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If successful, Chang’e-5 will be the first Chinese craft to bring back lunar material to Earth.

By Smriti Mallapaty, 23 NOVEMBER 2020

A Chinese spacecraft is on its way to the Moon after launching off the coast of Hainan Island, in southern China, this morning at 4:30 AM local time.

Chang’e-5’s mission is to retrieve rocks from the Moon and return them to Earth. If successful, the craft will be the first to collect lunar material in 44 years — and a first for China, ushering in the next phase of its increasingly complex lunar exploration programme. Several Chang’e spacecrafts, which are named after a Chinese Moon goddess, have reached and touched down on the Moon, including landing on its far side.

Chang’e-5 blasted off from Wenchang Satellite Launch Center aboard the Chinese Long March-5 rocket, and began its 800,000 kilometre roundtrip to the Moon, which will take about three weeks.

“I just left the coast after seeing the rocket take off. I was so excited, and tears filled my eyes,” says Xiao Long, a planetary geologist at the China University of Geosciences in Wuhan. “This will greatly encourage people, especially the younger generation to study and explore the worlds beyond our Earth.”

Clive Neal, a geoscientist at the University of Notre Dame in Indiana, says if successful, the mission marks the beginning of a new era of robotic sample returns from the Moon that will undoubtedly change scientists’ understanding of the planetary body. “Now we wait for the samples to be collected and returned.”

The Chinese National Space Administration-led mission is receiving communications support from the European Space Agency to track the spacecraft’s journey through deep space, and on its return to Earth in mid-December.

Change’e-5 weighs some 8,200 kilograms and contains a lander, ascender, orbiter and returner. The craft is expected to arrive at the Moon within days. Once in lunar orbit, the lander and ascender will descend to the Moon's surface. A couple of hundred metres above ground, the probe will hover and use its camera to survey the surface for any hazards such as large boulders and to identify a safe place for the lander and ascender to touch down.

The proposed landing site is a 55,000 square-kilometre area in the north-western region of the expansive lava plains known as Oceanus Procellarum, on the Moon’s near side. The precise location won’t be determined until after Chang’e-5 reaches lunar orbit, but it is likely to be in the eastern area that contains some of the youngest volcanic material, says James Head, a planetary geoscientist at Brown University in Rhode Island.

This area is of particular interest to scientists because it could confirm whether the Moon was still volcanicaly active some one to two billion years ago. The age of the rocks is not yet known, but remote observations of the lunar surface suggest that the rocks are roughly two billion years younger than the lava samples collected by the United States and Soviet lunar missions in the 1960s and 1970s.

The landing region is “one of the most interesting scientific sites to be explored on the Moon, and the samples, when returned and analysed, will give us a treasure trove of new information that will revolutionize our understanding of lunar history,” says Head.

The craft will collect at least two kilograms of lunar samples by scooping up soil from the surface, and drilling up rocks and dust.

With the lunar material in tow, the ascender will take off from the Moon’s surface, reconnect with the orbiter and returner, and transfer the materials while in orbit. The orbiter and returner will then make their way back to Earth — a distance of around 380,000 kilometres.

Some 5,000 kilometres from Earth, the lander will separate and begin the final high-speed drop to the grasslands of Inner Mongolia, in northern China. Once retrieved from the landing site, the lunar samples will be transported and stored at the Chinese Academy of Sciences National Astronomical Observatories of China in Beijing. Some material will also be kept at Hunan University for long-term safekeeping, describes Head in a background paper on the mission.

If Chang’e-5 proves successful, Chang’e-6 will seek to return samples from the Moon’s south pole in 2023.

(Sources: Nature)