Original title: The rabbit who learned to detour the first time to patrol the back of the moon
On January 10, after nearly a week of "noon break", the patrol jade rabbit waking up on the 2nd, and on January 11th and the lander 嫦娥 4th "confirmed the eyes", then the two shots left each other to leave "beauty" . Since then, Yutu No. 2 "Farewell" on the 4th, to open a real month back tour.
The No. 4 Lander Terrain Camera imaged the Yutu No. 2 Patrol. Photo courtesy of the National Space Administration
Author | Qiu Chenhui
The famous science fiction writer Isaac Asimov predicted 35 years ago: by 2019, we will re-enter the moon. At that time, it was not a “single fight” of a certain country, but a large-scale international force; instead of collecting only the moon rock, it built a mining station.
Asimov only said half right.
At this moment, in the von Carmen crater of the Antarctic-Aitken Basin on the back of the Moon, the No. 4 and Yutu No. 2 from China are representing the entire human race for the first time on the back of the moon.
However, this trip to the moon is not all of China’s “single fight”, nor is it a large-scale international force. The No. 4 and Yutu No. 2 are covered with eighteen "weapons". Among them, there are three scientific loads. It is China's cooperation with the Netherlands, Germany and Sweden to jointly explore this virgin land on the back of the moon.
The sci-fi writers are not accurate enough, and some inconspicuous conjectures in the online world seem even more absurd: car people, alien bases… But what disappoints the "guessler" is that China’s fourth moon trip so far These phenomena have not been discovered.
On January 10, after nearly a week of "noon break", the patrol jade rabbit waking up on the 2nd, and on January 11th and the lander 嫦娥 4th "confirmed the eyes", then the two shots left each other to leave "beauty" . Since then, Yutu No. 2 "Farewell" on the 4th, to open a real journey of the moon back – scientific exploration.
"Flag of the Flag" on the back of the month
Many people still remember that on December 15, 2013, the Luzhou No. 3 and the Yutu Lunar Rover stared at each other and completed the mutual shooting. At that moment, the five-star red flag pattern on their chest attracted the attention of the whole world.
Today, on the 4th, the flag is again marked with the Chinese flag in space. On January 11, 2019, the relay star "Yuqiao" was first transmitted back to the 4th with a clear panoramic photo of the five-star red flag.
The National Space Administration released photos and the five-star red flag was clearly visible. A question comes along: Is the color of the national flag on the moon the same as on the ground?
"If we can reach the moon, we will see the same bright five-star red flag on the ground." The experts of the No. 4 lunar detector of the 510 Institute of Aerospace Science and Technology Group told reporters that when the sun reaches the ground through the atmosphere, people The portion of the visible light that the eye can recognize changes little, and it can be considered that the visible light is the same as the ground outside the atmosphere including the moon.
The only difference is that the visible light intensity of the moon is slightly larger than the ground. According to experts, the reflection of the detector flag on the moon's surface is the same as that on the ground. Correspondingly, the color of the flag seen on the moon is the same as on the ground.
However, the flag material on the No. 4 and Yutu No. 2 has a "natural difference" from the common flag on the ground.
The common national flag is generally made of textile fabrics, silk, cotton and other textiles. Of course, there are also national flags made of paper, plastic and other materials. The national flag of the lunar probe is made of an organic polymer called polyimide. Made of thin film materials. Experts from 510 hospitals said that this material can be used in temperatures ranging from -200 ° C to 200 ° C.
On the earth, clothing can not be exposed to the sun for a long time, otherwise it will fade; clothing can not be washed with hot water, otherwise it will be deformed; color billboards placed outdoors will fade after a period of wind and sun… The reason is that the environmental factors such as ultraviolet rays and temperature affect and destroy the materials. The national flag made of textiles, etc., is no exception.
Will it be the same on the moon? The answer given by the experts of the 510 hospitals is that the common flag materials on the ground cannot withstand the test of the lunar surface environment, and will soon fade, deform and even decompose.
First, the temperature difference of the lunar surface reaches 300 ° C or higher, the temperature is below -180 ° C, and the highest is above 130 ° C. Second, there is no atmosphere on the surface of the moon, and the space environment is the same as the space of the universe; On the moon, the ultraviolet rays generated by the sun are very strong; finally, the surface of the moon also has the effect of cosmic rays and high-energy particles.
In contrast, the temperature difference on the ground is also tens of degrees Celsius, while the atmosphere is protected. After the space particles and most of the ultraviolet rays are isolated, the damage has been "gentle". The harsher and harsher environment on the moon is also a natural challenge for the lunar flag created by researchers.
"Photographer" on the back of the month
Speaking of the national flag on the back of the moon, it is natural to mention the "photographer" of this photo – Yutu No. 2. More precisely, it is the panoramic camera carried on the Yutu No.2.
The Yutu No. 2 patrol camera was used to image the No. 4 lander. Photo courtesy of the National Space Administration
This camera, and the panoramic camera mounted on the No. 3, is a "twin" developed by the Xi'an Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences. It is placed on the mast of Yutu No. 2, 1.5 meters away from the lunar surface, and looks like the "eyes" of Yutu No.2.
According to Yang Jianfeng, director of the panoramic camera load, the panoramic camera can be rotated around the mast to capture the surrounding landscape. The camera is divided into black and white and color modes, and the resolution is comparable to that of the human eye.
