Scientists eager for Chang'e-6 lunar farside samples to bring new discoveries
The tidal locking effect keeps the Moon consistently presents its one side—the near side—to Earth, rendering the other side—the far side—inaccessible for people standing on Earth. Consequently, the far side of the Moon remained shrouded in mystery for human observers until the onset of space exploration.
In 1959, the Soviet Union’s Luna 3 spacecraft returned the first views ever of the far side of the Moon. Despite the blurriness of the photo by contemporary standards, the stark contrast between the near side and far side of the Moon was striking. Since then, a growing number of orbital probes have revealed significant differences between the two sides of the Moon, including lunar crust thickness, magma activities, and compositions. However, the origins of these differences remain unexplained.
On January 3rd, 2019, China’s Chang’e-4 mission successfully achieved landing on the far side of the Moon for the first time in human history. The landing site was situated within the Von Kármán crater (177.577°E, 45.457°S) in the South Pole-Aitken basin. Following the landing, the Yutu-2 rover executed surface exploration missions. The rover identified materials potentially derived from the lunar mantle and was operational for a continuous period of 67 lunar days.
On May 3rd, 2024, China’s Chang’e-6 probe was launched from the Wenchang satellite launch site in Hainan with the aim of retrieving 2-kg samples from the far side of the Moon. The landing took place on June 2nd on a basalt unit (153.9856°W, 41.6383°S) in the southern Apollo basin.1 Similar to the Chang’e-5 mission,2 the Chang’e-6 lander-ascender collected samples using core drilling and surface scooping techniques. On June 4th, the ascender separated from the lander, took off with samples, and later docked with an orbiter-returner in orbit and then transferred samples to the orbiter-returner on June 6th. The Chang’e-6 returner is expected to deliver the samples to Earth on June 25th.
The Chang’e-6 mission represents a significant milestone in the history of human lunar exploration, marking the first sample return from the far side of the Moon (Figure 1A). To date, ten successful lunar sample-return missions were all conducted on the near side of the Moon. These nearside samples have significantly advanced our understanding of the Moon, including its chemical characteristics, physical processes, and geological evolution. This knowledge has led to the proposal of hypotheses regarding the giant impact origin of the Moon and the lunar magma ocean model.
