Two years ago, China's "Shepherd" rescued a blockbuster satellite

The Global Satellite Navigation System, which was comprehensively built on July 31, 2020, was one of the most dazzling achievements in Chinese aerospace in the past ten years. This global satellite navigation system independently built and independent of China has played an irreplaceable role in maintaining national security and serving economic and social development. From the official launch of 1994 to the completion of 2020, the Beidou satellite navigation system took 26 years. A total of 44 Beidou launch tasks were organized, and 59 Beidou satellites were sent to the scheduled track, and the task success rate reached 100 %!

Behind the world's attention, in addition to the star and arrow with excellent performance, there is also a mysterious "shepherd" team always guarding the largest constellation system in China so far. Especially in the deployment of the GEO-2 satellite networking deployment in March 2020, this team overcomes various unfavorable factors such as the new crown epidemic. In the satellite sudden failure, facing the situation of out of control, relying on oversupply, carry forward the spirit of the spirit Successfully rescued this satellite and sent it into the scheduled track to ensure that the Global satellite navigation system of Beidou III was successfully completed as scheduled. As the guardians of Chinese space assets, this unknown team also tried to turn the tide again and again, practicing the great spirit of "integrating glorious into the constellation of the motherland".

Global satellite navigation system schematic diagram of Beidou III

A thrilling 5 minutes

At 19:55 on March 9, 2020, in the Xichang Satellite Launch Center, my country uses the Long March No. 3 to carry the Rockets to successfully send the Beidou No. 3 satellite to more than 200 kilometers near the nearby location, and the distance of more than 36,000 kilometers from a distance of more than 36,000 kilometers The large ellipse orbit, with the opening of the satellite solar windsurfing, the launch task was successful. As the 29th satellite of the Global Satellite Navigation System of Beidou, the successful launch of the GEO-2 satellite in Beidou III means that China Beidou is only one step away from the global network. Next, as long as the GEO-3 satellite is successfully sent to the scheduled track in June of that year, the deployment of the Global Satellite Navigation System of Beidou III will be successfully ended.

However, at the Xi'an Satellite Surveying and Control Center, the successful big red screen of launch shows the beginning of the "shepherd" in China's "Shepherd". According to the plan, after entering the large ellipse orbit, the GEO-2 satellite of Beidou III will implement 5 orbit changes, gradually raising the height of the near-near place of the satellite track, and reducing the orbital inclination angle. The ultimate goal is to allow satellites to enter the earth's static track more than 36,000 kilometers away from the earth.

In the first orbit on the second day of launch, everything was as usual, but accidents occurred in the process of implementing the second track. After the satellite main engine continued to ignite ten minutes, remote test data showed that the satellite posture suddenly changed. "The screen of the command hall shows that there is an interference torque that leads to the disturbance of the satellite posture. , Push this person to the left, and push it to the right.

The abnormality of satellite posture usually causes a series of catastrophic consequences. Wang Xin said that the unstable attitude of the satellite will cause the device on the star to be damaged, so that it is not completely unable to work. What is more serious is that the communication between the satellite and the ground may cause the ground personnel to be unable to monitor and control the satellites. Essence

Beidou No. 3 GEO-2 Satellite Rescue Mission Scene

In the face of sudden abnormalities, the flying control staff of the Xi'an Satellite Surveying and Control Center did not even have much time to be shocked and dazed. Although the gesture of the satellite is unknown for the first time, everyone must urgently formulate the gesture of the satellite to quickly control the satellite.

Generally speaking, each launching task is in the command hall of the Xi'an Satellite Surveying and Control Center, and the technical team of the central flight control team and the satellite developer will jointly perform early measurement and control tasks in order to better grasp the relevant situation and the satellite related situation and state. However, in March 2020, the new crown epidemic was raging throughout the country. Although the technical team of satellite developers was also at the Xi'an Satellite Surveying and Control Center, due to the requirements of the epidemic prevention and control, the two teams could only be scattered in the two work halls to implement this. In the secondary task, at the crisis of the satellite sudden failure, the data cannot be shared face -to -face, and the exchange of ideas can only be discussed by telephone and dispatching personnel. At that moment, this will undoubtedly add difficulty to emergency disposal.

