At 14:07 on June 25, the Chang'e-6 returner landed safely in a predetermined area in Siziwang Banner, Inner Mongolia, carrying lunar samples from the far side of the moon. Xi Jinping, General Secretary of the CPC Central Committee, President of the State, and Chairman of the Cent

At 14:07 on June 25, the Chang'e-6 returner landed safely in the predetermined area of ​​Siziwang Banner in Inner Mongolia carrying lunar samples from the far side of the moon. Xi Jinping, General Secretary of the CPC Central Committee, President of the State, and Chairman of the Central Military Commission, sent a congratulatory message. On behalf of the Party Central Committee, the State Council and the Central Military Commission, he extended warm congratulations and sincere greetings to all comrades at the Chang'e-6 mission command headquarters of the lunar exploration project and those participating in the mission. Xi Jinping pointed out in his congratulatory message that Chang'e-6 has returned samples from the far side of the moon for the first time in human history, which is another landmark achievement in building my country into a powerful country in space and science and technology. Over the past 20 years, all comrades involved in the development and construction of the lunar exploration project have carried forward the spirit of lunar exploration, bravely climbed to the peak of science and technology, made major achievements that have attracted worldwide attention, and embarked on a path of high-quality and high-efficiency lunar exploration. Next, let’s take a look at what challenges Chang’e-6 experienced during this lunar exploration trip.

On June 25, 2024, the Siziwang Banner Space Landing Site in Inner Mongolia welcomed a special "guest". After 53 days of space roaming, the Chang'e-6 returner landed successfully. Chang'e-6 brought a gift to the earth - a lunar sample from the far side of the moon. This is also the first time that humans have achieved sampling and return from the far side of the moon.

This morning, the Chang'e-6 returner has been airlifted to Beijing, and subsequent sample storage, analysis and research work will also begin. From its launch on May 3 to its return on June 25, the Chang'e-6 probe successfully completed its mission and once again left China's lunar exploration footprint on the moon. During these 53 days, behind the moon, which is invisible to the naked eye, Chang'e-6 experienced challenges again and again. Among these many challenges, the most intriguing is landing on the moon.

At about 6:00 on June 2, the Chang'e-6 probe is about to land on the back of the moon. The pre-selected landing area for this mission - the South Pole-Aitken Basin on the far side of the moon, has a drop of more than 10 kilometers. This is like landing a small truck into the mountains. It not only requires precise obstacle avoidance, but also advanced guidance. navigation and control systems to ensure safe landing.

At 6:09, the Chang'e-6 lander and ascender assembly began a powered descent, and then the main engine was turned on. During this period, the combination quickly adjusts its attitude and automatically detects obstacles, and selects a rough safe point based on the brightness of the moon. Chang'e-6 hovered at an altitude of 100 meters from the landing point. These three seconds of hovering were particularly critical for the landing of the moon.

Guan Yifeng of China Aerospace Science and Technology Corporation: images and recognizes obstacles when hovering, and then avoids them. It is equivalent to two parts. First, confirm with eyes, take a look at which place is relatively flat, remember that place, and then transfer it to the brain. Knowing it's flat, move over and drop down over the flat area.

The eye that experts refer to refers to a three-dimensional imaging sensor. Before landing on the moon, the three-dimensional imaging sensor uses laser three-dimensional scanning to take precise pictures to detect obstacles on the lunar surface, and finally selects a landing site to complete the landing.

In a test field at Tongji University, large and small wooden boards are used at different heights and angles to simulate the undulations of the ground seen from the air to verify the accuracy of laser imaging technology.

Dean of the School of Surveying, Mapping and Geographic Information of Tongji University Xie Huan : For landing obstacle avoidance, the main concern is whether the ground is flat, and pits and stones exceeding 20 cm must be avoided, so we simulated it in the field Different scenes, large and small pits and rocks of different sizes were created to try to recreate the scenes on the lunar surface that might threaten a safe landing.

However, no matter how high the accuracy of static experiments on the ground is, it cannot cope with the shaking of the detector during actual operation. It's like taking a picture on a bumpy car with poor imaging results. The scientific research team's response was in one word: fast.

