Tiangong-1 is China’s first target aircraft. It was launched from the Jiuquan Satellite Launch Center at 21:16:03 on September 29, 2011. The aircraft has a total length of 10.4 meters, a maximum diameter of 3.35 meters, and a mass of 8.5 tons, consisting of an experimental cabin and a resource cabin. Tiangong-1's orbit time around the Earth is approximately 90 minutes.
The launch of Tiangong-1 marks China's entry into the second step and the second stage of China's "three-step" space strategy.
The so-called "Three Steps for China's Aerospace": In September 1992, the central government decided to implement the manned space project and determined the "Three Steps" development strategy for my country's manned space:
The first step is to launch a manned spacecraft, build a preliminary supporting experimental manned spacecraft project and carry out space application experiments;
The second step is to make breakthroughs in astronaut extravehicular activity technology and space vehicle technology. Rendezvous and docking technology, launching space laboratories, to solve the problem of short-term manned space applications on a certain scale;
The third step is to build a space station to solve the problem of large-scale, long-term manned space applications.
If the three-step plan is successfully completed, China will eventually build a basic space station. Later, our country will build a fourth space launch site in Wenchang, Hainan, after Jiuquan, Taiyuan, and Xichang. It will mainly undertake the launch missions of geosynchronous orbit satellites, large-mass polar orbit satellites, large-tonnage space stations, and deep space exploration satellites. .
Tiangong-1 completed two dockings: the first time: in the early morning of November 3, 2011, it completed the docking mission with the Shenzhou-8 spacecraft. The second time: Successfully docked with Shenzhou-9 on the afternoon of June 18, 2012 (14:14). The third time: Shenzhou 10 and Tiangong 1 completed automatic rendezvous and docking at 13:18 on June 13, 2013.
The Tiangong-1 target aircraft officially terminated its data service on March 16, 2016, fully completed its historical mission, and re-entered the atmosphere at 8:15 on April 2, 2018, with the landing area located at Central South Pacific region. Tiangong-1 fell to the earth under command control or burned up in the atmosphere. The landing area is in the central area of ??the South Pacific. It will not become space junk or endanger the ground.
Tiangong-2 (official version of space laboratory)
Tiangong-2 Space Laboratory is the second space laboratory independently developed by China after Tiangong-1. It is used for Further verify the space rendezvous and docking technology and conduct a series of space experiments.
If "Tiangong 1" is the experimental version of the space laboratory, then Tiangong 2 is the official version of the space laboratory.
The purpose of Tiangong 2: mainly to carry out Applications and experiments in the fields of earth observation and space earth system science, new space application technologies, space technology and aerospace medicine. Build China's first true space laboratory and release accompanying small satellites during launch. The future Tianzhou-1 cargo spacecraft will dock with the "Tiangong-2".
Achievements of the Tiangong-2 Space Laboratory: 1) Launched into orbit on September 15, 2016, it has completed 4 missions with the Shenzhou-11 manned spacecraft and the Tianzhou-1 cargo spacecraft. rendezvous and docking; 2) Tiangong-2 successfully supported two astronauts working and living in orbit for 30 days; 3) Breakthrough mastered a series of key technologies such as astronaut mid-term residence and propellant replenishment in orbit, and successfully completed the mission after the expiry date During its more than 300 days of service, a number of expansion tests were completed;
At 21:06 on July 19, 2019, the Tiangong-2 Space Laboratory controlled deorbiting and re-entered the atmosphere, and a small amount of debris fell into the South Pacific. Book a safe area.
The internal structure of Tiangong-2: The first is the main part. The actual cabin has a maximum diameter of 3.35 meters. The shape seems to be relatively simple in structure and is a cylinder. The internal equipment of Tiangong-2 carries the world's first dedicated high-sensitivity gamma ray burst polarization measurement instrument, as well as handles, astronaut operating desks, displays and other related high-end equipment that facilitate astronauts' movements in a weightless environment. Technology facilities.
Secondly, Tiangong-2 has optimized the design of the habitable environment for humans, improved the dining and sleeping environment, and added exercise equipment and entertainment facilities. In fact, the space laboratory is also a place for work. A warm home where you can rest can make the astronauts' 30-day life in Tiangong more comfortable, more convenient, and more colorful;
Tiangong-2 also built a liquid tank composed of mechanical, electrical, hydraulic and other components. Conducting on-orbit maintenance tests on the loop verification system and the robotic arm operation test terminal will accumulate experience for subsequent space station on-orbit maintenance design.
