Chang'e 6

Spacecraft design

Chang'e 6 comprised four main modules — orbiter, lander, ascender, and return capsule — closely derived from the Chang'e 5 architecture. The total spacecraft mass was approximately 8,300 kg with a height of about 7.2 m and a diameter of 4.5 m.

The orbiter remained in lunar orbit throughout surface operations, providing propulsion, power via solar arrays, attitude control, and communications for the return leg to Earth. It formed an 'orbiter–returner' assembly with the return capsule while awaiting the ascender's docking after sample collection.

The lander separated from the orbiter in lunar orbit and performed powered descent to the far-side SPA basin. It housed the sampling system — including a four-degree-of-freedom robotic arm, scooping sampler, drilling system, and binocular camera for vision-based sampling — as well as Chinese and international science payloads. The ascender was mounted atop the lander; after receiving the collected samples it launched from the surface, rendezvoused and docked with the orbiter–returner combination, and transferred the sealed sample container to the return capsule.

The return capsule was attached to the orbiter for most of the mission. After receiving the samples in lunar orbit, it separated from the orbiter near Earth and performed a high-speed skip re-entry — bouncing off the upper atmosphere to manage re-entry heating and speed — before landing under parachutes in Inner Mongolia.

Because the lunar far side has no line-of-sight to Earth, the Queqiao-2 relay satellite was essential for all phases of far-side operations. Launched on 20 March 2024 on a Long March 8 rocket, Queqiao-2 was equipped with a 4.2-metre-diameter parabolic antenna — one of the largest deep-space relay antennas flown beyond Earth. All telemetry, science data, and command uplinks between the lander or ascender and ground stations were routed through Queqiao-2 during the surface phase, and the relay was also used during orbital rendezvous and docking when geometry required it.

Landing site: Apollo Basin and the South Pole–Aitken Basin

Chang'e 6 landed in southern Apollo Basin, an impact crater approximately 492 km in diameter situated in the northeastern portion of the South Pole–Aitken (SPA) Basin. The SPA Basin is the oldest and largest recognized impact structure on the Moon, spanning roughly 2,500 km across. Radiometric dating of impact-melt norite clasts in the Chang'e 6 samples has anchored the SPA-forming impact at approximately 4.25 billion years ago.

The specific landing area — designated Statio Tianjiang — lies on a mare basalt unit within Apollo Basin with a model age of approximately 2.5–2.8 billion years, representing a relatively young volcanic fill inside a much older impact basin. The site was selected because it simultaneously offered access to young far-side basalts, deep impact-excavated materials mixed into the regolith from both Apollo and SPA events, and sufficient solar illumination and flat terrain for a safe far-side landing.

Key scientific objectives connected to this site included dating the SPA and Apollo basin-forming events via impact-melt clasts, characterizing far-side mare volcanism and understanding why it appears more limited than nearside volcanism, probing the subsurface regolith structure with a penetrating radar, constraining lunar interior composition via deep-seated materials excavated by the impacts, and providing the first in-situ calibration reference for remote-sensing datasets over the SPA Basin.