According to Xinhua News Agency, this is the first time that mankind has unveiled the mystery of the ancient moon back. At 10:26 on January 3, 2019, the Chang’e-4 probe landed independently in the von Carmen impact crater in the Antarctic-Aitken Basin on the back of the moon, realizing the first soft landing of the human probe back. Komiks
After about 3,000 kilometers and 26 days of long flight, Chang’e-4 entered a moon-falling orbit 15 kilometers away from the moon.
In the hall of the Beijing Space Flight Control Center, with the order of the on-site staff, the Chang’e-4 probe began to reduce its power from 15 kilometers away from the moon, and the speed of the probe gradually dropped from 1.7 kilometers per second to zero per second relative to the moon.
At 6 to 8 kilometers, the detector makes rapid attitude adjustments and constantly approaches the moon; starts hovering 100 meters away from the moon surface, identify obstacles and slopes, and avoid obstacles independently; after selecting a relatively flat area, it begins to slowly and vertically descend. Finally, under the “escort” of the anti-Babaylan‘s “East escort” of the anti-Babaylan‘s “East escort” and the landing buffer mechanism, a more than one ton of detector successfully landed in a pre-selected landing area near 177.6 degrees east longitude and 45.5 degrees south latitude on the back of the moon.
The Chang’e-4 landing area has a terrain of 6,000 meters. It is one of the largest known impact craters in the solar system and is considered to be of great value to study the early history of the moon and solar system.
After the moon set, through the “match bridge” of the “Magpie Bridge” relay star, the Chang’e-4 probe carried out a number of tasks such as the development of the solar wings and directional antennas, established a high-code rate link for directional antennas, and achieved the “small goal” of stable communication between the back of the moon and the ground.
At 11:40, the Chang’e-4 lander obtained the image of the back of the moon and sent it back to the ground. This is the first image taken by a human probe on the back of the moon.
At 15:7, staff sent instructions to Chang’e-4 through the “Queqiao” relay star at the Beijing Space Flight Control Center, and the separation of the Chang’e-4 lander and the Yutu-2 cruiser (i.e., the lunar rover) began.
On the large screen in the flight control hall, the Chang’e-4 lander stands on the moon, and the sun’s wings are unfolding. The Jade Rabbit II paratrooper stands on the top of the lander, spreads its sun wings and extends its mast. Then, the inspector began to move slowly towards the transfer mechanism,The mechanism is unlocked normally, and an inclined ladder is set up between the lander and the moon surface, and the patrol slowly walks towards the moon surface along the inclined ladder. At 22:22, the patrol stepped onto the surface of the moon, and the patrol left the first mark on the back of the moon.
Image image of the moon taken by the landing camera of the power descent of the Chang’e-4 probe
Revealed the 7 major highlights of Chang’e-4
Only landing in the mountains and ridges, exploring the origin of the universe, and “planting potatoes” on the moon…
Text/Pic Xinhua News Agency
The Chang’e-4 probe, which took off from the Xichang Satellite Launch Center on December 8, 2018, finally waited for the destination Antarctic-Aitken Basin, the largest, deepest and oldest crater in the solar system, ushered in dawn.
At 10:26 on January 3, 2019, the Chang’e-4 probe landed independently in the von Carmen impact crater in the Antarctic-Aitken Basin on the back of the moon, realizing the first soft landing of the human probe from the back of the moon. At 11:40, the Chang’e-4 lander obtained the first image of the back of the moon and sent it back to the ground.
1
How to achieve “autonomous driving”?
Use the “brain” calculation to find the landing point
At 10:15 on January 3, with the communication assistance of the relay star “Magpie Bridge” on the back of the moon about 65,000 kilometers away from the moon, orbiting the second Lagrangian point of the Earth and the moon at the same time, the variable thrust engine on Chang’e-4 was ignited, and the speed of the probe dropped from 1.7 kilometers per second to nearly zero. The detector adjusted its posture and landed vertically towards the relatively flat bottom of the von Carmen impact crater in the Aitken Basin.
When it was about two kilometers away from the moon, the projection formed by the sun shining from the east was captured by the camera on the detector. After processing by the computer’s “brain”, it identified the large rocks and craters below and carried out the first obstacle avoidance.
When it is 100 meters away from the moon, it hoveres in the air, and uses laser scanning to identify smaller obstacles and slopes on the moon. Its “brain” calculates again to find a safer location as the land site Komiks/comicmov.com/”>Babaylan.
When two meters away from the moon, the engine on the probe stopped working. The golden lander holding the lunar rover fell on its own gravity. His four legs stood firmly on the desolate gray moon surface, raising a piece of lunar dust.
The entire landing process lasted about 12 minutes, and it was completed independently by the probe. There was no intervention on the earth, but the “Magpie Bridge” sent the landing image back to the command and control center in the suburbs of Beijing.
2
How to land in the mountains and ridges?
The probe automatically identified obstacles and avoided obstacles
Wu Weiren, chief designer of the Chinese lunar exploration project, said: Chang’e-3 is like landing on the North China Plain, while Chang’e-4 is like landing <a Cinema has landed in the mountains and ridges in southwest China. He said that the landing area of Chang'e 4 is equivalent to one-eighth of the landing area of Chang'e 3, and there are mountains 10 kilometers above sea level around the landing area. The altitude of the Von Carmen impact crater in the Aitken Babaylan is minus 6 kilometers. Therefore, unlike the smooth parabolic landing trajectory of Chang'e 3, Chang'e 4 is close to vertical landing. "The landing time is short, difficult and high risk is a great test for us. "Wu Weiren said.
