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China launches Chang’e-6 to recover samples from the far side of the Moon – China.org.cn

China on Friday launched the Chang’e-6 spacecraft to collect and return samples from the moon’s mysterious far side, the first such effort in the history of human lunar exploration.

A Long March-5 rocket, carrying the Chang’e-6 spacecraft, lifted off from its launch pad at the Wenchang Space Launch Site on the coast of south China’s island province of Hainan at 5:27 p.m. ( Beijing time).

About 37 minutes after liftoff, the Chang’e-6 spacecraft separated from the rocket and entered its planned Earth-Moon transfer orbit, which had a perigee altitude of 200 kilometers and an apogee altitude of about 380,000 kilometers. according to the National Space of China. Administration (CNSA).

The launch of the Chang’e-6 spacecraft was a complete success, the CNSA announced.

“Collecting and returning samples from the far side of the Moon is an unprecedented feat. We now know very little about the far side of the Moon. If the Chang’e-6 mission can achieve its goal, it will provide scientists with the first evidence “direct to understand the environment and material composition of the far side of the Moon, which is of great importance,” said Wu Weiren, an academician at the Chinese Academy of Engineering and chief designer of China’s lunar exploration program.

“However, the mission is very difficult and risky. We hope it will be successful,” Wu said.

The Chang’e-6 spacecraft, like its predecessor Chang’e-5, consists of an orbiter, a lander, an ascent module, and a return module.

After reaching the Moon, it will make a soft landing on the opposite side. Within 48 hours after landing, a robotic arm will extend to collect rocks and soil from the lunar surface, and a drill will drill into the ground. Simultaneously, scientific detection work will be carried out.

Once the samples are sealed in a container, the ascender will lift off from the moon and dock with the orbiter in lunar orbit. The repatriate will then take the samples back to Earth, landing in the Inner Mongolia Autonomous Region in northern China. The entire flight is expected to last about 53 days, the CNSA said.

THE TWO FACES OF THE MOON

Since the Moon’s revolution cycle is the same as its rotation cycle, it always faces the Earth in the same direction. The other side, most of which cannot be seen from Earth, is called the far side or “dark side” of the Moon. This term does not refer to visible darkness, but rather to the mystery that shrouds the moon’s largely unexplored terrain.

Remote sensing images show that the two sides of the Moon are very different. The near side is relatively flat, while the far side is densely dotted with impact craters of different sizes and has far fewer lunar mares than the near side. Scientists deduce that the lunar crust on the far side is much thicker than that on the visible side. But it remains a mystery why this is so.

An impact crater known as the Apollo Basin, located within the South Pole Aitken Basin (SPA) on the far side of the Moon, has been chosen as the primary landing and sampling site for the Chang’e-6 mission, according to Wang Qiong, deputy chief designer of the Chang’e-6 mission.

The colossal SPA Basin was formed by a celestial collision more than 4 billion years ago and has a diameter of 2,500 kilometers, equivalent to the distance from Beijing to Hainan, and a depth of about 13 kilometers. It is the largest and oldest impact crater on the Moon and in the solar system, and may provide the earliest information about the Moon, scientists say.

The enormous impact of the celestial collision that formed the SPA Basin may have ejected materials from the depths of the moon. If those materials can be collected and returned to Earth for study, they would provide new insights into the early impact history of the solar system and the geological evolution of the Moon, said Zeng Xingguo, a scientist at the National Astronomical Observatories of China. Academy of Sciences (CAS).

“First-hand direct samples of the far side of the Moon are essential to give us a deeper understanding of the characteristics and differences of the two sides of the Moon and to reveal the secrets of the Moon,” Zeng said.

More than 300 kilograms of lunar samples have been recovered over the course of 10 missions carried out by the United States, the Soviet Union and China, and all were collected on the near side of the Moon, said Yang Wei, a researcher at the Institute of Astronomy. of the CAS. Geology and Geophysics.

