Far-Side Lunar Sample Discoveries
The Moon’s far side has remained a scientific mystery for decades until the Chang’e 6 mission finally explored it. Launched by China in 2024, Chang’e 6 became the first mission in history to collect and return samples from the Moon’s far side, bringing back 1.935 kg of rock and regolith, the layer of loose, fragmented material, that covers the solid bedrock of the moon from the South Pole–Aitken (SPA) basin, the largest and oldest impact crater on the Moon. These rare materials are essential for answering long-standing questions, including why the Moon’s two hemispheres look so different, how the giant impact that formed the Moon shaped its interior, and what its early water history might have been. According to researchers, these far-side samples provide the first direct evidence needed to deepen our understanding of lunar formation and the early solar system. (Science, 2024)
Unlike the near side, the Moon’s far side remains one of the least understood regions of the lunar surface. It has a thicker crust, more rugged highlands, and far fewer volcanic plains. These features indicate significant differences in the Moon’s interior and thermal history. Scientists believe that the far-side mantle may be cooler and drier than the near side, and the samples returned by Chang’e-6 now allow researchers to test this directly. By examining the mineral content, isotopic ratios, and traces of water in the material, researchers hope to explain why the two hemispheres developed so differently and what these contrasts reveal about the Moon’s early evolution. (PMC11495410, 2024)
Chang’e-6 builds on nearly two decades of China’s growing lunar exploration program. Earlier missions such as Chang’e-1 and Chang’e-2 created detailed maps of the lunar surface, while Chang’e-3 introduced a lander and rover that demonstrated precise soft-landing capabilities. Chang’e-4 then achieved the first soft landing on the Moon’s far side and proved that long-distance communication through a relay satellite was possible. Chang’e-5 successfully collected and returned samples from the near side in 2020, marking a key step in preparing for a far-side sample mission. Chang’e-6 is the result of all these advances and stands as the first mission in history to return material from the Moon’s far side, a goal no other nation has accomplished. (CNSA, 2024)
Chang’e-6 was a four-part spacecraft consisting of an orbiter, a return module, a lander, and an ascent vehicle. The orbiter and returner remained in lunar orbit, while the lander and ascent vehicle descended to the Moon’s far side. The mission launched on May 3, 2024, aboard a Long March 5 rocket from Wenchang. On May 30, the orbiter and returner separated from the lander and ascent vehicle. At 6:09 a.m. on June 2, 2024, the lander touched down in the Apollo crater within the South Pole–Aitken (SPA) basin. Because the far side of the Moon cannot communicate directly with Earth, all signals and commands were routed through China’s Queqiao-2 relay satellite. (CNSA, 2024)
During the descent, the lander used an advanced autonomous hazard-avoidance system. A visible-light camera scanned the surface for obstacles while a 3D laser imager mapped the terrain as the lander descended to roughly 100 meters above the ground. In the final moments, the engine plume shut off to avoid disturbing the surface, allowing the lander to free-fall a short distance onto shock-absorbing legs. Gamma-ray altimeters helped determine altitude even through dust clouds, ensuring a precise landing. (CNSA, 2024)
After two days of surface operations, the ascent vehicle lifted off on June 4, 2024, carrying a sealed container filled with nearly 1.94 kg of material collected by a robotic scoop and drill. These samples included surface soil, subsurface material, and fragments of ancient volcanic and impact-generated rock from the Apollo crater floor. On June 6, the ascent vehicle automatically rendezvoused and docked with the orbiter-returner in lunar orbit. Once the sample container was transferred to the return module, the spacecraft began its journey back to Earth. Thirteen days later, the return capsule re-entered Earth’s atmosphere and landed in Inner Mongolia. Mission leaders reported that Chang’e-6 achieved breakthroughs in retrograde-orbit control, the capability to manage a spacecraft's path in an orbit that moves in the opposite direction of the body it orbits; autonomous sampling, precision landing, and far-side ascent, which are engineering achievements that now serve as a foundation for future lunar exploration. (Science, 2024)
