Chang'e-5 marks the third and final stage of the original China Lunar Exploration Program (CLEP) approved in the early 2000s, which set out to first orbit and map the Moon (Chang'e-1 and 2), then land and rove on the lunar surface (Chang'e-3 and Yutu), and finally collect samples and bring them to Earth for analysis.

Following earlier successes and technological breakthroughs, Chang'e-5 is now scheduled to launch in late November from Wenchang on a new Long March 5 heavy-lift rocket.

The last lunar sample return was the Soviet Union's Luna 24 in 1976, so China is clearly still catching up. But rather than merely copying Cold War-era missions, as has often been suggested, this will also provide lessons and experience for more ambitious missions in the future.

The Luna 24 ascent stage returned directly to Earth, but China has decided that the Chang'e-5 mission will rely on a lunar orbit rendezvous similar to that used for the Apollo landings. The 8.2 metric ton Chang'e-5 spacecraft thus consists of a service module, lander, ascent unit, and a return vehicle.

After collecting samples, the ascent module will lift off and dock with the service module in orbit around the Moon, nearly 400,000 kilometers away from Earth. The samples will be transferred to the reentry capsule, which itself will separate from the service module a few thousand kilometers from Earth before reentry and landing.

The lunar orbit rendezvous approach is a very interesting choice we'll look at later, but note for now that this will be the first robotic rendezvous and docking around a planetary body other than the Earth.

Landing sites and science goals

Six Apollo and three Soviet robotic Luna missions brought lunar rocks and regolith back to Earth, but the Moon is a large and diverse body and there is much to be learned. According to a paper recently presented at the 48th Lunar and Planetary Science Conference, a number of target sites near Mons Rümker in the northern Oceanus Procellarum are being considered.

Spectral analysis of craters using imaging data from the Chandrayaan-1 Moon Mineralogy Mapper suggests that material at one candidate area is just 1.33 billion years old, meaning Chang'e-5 could be returning by far the youngest lunar basaltic samples yet (Apollo basalt samples were 3 to 4 billion years old).

Planetary Scientist Phil Stooke, using information from another paper to be presented at the European Geoscience meeting in April, mapped out the region containing seven candidate sites identified by scientists with the Chinese Academy of Sciences. Within this, the 'preferred landing area' box marks the candidate site discussed above.