“Our understanding of the formation and evolution of the Moon comes almost entirely from the study of lunar samples, and this study is also necessary for future deep space exploration,” Yang added.

NEW CHALLENGES

“The entire mission is fraught with numerous challenges, and each step is interconnected and nerve-wracking,” Wang said.

To achieve communication between Earth and the probe on the far side of the Moon, China earlier this year sent the Queqiao-2 relay satellite, whose name translates as “magpie bridge-2,” into lunar orbit. frozen highly elliptical.

Although the Chang’e-4 mission achieved the world’s first soft landing on the far side of the Moon in 2019, Chang’e-6 still faces significant risks as the rugged terrain of the far side of the Moon poses great challenges to its landing, space. the experts say.

The Chang’e-6 mission needs to see new technological advances in areas such as retrograde lunar orbit design and control, rapid intelligent sampling and takeoff from the far side of the Moon, Wang said.

The design of the Chang’e-6 probe is similar to that of the Chang’e-5 probe, which collected samples from the northern hemisphere of the moon’s near side, said Huang Hao, a space expert with China Aerospace Science. and Technology Corporation (CASC).

But Chang’e-6 will land in the southern hemisphere of the far side of the Moon, so the mission will use a retrograde lunar orbit to accommodate its sampling task, Huang added.

While the Queqiao-2 relay satellite orbits the Moon, the Chang’e-6 probe will not be able to communicate with controllers on Earth for some time during its operations on the far side of the Moon, said Deng Xiangjin, another CASC expert. .

“We conducted extensive data analysis from hundreds of ground experiments and used artificial intelligence to improve the design of the spacecraft to improve its autonomous control capabilities and improve its sampling efficiency,” Deng said.

“The number of samples that Chang’e-6 can collect is uncertain and cannot be accurately estimated at this time. Our goal is to collect 2 kilograms,” Deng added.

BEYOND THE BORDERS

The Chang’e-6 mission carries four payloads developed through international cooperation, providing more opportunities for the world’s scientists and merging human experience in space exploration.

Scientific instruments from France, Italy and the European Space Agency (ESA)/Sweden are on board the Chang’e-6 lander, and a small satellite from Pakistan is on board the orbiter.

After the Chang’e-6 spacecraft enters lunar orbit, the small satellite will be released to perform in-orbit imaging tasks. A laser retroreflector developed by Italian scientists will be used for positioning and ranging in future lunar missions, Wang said.

A lunar surface negative ion analyzer developed by ESA/Sweden will be used to detect negative ions and study the interaction between plasma and the lunar surface. And a scientific instrument developed by French scientists will detect radon isotopes and study the transmission and diffusion mechanisms of volatile compounds in the lunar environment, Wang said.

China adheres to the principles of broad consultation, joint efforts and shared benefits in its international cooperation in lunar exploration, and is willing to engage in multiple levels and types of cooperation with countries and international organizations around the world, on the basis of equality and mutual respect. benefits, said Ge Ping, deputy director of the CNSA’s Lunar Exploration and Space Engineering Center.

China has opened applications to borrow and study lunar samples obtained by the Chang’e-5 mission to the international community and welcomes scientists from around the world to participate in its future lunar and planetary exploration projects, Ge added.

Qamarul Islam, professor at the Pakistan Institute of Space Technology, expressed great appreciation for the collaboration experience with China. He said relatively small countries that cannot go to space on their own should have the opportunity to do some space research.

“We are very proud to be part of this historic mission,” said Pierre-Yves Meslin, principal investigator for Degassing Detection at France’s RadoN, adding that he looks forward to further space cooperation between the two countries.

“The very nature of space exploration encourages us to think of our planet as one and encourages us to think of humanity together. It is absolutely key for us to continue our young journey into the cosmos by working together,” said Neil Melville. Kenney, ESA Technical Officer for Negative Ions on the Lunar Surface.