Chang’e-6 was equipped with an array of scientific instruments designed to collect and analyze a wide variety of lunar materials directly on the far side. Its lander used a robotic arm fitted with both a scoop and a drill to gather rock fragments, fine regolith, and deeper subsurface soil, ultimately collecting material that records billions of years of lunar history. The small rover Jinchan explored the surrounding terrain to contextualize these samples, capturing panoramic images and performing infrared spectroscopy, the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection, which helped identify important minerals such as pyroxene, olivine, and impact-altered glass. In addition to Chinese-made instruments, the lander carried several international payloads, including a French radon detector, an Italian laser retroreflector, and a Pakistani CubeSat camera, each of which contributed environmental and geophysical measurements. Together with the orbiter’s high-resolution cameras and magnetometers, these instruments enabled studies of local magnetic anomalies, surface mineralogy, particle radiation, and dust behavior, which are key factors for understanding far-side geology and planning future missions. (NASA, 2024)
The Apollo crater was selected from multiple candidate sites within the South Pole–Aitken basin because it exposes ancient deep-crust and upper-mantle materials excavated by past meteorite impacts, providing scientists with access to regions of the Moon that have never been sampled before. Over roughly 14 hours, Chang’e 6’s autonomous sampling system successfully drilled, scooped, sealed, and stored the collected material for its long journey back to Earth. (CNSA, 2024)
Even before full laboratory analysis is complete, Chang’e 6’s far-side samples are providing insights into the Moon’s interior and the early solar system. Early results indicate that the far-side mantle is cooler and drier than the near side, supporting models that predict lower concentrations of heat-producing radioactive elements, such as potassium, thorium, and uranium. These findings align with giant-impact theories, which suggest that the Moon formed from debris after a massive collision between the early Earth and a Mars-sized body, leaving the far-side mantle depleted in heat-producing elements (PMC7043921, 2020). The samples also reveal a previously unknown volcanic history, indicating two distinct lava flows dated to approximately 4.2 and 2.8 billion years ago, showing sustained magmatic activity on the far side over a span of more than a billion years. In a surprising discovery, tiny fragments of water-rich CI chondrite meteorites were found embedded in the regolith, confirming that the asteroids that struck the Moon likely contributed water to both the Moon and Earth. Collectively, these results challenge earlier hypotheses that assumed the Moon’s far side mirrored the near side's composition and volcanic history, refine the timeline of lunar impacts and volcanism (PMC11495410, 2024), and have major implications for understanding the Moon’s formation and the delivery of water to Earth.
In conclusion, Chang’e 6 has significantly enhanced our understanding of the Moon and its geological history. By successfully landing on the far side and returning nearly 2 kg of lunar material, the mission achieved a historic milestone, building on China’s Chang’e 4 first far-side landing in 2019 and complementing prior missions such as India’s Chandrayaan-3, which landed on the far side but did not return samples. Analysis of the far-side material confirms a cooler, drier mantle and documents ancient volcanic activity. It identifies water-bearing meteorite dust, collectively providing crucial evidence to answer questions that previous near-side missions could not address. These breakthroughs not only lay out the Moon’s formation and geologic evolution but also expand our understanding of the early solar system, establishing a foundation for future scientific exploration and international missions on the lunar surface. (Science, 2024)
References
China National Space Administration. CNSA – China National Space Administration. Retrieved November 26, 2025, from https://www.cnsa.gov.cn/english/
European Space Agency. ESA – European Space Agency. Retrieved November 26, 2025, from https://www.esa.int/
Lin, Y., Li, C., Liu, D., Wang, S., & Zhang, X. (2024). Nature of the lunar far‑side samples returned by the Chang’e‑6 mission. PMC Journal – In Process. https://pmc.ncbi.nlm.nih.gov/articles/PMC11495410/
National Aeronautics and Space Administration. (n.d.). NASA Science. Retrieved November 26, 2025, from https://science.nasa.gov/
Wu, Y., Zhang, X., Lin, Y., & Li, C. (2024). A sample of the Moon’s far side retrieved by Chang’e‑6 contains 2.83‑billion‑year-old basalt. Science. https://www.science.org/doi/10.1126/science.adt1093
Author(s) unknown. (2020). Lunar impact history and geological evolution. PMC article. https://pmc.ncbi.nlm.nih.gov/articles/PMC7043921/