The far side of the moon and distant Earth, imaged by the Chang’e-5 T1 mission service module.
The far side of the moon and distant Earth, imaged by the Chang’e-5 T1 mission service module. Credit: Chinese Academy of Sciences

HELSINKI — Components for China’s Chang’e-6 lunar far side sample return mission spacecraft arrived at Wenchang spaceport Wednesday.

The delivery is part of preparations to launch a stack of four spacecraft to land on the far side of the moon, collect samples and deliver them to Earth. The 8,200-kilogram probe will launch on a Long March 5 rocket around May this year.

The spacecraft components were delivered to Hainan island via Antonov An-124 and Xi’an Y-20 transport planes, the China National Space Administration (CNSA) announced Jan. 10. These were then transferred to Wenchang Satellite Launch Center. Assembly and testing will begin in the near future.

CNSA stated the mission will launch within the first half of 2024. Earlier indications suggest the Chang’e-6 will launch around May.

Chang’e-6 is a follow up to the 2020 Chang’e-5 mission which collected 1,731 grams of lunar material from Oceanus Procellarum on the near side of the moon. 

The new and more ambitious mission will require the support of a relay satellite known as Queqiao-2 (“Magpie Bridge-2”). This is because the far side of the moon never faces Earth due to tidal locking, making direct communication with that lunar hemisphere impossible. 

Queqiao-2 is expected to launch from Wenchang on a Long March 8 rocket in the coming months. Its planned 24-hour-period, elliptical frozen orbit will take it out beyond the moon, from which it will have line of sight with both ground stations on Earth and Apollo crater on the lunar far side.

A map of the lunar far side, indicating the Chang’e-6 landing zone within Apollo crater. Credit: CNSA

Chang’e-6 will subsequently launch and target a landing in a southern portion of Apollo crater, located at 150–158 degrees west, 41–45 degrees south. Apollo lies within the South Pole-Aitken (SPA) basin, a gigantic, ancient impact basin. The lander will attempt to collect 2,000 grams of material, both scooped from the surface and collected by a drill. 

An ascent vehicle will send a canister of collected samples back into lunar orbit for rendezvous and docking with the service module. The service module will then return to Earth. Just before arrival it will release a reentry module designed to protect the samples during a high-speed atmospheric reentry. 

It is thought that material from beneath the moon’s crust is accessible in the SPA basin. Analysis of such material could provide new insights into the history of the moon and by extension the Earth and wider solar system. It could also help explain why there is a difference in composition of nearside versus far side lunar rock.

The mission is expected to last 53 days from launch till landing, according to China’s Deep Space Exploration Laboratory (DSEL). Chang’e-5 was a 23-day mission.

International participation, future moon base

Chang’e-6 will also carry international payloads. 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 ICUBE-Q cubesat for Pakistan is also part of the mission.

Samples collected by Chang’e-6 will initially be available to Chinese scientists and institutions before being opened to research proposals internationally. 

CNSA made the Chang’e-5 material open to applications from international scientists in August 2023, nearly three years after the return of the spacecraft. NASA-funded researchers were granted permission to apply for access to the samples in late November, despite Congressional barriers to bilateral activities with Chinese entities.

The only previous soft landing on the lunar far side was made by China’s Chang’e-4. That lander and rover mission set down in Von Kármán crater in early 2019. That mission was supported by a first Queqiao satellite. Both spacecraft were stated to still be operational early this year, though China provides few updates on the mission.

The Chang’e-5 and 6 missions can also be seen as miniature test missions for getting astronauts onto the moon and safely back to Earth. China has recently stated it intends to put a pair of astronauts on the moon before 2030

Chang’e-6 is also nominally part of the China-led International Lunar Research Station (ILRS) program. The aim of the project is to establish a permanent lunar base in the 2030s. Like the U.S. and its Artemis program, China is attempting to attract partners for the ILRS initiative. 

As of early December 2023, eight countries—China, Russia, Venezuela, Belarus, South Africa, Azerbaijan, Pakistan and Egypt—had signed up to the ILRS. A handful of inter-governmental organizations, firms, universities and other entities have also joined.

The first steps to establishing an ILRS robotic moon base are the Chang’e-7 and 8 south polar missions. These are scheduled for 2026 and 2028 respectively. Both China and NASA are interested in overlapping areas at the lunar south pole. The ILRS will be constructed using super heavy-lift rocket launches in the 2030s.

Andrew Jones covers China's space industry for SpaceNews. Andrew has previously lived in China and reported from major space conferences there. Based in Helsinki, Finland, he has written for National Geographic, New Scientist, Smithsonian Magazine, Sky...