Shallow Multi-Layered Structures Within the Lunar Regolith Observed by the Chang’E-5 Radar

Layered subsurface regolith structures and estimated regolith properties are crucial for revealing the evolutionary history of the Moon. We employed the Lunar Regolith Penetrating Radar (LRPR) onboard the Chang’E-5 (CE-5) probe, achieving high-resolution imaging of the shallow regolith. Through the full-waveform inversion (FWI) permittivity results of the LRPR data and the drilling pressure curve, we discovered multiple layers within 1.2 m beneath the lunar surface, and there are ejecta rock fragments in some areas. The multi-layered structure suggests they likely formed from ejecta deposition from small impact craters surrounding the landing site. Furthermore, we inferred that the evolutionary history of the impact craters in the landing area was approximately 70 million years (Ma) based on the thickness of the ejecta. The permittivity of the weathering layer correlates with the test results of lunar samples, confirming the reliability of our methodology. These findings provide crucial technical guidance for future lunar surface drilling and sample return missions.