When did the China spacecraft land on Mars?

"Lookout" article: When will the China spacecraft land on Mars?

After the US Mars Reconnaissance Orbiter sent back the first batch of high-definition photos of the surface of Mars, people began to pay attention. Can China also land on Mars?

Text/"Looking at News Weekly" reporter Sun Yinglan

"I noticed the news of the first batch of high-definition photos of the surface of Mars sent back by the US Mars Reconnaissance Orbiter in March 10. These photos were taken when the spacecraft was 2489 kilometers away from the surface of Mars. Next, the aircraft will also enter the atmosphere of Mars and run in a circular orbit closer to the surface of Mars.

The height of the plane will be much lower than it is now. This scientific research activity once again shows that American space technology still occupies a leading position in the world in various fields. In contrast, there is still a big gap in China. Jiang Jingshan, academician of China Academy of Engineering and deputy chief designer of China Lunar Orbiting Project, made the above remarks in an interview with Outlook News Weekly.

The US Mars Reconnaissance Orbiter was launched on August 12 last year. NASA's Jet Propulsion Laboratory announced that the spacecraft will explore water resources and life clues on Mars and find a suitable place for future Mars landing. The vehicle weighs about 2. 1 ton and is equipped with six scientific detection instruments, including high-definition imaging equipment, Mars background camera, color imager, small Mars detection imaging spectrometer, climate detector and shallow surface detection radar.

Explore Mars after the lunar exploration.

The distance from the spaceship to Mars far exceeds the distance to the moon. Can China land on Mars?

Long Lehao, academician of China Academy of Engineering, director of Science and Technology Committee of China Academy of Launch Vehicle Technology and deputy chief designer of China's lunar exploration project, told Outlook News Weekly that China has the ability to launch spacecraft with practical value such as satellites and detectors into any planetary orbit. But judging from China's economic strength and comprehensive technology, there is still a big gap. Only the rocket technology itself, the gap between China and the United States is about 10 ~ 20 years, and the satellite detection method is relatively backward.

"Satellite applications and satellite applications, manned space flight and deep space exploration are the three major areas of human space activities. China is conducting research in these three areas. " Zhu Yilin, a researcher at the China Academy of Space Technology and an academician of the International Academy of Astronautics, said in an interview with Outlook News Weekly.

China has always attached great importance to satellite application and its research, because it is closely related to national economic and social development. Man-made earth satellites have the widest uses, the largest number of launches and the most obvious benefits. After more than ten years' efforts, we have mastered the basic technology of manned space flight and broke through the first level, namely manned space flight and safe return. The second step is astronaut extravehicular activities and space rendezvous and docking, which are currently being done. Deep space exploration, China is still in its infancy, such as China's "Chang 'e-1" project around the moon. As for Mars exploration, it should be after a major breakthrough in the lunar exploration project.

In Zhu Yilin's view, besides the long distance, there are many aspects of lunar exploration that can accumulate experience for Mars exploration, so China will explore the moon first.

"Regarding Mars exploration, the country has no specific plans at present, but I think that as long as the lunar exploration plan is completed, Mars exploration will be put on the agenda. Be sure to explore Mars after exploring the moon. It is estimated that it will be 20 10 years before it can be put on the agenda. By then, we will have certain conditions for deep space exploration, regardless of the country's economic strength or technical level. Of course, we can also cooperate with other countries to jointly launch detectors. From an international perspective, the development trend of Mars exploration is to carry out international cooperation, which is an important way to save money, improve the level and shorten the development cycle. "

Mars exploration is the frontier of space technology today. Scientists in China began to study the necessity and feasibility of Mars exploration as early as 10 years ago. Both the National "863" Plan and the "973" Plan have the topic of "Planetary Exploration", which mainly investigates the exploration progress of Mars and other planets abroad, summarizes the scientific achievements of foreign Mars exploration, and makes a preliminary study on the scientific objectives and detector scheme of China's initial Mars exploration. The white paper "China Aerospace" also lists "deep space exploration" as an important content of space science.

The difficult problem of Mars exploration

Jiang Jingshan believes that deep space exploration needs technical capabilities in transportation, measurement and control, orbit, information and data transmission and detection. "It seems that we all have these technical capabilities, but the question is on what scale and at what level."

Judging from the carrying capacity of satellites, it is not a big problem to send an aircraft to Mars. In terms of measurement and control (detection and control), including orbit measurement and data transmission, the technology is mastered, but there is still a big gap to achieve the high accuracy of photos sent back by the American Mars reconnaissance orbiter.

To detect Mars, we must first solve the problem of large antenna in measurement and control and data transmission. The straight-line distance from the earth to Mars is about 60 million to 80 million kilometers at the latest and about 300 million kilometers at the farthest. How to transmit information at such a distance is very important. German antenna diameter 100 meter, the United States 60 meters 80 meters. At present, China has developed an antenna with a diameter of 50 meters, and many problems need to be solved to develop an antenna with a larger diameter. In precision orbit measurement, we have an improved USB system, which will be used together with VLBI technology in the lunar orbit project next year. There is basically no big problem with the detection technology.

Generally speaking, the realization of Mars exploration needs to establish a powerful antenna system, and our biggest difficulty is that the ground measurement and control and data receiving system can not meet the technical requirements of Mars exploration. For example, American camera instruments have extremely high resolution. We have mastered this technology, but it is still difficult to achieve such high accuracy, which is related to the economic strength of China, and the device integration needs to be improved.

