The 8.2-tonne probe will launch on a Long March 5 rocket from the Wenchang Satellite Launch Centre on Hainan island, and attempt the first lunar sample return since the Soviet Union's Luna 24 mission in 1976.
The mission will be complex, with some of the key technologies and techniques involved will also be applicable for a Chinese Mars sample return mission, planned for around 2030, as well as future crewed journeys to the lunar surface.
"The lunar probe is comprised of four parts: an orbiter, a return module, an ascender and a lander," state media Xinhua quoted Ye Peijian, one of China's leading aerospace experts, as saying.
Having soft-landed on the Moon and drilled for and collected samples, an ascent module will perform an automated docking with an orbiter in a lunar orbit 380,000 km away from Earth.
Above: Image of the apparent planned landing spot for Chang'e-5 (Chinese Academy of Sciences).
The orbiter will then head on a trajectory for home, with the return module separating from the orbiter close to Earth and making a high speed atmospheric 'skip' reentry.
After landing in Siziwang Banner, Inner Mongolia - the same area where China's crewed Shenzhou missions touch down - the samples will be taken to laboratories.
Above: The Chang'e-5 reentry capsule (Framegrab/CCTV).
"Once the samples are back, we can begin our analysis right away." Ouyang Ziyuan, a cosmochemist and a chief scientist on China's Lunar Exploration Project (CLEP), told press in October.
The total mass of samples to be collected has not been revealed. The landing site for Chang’e-5 has apparently been chosen and imaged (above), but the coordinates have not been released.
The mission duration was not mentioned, but it is likely that the aim will be to have objectives on the surface completed within one lunar day, or around 14 Earth days, in order to reduce complexity.
'Orbit, land, return'
Chang’e-5 marks the third phase of a Chinese project to first orbit, then land and rove, and finally retrieve samples from the surface of the Moon.
Chang'e-1 and -2 first orbited and mapped the Moon in 2007 and 2010 respectively, before the Chang'e-3 soft landed in December 2013, setting a lander and the Yutu, or Jade Rabbit, rover on the surface.
Above: China's Yutu ('Jade Rabbit') lunar rover and lander on the Moon.
The sample return phase is now made possible by the successful development of the Long March 5 heavy-lift carrier rocket, which debuted (dramatically) in November.
The new rocket doubles China’s capacity to launch payloads, allowing plans to send a mission to Mars and construct a large, modular space station to move forward.
From the Moon to Mars and beyond
The mission will be the first to collect samples from the Moon since the early 1970s, when US crewed and Soviet Union robotic missions gathered and returned lunar materials.
While marking the culmination of China’s first lunar exploration project, Chang’e-5 will, as well as testing necessary techniques for potential future crewed missions, provide experience for missions beyond the Earth-Moon system.
“We will later conduct research of Mars and other asteroids. We expect to go further in the exploration of deep space,” Ruan Jianhua, deputy chief designer of Chang’e-5, told CCTV earlier in January.
Chinese robotic activity on the Moon will not end with Chang’e-5, however. In 2018 China will attempt the first ever landing on the lunar far side with Chang’e-4, using the back-up lander and rover for the ongoing Chang’e-3 mission, and a relay satellite positioned beyond the Moon to facilitate communications.
Above: A view of the far side of the Moon and the distant Earth, captured by the service module for the 2014 Chang’e 5-T1 mission (Chinese Academy of Sciences).
Due to ‘tidal locking’, the far side of the Moon remains permanently facing away from the Earth, with images showing a distinctly different surface to the near side, including a huge, scientifically intriguing impact zone, the South Pole-Aitken basin, which the Chang’e-4 is expected to target.
Chang’e-6 could, potentially by around 2020, combine these missions to attempt a sample return from the lunar far side.
Other Chinese missions being researched include robotic missions to the Moon’s poles in the early 2020s.
Renewed focus on the Moon
China is not the only country interested in exploring our celestial neighbour. India is developing its first landing and roving mission, Chandrayaan-2, while Japan's JAXA could launch two missions before the end of the decade.
NASA is working on a range of missions to launch in the coming years, including Lunar Flashlight, a cubesat orbiter to investigate ice deposits, along with three other small Moon-bound payloads as part of the first test of the Space Launch System.
A host of private entities are also competing for the $30 million Lunar XPrize, sponsored by Google, with four teams from Israel (SpaceIL), the US (Moon Express), India (Team Indus) and an international consortium (Synergy Moon) earning launch contracts for 2017 in a race to operate a rover on the Moon.