Faced with the dangerous situation of continuous increased satellite interference torque data on the big red screen, the ground flight control personnel decided to set a critical parameter for satellite after research. Once the parameters of the satellite posture change reached this value, the ground personnel must send it immediately to send it immediately Instructions to urgently turn off the main engine of the satellite to ensure the safety of the satellite. "At that time, if the satellite attitude variable parameters exceeded this critical point, the satellite may be lost and out of control. Before that, if we did not implement the main engine switching, then the satellite can no longer accept the instructions to implement the shutdown and shut down. In the end what the satellites are in, we can't know where to fly. "Wang Xin said that because the main engine was working in the power system of the satellite at that time, everyone was initially judged that it should be that the main engine of the satellite should cause problems to cause problems to cause problems to lead to problems. The change of the satellite posture, once the main engine is closed, the gesture of the satellite should be able to stabilize.

In the end, five minutes after the satellite posture was changed, the mutation parameters reached the critical point, and the ground personnel urgently sent the instructions to implement the main engine engineering of the satellite. After shutting down, the big screen of the command hall soon showed that the trend of satellite attitude change gradually slowed down. "In other words, within about five minutes of the satellite, we have initially discussed the problem of satellite, formulated and implemented the treatment methods to ensure that the satellite is not completely out of control. Memories say. 20 days when you are angry

Rescuing the satellite from the edge of the out of control did not let the ground flight control staff relieved. As a satellite with the most functional, most signals, largest body shapes, and longest life span as the Beidou No. 3 satellite system, the cost of the GEO 3 GEO rail satellite is naturally expensive. As a result, losing its due role will undoubtedly cause huge economic losses.

In addition, according to the overall planning of the Global Satellite Navigation System of Beidou III, since November 2017, it is necessary to complete the deployment of 30 Beidou 3 satellites through high -density 18 times in more than two years, thereby achieving Beidou 3 The global network of satellites. Wang Xin said that the networking plan is very full and interlocking. For the major systems of the entire large project, it is difficult to have a "balance" to replenish a satellite shortage within the scheduled time. "As the second puppet satellite before the comprehensive completion of the system, if the GEO-2 satellite of Beidou III fails to put it in operation normally, it will need to wait at least the previous year to complete the launch of the 'substitute' satellite, which means this means The expected goal of completing the network in 2020 will be difficult to achieve, and the relevant plans for building Beidou III global satellite navigation systems will be delayed. "

Beidou No. 3 GEO-3 satellite test and control task site

Faced with such a satellite that was not allowed to lose, the task staff who followed the Beidou project along the scene were not willing to give up. After resolving the crisis of satellite out of control, the ground flight control staff immediately sent instructions to allow the satellite posture to gradually return to normal and enter the security working mode. Then they began to conduct meticulous development of satellite abnormalities and data with the technical team of the satellite developer. Analysis, try to locate the fault point of the satellite as soon as possible.

Combined with the results of the analysis, the satellite developer applies the identification of satellites to conduct a "re -inventory" test on the ground through simulation and other means. As a result, the reason why the satellite is out of control is because Ferry phenomenon. "Popularly, a hole in the throat of the satellite main engine ink is burned out, which will cause the thrust of the engine to unstable. The work quality leaked from the burned place will disturb the satellite attitude, resulting in a change of satellite posture change. "Wang Xin said.

At that time, satellites stayed at a transition orbit of more than 6,000 kilometers in a nearly place. If you want to continue to climb to the earth's static track, you must rely on the height of the satellite's own power system to raise more than 30,000 kilometers. Because the previous rail transformation schemes were formulated around the normal operation of the satellite main engine, there was a sound claim that since the satellite attitude has stabilized, you can try to re -ignite the satellite main engine and implement the track change according to the original plan.

However, there is another voice that the ablation point of the satellite main engine injector will always produce interference torque, affecting the stability of the satellite gesture, and the sprayed of the work quality may Cause damage, the risk of this plan is too great. So a more complicated but safer solution eventually won: the main engine of the satellite, but using the smaller thrust on the star to maintain the stable track of the satellite gesture Essence

However, this scheme must also face multiple restrictions in the process of implementation. Wang Xin introduced that during the process of satellite -changing, it is particularly critical to master the state of satellite at any time and send instructions to accurately implement the satellite thrust device to open and shut down. However, due to the limited scale of my country's measurement network and control network, the full arc test and control of satellites cannot be achieved at rail operations. Therefore, in the choice of satellite -changing points, in addition to as much as possible to the most "time -saving and labor -saving" rails at the orbit, The track change point must also be within our scope of measurement and control.