Thirdly, Tiangong-2 is equipped with a solar sail panel specially made for the satellite. The original solar sail panel has a wingspan of about 18.4 meters after unfolding. It is a polymer panel made of a special material and can provide sufficient power for Tiangong-2 to travel. Provide solar power storage to reduce the consumption of its own resources.
In addition, the Tiangong-2 Space Laboratory is equipped with a specially customized high-performance aerospace "digital camera", which is installed on the "belly" of Tiangong-2's earth observation surface and can follow Tiangong-2. The flight angle changes to image the ground from multiple directions.
The "digital camera" has the characteristics of high signal-to-noise ratio. The ground resolution can reach 100 meters, and the details of the surface scenery seen are very fine. These new detection images will be widely used in meteorological forecasting, atmospheric detection, climate change, agricultural production, marine disaster prevention, navigation safety and other fields.
The real purpose of Tiangong-2 is to complete a small space laboratory, aiming to solve space application problems of a certain scale and with short-term manned care, and to have the conditions to carry out various work and experiments.
The Tiangong-2 Space Laboratory is equipped with 14 space application loads such as the space cold atomic clock. Most of these application projects represent the international advanced level in related science and technology fields and are expected to achieve a number of major application results, which will Vigorously promote the development of my country's space science and applied technology, lead scientific and technological progress in related fields, and accelerate the implementation of the innovation-driven development strategy.
What’s great about Tiangong-2:
What’s great about Tiangong-2: Tiangong-2 is equipped with the world’s first space cold atomic clock (a cold atomic clock made using laser-cooled atoms, which can Further improve the time measurement accuracy), it is expected to achieve ultra-high accuracy of 10-16 seconds, and improve the current time measurement accuracy of humans in space by 1 to 2 orders of magnitude, which means that it takes about 30 million years for the cold atomic clock to generate 1 The error is within one second, which is a global leading level that the Chinese can be proud of in this field.
Amazing feature two: Tiangong-2 is equipped with a gamma-ray burst polarization detector. The Gamma-ray Burst Polarization Detector (POLAR), jointly developed by relevant scientific research institutions of my country and ESA, is the world's first high-sensitivity special equipment for measuring the polarization of Gamma-ray bursts and will provide an important means for studying Gamma-ray bursts
By conducting high-sensitivity polarization observations of gamma bursts and solar flares, it will help to further understand the nature of gamma bursts and further conduct research on the structure, origin and evolution of the universe. This payload will fill the gap between current gamma bursts and solar flares. There is a gap in high-sensitivity polarization measurement methods in burst observation (Gamma burst: It is a phenomenon in which the intensity of gamma rays from a certain direction in the sky suddenly increases in a short period of time, and then weakens rapidly. The duration is 0.1-1000 seconds, and the radiation is mainly Concentrated in the energy range of 0.1-100
Gamma burst was discovered in 1967).
Three great features: 1) It is equipped with a wide-band imaging spectrometer; 2) It is equipped with a three-dimensional imaging microwave altimeter; 3) It is equipped with a new generation of earth observation remote sensing instruments and earth sciences such as the ultraviolet limb imaging spectrometer. Research instruments: The application of these loads will improve my country's technical level in the fields of global climate change research, air pollution and atmospheric composition monitoring.
The fourth great thing: equipped with an incubator. A mini incubator with suitable temperature and controllable light was configured and designed on Tiangong-2. The entire process from planting seeds to harvesting can be realized. Previous space plant cultivation experiments lasted no longer than 20 days, and could only carry out experiments at the seedling stage. This is the first time that my country has completed the entire process of "from seed to seed" space plant cultivation experiments in space.
In addition, Tiangong-2 will also carry out a number of new material preparation tests and space experiments in basic science fields such as fluid physics. It will also release a companion satellite to carry out joint flights with Tiangong-2. test.
The achievements and significance of Tiangong-2
1. Tiangong-2 docking with the Shenzhou-11 spacecraft: a comprehensive test and proof of China’s spacecraft rendezvous and docking technology, and importantly, it marked the The Chinese have fully cracked and mastered the most cutting-edge technology that was once monopolized by the Soviet Union and the United States for 50 years. China is even the second country in the world that can implement space teaching. This technology requires Skylink communications, which currently only the United States and China can achieve.
