For nearly 20 years, there has been a debate over whether the water content in the Moon’s mantle, the middle layer between its surface and core, is abundant or scarce, while all published estimates were derived from near-side samples.
China’s Chang’e-6 lunar probe retrieved the first-ever lunar far-side samples from the Apollo crater within the South Pole–Aitken Basin, providing the first opportunity to determine the water content of the lunar mantle in this region.
The study revealed that a unique volcanic event dating back 2.8 billion years had not been observed in previous samples obtained from the near side.