The sensor can conduct precise detection of a certain range of terrain on the moon within 0.25 seconds. Moreover, in just 3 seconds of hovering, the autonomous obstacle avoidance system has to complete all measurement and calculation work, and it only has three opportunities to make a judgment.

At 14:07 on June 25, the Chang'e-6 returner landed safely in the predetermined area of ​​Siziwang Banner in Inner Mongolia carrying lunar samples from the far side of the moon. Xi Jinping, General Secretary of the CPC Central Committee, President of the State, and Chairman of the Central Military Commission, sent a congratulatory message. On behalf of the Party Central Committee, the State Council and the Central Military Commission, he extended warm congratulations and sincere greetings to all comrades at the Chang'e-6 mission command headquarters of the lunar exploration project and those participating in the mission. Xi Jinping pointed out in his congratulatory message that Chang'e-6 has returned samples from the far side of the moon for the first time in human history, which is another landmark achievement in building my country into a powerful country in space and science and technology. Over the past 20 years, all comrades involved in the development and construction of the lunar exploration project have carried forward the spirit of lunar exploration, bravely climbed to the peak of science and technology, made major achievements that have attracted worldwide attention, and embarked on a path of high-quality and high-efficiency lunar exploration. Next, let’s take a look at what challenges Chang’e-6 experienced during this lunar exploration trip.

On June 25, 2024, the Siziwang Banner Space Landing Site in Inner Mongolia welcomed a special "guest". After 53 days of space roaming, the Chang'e-6 returner landed successfully. Chang'e-6 brought a gift to the earth - a lunar sample from the far side of the moon. This is also the first time that humans have achieved sampling and return from the far side of the moon.

This morning, the Chang'e-6 returner has been airlifted to Beijing, and subsequent sample storage, analysis and research work will also begin. From its launch on May 3 to its return on June 25, the Chang'e-6 probe successfully completed its mission and once again left China's lunar exploration footprint on the moon. During these 53 days, behind the moon, which is invisible to the naked eye, Chang'e-6 experienced challenges again and again. Among these many challenges, the most intriguing is landing on the moon.

At about 6:00 on June 2, the Chang'e-6 probe is about to land on the back of the moon. The pre-selected landing area for this mission - the South Pole-Aitken Basin on the far side of the moon, has a drop of more than 10 kilometers. This is like landing a small truck into the mountains. It not only requires precise obstacle avoidance, but also advanced guidance. navigation and control systems to ensure safe landing.

At 6:09, the Chang'e-6 lander and ascender assembly began a powered descent, and then the main engine was turned on. During this period, the combination quickly adjusts its attitude and automatically detects obstacles, and selects a rough safe point based on the brightness of the moon. Chang'e-6 hovered at an altitude of 100 meters from the landing point. These three seconds of hovering were particularly critical for the landing of the moon.

Guan Yifeng of China Aerospace Science and Technology Corporation: images and recognizes obstacles when hovering, and then avoids them. It is equivalent to two parts. First, confirm with eyes, take a look at which place is relatively flat, remember that place, and then transfer it to the brain. Knowing it's flat, move over and drop down over the flat area.

The eye that experts refer to refers to a three-dimensional imaging sensor. Before landing on the moon, the three-dimensional imaging sensor uses laser three-dimensional scanning to take precise pictures to detect obstacles on the lunar surface, and finally selects a landing site to complete the landing.

In a test field at Tongji University, large and small wooden boards are used at different heights and angles to simulate the undulations of the ground seen from the air to verify the accuracy of laser imaging technology.

Dean of the School of Surveying, Mapping and Geographic Information of Tongji University Xie Huan : For landing obstacle avoidance, the main concern is whether the ground is flat, and pits and stones exceeding 20 cm must be avoided, so we simulated it in the field Different scenes, large and small pits and rocks of different sizes were created to try to recreate the scenes on the lunar surface that might threaten a safe landing.

However, no matter how high the accuracy of static experiments on the ground is, it cannot cope with the shaking of the detector during actual operation. It's like taking a picture on a bumpy car with poor imaging results. The scientific research team's response was in one word: fast.

The sensor can conduct precise detection of a certain range of terrain on the moon within 0.25 seconds. Moreover, in just 3 seconds of hovering, the autonomous obstacle avoidance system has to complete all measurement and calculation work, and it only has three opportunities to make a judgment.

