(China Focus Face-to-face) How to use "Space Express" after returning from "Changwu"? How to "pick" the stars in the sky?
China News Agency, Beijing, December 17th, title: How to use "Space Express" after returning from "Five"?
How to "pick" the stars in the sky?
——Interview with Pei Zhaoyu, spokesperson for the Chang'e 5 mission
Author Guo Chaokai
On December 17, the Chang'e-5 probe returned to Earth after completing automatic lunar sampling and successfully landed at the Siziwang Banner Landing Field in Inner Mongolia.
The Chang'e-5 mission is a three-step final battle of the Chinese lunar exploration project, and it is also one of the most complex and difficult missions in China's aerospace industry so far.
Why does China go to the moon to "dig earth"?
How did the Chang'e-5 probe reenter and return to Earth?
How will the lunar samples brought back be used?
Which planets will China explore in the future?
Pei Zhaoyu, deputy director of the China National Space Administration's Lunar Exploration and Space Engineering Center, deputy chief designer of the third phase of the lunar exploration project, and spokesperson for the Chang'e 5 mission, accepted an exclusive interview with China News Agency "China Focus Face-to-face" for an authoritative interpretation.
Excerpts from the interview are as follows:
China News Agency reporter: On December 17, the Chang'e-5 probe "Walking Alone" completed its lunar mission and returned to Earth. It successfully landed at the Siziwang Banner Landing Field in Inner Mongolia. Can you take us briefly to review how the Chang'e 5 lunar exploration journey "passed through all the way"? What happened during the period?
Pei Zhaoyu:
Since the launch of Chang'e 5 on November 24, 2020, it has undergone earth-moon transfer, near-moon braking, and round-the-moon flight. The lander and ascender (combined body) landed on the lunar surface, carried out lunar surface sampling, The lunar surface rises, rendezvous and docking with the orbiter, and sample transfer. After that, the orbiter-back assembly will wait for flight around the moon, and then perform two more lunar-to-earth incidents, lunar-to-earth transfers, and high-speed reentry to the earth. It is about 11 (Flight) stage.
At 4:30 on November 24th, China successfully launched the lunar exploration project Chang'e 5 probe with the Long March 5 Yaowu carrier rocket at the Wenchang Space Launch Site. After the rocket flew for about 2,200 seconds, the probe was successfully sent into the intended orbit. , To start China's first return journey of sampling of extraterrestrial objects.
Photo by China News Agency reporter Luo Yunfei
Reporter from China News Service: You just mentioned the plan of Chang'e 5's re-entry and return. In order to make it go home smoothly, the scientific and technical personnel designed a unique method, commonly known as "floating in space". Can you explain to us what is "fighting" in space? What are the difficulties and key points in the implementation of "drifting"?
Pei Zhaoyu:
The reentry plan chosen by Chang'e-5 this time is called a semi-ballistic jump reentry to be precise.
There are two key points, one is semi-ballistic and the other is jumping.
Chang'e-5 reenters the earth at a speed of about 11 kilometers (per second), and it faces two main problems.
One (yes) a high speed will bring about the influence of force and heat. This speed is three points and several kilometers longer than the earth's orbital reentry speed (per second).
We use the jump style to re-enter the earth twice to increase the voyage and increase the re-entry time, which reduces the impact of force and the effect of heat.
The semi-ballistic type is adopted, which uses the initial re-entry speed, attitude, and re-entry angle as the initial conditions of re-entry, and realizes the heading and pitch control of the flight trajectory through lift control, so that it can land on the scheduled landing more accurately location.
Therefore, the semi-ballistic jump reentry solves the problem of the accuracy of the landing point and the influence of force and heat in the reentry process.
We have usually played water-floating, using a stone to hit the surface of the water. After entering the water, the lift of the water will make the stone bounce again, and then gravity will make it enter the water again.
The Chang'e-5 returner is also about this process. After it enters the atmosphere for the first time, the atmosphere will provide it with a certain lift. The lift makes it come out of the atmosphere and enter the atmosphere, and then gravity will make it enter the atmosphere again. , This is what we call "fighting water."
Pei Zhaoyu, deputy director of the China National Space Administration's Lunar Exploration and Space Engineering Center, deputy chief designer of the third phase of the lunar exploration project, and spokesperson for the Chang'e 5 mission, accepted an exclusive interview with China News Agency "China Focus Face to Face".
Photo by China News Agency reporter Sheng Jiapeng
China News Agency reporter: During the work of the Chang'e-5 probe, the automatic lunar surface sampling was completed in only 19 hours, which was smoother than expected. Looking back at the whole process, do you think its actual operation difficulty is higher or lower than expected?
Pei Zhaoyu:
In the Chang'e-5 mission, many links after landing were inexperienced in the past.
The first (difficulty) is the sampling of the moon surface, because the unmanned method is closely related to the state of landing, as well as the topography, landform, and geology of the moon surface.
