the PAVER Project, came from a call for ideas run by the Discovery element of ESA’s Basic Activities through the Open Space Innovation Platform (OSIP)

It was led by the BAM Institute of Materials Research and Testing and Aalen University in Germany, LIQUIFER Systems Group in Austria, and Clausthal University of Technology in Germany, with support from the Institute of Materials Physics in Space of the German Aerospace Center, DLR.

Participating scientists include Jens Günster, Andrea Zocca, Janka Wilbig, and Miranda Fateri.

More about lunar dust

When astronauts first stepped on the moon, little did they know that the powdery substance under their feet, commonly known as “moon dust,” would become one of the most discussed materials in space exploration. In addition to being used to build moon roads, this unique substance, more scientifically known as lunar regolith, presents challenges, surprises, and great potential for future missions.

What is moon dust?

Moon dust refers to the fine, unconsolidated debris covering the lunar surface. It forms primarily from meteoroid impacts and solar wind interactions, which pulverize and weather the moon’s rocks over billions of years. Unlike Earth, where weather, water, and biological processes help soften rock breakdown products, the moon’s lack of atmosphere preserves the sharp, jagged nature of the lunar soil particles.

Composition of lunar soil

Interestingly, moon dust carries a significant scientific story about the moon’s past. It comprises various materials, including glass beads, silica, and metallic iron particles. These constituents differ based on the location on the moon, thus providing vital information about the moon’s geological history.

The glass beads in the regolith are particularly fascinating as they form through the high heat of meteoroid impacts. These beads capture miniature gas bubbles, offering insights into the moon’s ancient interior and the solar wind.

Hazards posed by moon dust

Astronauts quickly recognize the challenges posed by moon dust during lunar expeditions. It clings to spacesuits, helmets, and equipment due to its static nature, making it extremely cumbersome to handle and remove. The sharpness of lunar dust particles also makes them particularly abrasive, wearing down spacesuits and potentially damaging seals and equipment over time.

More critically, moon dust poses health risks. Astronauts during the Apollo missions reported ‘lunar hay fever’ upon inhalation of the regolith, as the minute size of the particles allows them to penetrate deep into the lungs, potentially causing significant respiratory issues.

Harnessing moon dust for moon roads

Despite these challenges, moon dust holds immense potential. Scientists and engineers are exploring ways to use regolith as a resource for lunar construction and in-situ resource utilization (ISRU). Concepts like using moon dust in 3D printing technology could lead to the building of structures directly on the moon, crucial for potential lunar bases or colonies.

Moreover, the oxygen bound within the lunar soil presents an invaluable resource for supporting sustained human presence and even fuel production. Initiatives for moon dust electrolysis aim to extract this oxygen, significantly reducing the need for costly resupply missions from Earth.

Future plans for lunar regolith

Understanding, mitigating, and harnessing moon dust requires comprehensive study and innovative technology. Future missions plan to incorporate advanced equipment to study regolith’s properties and behavior extensively. For instance, handling equipment might feature materials or coatings resilient to abrasion, while habitat designs may include dust mitigation measures like airlocks or specialized cleaning systems.

As plans for returning humans to the moon and establishing a sustained presence advance, the interaction with lunar soil will evolve from a novelty to an everyday reality, as we discussed previously with the construction of moon roads. The challenges are real, but so are the opportunities, and our growing understanding of moon dust will play a crucial role in the future of lunar exploration.

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