just  The last global networking satellite of beidou-3  Fire up and take off!  
   
   This is the third geostationary orbit satellite of beidou-3 global satellite navigation system. With the completion of the satellite in the "big chess game" of beidou-3 global networking, all 30 beidou-3 networking satellites have been in place,  The deployment of beidou-3 global satellite navigation system constellation has been fully completed.  
   Beidou-3 global satellite navigation system consists of three satellites in different orbits: MEO satellite (earth mid circular orbit satellite), IGSO satellite (inclined geosynchronous orbit satellite) and GEO Satellite (geostationary orbit satellite), including 24 MEO satellites, 3 IGSO satellites and 3 geo satellites.
 
 Among them, geo satellites are quietly stationed in the space 36000 kilometers above the earth and shoulder an important mission - to provide enhanced services for the improvement of the technical indicators of Beidou navigation system. They are also affectionately known as "auspicious stars".  The successful launch was the third in the "lucky star" family, and everyone affectionately called it "Fuxing".  

According to the relevant person in charge of the Fifth Academy of engineering, as the "big man" of the Beidou family, the Jixing family has a broad body and strong physique. The satellite platform adopted is a large-scale satellite platform in active service in China.  The auspicious star family has inherited the most distinctive features of Beidou system, active positioning and short message communication, which is the innovation of Beidou System in China.  
 

 The strong carrying capacity enables "Yixing", like the two "brothers", to have six abilities: radio navigation, radio measurement, satellite based enhancement, precision single point positioning, power enhancement, inter station time synchronization and positioning, which can provide navigation and enhanced services for users in China and surrounding areas.  
 

 The reporter learned that as the last "closing star" of Beidou global navigation system,  "Yixing" is also a masterpiece in terms of localization. With independent intellectual property rights and core technologies, the localization rate of Beidou navigation satellite stand-alone and key components has reached 100%.
 
 In addition, the service capacity of Beidou 3 is 10 times larger than that of Beidou 2. More people can enjoy the inclusive services of Beidou navigation system in the fields of communication, electric power, finance, surveying and mapping, transportation, fishery, agriculture, forestry and so on.  

Behind the scenes:

Why press the pause button 12 hours before launch?

according toLi Zhen, deputy chief designer of Long March 3A series rockets of rocket AcademyOn the evening of June 15, when the launch team was conducting a negative 12 hour pre launch function inspection, a technical problem was found, resulting in the pressure data lower than the design index requirements. Then the launch team carried out problem troubleshooting and found the fault point in a short time.

Although the indicators have been normal after troubleshooting, the astronauts have a basic principle before launch, that is, filling without doubts and going to heaven without hidden dangers.Therefore, the Beidou Engineering Headquarters conducted careful research on this technical problem. After discussion, the headquarters decided to postpone the launch.

"Astronauts who insist on 'being strict, careful, meticulous and realistic' in their work are also fighting for honor. For astronauts, every success will add one point of honor, and one failure is enough to clear the past honor." Li Zhen said.

When asked why he dared to press the "pause" button on such a launch mission of national concern,Li Zhen said, "this launch is the last star of the last step of the Beidou global navigation project and the symbol of the full completion of the construction of the Beidou system. Behind the decisive decision-making, it is deceptive to say that there is no pressure,However, in the face of great pressure, the headquarters made such a decision because it respected science and adhered to principles.

 

      Highlight 1:  Constellation inter satellite link technology to realize unlimited connectivity     The beidou-3 development team of the Fifth Academy of Aerospace Science and Technology Group has conquered the constellation inter satellite link technology and adopted the integrated design of inter satellite and satellite ground transmission functions to realize the link interworking between satellites and satellites and between satellites and ground stations. That is to say, although the Beidou satellite on the other side of the earth is "invisible", the inter satellite link of Beidou satellite can also contact them.

 Highlight 2:  New technology to achieve long satellite life  Chi Jun, chief commander of beidou-3 satellite of the Fifth Academy of Aerospace Science and technology group, said that once the satellite navigation service is interrupted, the normal operation of the country and society will be greatly affected. Therefore, strict design requirements are put forward for the reliability and continuity of satellite navigation.  Beidou-3 satellite has taken a number of reliability measures to make the design life of the satellite reach 12 years and reach the advanced level of international navigation satellites.

    Highlight 3:  The new "artifact" makes the service "zero error"     China's Beidou satellite adopts rubidium atomic clock and is also equipped with a newly developed domestic hydrogen atomic clock with higher performance. Although the mass and power consumption of hydrogen atomic clock are larger than rubidium atomic clock, its stability and drift rate are better. The on orbit application of spaceborne hydrogen atomic clock plays an important role in realizing Beidou navigation and positioning.
 