2. The space station can accommodate many people for long-term stays: Jing Haipeng and Chen Dong lived on the space station for 33 days, setting a record for China’s longest manned space flight, marking China’s ability to produce astronauts for long-term stays. space station.
3. The space station docked Tianzhou-1: Tianzhou-1 is China’s first cargo spacecraft. The completion of docking of Tianzhou-1 is a very important final battle for our country’s space laboratory mission. China The successful docking of the first cargo spacecraft means that the Chinese have mastered the long-term stable cargo technology of the future space station.
4. On-orbit refueling: This is the so-called space refueling. This technology was completed by Tianzhou-1, which means that China’s fuel supply technology for long-term on-orbit flight of the Tiangong Space Station in the future has become mature.
5. Completed 14 high-level space experiments: The most noteworthy space cold atomic clock experiment is the first in the world. In particular, the quantum communication experiment is a major technological breakthrough completed by China in recent years. In addition, there are Biological experiments, etc.
6. The space station completed the robotic arm experiment: Tiangong-2 conducted its first test in my country.
The robotic arm is an essential artifact for China’s future construction of space stations, extravehicular maintenance and handling, and spacecraft rendezvous and docking. The robotic arm in the experiment is required to meet a series of stringent requirements such as light weight, high strength, high degree of freedom, and complex functions.
7. Adopt advanced modular system design. If a technical failure occurs on the space station, it can be quickly replaced and repaired in orbit. This is also an important breakthrough in China's aerospace technology.
8. The space station’s accompanying satellites and skylink technology have matured. The skylink communication designed by China that covers the whole world can achieve barrier-free communication between heaven and earth at any time. Currently, only China and the United States have this cutting-edge technology. Therefore, Chinese astronauts can watch "News Network" on the space station.
9. Completion of international cooperation: China’s space station carries the world’s first dedicated high-sensitivity gamma ray burst polarization measurement instrument. The cooperation project between China and Switzerland shows that China has opened up the door to international cooperation in the aerospace field. door.
10. The construction of China’s space station is accelerated: For example, the overdue service of Tiangong-1 and Tiangong-2 has helped my country master the relevant technologies for manufacturing and constructing the future Tiangong space station in advance, and the original plan of Tiangong-3 has been cancelled.
Since Tiangong-2 has been in orbit for more than two years, it has achieved fruitful results in earth observation. Up to now, the China Manned Space Engineering Space Application System has distributed 37TB of data products such as earth observation payloads, supporting more than 70 related project research. A number of breakthroughs and verifications of new technical systems and key technologies have been achieved on Gong-2, and relevant technical achievements have been transferred to operational applications such as ocean water color satellites, ocean power satellites, Fengyun precipitation measurement satellites, and Fengyun meteorological satellites. The adoption of these new technology systems and the substantial improvement in equipment functional performance have continuously extended the breadth and depth of earth observation applications.
The Tiangong-2 space laboratory was controlled to deorbit at 21:06 on July 19, 2019 under the instructions of the ground commander. The main body burned in the atmosphere, and a small amount of debris fell into the predetermined waters of the South Pacific.
Compared with the Tiangong-1 target aircraft, it is an uncontrolled re-entry into the atmosphere. Tiangong-2 adopted a controlled deorbiting method. This is the second time that my country has implemented a controlled deorbiting of a spacecraft after the Tianzhou-1 cargo spacecraft. The purpose of controlled deorbiting: to eliminate the threats that Tiangong-2 may pose to the space and ground environments in the future.
Why is controlled deorbiting adopted?
As the overdue service time of Tiangong-2 continues to increase, the on-orbit reliability will decrease. Once an on-orbit abnormality occurs, it will be in low-Earth orbit. Tiangong-2, which is out of control, will gradually fall. After falling into the atmosphere, some high melting point materials may not be completely burned, and a small amount of debris will fall to the ground, endangering the safety of people on the ground.
Currently, there are more than 20,000 space debris with a diameter larger than 10 centimeters around the earth. If space debris larger than 10 centimeters hits a spacecraft, it will be a disaster.
