At 23:11 on December 1, the Chang'e-5 probe successfully landed on the pre-selected landing area near the front of the moon at 51.8 degrees west longitude and 43.1 degrees north latitude, and returned the landing image.
At 22:57 on December 1, the Chang'e-5 lander and ascender combination began to perform a power reduction from a distance of about 15 kilometers from the lunar surface. The 7,500 N variable thrust engine was turned on, and the probe's relative lunar speed was gradually increased from about 1.7 kilometers. /Sec drops to zero.
During this period, the probe made rapid attitude adjustments and gradually approached the moon surface.
After that, automatic obstacle detection was carried out. After the landing site was selected, the obstacle avoidance and slow vertical descent began, and the land steadily landed in the area north of the Rumk Mountains in the storm ocean on the front of the moon.
The reason why "Chang'e 5" chose to land near the Rumke Mountains in the northern part of the Storm Ocean, which is the largest moon sea on the moon, and conduct sampling is because scientists believe that this area is compared with the previous United States and the former Soviet Union. Geologically speaking, there may be relatively young basalt in this area. If new samples can be obtained here, it will help advance the understanding of the lunar volcanic activity and evolution history.
According to the mission plan, "Chang'e-5" plans to obtain a sample of about 2 kilograms from the moon and bring it back to Earth.
So how is the weight of 2 kg determined?
Chang'e 5's first lunar sampling plans to obtain 2 kg samples >>
Through the accumulation of technology from Chang'e-1 to Chang'e-4 missions, China hopes to reach the kilogram-level goal in the Chang'e-5 lunar sampling mission.
In order to ensure the success of the mission, combined with the rocket carrying capacity, sampling 2 kg is a reasonable result.
Pei Zhaoyu, deputy chief designer of the third phase of the lunar exploration project of the National Space Administration's Lunar Exploration and Space Engineering Center: We used two kilograms as input to design the detector, and the detector reached 8.2 tons.
If we want to increase the amount of samples, many indicators of the entire detector will increase, which will exceed the carrying capacity of the rocket.
In order to improve the reliability of sampling and increase the diversity of samples, the Chang'e-5 mission will collect samples in two ways: drilling and table picking.
Pei Zhaoyu, deputy chief designer of the third phase of the lunar exploration project, deputy director of the National Space Administration's Lunar Exploration and Space Engineering Center: For example, the initial consideration is 0.5 kg for drilling, and 1.5 kg for the table. This is our design arrangement.
Pei Zhaoyu said that the main goal of the Chang'e-5 mission is to complete the moon sampling and return.
After the lander has successfully landed on the surface of the moon, it must complete a number of tasks such as terrain survey, drilling and surface extraction within a limited time.
Although a sampling volume of 2 kg is set, this cannot be used as a final measure of the success or failure of the task.
Pei Zhaoyu, deputy chief designer of the third phase of the lunar exploration project of the National Space Administration's Lunar Exploration and Space Engineering Center: Our goal is to sample and return, and to collect samples to return to the earth. This is our assessment indicator.
These two kilograms are a design value, and we cannot take these two kilograms more or less as a hard indicator for judging the success of the task.
Two ways to complete the sampling task together >>
How should the 2 kg sample be collected after landing?
Pei Zhaoyu, deputy chief designer of the third phase of the lunar exploration project, mentioned two collection terms when introducing the data they designed and arranged. He said: "Drilling" initially considers 0.5 kg and "showing" 1.5 kg. These two methods are common. To complete the sampling task.
And this design is designed by the development team to improve the reliability of this sampling and the richness of the samples.
So what is drill and table fetch?
·Table take: unmanned self-collecting samples on the surface of the moon
First, let's introduce the table take, as the name suggests, is to collect samples on the surface of the moon.
However, unlike the lunar sample collection methods of other countries, my country's Chang'e-5 mission will collect samples in an unmanned manner.
Jiang Shuiqing, the chief designer of the Chang'e-5 probe of the Fifth Academy of Aerospace Science and Technology Group: Globally, it is also the world's first unmanned autonomous sampling task on the lunar surface.
In order to achieve this task, we actually designed three products, a four-degree-of-freedom sampling robotic arm, and two samplers at the end, one for shoveling and the other for shallow drilling. To achieve a collection of different types of lunar soil.
According to the plan, the sampling robotic arm will conduct multiple sampling tasks in the area surrounding the landing site.
Jiang Shuiqing, chief designer of the Chang'e-5 probe of the Fifth Academy of Aerospace Science and Technology Group: It can sample within the reach of the entire lander.
Assuming that our landing site is not so ideal, if there is a big rock, I can't pick it, I can change it a little bit, a little softer, I can be sure that I can pick a certain sample.
·Drilling to obtain samples and tables below the surface of the moon as backups for each other
It is understood that before taking the table, a drill will be performed to obtain samples below the lunar surface.
The two methods are mutually backup, not only can improve the success rate and reliability of sampling, but also can obtain more abundant sample types, and provide more reliable original data for subsequent scientist research.
Wang Guoxin, chief designer of the Chang'e-5 probe of the Fifth Academy of the Aerospace Science and Technology Group: I have drills and tables, and I can get them back. Then we can complement each other. The ability we currently have is to work below the surface of the moon. Two meters, and then get a sample of this lunar soil. Its characteristic is that it can be drilled in. Then the lunar soil has a layered distribution inside, which does not damage its layered distribution.
The Chang'e-5 probe has successfully landed in the pre-selected landing zone on the front of the moon.
Look back at the wonderful moments of the "Five" moon.
Luan Enjie: After the lunar surface samples are collected, we still have to "install sausages" >>
Two sampling methods are used to back up each other to ensure that Chang'e-5 can collect the lunar surface samples that scientists need.
But just collecting it is not enough. Just like our long-distance express items, you need to wrap the items before sending them to the courier to avoid damage or omissions on the way.
And "Chang'e 5" also has a similar process, and it is completely completed by it independently, the difficulty can be imagined.
Luen Enjie, the first commander-in-chief of the lunar exploration project, said in an interview with reporters that after the Chang'e-5 lander landed safely and began sample collection, there was another brand new attempt for China's aerospace. His metaphor was "installing sausages." .
Luan Enjie, academician of the Chinese Academy of Engineering, the former director of the National Space Administration, the first commander-in-chief of the lunar exploration project: After landing, I started sampling. Organization, this is the first design in our country, I describe it as Harbin sausage.
When drilling, it needs to pack the drilled core and the core part into a package. This package is a long one, so like a sausage, it should be tightly wrapped and sealed.
These soils cannot be contaminated by the earth when they are transferred to the earth, because the earth environment and the lunar environment are not the same. Some substances must be kept in a very clean environment to keep us from obtaining such things.