HELSINKI — China launched its complex and ambitious Chang’e-6 mission Friday to collect the first ever samples from the far side of the moon.
A 57-meter-tall Long March 5 lifted off from the Wenchang Satellite Launch Center at 5:30 a.m. Eastern (0930 UTC) May 3, carrying the roughly 8,200-kilogram Chang’e-6 into orbit.
A first second stage burn was completed 12 minutes after launch, with a translunar injection burn set for around 14 minutes later. Spacecraft separation is scheduled for around 37 minutes into flight.
If successful, samples delivered by the 53-day-long mission could change our understanding of the Earth and moon and the history of the early solar system.
Chang’e-6 consists of a stack of four spacecraft that will perform specific roles. Its orbiter will take the mission into lunar orbit. From there, a lander will separate and target a landing within Apollo crater on the far side of the moon. As the far side of the moon is never visible to Earth, due to our planet slowing the moon’s rotation and leaving it tidally locked, a communications relay satellite is required to provide communications between the ground and the lunar far side. For this, China launched Queqiao-2 in March into a specialized lunar orbit.
Once landed, the lander spacecraft will collect up to 2,000 grams of lunar samples with a drill, descending to a depth of up to two meters, and a scoop. These will be loaded into an ascent vehicle and launched back into lunar orbit for a carefully choreographed and challenging rendezvous and docking with the orbiter.
From here, the samples will be transferred to a reentry capsule. The ascender will be jettisoned and the orbiter will prepare for the return to Earth. The reentry capsule will be released just before reaching Earth and will first skip off the planet’s atmosphere. This will help it slow it down before a final, fiery plunge through the atmosphere and a landing in Inner Mongolia.
The mission is a repurposed backup to the 2020 Chang’e-5 sample return mission. That mission successfully collected the youngest samples so far from the near side of the moon. It also builds on the Chang’e-4 mission which put a lander and rover on the lunar far side in 2019.
Lunar mysteries and dichotomy
Apollo lies within the South Pole-Aitken (SPA) basin, a gigantic, ancient impact basin on the lunar far side. This is thought to hold tantalizing clues as to a number of moon mysteries, making the added cost of complexity of a relay satellite worthwhile scientifically.
A map of the lunar far side, indicating the Chang’e-6 landing zone within Apollo crater. Credit: CNSA
The far side of the moon is not, as sometimes assumed, in perpetual darkness. Instead, that lunar hemisphere could prove uniquely illuminating. The samples could deliver a vast range of insights into the Earth and moon, Yuqi Qian, a postdoctoral fellow at the University of Hong Kong, told SpaceNews.
Chief among these would be insights into the lunar dichotomy, or why the nearside and farside are so different. Studying mare basalts could be revealing, Qian says, because they originated from the lunar mantle and contain crucial information about it.
The SPA Basin readily excavated lunar mantle materials which may be contained in Chang’e-6 samples. “They are the best materials for studying the lunar magma ocean model because the lunar mantle is the direct product of the solidification of the lunar magma ocean but we have no access to them before.”
Qian adds that studying exotic impact materials like impact breccias will also be revealing as to the history of the Earth-Moon system. “By studying them, we would know better the early bombardment history of the Earth-Moon system like the Late Heavy Bombardment Hypothesis.”
Chang’e-6 collaborations
As well as the main goal of collecting samples, the Chang’e-6 lander carries a landing camera and a panoramic camera for imaging its surroundings. A ground-penetrating radar to provide insights below the lunar surface. It also carries a lunar mineral spectrometer to assess the composition of the surface. The spacecraft is expected to deploy a Chinese national flag, as done by the Chang’e-5 lander.
A panorama returned by the Chang’e-5 lander, showing robotic sampling arm and scoop marks in lunar regolith. Credit: CNSA/CLEP
The mission also carries international scientific payloads from France, Sweden, Italy, and a Pakistani cubesat. The collaborations reflect Chinese efforts to boost its international cooperation in space exploration.
France is providing the Detection of Outgassing RadoN (DORN) instrument which will detect radon outgassing from the lunar crust. Sweden, with ESA support, will contribute the “Negative Ions at the Lunar Surface” (NILS) payload. An Italian passive laser retro-reflector will also be aboard. The 7-kg ICUBE-Q cubesat is a collaboration between Pakistan’s national space agency, SUPARCO, and China’s Shanghai Jiao Tong University.
Chang’e-6 is part of China’s broader lunar goals. The country will follow up with two missions to the south pole of the moon. These are Chang’e-7 in 2026 and Chang’e-8 around 2028.
Beyond this, the country aims to launch its first crewed lunar mission by 2030. Both sets of missions are part of a plan to establish a permanent lunar base. This project is known as the International Lunar Research Station (ILRS) program, planned for the 2030s. A number of countries and organizations have signed up to the project.
Chang’e-6 will also provide experience of some of the operations and maneuvers needed to collect and return samples from Mars. China aims to launch such a mission around 2030.