 

      Long march 3A series launch vehicles are composed of three large cryogenic liquid launch vehicles: Long March 3a, long march 3b and long march 3C. They are the rocket series with the largest number of launches and the highest success rate in China. They cover the launch tasks of most high orbit spacecraft in China. They are the "main force" of high-density launch of long march series launch vehicles.
 
 On June 23, 2020, the long march 3B carrier rocket developed by the first Institute of China Aerospace Science and Technology Corporation put the Beidou 3 satellite into the predetermined orbit. So far,  The long march 3A series launch vehicle has carried out 44 launches, successfully escorted 59 Beidou navigation satellites into the sky (including this mission), and completed all the launch tasks of the Beidou navigation project, with a launch success rate of 100%. The long march 3A series rockets are also vividly known as the "Beidou special train".  
 

 

20 years       The duration of Beidou navigation mission performed by long 3A series rockets
       

 Since the long march 3A series launch vehicle launched China's first Beidou navigation test satellite on October 31, 2000, the long march 3A series rocket has carried out 44 launches, successfully escorting 4 Beidou navigation test satellites and 55 Beidou navigation satellites into the sky, with a success rate of 100%, Therefore, the long march 3A series rockets are also known as the "only car" of the Beidou navigation project.
 
 100%  Beidou navigation satellite launch mission won
 
 Since the launch of the first beidou-2 navigation test satellite in 2007, 55 Beidou navigation satellites have been put into the predetermined orbit with 40 successful and perfect performances of the chang-3a series rockets in the past 12 years. If we include the Beidou navigation test satellite launched earlier, then the chang-3a series rocket escorted 59 Beidou satellites into orbit with a 100% success rate of 44 launches.
 
 19 days  Beidou networking high density launch record
 
 Since the global networking construction was launched in November 2017, Beidou navigation project has entered the "fast lane" of construction. In particular, in 2018, long march 3A series rockets were launched 10 times and 18 Beidou navigation satellites were successfully put into orbit.  
 It is worth mentioning that in the 133 days from July 10, 2018 to November 19, 2018, the long march 3A series rockets were launched seven times and successfully put 12 Beidou navigation satellites into orbit. The average interval between one rocket launch is only 19 days, creating a record of high-density launch of Beidou networking.

 12 times  Times of beidou-3 networking tasks performed by the upper level of expedition-1
 
 On November 5, 2017, the long march 3B / yuanzheng-1 carrier rocket successfully put the first double satellite of beidou-3 into the predetermined orbit at Xichang Satellite Launch Center. The satellite launched this time is the 24th and 25th satellites of Beidou satellite navigation system, and also the 1st and 2nd networking satellites of Beidou 3, opening a new era of global networking of Beidou satellite navigation system.
 
 The upper level of expedition 1 successfully completed 12 missions during the launch of Beidou 3 project, and accurately put 24 MEO orbit satellites into the predetermined orbit, which laid a solid foundation for the final successful completion of the networking task of Beidou 3 project.

 112 times  China's single series launch vehicle with the largest number of launches
 
 The chang-3a series rocket is the single series launch vehicle with the largest number of launches in China. Up to this launch mission, it has been launched 112 times.
 
 The reason why it can become the single series launch vehicle with the largest number of launches in China is that the chang-3a series rocket can be launched with one arrow and one satellite or multiple satellites. It can be used not only for standard geosynchronous transfer orbit launch, but also for hypersynchronous transfer orbit or low angle synchronous transfer orbit launch, as well as deep space detector launch, It can also realize lateral maneuvering orbit change, multiple spins, racemization, orientation, etc. during flight, which can meet a variety of different use requirements of satellite users.

   18 times  Number of beidou-3 missions performed by long-range 3A series rockets
 
 Since the first beidou-3 launch of the long-range 3A series rockets on November 5, 2017, the long-range 3A series Rockets have completed 18 launches in more than two years, meeting the requirements of beidou-3 rapid networking.
 
 The development team has increased the development and production capacity of liquid launch vehicles from 2 to 3 rounds a year to 8 to 10 rounds; The launch cycle was reduced from 60 days to 21 days, and the launch team was reduced from more than 200 to about 100, laying a solid foundation for the successful completion of high-density launch missions and the innovative development of launch vehicle management technology.

 22 times  Number of Beidou navigation satellite launch missions performed by long march 3B carrier rocket
 
 Since the Beidou navigation project was launched for the first time in 2012, the changsany rocket has carried out 22 Beidou navigation project launch missions and successfully sent 37 Beidou navigation satellites into space.  Because it has the characteristics of high task adaptability and high reliability  , Chang San Yi is also the most frequently launched rocket among the "three brothers". (the long march 3A rocket was launched 12 times and the long march 3C rocket was launched 10 times.)  
 Huaxia Beidou,  The sword points to the sky.  The sea of stars,  Here we come!

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