NASA’s willpower Mars rover successfully landed on Mars
Tencent technology news in the early morning of February 19, Beijing time, the Mars Rover “willpower” has completed the most dangerous step. After spending “seven minutes of terror” safely, it successfully landed in the Jezero crater of the “red planet”. Although this is the ninth visit to Mars by an American spacecraft, the mission and “black technology” used by the willpower are different from those in the past.
As the “old driver” of landing on Mars, NASA has tried to find a foothold in the future of human beings on Mars as early as 2015. According to the principle that both the gathering place of early human beings and the birthplace of civilization are near the water source, NASA researchers believe that only with water can we find signs of life on the red planet. Therefore, willpower chose Jezero crater, a plateau lake once full of water, as its foothold.
Will willpower find life on Mars? In order to successfully spend “7 minutes of terror”, what high technologies are used? What’s the function of the UAV placed in the belly of willpower? Why Mars is “the most familiar stranger”? When will man realize his dream of emigrating to Mars?
On February 19, Duan Yulong, Beijing Science Popularization ambassador and producer of science programs, was invited to talk with Zheng Yongchun, a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, in the sixth issue of “star dialogue” launched by Tencent News’s “sky program” to talk about the mission of willpower to Mars and the mystery behind it.
As for the origin of “seven minutes of terror”, Zheng Yongchun explained that the long distance between the earth and Mars caused the time delay of signal transmission to the earth, and scientific researchers were unable to command the probe to enter the Martian atmosphere. Therefore, the time delay may lead to unpredictable results. However, the successful landing of willpower made mankind take a solid step on the road of exploring Mars.
“Willpower will use Martian carbon dioxide to produce oxygen, and one of its missions is to explore the feasibility of this technology,” Zheng said. It is hoped that in the future, people will go to Mars without carrying an oxygen bag, but only with a small machine carrying an oxygen production device. “
The following is a transcript of the dialogue:
Duan Yulong: Hello, Tencent News netizens. Welcome to our program. Today, we’re going to talk with you about the willpower Mars rover. In the early morning of February 19, the US Mars probe willpower has successfully landed on Mars. Today, let’s talk about the protagonist of the landing “willpower Mars Rover”. I’m Duan Yulong, the host of the science program. At the moment, an astronomer from the National Astronomical Observatory of the Chinese Academy of Sciences is here to discuss this topic with us. Hello, Yongchun.
Zheng Yongchun: Hello, Tencent netizens!
Duan Yulong: as far as I know, this probe has been launched since July 2020. In fact, there are three probes launched in July last year: hope, tianwen-1 and perseverance. Now perseverance has landed on the surface of Mars, and perseverance has landed on the surface of Mars. Many media reports say that there is a stage called “7 minutes of terror”. Why do so many people pay attention to it Seven minutes? What are the technical content and high-tech highlights of these seven minutes?
Zheng Yongchun: in fact, Mars exploration is no longer a new thing. Today, according to different statistics, there have been about 47 times, nearly 50 times. Among so many Mars explorations, the most difficult one is landing on Mars, circling, leaping and other exploration methods, which are relatively easier, because they don’t need to enter the atmosphere of Mars. The most difficult point is to enter the atmosphere of Mars, which takes seven minutes. It takes seven minutes for it to enter Mars from outside the atmosphere and then fall to the surface of Mars. It’s just like a popular meteorite in our sky that passes through the atmosphere. It takes seven minutes from it entering the earth’s atmosphere and being seen by us to it falling to the ground and becoming a meteorite. Because the distance between the earth and Mars is very long, signal transmission takes more than ten minutes, and the length of this time is also different. According to the distance between Mars and the earth, the short time is a few minutes, and the long time is more than ten minutes to twenty minutes.
