First analysis of samples from the far side of the Moon

The Chang’e-6 spacecraft’s sample capsule brought 1,935.3 grams of rock and soil from the far side of the moon back to Earth on June 25, making China the first country to achieve this feat. The samples were taken to special facilities for preservation, analysis, and then distributed for research. New research on the samples, published in the journal National Science Review, offers a first look at this precious material, Space September 21 news.

Li Chunlai, a scientist at the Chinese Academy of Sciences (CAS), and other experts studied the samples collected by the Chang’e 6 spacecraft. They found that they were less dense than previous samples taken from the near side of the moon. Specifically, the far side sample had a looser structure and more voids. “The sample is quite loose and would be even more loose in its ‘natural’ state on the lunar surface,” the team wrote.

Compared to the samples collected by the Chang’e 5 spacecraft from the near side of the Moon in 2020, the new samples contained more light-colored grains such as feldspar and glass. This, along with other compositional data, suggests that more distant material was ejected to the sampling site. This can occur when impact events (such as asteroid strikes) cause surrounding material to be ejected and thrown away from the impact site. The composition of basalt at the sampling site is thought to have mixed with material ejected from regions that do not contain basalt.

The Chang’e-6 sample also contained lower concentrations of KREEP rocks, which are rich in potassium (K), rare earth elements (REEs), and phosphorus (P), which are more common on the near side of the Moon. This disparity may partly explain why the far side is so different from the near side.

According to the team, the new sample helps advance understanding of several important aspects of lunar science, including early evolution, differential volcanic activity between the near and far sides, the collisional history of the inner solar system, traces of galactic activity preserved in lunar regolith, and the composition and structure of the lunar crust and mantle.

“These insights may provide new concepts and theories about the origin and evolution of the Moon,” the team concluded. The Chang’e 6 samples will be made available to Chinese researchers in the near future, while international researchers are expected to be able to apply for samples after two years.