In the Chang'e-5 mission, although sampling only took 19 hours, from the point of view of the process, at first we thought that the surface of the (landing site) was a bit like the landform at the junction of the desert and the Gobi, and that the (moon surface) was relatively hard. Later) using the meter to take samples feels okay and easier to take, so the sampling time is saved.
(Utilizing) the time saved, we have carried out some other tasks, such as the display of the national flag, the second full detection of the payload, and some preparations for the ascent. These tasks were originally reserved for 8 hours, but now it seems More calm.
A reporter from China News Service: After the automatic sampling of the lunar surface, Chang'e 5 has also carried out a series of work. One of the people is more concerned about the "independent display" of the five-star red flag on the lunar surface. Now that Chang'e 5 has returned to Earth, netizens are also very curious, did the five-star red flag stay on the moon or brought it back to the earth?
Pei Zhaoyu:
Chang'e 3 and Chang'e 4 are both landing and patrolling missions. We put national flags on the surface of the lander and patrol of the landing. The national flags of these two missions will stay with Chang'e 3 and 4 permanently. The surface of the moon.
In the Chang'e 5 mission, we used another method to display the national flag, and there was a special flag deployment mechanism.
After completing the sampling mission, (Chang'e 5) activated the flag deployment mechanism, which protruded from the side of the lander.
After the lander completes sampling and takeoff support, it will stay on the moon forever, and the flag will stay on the moon forever.
The picture shows the Chang'e-5 lander and ascender combination panoramic camera shooting the five-star red flag successfully deployed on the moon.
Photo courtesy of China National Space Administration
China News Agency reporter: After we get the "space express" of the moon sample, what will we do? How does this sample help us understand the moon?
Pei Zhaoyu:
First, it must be unsealed. The sample container is encapsulated in a vacuum state. After entering the earth, it must be operated in the environment of the earth, which is different from ordinary cans.
After unsealing, sample the samples for basic characteristics and physical and chemical characteristics tests.
Then register samples and create files for each sample.
From the perspective of scientific research, we will formulate a sample management method, and make specific regulations on how to manage samples and how to distribute them.
Samples are important basic materials for scientific research. On the one hand, we will organize domestic scientists to conduct research on samples. At the same time, the management measures also propose active international cooperation in sample research. We also welcome foreign scientists to carry out sample research.
The sample management method mentions that a committee of scientists should be established to solicit plans and suggestions for sample research from the international community. The committee of scientists will evaluate these suggestions and determine which suggestions are of scientific value, the use of samples is reasonable, and the management of samples is orderly and reliable.
In this way, decide which samples to provide and which research to conduct.
We did not propose country-specific restrictions and encourage scientists to collaborate on sample research.
Reporter from China News Service: It was previously reported that the lunar samples brought back by Chang'e 5 would be divided into two copies, one is kept in Beijing and the other is kept in Hunan. Is this news true? After processing and researching lunar samples, how will we save these samples in the future?
Pei Zhaoyu:
When demonstrating the overall plan for the third phase of the lunar exploration project, considering that the lunar samples are very precious, there should be a safe way to ensure the safety of the samples.
So I thought of a place in Beijing, because this is where the ground application system is located, responsible for sample processing, preservation, and management.
There is another place where it should play a role in remote disaster recovery and backup. From this perspective, it is necessary to choose a place with better geological conditions. (Everyone) thinks Hunan is suitable.
At 12:35 on December 6, Beijing time, the Chang'e-5 orbiter and returner assembly was successfully separated from the ascender and entered the phase of waiting around the moon, ready to return to Earth.
The picture shows the simulation diagram after the orbital return assembly is separated from the riser.
Photo courtesy of China National Space Administration
China News Service: In addition to "Chang'e", China also has many romantic names with profound meanings, such as "Beidou", "Tianwen" and "Tiangong". Many netizens also said that Chinese astronauts are "plain names". "Genius", can you tell us how these major projects are named and what is behind them?
Pei Zhaoyu:
First, the Chinese nation has a 5,000-year history of civilization and has created a splendid culture, including many myths and dreams. This has provided us with an inexhaustible source of names.
The Chinese nation is a nation that pursues dreams. Aerospace is actually a career that pursues dreams. There is a good match here. This is the spark of thought brought to us by Chinese culture.
Second, naming is also a serious matter.
The naming of the task should take into account the matching of the name and the task, the matching with the mythology, and the acceptability and recognition of the people.
Of course, there is a strict procedure for naming. The general practice is to first collect from the Internet or the public, and then invite experts to screen, leave a few (names) with higher recognition, and then make the final decision.
At 1:59 on December 17, Beijing time, the Chang'e-5 returner successfully landed in the planned area of Siziwang Banner, Inner Mongolia, marking the successful completion of China's first mission to sample and return extraterrestrial objects.
