Plate Nº 71 · recorded October 10, 2026
Space & AstronomyReported finding
Apollo 14 and 16 sampled unusually thin lunar soil
A September 24, 2026 AGU preview finds NASA's Apollo 14 and Apollo 16 missions, the only Apollo landings to measure highland regolith directly, touched down on lunar soil tens of feet thinner than the surrounding terrain.
By Elena Vasquez3 min read636 words
In brief
- September 24, 2026: AGU issued a press notice previewing the study ahead of its 2026 fall meeting.
- Apollo 14 and Apollo 16 are the only two of the six Apollo landings to directly measure regolith depth in the lunar highlands.
- The revised estimate describes the highland soil at both sites as tens of feet thinner than the surrounding terrain.
- Edgar Mitchell, Apollo 14's lunar module pilot, appears in an archival NASA photograph released through Wikimedia Commons.
- The authors describe their revised depth as preliminary and intend to present full methodology at the AGU fall meeting.
A press notice issued September 24, 2026 by the American Geophysical Union previews a study showing that NASA's Apollo 14 and Apollo 16 astronauts walked on lunar soil that was tens of feet thinner than the surrounding terrain at their landing sites in the moon's highlands.
The two missions are the only Apollo landings to directly measure the thickness of this dust-and-rubble layer, known as regolith, in the rugged highland terrain that covers most of the moon's surface. Their original readings therefore anchor almost every modern estimate of highland soil depth, which makes the new downward revision significant for planetary scientists.
What is "regolith"?
Regolith is the loose blanket of dust, powdered rock, and impact debris that rests on top of the moon's solid bedrock. Its depth records how much surface churning large impacts have caused over billions of years. A deep regolith layer implies steady, repeated bombardment, while a thin one means that fresh bedrock sits closer to the surface and that geologists may be sampling relatively young material.
What makes Apollo 14 and Apollo 16 stand out?
Of the six Apollo missions that placed humans on the moon between 1969 and 1972, only Apollo 14 and Apollo 16 carried experiments to measure soil thickness in the highlands. The other landings settled in smoother, darker mare regions made of hardened lava.
Apollo 14 arrived at Fra Mauro in early 1971. Edgar Mitchell, the lunar module pilot, appears in an archival NASA photograph released through Wikimedia Commons checking a map during one of his moonwalks. The Apollo 16 crew followed a year later at the Descartes highlands, repeating a comparable experiment in a different highland setting.
What did the researchers actually find?
Scientists combined the half-century-old Apollo surface readings with later orbital surveys of the moon. Their recalibrated estimate places the regolith at both Fra Mauro and Descartes well below the typical highland thickness. The AGU summary describes the deficit as "tens of feet."
In metric terms, the gap amounts to several meters relative to the average depth of comparable terrain nearby. A multi-meter shift appears small against the moon's largest basins, but it matters when scientists calibrate remote sensing models against the only direct measurements available.
How reliable are the revised numbers?
The authors describe the new depth as preliminary and plan to walk through the full data set at the AGU fall meeting, where peer feedback and outside specialists will weigh in. Conference-stage results typically carry uncertainty bars that are wider than those in peer-reviewed papers, and direct drilling remains the only technique that can pin a regolith depth to within a meter.
Independent checks using updated gravity models and any future seismic readings from instruments placed near the landing sites would provide obvious next tests.
Why does it matter for future landings?
Future crewed missions, including the surface legs of NASA's Artemis program, will lean on accurate regolith maps when choosing drill cores, anchoring equipment, and routing rovers. If two of the moon's most carefully studied highland locations turn out to be unusually shallow, planners may need to recalibrate how they translate orbital data into terrain risk at sites far from Fra Mauro and Descartes.
The revised figures also feed back into impact history. Thinner dust layers expose older craters and larger boulders, giving geologists a clearer view of how the moon's surface has been reworked in the distant past.
When will full details arrive?
AGU has opened press registration for the 2026 meeting, where the study's authors will present their methodology and updated depth estimates. A peer-reviewed paper, if the findings hold up under external scrutiny, would likely follow months later, alongside an updated map of where the moon's outer skin is unusually thin.
via registration.experientevent.com (Original)
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