Explained | Significance of China’s Chang’e-6 mission

China launched an uncrewed spacecraft on a 53-day-long lunar probe mission to retrieve rocks and soil from the far side of the Moon.

The far side of the Moon is not visible from Earth.

It is the first endeavour of its kind in the history of human lunar exploration.

The Long March-5, China’s largest rocket, from Wenchang Space Launch Center on the southern island of Hainan with the more than 8 metric tonne Chang’e-6 probe.

The liftoff marked the beginning of the country’s second lunar sample-return expedition after the successful Chang’e-5 mission in 2020.

India became the first country to land near the little-explored lunar South Pole region last year when its Chandrayaan-3’s lander, carrying the Pragyaan rover successfully landed there.

Significance of the mission

• Earlier, 10 lunar sample-return missions were undertaken by the United States, the former Soviet Union and China, but all these samples were collected from the Moon’s near side.

• Since the first Chang’e mission in 2007, named after the mythical Chinese Moon goddess, China has made leaps forward in its lunar exploration.

• In 2020, Chang’e-5 marked the first time humans retrieved lunar samples in 44 years. China returned samples from the Moon’s near side, the first time anyone had done so since the former Soviet Union in 1976. 

• Samples brought back by the Chang’e-5 probe have helped scientists find that there were volcanic activities on the Moon’s near side around two billion years ago.

• The launch marks another milestone in China’s lunar and space exploration programme.

• Chang’e-6 is tasked with landing in the South Pole-Aitken Basin on the far side of the Moon, which perpetually faces away from the Earth, after which it will retrieve and return samples.

• Scientific instruments from France, Italy and the European Space Agency/Sweden are onboard the lander of the Chang’e-6 mission and a Pakistani payload on the orbiter. 

• This is the first time that China has included an orbiter from its all-weather ally Pakistan in its Moon mission.

• Remote-sensing images show the Moon’s two sides are very different. The near side is relatively flat, while the far side is thickly dotted with impact craters of different sizes and has much fewer lunar mares than the near side. 

• Scientists infer that the lunar crust on the far side is much thicker than that on the near side. But why that is so remains a mystery.

• China in the past successfully launched unmanned missions to the Moon, including landing a rover. China has also sent a rover to Mars and built a space station, which is currently in operation.

• Earlier, China announced plans for a manned lunar landing by 2030.

• China also plans to have a lunar station on the Moon in future.

How the samples will be collected?

• Chang’e-6 consists of four components: an orbiter, a lander, an ascender and a re-entry module.

• After the probe reaches lunar orbit, its components will separate into two parts, with the orbiter and re-entry capsule remaining in orbit, while the lander and ascender start approaching the lunar surface.

• The lander-ascender combination will make a soft-landing in the South Pole-Aitken Basin — a gigantic crater on the lunar far side and also the largest, oldest and deepest basin recognized on the moon. 

• It will then start using a drill and a mechanical arm to gather surface and underground samples.

• Up to 2 kilograms of stones and soil will be collected and packed in a vacuum-sealed metal container inside the ascender.

• After the samples are sealed in a container, the ascender will take off from the Moon and dock with the orbiter in lunar orbit. 

• The returner will then carry the samples back to Earth, landing in north China’s Inner Mongolia Autonomous Region. 

• The mission is poised to make breakthroughs in key technologies, such as automatic sample collection, take-off and ascent from the far side of the Moon.