Building a permanent base on the Moon will require more than habitats and spacecraft: crews will need roads, landing pads, and protective berms capable of supporting heavy vehicles and repeated landings. Most of this infrastructure will be built on, and potentially even from, lunar regolith, the loose layer of fragmented rock covering much of the Moon’s surface.
Image Credit: buradaki/Shutterstock.com
Researchers are exploring ways to compact, sinter, and melt this material into durable surfaces, while using local boulders and natural terrain to protect equipment from rocket-plume ejecta. Understanding the regolith’s strength, density, and behavior under load will be central to deciding where to build lunar infrastructure and how much material and energy construction will require.
What Is Regolith?
Every road, pad, and berm planned for a Moon base will rest on regolith, a layer of fragmented rock several meters thick that covers almost the entire lunar surface. This regolith accumulates over billions of years as small bodies strike the Moon's crust, crushing and melting the material.
Only on steep crater slopes and inside lava tubes does this layer become significantly thinner. Across the majority of the surface, however, engineers will be building directly on regolith and must account for the unusual shape and behavior of its grains, which are usually around 70 µm in size.
Unlike terrestrial soil, lunar regolith has never been weathered by flowing water, wind, or ice. Therefore, its grains retain sharp edges, irregular hollows, and open pores that allow them to interlock tightly when compressed.1
How Much Weight Can Lunar Soil Support?
Bulk density governs what the lunar ground can safely carry. The uppermost millimeters are very fine and loosely deposited at a density of about 1100–1300 kg/m3. Compaction rises steeply below that, exceeding 1500 kg/m3 within the first 15 cm and stabilizing near 1800–1920 kg/m3 at about half a meter of depth.1
Builders will therefore work above a weak surface skin that rests on firmer material beneath. Grading and compacting that skin turns a hazard into a competent subbase. What lies deeper, however, is less certain. Confidence drops below three meters, the depth reached by the deepest lunar boreholes, leaving deep foundation design dependent on assumptions.1
Building Roads from Lunar Soil
Lunar roads address both mobility and contamination problems simultaneously. Rovers crossing loose soil raise clouds of suspended dust that
reach radiators, optics, bearings, and seals on every vehicle working nearby. Fusing the top few centimeters into a solid crust binds those particles in place, which is why paving ranks among the earliest surface tasks at a base site.2
A recent experiment published in Scientific Reports tested that idea using a 10 kW carbon dioxide laser to simulate concentrated sunlight. The beam worked directly on a powder bed of EAC-1A simulant with no molds, binders, or furnaces.
A single pass could produce a track approximately 95 mm wide, 500 mm long, and 18 mm thick. Adjacent tracks overlapped by 15%, allowing researchers to build up a continuous paved surface.2
In the experiment, researchers found that the geometry of the paving elements was as important as the thermal input itself. In light of this discovery, the team developed interlocking paving units that measured 250 mm on each side; if one cracks, its neighbor holds it in place, allowing the paved surface to continue carrying traffic
Scaling the scanned powder bed could make it possible to lay these units across increasingly large roads and pads.2
Tests also showed why fully melting the material may be preferable to lightly sintering it. Cubic laser-melted specimens reached compressive strengths ranging from 56 to 216 MPa, with an average strength of about 94 MPa; this is approximately 50 times stronger than the 2.49 MPa recorded for solar-sintered samples in the RegoLight project.
These results show that melted regolith can become a strong construction material, but the wide range also points to an important problem: its performance is not yet consistent
Those results varied considerably, however. Internal pores and microcracks produced the wide spread in measured strength, making it harder for engineers to determine how much stress the material could safely carry in practice.³
There are several methods used to supply the heat needed to fuse lunar regolith, and each offers a different balance between geometric precision and the area it can cover.
Download a free copy of this page here!
For example, a 1 m2 solar concentrator, mounted on a sun-tracking frame, reached 1350 °C, well above the melting point of the regolith simulant. In a different study, concentrated xenon light was focused onto a 20 mm spot to sinter layers just 100 µm thick, demonstrating the level of control possible when heating the material.3
This relatively broad optical approach could suit large surfaces such as landing pads and stabilized roads. Microwave heating offers an alternative approach, with researchers producing a 1.4 kg paver from fully in situ material in a vacuum chamber.
Pad Design for Repeated Landings
Landing pads must be able to handle heavy, concentrated loads rather than steady rolling traffic.