Chang’e-6’s autonomous obstacle avoidance ability helped it stay away from dangerous areas and successfully landed on the back of the moon. The successful landing is only the critical first step in completing this lunar surface work mission. The next step is to conduct a sampling mission, which is an even more difficult challenge. Limited by the length of relay communication on the far side of the moon, Chang'e-6 adopted fast intelligent sampling technology to shorten the effective working time of lunar surface sampling to less than 20 hours. It used two methods: drill drilling sampling and robotic arm surface sampling. Collect lunar samples separately.

China Aerospace Science and Technology Group Shi Wei: After the moon falls, the camera must first image the entire sampling area. The roughness of the sampling area, whether there are rocks or not, is to avoid risky areas, so we must first truly restore the environment of the entire lunar surface in the infield.

In what is known as the "pre-training ground" of Chang'e-6, based on the images of the landing area shot and returned by Chang'e-6, in the ground laboratory of the Fifth Academy of China Aerospace Science and Technology Corporation, scientific researchers quickly restored the surroundings of the landing site. of landforms. After landing on the moon, Chang'e-6 does not start sampling directly, but first conducts experimental verification here and uploads the operating instructions to the moon before starting actual sampling.

The drilling process lasted about 3 hours and obtained lunar samples at different depths on the far side of the moon. In addition to drilling sampling, lunar samples were also collected through robotic arm surface scooping to achieve automatic sampling at multiple points. To this end, researchers have designed more than ten surface sampling collection points. Compared with Chang'e-5, Chang'e-6 has made great improvements in intelligence and autonomy.

China Aerospace Science and Technology Corporation Ma Ru Qi : only needs to send one command, and it will connect the entire task, such as touching the moon, sampling, and then setting out. The whole process only needs one command to connect it all. Everything is executed as soon as you get up, which improves efficiency.

What the astronauts did not expect was that after the surface sampling was completed, the word "中" appeared on the lunar surface.

China Aerospace Science and Technology Group Jia Xiaoyu: The initial selection of sampling points for was only based on the graphics seen on the surface. We will dynamically adjust the position of the sampling points based on the extracted samples. The slanted pen of "中" and "中" This is actually how the head of the character is created. Originally, we might have shoveled a few more shovels in addition to the word "中", but in the end we found that after the last stroke of the word "中" was formed, the sample container was almost full. Various accidents contributed to the creation of the word "中", which may have destined China to leave its mark on the moon.

The mark of China left on the back of the moon may be just a beautiful coincidence, but this mark not only records the working trajectory of the Chang'e-6 probe, but also witnesses the Chinese people's firm determination and unremitting efforts in lunar exploration. After the sampling work was completed, the five-star red flag carried by the Chang'e-6 lander was successfully unfurled on the far side of the moon.

Throughout the world’s space history, before Chang’e-6, all human lunar samples were located on the front side of the moon. Therefore, scientists all over the world are paying attention to the lunar back sample brought back for the first time by Chang'e-6.

Chang'e-6 carries four international payloads, respectively from ESA, France, Italy and Pakistan. Among them, the laser angle reflector used for ranging and positioning developed by the Italian National Institute of Nuclear Physics is a kind of laser angle reflector that can carry out Instruments for distance measurement and positioning with millimeter-level accuracy. In the laboratory, one of the researchers' main tasks is to simulate the space environment through a vacuum chamber and continuously test the accuracy of the laser corner reflector. The person in charge said that China’s open cooperation in the field of space exploration is impressive.

At the Institute of Geology and Geophysics, Chinese Academy of Sciences, the laboratory is already ready, waiting for the return of Chang'e-6. In 2021, through the study of Chang'e-5 lunar samples, this scientific research team revealed that there was still magma activity on the moon 2 billion years ago, refreshing humankind's understanding of lunar magma activity and evolution history.Scientists hope that the study of Chang'e-6 samples will lead to more new discoveries.

Li Xianhua, academician of the Chinese Academy of Sciences and researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences: The South Pole-Aitken Basin is the oldest impact crater on the moon and the largest impact crater, even the largest impact crater in the entire inner solar system. This time The impact had profound implications for the later evolutionary history of the Moon. We naturally ask when did it hit? This time we go to this place to take samples, and it is very likely that we will collect some records related to this impact, and we can determine its age. Second, the front and back of the moon are different. Why are they different? Samples are needed for analysis.