In the seven minutes to enter the Martian atmosphere, we have no way on earth to command it in real time. If it has any conditions, for example, its landing site may not be suitable for landing, or it needs to adjust its posture during landing, it must adjust by itself, because it is too late for us to command it from the earth. This is the result of 7 minutes’ unpredictable delay. NASA predicted that the success probability of the willpower landing on Mars is 40%, because there is no way to command the landing process on the ground in real time. It can only rely on the previous understanding of Mars and the spacecraft’s own judgment of the deceleration time to decelerate.
Duan Yulong: the earth is too far away from Mars. If we use the online direct remote control method, we will find that after the command is sent to Mars, maybe the action of the Mars rover has already been completed, so we still need to leave the whole process of the Mars rover landing on Mars to the Mars rover itself to complete independently.
We know that there is a big difference between the landing of a Mars rover on the surface of Mars and the landing of a spacecraft on the surface of the earth, because the density of the atmosphere of Mars is different from that of the earth, which means that it is also a parachute. This parachute can be opened on the earth, and it can be calculated according to past experience and mathematical methods to determine how large parachute it needs and when It can land on the ground. If the parachute is opened on the surface of Mars, it will be totally different from that on earth, because the atmospheric density of Mars is only 1% of that of earth, and the whole landing process is also full of risks for willpower. Just now Yongchun said that NASA expects the success rate of willpower to be 40%, but today it seems to be 100%. What geomorphological and geological features on Mars are different from those on earth?
Zheng Yongchun: what are the similarities and differences between the landforms of Mars and the earth? In fact, we say that Mars is neither the past nor the future of the earth. It is a Mars. Mars and earth have similarities and differences. We call it “familiar stranger”. The landforms, topography and some geological phenomena you see on Mars can actually find some similar examples on earth. This is the similarity of them. There are traces of volcanoes, canyons, rivers and coastlines on Mars, all of which can be found on the earth. There are even some micro geomorphic features on the earth, which are the similarities between Mars and the earth.
At the same time, Mars and earth are different. Where is the difference? There are many kinds of life on the earth, including organisms, animals, plants and microorganisms. However, no animals, plants or microorganisms of any kind have been found on Mars, and so far they have not been found. Mars is very different from earth. It has no function of life.
Second, there are rivers, lakes and seas, wind, frost, rain and snow, and atmospheric precipitation on the earth every day. The effect of water power has a significant effect on the formation of the earth’s landform. Until now, there is no large-scale liquid water on Mars, and there may be liquid water in some places, but there is no clear evidence, so the hydraulic effect is mainly traces of the past. For the formation of Mars landform, the most important role is actually wind, that is, sandstorm. Yulong, you are from Northwest China. You know the power of wind. Wind can shape the terrain of Mars and Northwest China.
Zheng Yongchun: Mars is mainly affected by wind force. We can find some landforms similar to Mars in Qinghai, Gansu and Xinjiang of China. We also call it “Mars simulation base”, which can be used to understand some geological processes and geomorphic formation processes on Mars. We call Mars “familiar stranger”.
Duan Yulong: we can see the same landforms on earth as on Mars. You just said that there are landforms eroded by wind in Northwest China. I thought of Yadan landforms. Even I thought of many Mars themed movies shooting in akatama desert in Chile. We may be able to see the shadow of Mars on the earth, but after all, the earth is not Mars. As far as I know, this time the willpower probe landed on Mars, it actually took many pioneering missions. One of the missions is to do things related to the production of oxygen on Mars and to find traces of life on Mars. What are the major events, news and actions that will be done by the willpower on Mars this time?
Zheng Yongchun: from an objective point of view, the mission of willpower is not necessarily important. There is no distinction between large and small scientific exploration. We just find it interesting and interesting. Previously unknown, we wanted to know about it. This is the purpose of scientific exploration.
I just said that there are many Mars like landforms on earth, such as the akatama desert in Chile. The movie Mars rescue was shot in Jordan’s Rose desert. At the same time, there are some simulation bases in Utah of the United States, and even astronauts can experiment and train there. In some dry valleys in Antarctica, the temperature is very low, similar to that on Mars, because the air is too cold and the humidity in the air is very low. There is no ice and snow cover in those places, and there are some dry valleys. That place is also used as a simulation base for Mars.
