By 
September 21st, 2024
Image credit: CCTV/Inside Outer Space screengrab
Lunar collectibles from China’s Chang’e-6 far side Moon mission have been unveiled with geochemical researchers finding the returned-to-Earth samples markedly different from the samples retrieved by the Apollo missions and China’s earlier Chang’e-5 lunar sample mission.
The samples, weighing a total of 1,935.3 grams, were retrieved by Chang’e-6 in June this year, and spotlighted in a September 21 reveal, as reported by China Central Television (CCTV).
Image credit: CCTV/Inside Outer Space screengrab
Notable differences
“I have processed both separate samples from Chang’e-5 and 6,” said Liu Jianjun, researcher, National Astronomical Observatories. “We have observed notable differences in their physical properties. For example, when viewed under a microscope, the particles from Chang’e-6 show a bimodal distribution, whereas Chang’e-5’s particles present a single peak.”
Liu added that another difference is that during the selection process, “we found that there were noticeably fewer rock fragments in the Chang’e-5 sample, while Chang’e-6 contained more. We believe this is likely due to the impact crater near the Chang’e-6 landing site, which measures about 50 meters in diameter. It’s possible that ejecta from the crater was collected by Chang’e-6,” he told CCTV.
China’s Chang’e-6 lander/ascender in far side sampling scenery.
Image credit: CNSA/CLEP
“The overall petrochemical composition of the Chang’e-6 samples is quite different from Chang’e-5 samples,” Liu continued. “It’s a low titanium, low aluminum, low potassium basalt composition. There is almost no olivine in basalt from the Chang’e-6 samples, indicating that its rock genesis, material source, and chemical composition are quite different from that of the Chang’e-5 samples. It shows that the samples taken from the far side of the Moon are indeed very different from that from the near side.”
Mineralogical content
“In the breccia obtained by the Chang’e-6, we can find many small rock fragments that actually came from the non-lunar maria area, which is the highlands on the Moon, that is, the white or shiny part of the Moon that we see with the naked eye,” said Zhou Qin, researcher at the National Astronomical Observatories of the Chinese Academy of Sciences, who also serves as a deputy chief designer of ground application system of the Chang’e-6 mission.
Far side scenery taken by Chang’e-6 lander/ascender.
Image credit: CNSA/CLEP
“These fragments were sputtered onto their area by impact and then cemented into rocks. And the proportion of this kind of rocks is significantly higher than that of the Chang’e-5 samples,” Zhou told CCTV.
“Comparing the images of basalt in the Chang’e-5 and Chang’e-6 samples, we’ve found out that the rock structures of these two are similar. But the further detailed study of the mineralogical content indicates that the olivine content of the Chang’e-6 samples is significantly lower compared to the Chang’e-5 samples,” said Zhou.
Glass fragments
According to Li Chunlai, deputy chief designer of the Chang’e-6 mission and researcher with the National Astronomical Observatory of the Chinese Academy of Sciences: “The Chang’e-6 lunar samples contain a significant amount of white material, including feldspar minerals, which are more abundant than in the Chang’e-5 samples,” said “Additionally, there are significantly more glass fragments, contributing to a lighter overall appearance for the Chang’e-6 samples,” Li told CCTV.
Image credit: CCTV/Inside Outer Space screengrab
The team reports that Chang’e-6 soil samples have a lower density than previous samples, indicating a more porous and loosely structured composition. The plagioclase content of the Chang’e-6 samples is significantly higher than that of the Chang’e-5 samples, while their olivine content is significantly lower. The study has also revealed that the Chang’e-6 lithic fragment samples are primarily composed of basalt, breccia, agglutinate, glasses and leucocrate.
Image credit: CCTV/Inside Outer Space screengrab
Separated and packaged
In a lunar sample laboratory, the surface samples have largely been separated and packaged, CCTV reports. Experts explained that the process of unsealing, dividing, and preparing the samples for experimentation took approximately two months.
“For the surface samples, we will separate any rock fragments larger than one millimeter. These larger samples may have originated from different locations, and their research methods differ from those used for powdered samples,” Li said. “The remaining powder samples, smaller than one millimeter, will be thoroughly mixed and packaged into 10-11 bottles, each containing approximately 150 grams.”
The Chang’e-6 sample container is shown being removed from the Chang’e-6 return capsule.
Image credit: Jin Liwang via SegerYU X posting.
Stuck to the sample bag
In contrast, the processing of the drilled samples is more complex and is expected to take an additional one to two months, CCTV notes. Researchers are currently handling the remaining samples in a nitrogen-filled unit.
“In terms of weight, the scooped samples make up the majority of the total 1935.3 grams, roughly 1610 grams, and the remaining is drilled samples,” said Li. He also pointed out that a significant portion of the drilled samples are stuck to the sample bag and cannot be removed, complicating the determination of their exact weight.
“The drilled samples account for less than 20 percent of the total and are all contained within a single sample bag. We need to divide them into 1.5-centimeter segments to represent different depths,” Li added. “This process, which involves separating over 100 individual samples, requires extreme care. So, we may still need another month or two to finish the pre-processing.”
Image credit: CCTV/Inside Outer Space screengrab
Two-day stay
The Chang’e-6 lunar landing and sampling craft was launched from the Wenchang Spacecraft Launch Site in south China’s Hainan Province on May 3, 2024, touching down on the far side of the Moon on June 2.
During the lander’s two-day stay, Chang’e-6 used a scoop and drill, collecting nearly 2 kilograms of lunar material.
On June 25, the Chang’e-6 returner segment of the mission brought back the samples to Earth, with a sample container parachuting into a pre-designated landing zone in north China.
A set of new CCTV videos showcases the Chang’e-6 sample reveal at:
Posted in Space News