The first step after the scientific research team obtains the lunar soil is sample preparation. The selection work must be carried out under a microscope. Any extra shaking of the hands will prevent the particles from being effectively selected, making subsequent research impossible.

Experts said that the precious lunar samples collected by Chang'e-6 will provide humans with more valuable data and information about the moon, and are expected to deepen human research on the formation and evolution history of the moon.

Wu Fuyuan, academician of the Chinese Academy of Sciences and researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences: Before, we thought that the moon died 3 billion years ago. As a result, samples from Chang'e 5 found that there was still magma activity 2 billion years ago. Whether there will be more in the future, we are not sure now that it will definitely not exist, so human beings’ understanding of the moon is very limited. The Chang'e Project has been going on for 20 years, and only a few samples have been returned after so many years. We must turn our aerospace advantages into scientific advantages and concentrate our efforts on scientific output and breakthroughs.

From the launch on May 3, traveling 380,000 kilometers to the moon, to the accurate implementation of near-lunar braking; from the successful landing on the far side of the moon, intelligent sampling of the lunar surface, to the ascent from the lunar surface, in-orbit rendezvous and docking, and sample transfer, As of today, it has returned home to Earth and successfully completed its mission. Chang'e-6's lunar exploration journey lasted 53 days, and every step involved the efforts of countless scientific researchers. After the recovered Chang'e-6 returner completes necessary ground processing, it will be airlifted to Beijing to open the cabin and remove the sample container and cargo. The National Space Administration will choose an opportunity to hold a handover ceremony to formally hand over lunar samples to the ground application system, and will subsequently carry out work related to sample storage, analysis and research. We look forward to the good news from scientists, and believe that the work of Chang'e-6 will help us unlock more mysteries about the moon and the solar system.

Li Xianhua, academician of the Chinese Academy of Sciences and researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences: The South Pole-Aitken Basin is the oldest impact crater on the moon and the largest impact crater, even the largest impact crater in the entire inner solar system. This time The impact had profound implications for the later evolutionary history of the Moon. We naturally ask when did it hit? This time we go to this place to take samples, and it is very likely that we will collect some records related to this impact, and we can determine its age. Second, the front and back of the moon are different. Why are they different? Samples are needed for analysis.

The first step after the scientific research team obtains the lunar soil is sample preparation. The selection work must be carried out under a microscope. Any extra shaking of the hands will prevent the particles from being effectively selected, making subsequent research impossible.

Experts said that the precious lunar samples collected by Chang'e-6 will provide humans with more valuable data and information about the moon, and are expected to deepen human research on the formation and evolution history of the moon.

Wu Fuyuan, academician of the Chinese Academy of Sciences and researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences: Before, we thought that the moon died 3 billion years ago. As a result, samples from Chang'e 5 found that there was still magma activity 2 billion years ago. Whether there will be more in the future, we are not sure now that it will definitely not exist, so human beings’ understanding of the moon is very limited. The Chang'e Project has been going on for 20 years, and only a few samples have been returned after so many years. We must turn our aerospace advantages into scientific advantages and concentrate our efforts on scientific output and breakthroughs.

From the launch on May 3, traveling 380,000 kilometers to the moon, to the accurate implementation of near-lunar braking; from the successful landing on the far side of the moon, intelligent sampling of the lunar surface, to the ascent from the lunar surface, in-orbit rendezvous and docking, and sample transfer, As of today, it has returned home to Earth and successfully completed its mission. Chang'e-6's lunar exploration journey lasted 53 days, and every step involved the efforts of countless scientific researchers. After the recovered Chang'e-6 returner completes necessary ground processing, it will be airlifted to Beijing to open the cabin and remove the sample container and cargo. The National Space Administration will choose an opportunity to hold a handover ceremony to formally hand over lunar samples to the ground application system, and will subsequently carry out work related to sample storage, analysis and research. We look forward to the good news from scientists, and believe that the work of Chang'e-6 will help us unlock more mysteries about the moon and the solar system.