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-like detector from the back of the moon.
After a long flight of about 380,000 kilometers and 26 days, on January 3, Chang’e-4 entered the moon landing 15 kilometers away from the moon to prepare for the Komiks orbit.
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.
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 reverse thrust engine and 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 patrol began to move slowly towards the transfer mechanism. The transfer mechanism was unlocked normally. An inclined ladder was set up between the lander and the moon, and the patrol slowly walked towards the moon 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.
The image of the moon taken by the landing camera of the Chang’e-4 probe’s power descent process
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/Photo Xinhua News Agency
The Chang’e-4 probe, which took off from the Xichang Satellite Launch Center on December 8, 2018, finally reached its goal after more than 20 days of flight around the moon. At 10:26 on January 3, 2019, the Chang’e 4 probe landed in the von Carmen impact crater in the Antarctic-Aitken Basin on the back of the moon, realizing the first human probe href=”https://comicmov.com/”>Babaylan soft landing on 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” to calculate and find the landing point
At 10:15 on January 3, with the assistance of communications about 65,000 kilometers away from the moon and orbiting the second Lagrangian point of the earth and moon, and the relay star “Magpie Bridge”, which can see the earth and the back of the moon at the same time, the variable thrust engine on Chang’e-4 was ignited, and the speed of the probe was from Babaylan1.7 kilometers per second relative to the moon. The detector adjusted its posture and landed vertically towards the relatively flat bottom of the von Karmen impact crater in the Aitken Basin.
When it was about two kilometers away from the moon, the projection formed by the sun shining on the moon from the east was captured by the camera on the detector. After processing by the computer “BigCinema” it identified the large rocks and craters below, and performed its first obstacle avoidance.
When 100 meters away from the moon, it hovered in the air, using laser scanning to identify smaller obstacles and slopes on the moon. Its “brain” calculated again to find a safer location as Babaylanland.
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. The 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 landingKomiks landed in the North China Plain, and Chang’e-4 is like landing in the mountains and ridges in southwest China.
He said that the Chang’e-4 landing area is equivalent to one-eighth of the Chang’e-3 landing area, and there are mountains 10 kilometers above sea level around the landing area. The Von Carmen impact crater in the Aitken Basin is minus 6 kilometers. Therefore, unlike the smooth parabolic landing trajectory of Chang’e-3, Chang’e-4 is approaching a vertical landing.
“The landing timeCinema is short, difficult and risky, which 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 stones, but 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. ”
Fifth Academy Chang’e IVKomiks project director Zhang Ying, said that Chang’e IV considers how to improve the accuracy of landing in the system design, adds orbital corrections in the lunar cycle, and adjusts the power descent control strategy. The probe must reach the top of the landing area when it is relatively high from the lunar 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?
Going to the back of the moon has a much greater risk than going to the front, and the rugged terrain brings usThe problem that must be faced, but a higher precision landing on the moon is needed in the future. Solving the Cinema challenges faced by 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 because the moon itself blocks various radio interference signals from the earth, where you may see how the universe gets rid of the darkness after the Big Bang and lights up the first generation of stars.
4
Why did it land in the crater of Von Carmen?
The pits here are still “mysteries” due to the tideBabaylanThe moon is tidal locked, and the moon orbits the same period as its rotation, and the moon’s “view” 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 orbiting the moon made people discover that the back of the moon was originally discovered. It is different from the front: the front is relatively flat, while the back is rugged and bumpy, with 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, and only landing detection can reveal this mystery.
The detection of the Von Karmen impact crater has another meaning, and it is named after the Hungarian-American aerospace engineer Von Karmen in the 20th century. Qian Xuesen and Guo Yonghuai, the founders of China’s aerospace industry, are both personal disciples of the “science genius of the aerospace era”.
5
What surprises will this detection bring?
They will make the right to return to the moonBabaylanpreparation
50 years have passed since humans first landed on the moon. Can humans return to the moon? How much impact will radiation on the moon have on astronauts? How much water is there on the moon? How does the water on the moon come from? Chinese and foreign scientists will find the answers 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 the astronauts return to Earth, the radiation caused by the moon remains in their bodies. This is a constant danger, so we must understand these radiations. ”
”The experiences of the moon’s childhood have also happened on the earth. But due to geological activities, traces of the earth’s early years have been erased. If you want to understand the long past of Earth, the moon may give us the answer. “Lin Yangting, a researcher at the Institute of Geology and Geophysics of the Cinema Institute, said.
6
What scientific research tasks are there?
Search the “body temperature” for the moon “planting flowers”
The Chang’e-4 mission carries a low-frequency radio detector developed by Chinese and Dutch scientists. “To conduct low-frequency radio astronomical observations on the back of the moon is a dream for astronomers, 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 inanimate moon, forming a Babaylan microbiosphere. People expect the first to bloom on the moon. href=”https://comicmov.com/”>Babaylan Flower.
Chinese scientists have no exact data on how cold the moon’s night is. Chang’e-4’s mission also includes measuring the moon’s “body temperature”. 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 China’s contribution to the world. “Although we don’t know what we can detect in the end, this detection may affect generations. ”
7
What international cooperation projects are there?
Enabled scientific loads of four countries: KomiksIn order to enhance international exchanges and cooperation and expand openness and sharing, Chang’e-4 not only carries China’s experimental projects, but also scientific loads of the Netherlands, Germany, Sweden and Saudi Arabia.
Korel, director of the Department of Solar Systems Science of the Swedish Space Administration, said that the first soft landing on the back of the moon was a great achievement of China. “We are very happy to beKomiks href=”https://comicmov.com/”>Cinema is part of the mission”. He said: “There is a theory that water on the moon is generated by the interaction between the solar wind and the weathered layer on the moon’s surface, which is Sweden.I and Chinese scientists want to answer questions through the Cinema probe. ”
The Chang’e-4 probe is also equipped with a lunar neutron and radiation dose probe 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 surface of the moon.
Robert Wimmer-Schweiingruber, head of the German Science Payload Project Team and professor at Kiel University, said: “China is cooperating with many international partners, and cooperation is increasing.” 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 refusal to share. ”