As for the photo of the Yutu No. 2, it is the topographical camera of the No. 4 body. The load was developed by the Institute of Optoelectronic Technology of the Chinese Academy of Sciences.
The director of the load, Zhong Jie, told the reporter that the terrain and terrain camera was installed on the PTZ head of the No. 4, controlled by the gimbal. It can image the surroundings 360° and obtain the optical image around the lander for the science of the lunar landform. Inspection.
Of course, the photographers on the back of the moon are far more than these two. In fact, before the 4th arrived at the back of the moon, there were 4 mysterious small cameras that started to work, including 3 surveillance cameras and 1 landing camera, all from the 508 Institute of Aerospace Science Group.
These four small cameras are like a media group. Before they reached the moon on the 4th, they made a division of labor and preparations. They took pictures, took photos, recorded them, and passed them on, waiting to be opened globally. A visual feast for the exploration of the Moon.
Take the landing camera as an example. It is responsible for the "live" landing. The No. 4 lander will land on the Aitken Basin on the back of the moon – the largest and oldest impact basin on the moon, and its research may reveal the material conditions of the next month's shell or even the last month.
The landing camera is placed in the bottom compartment of the No. 4 lander. During the landing of the lander, the camera is photographed at a higher frame rate and a large amount of real lunar surface information is obtained. These can visually reflect the surface features of the moon. And regional geological conditions to enhance human understanding of the moon.
What is most interesting to the general public is the kind of immersive visual impact. The landing camera can obtain a lunar landscape similar to human visual habits, and the transmitted optical image can vividly describe the whole process of lander landing.
As for surveillance cameras, the reputation is even greater. On January 3, the No. 4 came back to the world's first close-up image of the back of the moon, and then blasted the network – that picture is taken by the surveillance camera C.
There are a total of three surveillance cameras, called surveillance camera A, surveillance camera B, and surveillance camera C. Experts from 508 hospitals told reporters that the main task of surveillance cameras is to monitor the release and separation process of the patrol and lander, to unlock the two devices, to drive the patrol off the connection bracket, to detach the umbilical cable, to drive to the transfer mechanism, and to release The monitoring of key processes such as separation improves the visibility of the moon system activity of the detector system.
These cameras, which are only slap-sized, look like the usual digital cameras, light three or four hundred grams, and weighs 700 grams.
However, according to the experts of the 508 Institute of the Five Institutes, these little guys have integrated advanced technologies such as light, machine, electricity and heat, and intelligent functions such as automatic exposure and real-time image compression. Under the harsh radiation and temperature environment in space, It can withstand the strong impact and vibration during launch, and has a long life and high reliability. It is a truly lightweight and portable “Aerospace Intelligence”.
"Scientist" on the back of the month
After the news of the landing on the back of the moon on the 4th, people kept asking: Why do you want to go to the back of the moon and find out what can be found on the back of the moon? These questions are expected to be answered by the scientific load on the "scientists" on the back of the moon – the No. 4 and Yutu No. 2.
嫦娥4 Lander Landform Landscape Camera Ring Panorama (Cylinder Projection) Photo courtesy National Space Agency
Taking the load of three international cooperation as an example, Zou Yongliao, deputy director of the National Space Science Center of the Chinese Academy of Sciences and director of the Moon and Deep Space Exploration Department of the Chinese Academy of Sciences, said that China’s moon-based low-frequency radio astronomical observation research and lunar neutron radiation dose, The scientific goal of lunar environment detection research, such as the atomic atom, is equipped with three loads such as a low-frequency radio detector, a neutral particle radiation dose detector, and a neutral atom detector.
Among them, the neutral atomic detector is mounted on the Yutu No. 2, mainly measuring the neutral atom of the moon, which is the payload of cooperation between China and Sweden.
Zhang Aibing, the chief expert of the Chinese side, said that the main goal of measuring the neutral atom of the lunar surface is to measure the neutral atom generated by the interaction between the solar wind and the lunar surface on the lunar surface, including the neutral atom produced by the ions of the solar wind itself. , and the neutral atom sputtered from the surface of the moon. The instrument allows scientists to further study the interaction between the solar wind and the moon. Some scientists believe that solar wind hydrogen ions may combine with oxygen in the moon to form water, which is also one of the research contents.
Of course, as a backup of the No. 3, many of the loads on the No. 4 are directly inherited from the “Three Sisters”, such as the moon-measuring radar and infrared imaging spectrometer.
The infrared imaging spectrometer is the only device on the mission that can perform chemical composition analysis. It is developed and produced by the Shanghai Institute of Technology, Chinese Academy of Sciences.
Unlike a camera, the spectrometer images each "narrow" bandwidth color, making the scale of the observations more microscopic. How "narrow" is this "very narrow"? Xu Rui, the deputy director of the load, said that the instrument can see the mineral characteristics of the moon surface with a resolution of 0.1 m on the moon surface, and at the same time, it can effectively detect the spectral components of the target in the infrared band.
Today, with the wake of the Yutu No. 2, these scientific payloads have been turned on. Looking at the back of the moon, there is still no smoke. People can see through the relay star "Bengqiao", there are still only the No. 4, Yutu No. 2, and the five-star red flag shining on their chest.
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