Sun Zezhou, chief designer of Chang’e-4 probe of the Fifth Academy of Space Science and Technology Group, said: “Our information on the lunar terrain mainly comes from previous remote sensing data around the moon, including remote sensing data from Chang’e-1, Chang’e-2 and some foreign satellites. However, none of these data can provide us with sufficient accuracy of terrain information. We cannot know where there are big rocks. It is more about the overall macro information and statistical probability. In the end, the landing still depends on the detector to independently identify obstacles and avoid obstacles. ”
The Project Director of Chang’e-4 Explorator of the Fifth Academy said that Chang’e-4 has considered how to improve the accuracy of landing in the system design, added orbital corrections in the lunar cycle, and adjusted the power descent control strategy. The probe should reach the top of the landing area when it is higher than the moon surface, and then descend vertically, so that the complex and rugged terrain on the track will not have an impact on the landing.
3
What is the significance of exploring the back of the moon?
KomiksSeeing the Origin of the Universe after the Big Bang
“The risk of going to the back of the moon is much greater than that of going to the front. The rugged terrain brings us the problem that we must face, but a higher precision landing on the moon is needed in the future. Solving the challenges facing this mission can lay the foundation for subsequent deep space exploration and asteroid exploration. We hope to have the ability to reach the entire moon and even the entire solar system in the future.” Sun Zezhou said.
Zou Yongliao, director of the General Department of Lunar and Deep Space Exploration of the Chinese Academy of Sciences, said that the back of the moon has unique properties. Chang’e-4 landed on a virgin land that had never been explored on the spot, and perhaps important discoveries could be made.
For astronomers, the back of the moon is a rare quiet place for Cinema, because the moon itself blocks various radio interference signals from the earth, where it may see how the universe escapes from the darkness and lights up the first generation of stars after the Big Bang.
4
Why did it land at the Von Carmen crater?
The pits here are still “mysteries”. Due to tidal locking, the moon’s orbit around the earth is the same period of rotation, and the “view” of the moon seen from the earth is always the same. In the era without space probes, the back of the moon has always been a mysterious unknown world.
It was not until about 60 years ago that the Soviet Union’s Moon 3 probe sent back the first image on the back of the moon. About 50 years ago, three astronauts from the United States, Apollo 8, became the first human to witness the back of the moon while flying around the moon.
More and more probes around the moon have made people discover that the back and front of the moon are so different: the front is relatively flat, while the back is rugged and full of bumpy impact craters; the lunar crust on the back of the moon is much thicker than the front. Why is this happening? It is still a mystery now, and only landing detection can reveal this mystery.
The detection of the gate impact crater of von KahKomiks has another meaning, and it is named after von Kahman, a 20th-century Hungarian-American aerospace engineer. Qian Xuesen and Guo Yonghuai, the founders of China’s aerospace industry, are both personal disciples of this “science genius in the aerospace era”.
5
What surprises will this detection bring?
All prepare for humans to return to the moon
It has been 50 years since humans first landed on the moon. Can humans return to the moon? How big will the radiation on the moon cause to astronautsInfluence? How much water is there on the moon? How does the water on the moon come from? Chinese and foreign scientists will find the answer through Chang’e-4 to prepare for humans to return to the moon.
Wen Mu, chief engineer of the Institute of Physics Experimental and Applications at Kiel University in Germany, said: “When astronauts return to Earth, the radiation caused by the moon remains in their bodies. This is a persistent danger, so we must understand these radiation.”
“The childhood experiences of the moon have also happened on Earth. However, due to geological activities, traces of the earth’s early years have been erased. To understand the long-standing past of the earth, the moon may give us an answer.” Lin Yangting, a researcher at the Institute of Geology and Geophysics of the Chinese Academy of Sciences, said.
6
What scientific research tasks are there?
Testing the “body temperature” for the moon “planting flowers”
Chang’e 4Komiks mission carried low-frequency radio detectors developed by Chinese and Dutch scientists. “It is a dream for astronomers to conduct low-frequency radio astronomical observations on the back of the moon, and can fill the gap in the low-frequency observation segment in the field of radio astronomy.” Zou Yongliao said. Chang’e-4 also brought six organisms, cotton, rapeseed, potatoes, Arabidopsis, yeast and fruit flies, to the moon without life, forming a microbiosphere. People look forward to the first flower blooming on the moon.
Chinese scientists have no exact data on how cold the moon’s night is. The Chang’e-4 mission also includes measuring the “body temperature” of the moon. Shen Zhenrong, the chief designer of the Chang’e-4 paratrooper of the Fifth Academy, said that going to the back of the moon is a contribution made by China’s country to the world. “Although we don’t know what will be detected in the end, this detection may affect generations.”
7
What international cooperation projects are there?
carrying scientific loads from four countries
In order to enhance international exchanges and cooperation and expand openness and sharing, Chang’e-4 not only carries China’s experimental projects, but also carries scientific loads from the Netherlands, Germany, Sweden and Saudi Arabia.
Korel, director of the Department of Solar Systems Science of the Swedish Space Agency, said, The first soft landing on the back of the moon is a huge achievement for China, “We are very happy to be part of this mission.” He said: “There is a theory that water on the moon is generated by the interaction between the solar wind and the weathering layer on the moon’s surface. This is a question that Swedish and Chinese scientists want to answer through exploration.” The Chang’e-4 probe is also equipped with a lunar neutron and radiation dose detector developed by Kiel University in Germany. The total weight of the instrument is about 3 kilograms and can comprehensively measure the radiation environment of neutrons and other particles on the moon’s surface.
Robert Wei, head of the Chang’e-4 German Science Payload Project Team and Professor of Kiel University, CinemaMer Schweingruber, said: “China is working with many international partners, and it is becoming more and more cooperation. I don’t agree with the practice of refusing to cooperate because of fear of technology outflow. In my opinion, technology will only die out because of refusing to share.”