There is also a Mars simulation base near Delingha, Haixizhou, Qinghai Province, including Lenghu and Dachaidan. There is also a Mars simulation base in Jinchang, Gansu Province. There is also a Mars simulation base in devil valley near Karamay, Xinjiang. In fact, some of these things are red geological landforms formed by flowing water and wind, These places are similar to those on earth, so scientists will use them to carry out some simulation and comparative studies between Mars and earth, mainly for comparison. It is also a very good theme for tourism development. Many films and documentaries are filmed there, and many people will go there to study, popularize science, educate and travel. This is the contrast between Mars and the earth.
Back to willpower, it’s the fifth Mars rover in the United States. I’ll take a stock of the first four: the first one is Mars Lander in the 1990s. It’s called “sojourner Rover”. This rover is called Mars Pathfinder (MPF). In fact, it’s very small. It’s about the size of a basketball, with a height of 20-30 cm. Its ability is also very limited. It can only circle around the lander and can’t go far.
At the beginning of the 21st century, around 2003, the United States launched a pair of twin Rovers called opportunity and courage. Many people have heard that these two rovers are twin Rovers with similar instruments, equipment and structures. However, they landed at different places on Mars with different research purposes and achieved good results. The design life of this rover is only 90 days. Originally, it only needs to work for 90 days to retire. It is not easy to work on Mars for three months. As a result, it has been working for more than ten years and has run a marathon on Mars. This is also the longest marathon record for a man-made spacecraft to travel on the earth. It has run a total of 45.5km. The second generation Mars rover is about half a person tall.
In 2012, curiosity, the third generation of Mars rover, has made great progress compared with opportunity and courage. Its height is more than one person, and its weight is also very large, nearly one ton. It is more complex and difficult to put a one ton Mars rover on Mars, which is equivalent to a ton of meteorite sliding down. The difficulty is that in the process of crossing the atmosphere, it has to withstand high temperature, high pressure and high speed, and it can’t be burnt out. After gradually reducing the speed, it won’t make a hole on the ground. This is the most troublesome thing in the landing process.
To a large extent, the willpower Mars rover has many similarities with the curiosity Mars rover. It can also be regarded as a replica of the curiosity Mars rover, which has been greatly improved on the basis of the curiosity Mars rover. For example, its weight is similar to that of curiosity, its energy supply mode is similar to that of curiosity, and its landing mode is also similar. Finally, it has to use the sky starter to land. It’s about the same weight as a car on the street. It weighs one ton. It’s also powered by nuclear power. In addition to these, there are also some new improvements. These improvements are also remarkable. Just now you mentioned the production of oxygen on Mars. In fact, the oxygen production device has been studied in the scientific community for many years, and it is relatively mature on the ground. But this is the first time that oxygen is produced on Mars, and the carbon dioxide in the Martian atmosphere is chemically changed into oxygen. This is the first time that oxygen is produced on Mars The oxygen produced by a small machine is enough for one’s life on Mars. If we really want to go to Mars, people don’t have to carry an oxygen bag and a machine. This is a great progress.
Duan Yulong: this time, the willpower will bring oxygen equipment. Is it for scientific verification or is it going to produce oxygen on Mars to prepare for human migration to Mars in the future?
Zheng Yongchun: in fact, all Mars exploration has two purposes. One is to understand the unknown, and the other is to prepare for the future human beings to go to Mars. These two purposes are not contradictory. Such a way is called in situ resource utilization. In situ utilization of resources on the moon, Mars and celestial bodies is to prepare for the survival of human beings on those planets. If you are interested, you can search the key word “ISRU” on the Internet, and you will find a lot of relevant information and research results. In fact, we have conducted a lot of in-situ resource utilization research on other planets. In situ resource utilization on Mars mainly uses carbon dioxide from Mars to produce oxygen, and the purpose is to explore the feasibility of this technology.