Academician Jiang Jingshan suggested, "For deep space exploration, we should take the lead in pre-research. Don't wait until the lunar exploration is completed to start deep space exploration, because the solution of many problems requires a process. "

Zhu Yilin also believes that it is difficult to develop a high-sensitivity ground receiving antenna with the technology we have at present. "It is also possible that after 20 10 years, we may build such a large measurement and control antenna, but this condition is not available yet."

Theoretically, the orbit of the probe launched from the earth is designed in advance, but it takes seven or eight months to fly from the earth to Mars, covering more than 300 million kilometers, and it is necessary to constantly adjust the flight orbit and adjust the deviation. The so-called "missing a millimeter is a thousand miles away." According to the ground instructions, it takes more than half an hour for electronic signals to be transmitted from Mars to the ground and then from the ground to Mars. It is very difficult to control the flight of the detector through ground observation, and it needs to rely on the "autonomous navigation ability" of the detector itself. However, we don't have this long-distance autonomous navigation capability at present.

Zhu Yilin said that the spacecraft consists of two parts, one is detection instruments, such as radars and other detectors; The second is the platform, which provides power supply, flight attitude, direction and temperature adjustment. For the detector, it is a guarantee service system. This system is extremely complicated.

First of all, we should design special detection instruments according to the mission and environment of Mars. And we don't know much about the environment on the surface of Mars. According to the available data, the environment of Mars is different from that of the Earth and the Moon, with severe storms and sandstorms, heavy dust, very low temperature, generally tens of degrees below zero, and extremely dry. Secondly, in terms of microelectronic devices, the materials are not light, small and miniaturized, and the accuracy is not enough, and the weight is relatively heavy. For example, satellites have the same function, but our satellites are heavier than those in the United States, and there are problems with raw materials and miniaturization. Third, in terms of time, the United States, Russia and other countries realized lunar exploration as early as the 1960s and 1970s, but we have just started, with a considerable gap. Because of the potential military application of space technology, we can't buy any key technology, so we can only innovate independently.

After 2020, the international situation may change greatly, and the possibility of international cooperation will increase. Deep space exploration at that time, Mars migration, etc. It is not only a matter of one country, but also requires international cooperation. "But in any case, cooperation needs capital and foundation, and key technologies can't be bought at any time. Only by mastering core technologies and key technologies can we have more voice in the international arena and have equal national status. "

Flying around the moon is the starting point of deep space exploration.

The white paper "China Aerospace" published in May 5438+065438+2000 10 clearly stated that China will "carry out deep space exploration, mainly lunar exploration" in the next decade. Specifically, we are carrying out the first phase of the lunar exploration project, planning the second and third phases, and studying deep space exploration at different levels.

As the deputy chief designer of China's lunar exploration project, Academician Jiang Jingshan believes that the lunar exploration project is the project that best reflects a country's comprehensive national strength and scientific and technological level, and it is also the hot spot of space activities in the world today. China's lunar exploration project will be divided into three steps. The first step is "circumnavigation". In 2007, a lunar probe will be launched to obtain information about the moon's resources and geographical structure. This year is a crucial year for the "Chang 'e Project". The five systems of satellite, launch vehicle, launch site, TT&C and ground application should complete system integration and joint test, and have the ability to perform tasks. The second step is called "falling". By 20 10, robots will be sent to the moon to "explore the road" and conduct on-the-spot scientific exploration on the moon. The third step is called "regression". The lunar lander not only landed on the moon, but also brought moon samples and research results back to Earth. The first lunar exploration initially identified four objectives: obtaining three-dimensional images of the lunar surface; Analyze the resource content and distribution of 14 elements on the lunar surface; Detecting the thickness information of lunar soil; Monitor the space environment of the earth and the moon.

Jiang Jingshan said that at present, the work of "circling the moon" is progressing smoothly, but "there is great pressure, because we have to strive for the success of the first round of circling the moon, and foreign projects around the moon have not yet succeeded."

Strictly speaking, the moon does not belong to deep space, it is only the starting point of deep space exploration. The moon is only 380,000 kilometers away from the earth, but it is not a simple thing for human beings to go that far away from the earth.

It has been more than 30 years since 1972, when the Apollo moon landing program ended. In 2004, the United States announced a new space exploration plan, preparing to send astronauts back to the moon and establish a permanent lunar base before 2020, and then try to land on Mars. Russia is also restarting its space development plan and preparing to walk on the moon around 20 15. Japan plans to establish a base on the moon around 2025, and let humanized robots take the lead. India plans to launch the first unmanned spacecraft around the moon in 2008. The European Space Agency plans to launch a lander to the moon around 20 10, and strive to send astronauts to the moon in 2020.

The unique minerals and energy of the moon are important supplements and reserves of the earth's resources, which will have a far-reaching impact on the sustainable development of human society. Jiang Jingshan summed up the unique resources of the moon into five types: height resources in space, environmental resources, hidden resources of planetary bodies (such as mineral objects and substances), solar energy resources and location resources.

As the beginning of deep space exploration, the lunar exploration project represents the overall strength of China, which is of national strategic significance and can also promote the development of many civil technologies. The moon is rich in resources, and the unique helium -3 element in the lunar soil is a clean, efficient, safe and cheap new nuclear fusion fuel that can be used for a long time in the future, which will change the energy structure of human society. Each gram of gold is 1 1 USD, while each gram of helium -3 is $400. Today, when the earth's resources are scarce, the rich resources on the moon have undoubtedly attracted the attention of all countries in the world.

Experts interviewed by Outlook News Weekly believe that space science and technology are of great significance to national economic development and national security. Only by using innovative thinking and mastering core technologies through independent innovation can China's comprehensive national strength be accelerated and there will be more and more "voices from China" in the international community.