Far side moon soil study points to stronger ground for future bases

by Riko Seibo
Tokyo, Japan (SPX) Mar 30. 2026
When China's Chang'e 6 mission returned to Earth in June 2024, it brought back the first samples ever collected from the far side of the Moon, giving scientists an unprecedented look at the regolith in this unexplored region. A team led by Beihang University has now carried out the first high throughput, nondestructive 3D characterization of these materials, showing that the far side soil has distinct mechanical properties that could strongly influence how future lunar bases are designed and built.

The researchers combined high resolution X ray micro computed tomography with a deep learning based image analysis pipeline to virtually reconstruct more than 349,000 individual particles from the Chang'e 6 regolith. By using a semi supervised framework to process large volumes of CT data, the team was able to accurately segment and separate tightly packed grains in three dimensions and generate detailed digital models of the particle shapes and sizes without physically disturbing the samples.

Analysis of these models indicates that the far side grains are markedly more irregular and rugged than those sampled on the lunar near side by the Apollo missions and by China's earlier Chang'e 5 mission. The team reports a lower average sphericity of about 0.74 for the Chang'e 6 particles, reflecting sharper, more angular geometries rather than rounded forms that are more common in terrestrial soils. They suggest that this morphology reflects the unique impact history and space weathering conditions in the South Pole Aitken basin, where the Chang'e 6 samples were collected.

To understand how these shapes influence bulk behavior, the researchers fed the reconstructed particles into Discrete Element Method simulations that model how granular materials deform and interact under load. The simulations show that the spiky, irregular grains develop strong geometric interlocking, similar to how jagged gravel can resist shearing more effectively than smooth beads. As a result, the far side regolith exhibits an internal friction angle of 47.96 degrees and a cohesion of 1.08 kilopascals, both higher than typical values inferred for near side soils from past Surveyor and Apollo data.

These results imply that the far side surface may offer a stiffer, higher bearing capacity foundation than previously assumed, which could be advantageous for landing pads, structural footings and heavy equipment associated with the planned International Lunar Research Station. At the same time, the enhanced interlocking and resistance may complicate operations that require penetration or excavation, such as drilling, anchoring systems and the mobility of rover wheels or tracks, which may experience greater resistance and wear in this environment.

Beyond mission specific implications, the work provides a quantitative benchmark for the geotechnical properties of far side lunar regolith based on direct 3D particle scale measurements and physics based simulations. The digital twin strategy developed by the team offers a path to extract mechanical information from rare planetary samples without destructive testing, and could be applied to other returned materials to guide engineering design for future exploration infrastructure on the Moon and elsewhere.

Research Report:Particle Morphology Controls the Bulk Mechanical Behavior of Far-Side Lunar Regolith from Chang'e-6 Samples and Deep Learning