We also know that some people have plans to try to land on Mars and emigrate to Mars in the future. The production of oxygen is only a very early step. Technologies like this need to be gradually verified in future space missions, and every technical link should be guaranteed to be safe. Then we can realize the idea of manned landing on Mars.
Duan Yulong: next, please continue to introduce the exploration equipment of willpower, including its design idea. What’s the difference between willpower and the previous Mars rovers?
Zheng Yongchun: in addition to the oxygen production equipment, another very important point is the higher landing accuracy. We know that Mars is very large, the area of which is equivalent to several China, twice as large as the moon. Scientists have a clear purpose for the selection of landing sites. For example, they want it to go to a certain Valley, a certain plain or a certain flat. The more accurate it lands, the closer it is to our investigation object. When the goal is to investigate the rocks in a certain Valley, it is obviously inappropriate to travel on the ground for a long distance. The accuracy of landing depends on our control of instruments, our understanding of Mars, and its own ability of maneuver and autonomous navigation.
Perseverance has made great progress in this aspect. It can conduct autonomous navigation in the process of landing, and control the distance between it and the ground with high precision. Only after measuring the distance from the ground and defining the landing position, can it land at the designated position more accurately. Perseverance has made great progress in this aspect. Another improvement is that willpower has a UAV called dexterous, which is the first UAV to take off from an extraterrestrial object.
Duan Yulong: why send a UAV to Mars?
Zheng Yongchun: UAVs will be very useful not only on Mars, but also on earth. For example, express delivery, disaster emergency rescue and so on. Now express delivery mainly relies on couriers walking through the streets. In the future, it can be delivered by UAV. UAV has a lot to look forward to, and even many application scenarios are unimaginable. If there is such a tool on Mars, it will also be very useful, not only for transportation, but also for improving the efficiency and scope of scientific investigation. We know that willpower weighs close to one ton and only relies on one of its radioactive nuclear power sources to generate electricity. The power generation capacity is very limited. In this case, it can only drive very slowly and the efficiency and scope of investigation are limited.
Another reason is that in an unknown environment, it still has a time difference of more than ten minutes with the earth. The slower it is, the safer it will be. There may be many unknown obstacles in front of a vehicle under remote control, and the speed of the vehicle can not be very fast. Therefore, the R & D personnel hope that the slower the rover drives, the better. How slow is it? About a few centimeters per minute.
Every step of it has a clear purpose. The R & D personnel hope that it can investigate what we want it to investigate, such as the rocks in front or some special phenomena. In this case, it takes several days, even more than ten days, to reach the target position. However, once it arrives, it may find that the previous phenomenon is a common phenomenon, just because the distance before it is far away, resulting in misjudgment. This often happens in the past, and it takes a long time to go to the next place. The UAV can improve this problem. It can take off from the Mars rover. After taking off, it will investigate the surrounding environment and design an optimal route.
Duan Yulong: I understand that one of the important reasons for the Mars rover carrying UAVs is that the Mars rover is very slow, and the ground investigation will take a long time. Now it will be different if there is a UAV. We can launch a UAV to investigate the surrounding environment first. Scientists will give instructions on the earth, and then the willpower will move, and then carry out relevant investigation and research. This is also a very interesting role of the small helicopter carried on the willpower Mars rover.
As far as I know, the small helicopter on the willpower is not as efficient as our small UAV on earth. The UAV on earth can fly for half an hour, but the flight time of dexterous on Mars is not so long, maybe only a few minutes, and the flight distance is also very short.
Zheng Yongchun: Yes, as the first UAV to take off on Mars, the biggest difficulty is how to make it fly. The atmospheric density of Mars is only 1% of that of the earth. The same propeller can’t bring the same heavy UAV on Mars. Only the bigger propeller and lighter fuselage can take off on Mars.
