Future astronauts walking on the Moon may step on rocks that came from deep inside it. Scientists have found that a colossal ancient impact scattered pieces of the lunar mantle across the surface near planned Artemis landing sites.
A low-angle strike that reshaped the Moon's far side
The South Pole-Aitken basin sits on the Moon's far side. It is the largest and oldest known impact crater on the Moon, and one of the oldest preserved structures in the solar system. Researchers from the Center for Lunar Origin and Evolution, a virtual NASA organization led by the Southwest Research Institute, used advanced computer simulations to recreate the impact that formed this basin. Their results show that a large, iron-cored object approached from the north and struck the Moon at a shallow angle. That low-angle collision explains why the basin has an elongated, tapered shape. The force of the impact was so great that it blasted material from deep inside the Moon, including rocks from the lunar mantle.
Where astronauts could find these deep lunar rocks
Two companion studies detail where this mantle material ended up. The simulations indicate that rocks from the Moon's deep interior are scattered in the region surrounding the South Pole-Aitken basin. Proposed landing sites for upcoming NASA Artemis missions near the lunar south pole lie within that area. That means astronauts could collect and study these rocks without traveling far from their landing zones. The material offers a rare window into the Moon's interior and its earliest history. Dr. William Bottke, director of the Center for Lunar Origin and Evolution and a co-author of the studies, said the basin gives scientists a rare opportunity to study the Moon's earliest history. The collision struck with such force that it may have excavated portions of the lunar mantle.
Why this matters for understanding the Moon's past
For local researchers and the broader scientific community, the discovery is significant because the Moon's mantle is normally buried deep beneath the crust. Direct samples of it have never been collected. If Artemis astronauts can retrieve these rocks, scientists could analyze them to learn about the Moon's composition, its internal structure, and how it formed. The South Pole-Aitken basin itself is a unique record of the early solar system. Understanding its formation helps scientists piece together the violent history of impacts that shaped the Moon and other rocky bodies. The findings come from data from NASA's GRAIL mission and the Lunar Reconnaissance Orbiter Laser Altimeter, combined with the new computer models.
The studies do not guarantee that astronauts will find mantle rocks, but they identify promising locations. The next step is for mission planners to consider these areas when selecting precise landing sites. If the rocks are there, future explorers will have a direct link to the Moon's hidden interior.
