The mission aims to bring lunar samples back to Earth for what will be the first time in around 40 years. It is hoped that laboratory analysis of the samples back on Earth could help give scientists an insight into the moon’s past.
The Chang’e-5 ascent vehicle, carrying the precious lunar sample, docked with the orbiting spacecraft at around 9:42pm on Saturday night.
It took multiple days to do so. The ascent vehicle lifted off from the lunar surface on Thursday.
A landing craft then touched down on the moon on December 1, marking the third time China has put a spacecraft there.
The craft then collected around 2 kilograms of moon samples, which it managed to return to the rest of the spacecraft over the weekend.
The orbiting spacecraft then separated from the ascent vehicle and began its 23-day trip back towards Earth.
Peng Jung, deputy chief designer of the Chang’e-5 probe, explained why the manoeuvre marked a challenge for the mission controllers.
The designer told Chinese media, according to Space.com: “It will be the historic first, and it will be very difficult.”
They said the only missions that had involved a rendezvous and docking in a lunar orbit were the Apollo missions run by Nasa, and that an un-crewed docking had never been achieved.
Controlling such a manoeuvre – in which the ascent vehicle had launch and meet up with its orbiting partner – was difficult from a distance because of the time delay.
To get around this, engineers had to make sure the operations were carried out automatically.
Liu Ran, head of the lunar exploration wing of the China National Space Administration, told Chinese media the mission has “laid a technical foundation” for future space exploration and manned missions to the moon.
When the orbiter reaches Earth, it will be travelling so fast that it will need to ‘bounce’ off of the Earth’s atmosphere once before re-entering at the right location to make a landing in Inner Mongolia.
Scientists will then extensively study the lunar samples to learn what they can about the moon’s history.
If China’s mission is successful, it will make the nation the third to have returned a lunar sample to Earth, following Russia and the US.
The difference with China’s mission is that it has chosen a volcanic area of the moon, meaning its samples should be different – notably, newer – than those collected previously.
Current moon samples are over three billion years old, but the ones the Chang’e-5 mission returns could be as young as 1.2 billion years old.
The first ever lunar sample was returned to Earth as part of the Apollo 11 mission in 1969, and the last sample returned was in 1976 as part of the Soviet Luna 24 mission.