Before it flew to Mars, it was very difficult to test even on earth. There was no such environment on earth as Mars for experiments. The volume of the artificial vacuum is very small, and it has not yet reached the real vacuum. To create a large space, reach the atmospheric density of Mars, and simulate the gravity on Mars, we can only hang a rope on the fuselage, use this rope to offset 2 / 3 of the gravity, and then simulate the large air tightness on Mars. After repeated tests, we can make it take off successfully on Mars.
Another problem is that dexterous is powered by solar energy, which is much weaker on Mars than on earth. The distance between the sun and the earth is one astronomical unit, 150 million kilometers, while the distance between the sun and Mars is 15 astronomical units, 225 million kilometers. It will take more than ten minutes for sunlight to reach Mars. The longer the distance, the weaker the energy. The intensity of the sun on Mars is less than half that on earth, so it needs a larger area of solar cells to have enough power. From this point of view, the UAV take-off on Mars is a very important progress.
Duan Yulong: if you want to be poor for thousands of miles, you can go to a higher level. Only when you stand high can you see far and improve the efficiency of scientific examination. The area where the willpower Rover landed was Jezero crater, where it went to look for traces of life. In your opinion, can we find any concrete evidence of life this time?
Zheng Yongchun: scientific exploration is progressing gradually. Our exploration and understanding of Mars is not only reflected in higher and higher technical ability, but also in deeper and deeper scientific understanding. This is the general direction of Mars exploration. Willpower has a mission to search for life on Mars. The main purpose of the previous Mars rovers is to chase the footprints of water, see the traces of water flow, find the minerals deposited in water and find the traces of water action. These are the work of previous Mars rovers and remote sensing satellites.
Curiosity and today’s willpower have transformed the entire Mars exploration strategy into a search for traces of life on Mars. As early as the 1970s, two rovers, Viking 1 and Viking 2, landed on Mars. At that time, some gases were released by adding reagents to a handful of Martian soil. Organic matter was detected from these gases, indicating that there might be life on Mars. Some gases released by microorganisms have been detected. But later, it was pointed out that there were some errors in data and instruments, and there were still some problems to be solved. The conclusion was not clear, but it had caused a great sensation at that time. In the 1980s, researchers found a meteorite called ALH84001, which was discovered in Antarctica in 1984. Some traces of suspected microbial deposition were found in this meteorite.
Duan Yulong: is this meteorite from Mars?
Zheng Yongchun: This meteorite is definitely a Martian meteorite. There is no problem with insect like traces in the meteorite, but there is no way to determine whether it is an insect or not. We also have some studies that point out that these may not be microorganisms, but some mineral remains, which are formed by some chemical changes rather than biological reactions, just like insects in shape. The world has been discussing for a long time whether there is life on Mars. Even Carl Sagan wrote a passage at that time: “Mars is the Mars of Martians, even if they are just microbes.”. The earth people occupy the earth, and the Martians occupy Mars. Even if they are microbes, we can’t disturb them. This leads to the code of conduct we have been implementing so far, which is called “planetary protection principle”. The spacecraft we launched from the earth, including willpower and curiosity, can not carry life on the earth.
Duan Yulong: how to get rid of all the creatures you carry?
Zheng Yongchun: it needs thorough and comprehensive disinfection, such as ultraviolet radiation, cooking at 120 ℃ for 24 hours to eliminate the microorganisms carried by the spacecraft. It’s very difficult to eliminate microorganisms on the earth, and it’s almost impossible to completely eliminate them, so some of them will be carried over, just to reduce the number as much as possible.
Our instruments can not be disinfected with disinfectant, so the existence of microorganisms is inevitable. “Planetary protection principle” means that we can’t take any microorganisms to Mars. If these microorganisms survive and go to find life later, it’s difficult to distinguish between large-scale reproduction of earth organisms and protozoa. Next, in the 21st century, Mars exploration has made some progress. Spacecraft from the United States and Europe have found methane in the atmosphere of Mars.
Duan Yulong: discovery of methane means life?