In addition, in this more complicated track change process, it is necessary to save as much as possible to save the fuel of satellite and reduce the impact of the life of the satellite rail control. "This requires us to formulate a reasonable ignition strategy, optimize satellite fuel consumption, ignition track position, and ignition arc segments, and use different thrust combinations to implement ignition at different orbit points. Satellite -rail control thrust device is super life. "Wang Xin said.

After considering various factors, after a group of "the strongest brain" in the task team, the combination of three sets of thrust -rail control thrustrs is matched with a reasonable working time of each group of thrustrs, adjusting the reasonable working time of each set of thrustrs, adjusting the adjustment, adjustment Good thruster jet direction. After pilot ignition, confirming that each set of thrustmen can ensure the stability of the satellite, and finally the exciting rail transformation plan began to implement.

3月28日，在耗时近20天，实施了近20次精确变轨后，北斗三号GEO-2卫星最终依靠星上十余台姿轨控推力器，实现了持续抬升轨道高度，逐渐Pressing the track inclination and smoothly set the earth still at the earth with a static earth of more than 36,000 kilometers away from the earth. The overall satellite of the Guan Beidou Project was finally successfully rescued! On June 30, 2020, the last network satellite Beidou III GEO-3 satellite fixed point of the Beidou III system was successful.

What is even more valuable is that after the calculation of the technical personnel of the Xi'an Satellite Surveying and Control Center, the unexpected "savior" task did not have a significant impact on the design of satellite design and use. According to Wang Xin, thanks to the redundant design of the satellite development team, the amount of fuel that the satellite carried, and the actual use of the star devices exceeded the design and use period. With the optimized rail change strategy, try to shorten the ignition time of the satellite rail control thrust, the ultimately consumed fuel, and the loss of the losses caused by the thrust device, the remaining service life of the satellite can still be greater than the design life of the design and use. "

Ten years of splendid and glorious

"Space assets are national strategic assets. We must take good care of it and protect it well." In the past ten years, the number of satellites in my country has become more and more, the functions are stronger, and the value is increasing. As the most solid guardian of Chinese space assets, the "Shepherd" team of the Xi'an Satellite Surveying and Control Center did not humiliate the mission, and wrote more "hidden and great" in the vast universe.

"The increasing number of Chinese satellites and the increasing complexity of the space environment means that the tasks we have undertaken are getting heavier, but the significance is getting more and more significant." "Reporter, now, the number of various satellites that the Xi'an Satellite Surveying and Control Center has long been managed for a long time has reached more than 300, of which more than one -third of the satellites are in the state of service. There are problems such as aging of device, but with their excellent operation and maintenance, the current working status of the satellite is still good, and in the space, it will give up the heat for the service of the national family and the people.

The secret of "Chinese Star" in space in space lies in the strong skills and the spirit of courage. Yang Yongan said that in the past ten years, the Xi'an Satellite Surveying and Control Center has carried out a number of innovative explorations. At present, it has formed a full -process failure diagnosis and maintenance of "physical examination", "diagnosis" and "treatment" on track satellites. ability. Summarize the satellite failure analysis plan and rescue plan formulated by the experience of performing surveying and control tasks over the years. It can deal with most of the current satellite failures. It is also the guarantee of this system. In ten years, many satellite rescue missions, including Zhongxing 9A and Beidou No. 3 GEO-2 satellites, created many space miracles.

Xi'an Satellite Surveying and Control Center Beidou Surveying and Control Team

However, the value created by satellite "rebirth" is not always known. Just like many other aerospace systems, "doing a lot of money and a famous name" is also deeply embedded in the tradition and belief of the Xi'an Satellite Surveying and Control Center.

In the 1970s, China ’s aerospace measurement and control network began construction. A group of highly knowledgeable young scientific and technological personnel participated in it and embarked on the road of vigorous construction in my country. They leaned over the foundation of the country, woven constellations, and shepherds. The story of winning space was a secret secret. The first song named "The Motherland will not forget". The phrase "I don't need you to praise me, I don't want you to repay me, and I integrate the glorious constellation of the motherland." Photo.

Global Times-Global Network Reporter Fan Wei special reporter Lu Binghong

- END -