To explore what this requires in practice, one NASA design study sized a square, unreinforced slab of microwave-sintered regolith for a spacecraft weighing up to 50 tons.4
The most demanding loading case occurs when a single lander leg sits at the corner of a slab. Sintered regolith behaves as a brittle material, far weaker in tension than in compression, and steel reinforcement remains unavailable, so the slab must remain uncracked under service loads.
In such a case, thermal gradients, plume pressure and heating, subbase friction near 1.5, differential settlement, and creep all enter the design. Together, these factors determine how stresses develop within the slab and therefore how thick it must be to remain uncracked.4
Building Barriers Against Rocket Debris
Berms serve to protect everything within the reach of a descending rocket plume. During the Apollo 12 landing, debris kicked up by the landing impacted the Surveyor III probe located 180 m away, causing damage only to the side facing the descent. A SpaceX Human Landing System is expected to disturb the surface hundreds to thousands of meters out, which pushes shielding into early base layout decisions.5
A design published in Frontiers in Space Technologies uses an autonomous excavator to gather unprocessed boulders with the longest axes between 0.5 and 1.5 m along their longest axis and stack them into a dry-stone retaining wall around the pad.5
The need for these barriers becomes clearer when the behavior of plume-driven debris is considered. With a gravity of 1.62 m/s² and the absence of an atmosphere, ejected grains can travel with minimal energy loss. Published models report speeds ranging from 800 to 2500 m/s at angles of just a few degrees, and some grains even exceed the 2.38 km/s escape velocity.6
Site selection can provide another layer of protection. Simulated landings at the centers of 238 craters, with radii ranging from 65 to 630 meters, showed that crater rims can intercept low-angle ejecta, creating sheltered ‘umbrella’ zones behind them. Depending on the crater, these protected areas can reach heights of one to 16 meters, accommodating everything from small rovers to large crewed landers.
Ultimately, roads, pads, and berms must function as an interconnected system.6
Designing the Base as One System
Such connection also shapes the order in which a lunar base can be built. Before crews can construct pads or berms, their machines first need routes that can be safely traversed.
For example, the Apollo rovers were only able to climb slopes of about 10 to 15° in practice. Current planning has established a travel limit of 20 ° in any direction. Route planners using the A* algorithm steer excavators around boulder fields and permanently shadowed ground, while a 50 m landing accuracy requirement fixes where hauling begins.5
Therefore, each decision affects the infrastructure around it. A well-positioned landing site can reduce the amount of ejecta that must be stopped; practical hauling routes constrain where those berms can be built; and uncertainty about the strength of the ground leads engineers to use conservative safety factors. For landing pads, that can mean thicker slabs and more energy spent melting regolith.
To reduce uncertainties, measurements must be made on the Moon itself, rather than terrestrial samples. Such measurements could enable the acquisition of better data on regolith strength, subsurface conditions, and material performance, and in turn, facilitate more efficient use of lunar resources.4
References and Further Reading
- Kaczmarzyk, M. (2025). Geotechnical properties of lunar regolith. Construction Materials. 634(6). DOI: 10.15199/33.2025.06.15. https://www.materialybudowlane.info.pl/images/2025/06/s128-134.pdf.
- Ginés-Palomares, J. C. et al. (2023). Laser melting manufacturing of large elements of lunar regolith simulant for paving on the Moon. Scientific Reports. 13(1). 15593. DOI:10.1038/s41598-023-42008-1. https://www.nature.com/articles/s41598-023-42008-1.
- Azami, M. et al. (2024). A comprehensive review of lunar-based manufacturing and construction. Progress in Aerospace Sciences. 150. DOI:10.1016/j.paerosci.2024.101045. https://www.sciencedirect.com/science/article/pii/S037604212400071X.
- Mount, E. et al. (2025). Lunar Landing and Launching Pad Design Considerations Using ISRU Materials. [Online] NASA. Available at: https://ntrs.nasa.gov/citations/20250011152.
- Walther, J. et al. (2024). Autonomous construction of lunar infrastructure with in-situ boulders. Frontiers in Space Technologies. 5. DOI:10.3389/frspt.2024.1345337. https://www.frontiersin.org/journals/space-technologies/articles/10.3389/frspt.2024.1345337/full.
- Anderson, S. L. et al. (2026). Mitigating plume surface interactions using lunar craters. Npj Space Exploration. 2(1). DOI:10.1038/s44453-026-00045-w. https://www.nature.com/articles/s44453-026-00045-w.
Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.