Zheng Yongchun: to put it simply, if there is methane on the earth, there will be life. Generally, life on the earth will release methane gas. For example, the silt at the bottom of the river will also release bubbles, which are evidence of life. In addition, a mineral, olivine, which reacts with water to produce methane gas. It is impossible to judge whether methane is produced by microbial reaction or by olivine reacting with water. Now we have no way to be sure. Although we find methane everywhere, with high and low concentrations, it is still difficult to judge whether it is related to life.
When it comes to the willpower, the landing place is carefully selected. Hundreds of places worth exploring have been listed on Mars. People think that these places are particularly strange. They may be related to life, rivers, and various special geological phenomena. After weighing the power, they think that Jezero is the most valuable place and the most priority to go.
Duan Yulong: why?
Zheng Yongchun: because the landing place is a river impact fan, a bit like our Pearl River Delta, Yangtze River Delta and Yellow River Delta. It is not so large. In fact, a large amount of sediment, minerals and nutrients pour into the Delta, and the river mouth water is very rich in products. For example, the Yangtze River Estuary, Jiangsu Qidong, Lvsi fishing port, Qiantang River Estuary, Zhoushan fishing ground, Guangdong, the Pearl River Delta and the Yellow River Delta are all rich in marine products. In fact, such places are the places most likely to have life.
See if there are any signs of life in the most likely places. In the end, I believe there will be some new progress, but there is no way to make sure that there is life on it. Now we can’t see the phenomenon of microbial activity directly. We only see some products of microbial life activity, such as methane gas. In fact, what we judge is this. In fact, the best way to really see living organisms, even living microorganisms, is to collect samples and bring them to the earth for cultivation under a microscope and in a Petri dish. Only then can we be sure that there is life on Mars. For now, there must be no life on the surface of Mars.
Because the Martian soil is toxic, it has a strong oxidation, a bit like hydrogen peroxide, has a strong oxidation. At the same time, the intensity of ultraviolet light on the surface of Mars is also very strong. Our safe life on earth depends on the filtration of ozone, and the ultraviolet light is not so strong. Ultraviolet is a kind of disinfectant. If ultraviolet can disinfect the surface of Mars for more than one billion years, will there be any living things there? Even organic matter can’t survive, let alone life. There is still no way to determine whether there is life on Mars. For this purpose, willpower has another important task. This time, it will take a lot of sample tubes, each of which is about one or twenty centimeters long. There are dozens of such tubes, which will collect interesting geological samples, collect soil and rocks, and seal them up, Next time or next time, I don’t know which one, 2026 or 2030, actually depends on the ability and specific plan. I hope to bring back the samples in the next Mars exploration. Each time the sampling capacity is very limited, and the sampling location is also very limited. Take advantage of this time to run on it, let it collect as many samples as possible, and bring them back to the earth in the future. As long as one gram, I emphasize, as long as one gram of sample, many of our mysteries about Mars can be answered. Real objects can be detected in experiments with the most powerful scientific and technological capabilities on earth. This sophisticated analytical instrument can detect every particle in a very detailed, multi-disciplinary, 360 degree and dead angle free way. As long as there is a trace, it can be detected on the earth To find out. Why do we work so hard now? There are 23 cameras, so many cameras and so many analytical instruments on the willpower, but we still can’t answer this question. It all comes from the fact that our analytical equipment on earth is too large to be transported to Mars.
If you take a look at some simple instruments, large telescopes and various microscopes in the major of geochemical research, you will know that every instrument is as big as a house, or even several houses, so we can’t transport it. These instruments need to undergo professional training, and scientific researchers need to carry out some very complex processing procedures, step by step, with many steps, each step is very fine, and such a process can not be realized on Mars. There is no way to answer whether there is life or not by relying on Mars rover alone, but there will be new breakthroughs.
Duan Yulong: for example, the next one to go to Mars is a man. After a man goes to Mars, he doesn’t need to bring back the samples. Can he come to the conclusion whether there is life on Mars?