Photo courtesy of China National Space Administration: Wang Jiangbo
China News Agency reporter: The Chang'e-5 mission is one of the most complex and difficult missions in China's aerospace industry so far. It is so difficult, why does China go to the moon to "dig earth"? What is the significance of lunar exploration for China's space industry? Does this mission also prepare for China's future manned moon landing?
Pei Zhaoyu:
(From an engineering perspective), China (the lunar exploration project) has planned a three-step "round and fall back". Through the round and fall, we have mastered some technologies, and through the return, we have the ability to go back and forth between the earth and the moon.
In terms of science, we conduct a comprehensive survey by "circumnavigation" and regional detailed surveys by "drop". However, due to the weight limitation, the weight of scientific instruments carried is limited and the accuracy is limited, which cannot be compared with ground-based instruments and equipment.
After obtaining the samples, through fine research on the ground, combined with the scientific data of "rounding" and "falling", the understanding of the moon may be more comprehensive and more refined.
(As for) the impact of lunar exploration on the development of aerospace, to make a metaphor, people’s perception of the moon is similar to people’s perception of the ocean and the deep sea 100 years ago. We might not know what the deep sea had 100 years ago. Unexpectedly, we really have the ability and need to mine it out to serve humanity.
The current moon, people's understanding of it is still at such a stage.
China has been conducting space activities in earth orbit for many years and is relatively mature.
At present (have) expanded from the stage of mastering space technology to the stage of space application, and we have rarely set foot in the moon and deep space.
The moon and deep space exploration are good carriers for driving the development of space technology. The development of the moon and deep space exploration is not only a long-term strategic need, but also a need for the development of space technology.
We have mastered the basic and main technologies of lunar exploration through the three steps of "rounding and falling back", which can lay the foundation for future lunar exploration and deep space exploration accumulation technology.
Some people commented that the return of the Chang'e-5 sample was like an unmanned version of the Apollo project.
Of course, from the point of view of the entire flight process, there are similarities with the Apollo program, but in the specific technical aspects, the manned and unmanned are different.
China News Agency reporter: What plans and arrangements are there for the follow-up China's lunar exploration project, and what goals are expected to be achieved?
Pei Zhaoyu:
"Walking back" can be said to be the beginning of China's lunar exploration. Through the implementation of these three stages, after we master the technology, the next step may be the comprehensive development of space technology, space science and space applications.
In order to better serve space science and space applications, everyone proposed the concept of a lunar research station.
For example, we went to Antarctica for expeditions. In the past, we sent ships to the Antarctic. Each time the ship went and returned, the expeditions in Antarctica were limited. Now we have built several research stations and research stations in Antarctica. The scientific research activities in Antarctica are more effective.
So we want to build a lunar research station on the moon, which can better serve space science and space applications.
Pei Zhaoyu, deputy director of the China National Space Administration's Lunar Exploration and Space Engineering Center, deputy chief designer of the third phase of the lunar exploration project, and spokesperson for the Chang'e 5 mission, accepted an exclusive interview with China News Agency "China Focus Face to Face".
Photo by China News Agency reporter Sheng Jiapeng
China News Service: In addition to China's plan to build a lunar research station, ESA, Russia, and Japan also have related plans and arrangements. In the future, has China considered cooperating with international counterparts in the construction of scientific research stations?
Pei Zhaoyu:
China's lunar exploration is becoming more and more open, and more cooperation with international partners.
Chang'e-4 is equipped with scientific instruments from four countries, and we have already announced cooperation opportunities for Chang'e-6 and asteroid exploration.
In terms of lunar scientific research stations, China regards it as the main target for future development of lunar exploration.
China is carrying out the construction of lunar scientific research stations in an open and cooperative manner; we have put forward an international proposal to jointly build an international lunar scientific research station, which has also received responses from some countries and international organizations.
In addition, in terms of planetary exploration, China launched Tianwen-1 in July this year, which was China's first Mars exploration mission.
According to the plan, China will also implement an asteroid detection mission, a Mars sampling return mission, and a deep space mission for Jupiter system exploration and interplanetary crossing in the next ten years.
On the whole, China's exploration targets have moved from the moon to the interplanetary. The exploration targets have moved from mastering space technology to the comprehensive development of space technology, space science and space applications, and the development mode has shifted from being independent and independent to a stage of full open cooperation.
At the same time, we have also noticed that many countries in the world are conducting lunar exploration. Lunar exploration is becoming a new hot spot in space. China is also willing to participate in missions organized by other countries.
China News Service: You mentioned earlier that China may choose Jupiter and asteroids for future planetary exploration. Will China go to Venus to explore after "fire exploration" and "lunar exploration"? In terms of choice for planetary exploration, why did China choose Jupiter and asteroids instead of Venus?
Pei Zhaoyu:
For interplanetary exploration, Chinese experts have conducted long-term demonstrations, thinking about how to achieve more exploration targets with the least cost and the least number of missions. From this perspective, temporarily put Venus aside.
But this is temporary, and we may carry out exploration activities on Venus or other planets through cooperation with other countries.
(Finish)