Therefore, there is a lot of space junk scattered in space, which often forces spacecraft to change lanes and avoid obstacles. Therefore, it has become international knowledge to actively destroy spacecraft.
What is the destination for a spacecraft to fall?
The wreckage of the spacecraft must fall into a designated location, the so-called "spacecraft cemetery." For example, the wreckage of Tiangong-2 is the same as that of Tiangong-1 and Tianzhou-1, both of which fell into the South Pacific.
According to the China Manned Space Engineering Office, the remaining small amount of Tiangong-2 debris will fall into the predetermined safe waters of the South Pacific within the range of 160 degrees to 90 degrees west longitude and 30 degrees to 45 degrees south latitude. .
It is a common international practice to fall into this area. After large spacecraft that usually operate in low-Earth orbit are retired, the common plan in various countries is to make the spacecraft fall into the deep sea area of ????the South Pacific in a controlled manner. The distance between this area and the land on all sides is more than 2,000 kilometers. The important thing is that there is almost no human activity in this area. Due to the influence of ocean currents, there are very few marine life, so it will not cause much damage to the ecology, so it is called "spacecraft" Cemetery".
According to statistics, in the past 50 years, more than 15,000 tons of spacecraft debris have fallen back to the earth, and there has never been an incident that harmed residents in densely populated areas. According to NASA statistics, in 2014 alone, more than 600 failed satellites, abandoned rocket stages and other debris entered the earth's atmosphere, with a total mass of more than 100 tons, but no reports of personal injury or property damage were ever received.
In history, spacecraft debris has fallen to the ground before, such as the United States' "Skylab 1" in 1979, but the designated location of the final fall deviated far from the prediction. NASA's original plan was to land in the ocean 1,300 kilometers south of Cape Town, South Africa, but the debris eventually fell to the surface of the southern Indian Ocean and the desert area of ??Western Australia. Moreover, "Skylab 1" fell in a partially controllable manner. Therefore, a fully controlled entry spacecraft can fall to a safe area more accurately.
In terms of spacecraft launches, according to statistics, since 2000, the success rate of more than 1,200 space launches around the world is approximately 94.3%. After all, space launches are a high-risk activity. China's Long March 2F T2 rocket, which is responsible for the launch mission of the Tiangong-2 Space Laboratory, is of very reliable quality. It has successfully carried out 11 launch missions and achieved consecutive victories. With such income, China still adopts a "start from scratch" attitude and strengthens quality control throughout the entire process in strict accordance with procedures and specifications to ensure the quality of flight product development.
Manned spaceflight is the most complex, technology-intensive, and innovative top technology in today's global science and technology field. It covers many scientific fields such as mechanics, astronomy, earth science, aerospace medicine, and space science. , involving systems engineering, automatic control, computers, aerospace power, communications, remote sensing, new energy, new materials, microelectronics, optoelectronics and other engineering technologies.
Since the launch of China's manned space program in 1992, it has obtained nearly a thousand national invention patents in the process of organizing and implementing 12 space missions, making breakthroughs and mastering a series of core key technologies, and promoted It has promoted the construction of my country's aerospace infrastructure and enabled my country's aerospace science and technology industry to achieve leapfrog development.
Over the past 20 years, China’s manned spaceflight has produced more than 2,000 technological achievements that have been widely used in various industries of the national economy. According to calculations by relevant research institutions, the input-output ratio is between 1:10 and 1:12. . Manned spaceflight has also driven technological innovation, process innovation and industrial improvement in raw materials, microelectronics, machinery manufacturing, chemical industry, metallurgy, textiles, communications, etc., expanded the channels for the transformation of scientific and technological achievements into real productivity, and injected innovation into the development of high-tech industries. Motivation and energy.
Honors won by Tiangong-2
The American "Time" magazine selected the 25 best inventions in the world in 2016, and the "Tiangong-2" space laboratory was among them. This is the first time that a spacecraft product from China appears on this list.
The 2016 "Influence on China" figure honorary ceremony selected by "China News Weekly" was held in Beijing. The China Aerospace Science and Technology Corporation’s Tiangong-2 and Shenzhou-11 manned space mission development teams won the title of Scientific and Technological Person of the Year.
"Scientific American" magazine selected the top ten science news around the world in 2016.
The Tiangong-2 and Shenzhou-11 manned missions were successfully selected.