Zheng Yongchun: in fact, with the development of aerospace and deep space exploration, the role and value of human beings have become more and more important. Of course, there has always been controversy. It is often said that there is no need to send people to manned space flight, because robots can do similar work. In fact, let’s look back and consider that the role and value of human beings are irreplaceable. Human experience, human professional knowledge and human professional skills are irreplaceable. I can easily judge what this is, what it is and what trace it is when I go to a scene with you. We say that a professional geologist can easily recognize what kind of stone it is in the wild. There was water, volcano, wind or life here. In fact, there is a lot of information and evidence to tell you. If you rely on robots, they don’t have the professional training, skills and abilities. Sometimes you can see it with your eyes and touch it with your hands. The first-hand person’s perception of the scene is still irreplaceable.
Whether people want to land on Mars or on the moon, on the one hand, people have the initiative. We know what we want to do, but machines don’t. Second, people have some professional accumulation and some experience, which can not be replaced by machines. What is particularly important is that human landing on a planet has a strong symbolic meaning, which represents a big step forward for us.
Next month, the core module of China’s space station will be launched. In the future, Chinese people will live in space for a long time. This is a step for us to go to space. The next step is to land on the moon, and the next step is to land on Mars. Every step out, we all have a strong symbolic meaning, not that the Chinese people out, but that the human race out. If the Chinese want to do such a thing, we have taken this step towards space on behalf of the whole human race. Human landing on other planets still has irreplaceable value and important symbolic value.
Duan Yulong: you mentioned that China’s aerospace, China’s “tianwen-1” and willpower were launched in July last year. Why did tianwen-1 orbit around Mars after its orbit change on Lunar New Year’s Eve, while willpower directly landed on Mars. Here we also learn why tianwen-1 has to wait for such a long time. News reports will only land on Mars in May. What should we do in the middle?
Zheng Yongchun: that’s a very good question. What’s the difference between Tianwen and perseverance? As a matter of fact, Mars is so big that there are many targets that can be explored, and their respective development stages are different. Our technological capabilities and technological foundations are also different. We can do different things to understand Mars. The reason why the U.S. willpower can land directly this time instead of taking an orbiter in the sky like us is that it has more than one orbiter in the sky. It has a Mars exploration orbiter called MRO, and an orbiter called maven, including those in Europe. Up to now, there are at least eight spacecraft working on Mars, and this time there will be another three. At this moment, it is equivalent to 11 spacecraft working on Mars.
The data obtained from the photos taken by willpower are all sent back to earth by Mars Reconnaissance Orbiter, and some Mars satellites have been sent back to earth. Why can it fall directly? Because there was something in the sky before, and it was sent many years ago, five or six years ago, seven or eight years ago, and it has been circling there. There is no way to lack relay satellites. Mars rover has no way to directly carry out high-speed data transmission with the earth. It does not have this ability. Although it has certain communication ability, it has no way to send a large amount of data back, so it needs relay satellites.
The relay satellite is the remote sensing satellite on Mars. They already have it. China needs tianwen-1 to bring it by itself. If tianwen-1 is divided into two parts, one is to launch a satellite first, and the other is to launch a car to let it fall. In fact, it can also be realized. These are two paths. We have to implement it in two times, and each launch window is very limited. We only have one opportunity in 780 days and 26 months. If one of the opportunities fails, the orbiter fails to go to the Mars rover, and the Mars rover fails to go to the orbiter. These are unacceptable results, so we choose to put the three things together. There are orbiters, remote sensing satellites, relay satellites, and landers, which are a Mars rover and lander. In this way, your spacecraft will be very heavy, and it will be difficult to bring the rover and the orbiter to Mars. The braking of big trucks and cars is definitely not the same order of magnitude. When big trucks brake at intersections, the distance is very long and the sound is harsh.
When tianwen-1 arrived on Mars on December 29, it made a key step on Mars. Now it has successfully orbited Mars. A few days ago, it changed from an equatorial orbit around Mars to an orbit around the poles of Mars. It can carry out remote sensing exploration of the whole world of Mars and obtain a large number of images and data of Mars. This orbit needs to be adjusted for a long time. When it just braked, it was a large elliptical orbit. The near fire point was only 400 km, the far fire point was more than 100000 km, and the distance between the earth and the moon was 380000 km. Therefore, for a very long distance, it took time to converge. It was getting closer and closer to Mars. In this process, it was not idle, and it would get a lot of Martian surface every time From these remote sensing images, we can deepen our understanding of Mars, and investigate the landing site we choose, that is, a certain base point in the utopian plain, which is roughly equivalent to the longitude and latitude of China’s Guangdong and Guangxi regions.
Such a place needs to be inspected by tianwen-1, so as to converge its orbit and find a suitable landing time. Why did tianwen-1 arrive on Mars on New Year’s Eve and land in May? In fact, it is because tianwen-1 has adopted different detection strategies.
Duan Yulong: look, some netizens also said that in the past, both Europe and even India, the Soviet Union and the United States have explored Mars a lot. The United States is in the lead. The United States has a lot of Mars data, so why can’t the data be shared? Why can’t we go directly to Mars? Because these data are not the first-hand data obtained by our country, if we want to go smoothly on Mars, we must obtain the first-hand data. From the end of February to may, we have a more comprehensive understanding of Mars. Only after we have established our own data, can we have a definite aim and let the rover go to the predetermined position. Moreover, the whole data acquisition process will also improve the success rate of the rover’s landing on Mars.
Zheng Yongchun: two Mars landings in Europe have failed. For the first time, Mars Express carried a lander called “headdog 2”, which disappeared when it landed. The second was in 2016 with a lander called the skiaparelli, which failed after landing. The relationship between Europe and the United States is good. Data should be fully shared and intelligence shared. When the Europeans failed, the Americans didn’t help. This shows that the core secrets and capabilities in these areas are still reserved, and you can expect that.
Second, for Mars exploration, first-hand data, first-hand experience and verification of technical capability all depend on one’s own step by step. Although Mars exploration is the cause of all mankind, the scientific data of Mars is released to the world, such as the terrain data, landform data, meteorology and environment data of Mars. Chinese scientists have been using these data for a long time, and some related papers have been published in China.
In general, from the perspective of technology and understanding of Mars, we need to take this step ourselves. No one can help you eat, no one can help you walk. From this point of view, we have gone very fast from the first step, not a small step, but a big step.
Duan Yulong: this big step is not a step that we can easily see. From rockets to satellites, to manned aviation, and the construction of tiangong-2, it is precisely the Chinese who have come step by step. With such accumulation, we have seen tianwen-1 arrive on Mars, making a very detailed observation of Mars, and getting enough data. After the formulation of a feasible plan, tianwen-1 will also land on Mars according to the original plan, which is of great significance to all mankind It’s a very important step. I hope that the Mars probe including tianwen-1, today’s hero perseverance, and other Mars probes can make a lot of achievements on the way to Mars, step by step, and bring more achievements, because these achievements are the progress of science, as well as the progress of science The progress of all mankind.
That’s all for today’s live broadcast. Thank you very much, Yongchun. I hope you will have the opportunity to meet and chat like this in the future. I hope you will continue to pay attention to Tencent News and the production of many wonderful scientific contents in Tencent News. I hope you will have the opportunity to get together with us to talk about Mars, the depths of the universe and the stars and the sea. Yongchun has a saying that I particularly like. Only when we have the stars and the sea in mind can we see further, go further, and establish a new understanding of ourselves and the world.
Zheng Yongchun: Yulong has finished what I said. The technology now makes us more convenient. We can often meet on the Internet, and also let us know the progress of the world in real time. All progress is the progress of human beings. The Chinese people also have such a mind. We can eagerly expect other countries and nations to achieve success in the journey of Mars exploration It’s a lot of work. Once again, I wish you all good luck and health in the year of the ox.
Duan Yulong: good luck in the year of the ox, good luck in the year of the ox. I wish you all the best. Today’s live broadcast ends here. Goodbye.