The above picture Before the practice of No. 20 satellite transfer, the researchers put it into a sealed container. (Profile picture)
The following figure shows the electric propulsion test site of Dongwu platform. (Profile picture)
With the continuous improvement of the national economic development level and the continuous acceleration of the modernization of national defense, the demand for performance of my country's communication satellites is becoming more and more urgent. The Practice 20 satellite launched this time represents the highest technology of my country’s satellites, and its research and development platform Dongfanghong 5 satellite public platform will also meet the gap in the spectrum of future large satellite platforms, and will be my country’s high-throughput communications for the next 20 years. Satellite development lays a solid foundation
Recently, my country's Shishi 20 satellite was successfully launched by the Long March 5 Yaosan launch vehicle at the Wenchang Space Launch Site in China. This satellite is the first flight test star of a new generation of large-scale geosynchronous orbit satellite platform independently developed by my country, the Dongfanghong 5 satellite public platform (hereinafter referred to as the Dongwu platform). It is of great significance to further promote the development of my country's aerospace technology.
The Practice 20 satellite was developed by the Fifth Academy of Aerospace Science and Technology Corporation. It weighs 8 tons. It is currently the heaviest satellite developed by my country and the satellite with the highest scientific and technological content in my country. The first task of the satellite is to verify the East The five platforms are technically stable and carry more than 10 internationally leading technical verification loads, shouldering the mission of technical verification. Academician Zhou Zhicheng, chief engineer of the Fifth Academy of Aerospace Science and Technology Corporation, commander-in-chief of the Shishi 20 satellite, and commander-in-chief of the Dongfanghong 5 satellite public platform, told the Economic Daily reporter, "The naming of the satellite after'practice' is for the exploration of the star. Best interpretation".
develop satellite platform first
The communication satellite is aimed at realizing information transmission and is the neural network of the information society. It has the advantages of long communication distance, large coverage area, high channel quality, and large communication capacity. It is widely used in international, domestic or regional communications, maritime communications, television broadcasting and other fields.
"Developing satellites, platform first." The application performance of satellites is often realized by loading different functional loads on a common platform. At present, many countries in the world have adopted the design method of satellite public platforms. The platforms can be loaded with different payloads with a small amount of adaptive modification, thereby shortening the satellite development cycle, saving development costs, and improving satellite reliability.
For a long time, my country has formed the Dongfanghong series satellite public platform and type spectrum products represented by Dongfanghong-3 and Dongfanghong-4. With the continuous improvement of the national economic development level and the continuous acceleration of the modernization of national defense, the demand for performance leapfrogging of my country's communication satellites has become more and more urgent. The communication needs to provide faster Internet speed and more people online at the same time have become the voice of the whole society. "The original intention of developing the East Five Platform is because our country needs high-throughput communication satellites." Academician Zhou Zhicheng said. The Dongwu platform has the characteristics of "high load capacity, high power, high heat consumption, and high control accuracy", reaching the international leading level. It will fill the gap in the spectrum of the Dongfanghong series of large-scale satellite platforms, and can meet the needs of China's high-throughput communication satellites in the past 20 years. Demand.
According to Pei Shengwei, deputy chief designer of the No. 20 satellite of the Fifth Academy of Aerospace Science and Technology Group, in order to better exert the effectiveness of the No. 20 satellite in orbit and aim at the future development needs of aerospace, the research team has collected numerous pilot projects from all over the country. China has carried out multiple rounds of selection, and finally selected more than ten internationally leading "frontier and strategic" technical test loads, many of which are international or domestic first.
"Black Technology" helps satellites take off
The successful launch of the Practical 20 satellite has condensed the tremendous wisdom and hard work of scientific researchers, and the numerous "black technology" blessings have also given it a real skill.
Many people compare the solar wing to the "wing" of a satellite, but its function is not to fly, but to provide energy for the satellite. The actual size of the No.20 satellite is huge. Its "wings" are the largest solar wing in my country so far, with the longest wingspan and the most complicated deployment method. The deployment of the two wings is 10 meters wider than the wingspan of a Boeing 737 aircraft. The large increase in the area of the solar wing can bring a continuous source of super current supply, so that the Shishi 20 satellite will always have sufficient physical strength to provide more radio and television, mobile communications and other services.
Although the huge solar wing of the Shishi 20 satellite cannot swing up and down like wings, it can rotate at a low speed to ensure that it is always facing the sun, so as to maximize solar energy. Driving the rotation of the solar wing is a "small joint"-the solar wing drive mechanism. Although the solar wing drive mechanism is petite, it is a "hercules" that is resistant to cold, heat and shock. It can easily withstand the giant sun. The impact load caused by the unfolding of the wings can drive more than a hundred kilograms of mass rotation.
The solar wing of the Shijian 20 satellite can also provide super current. How to make these currents neither too large nor too small, and able to flow obediently to every corner of the satellite installation, and maintain the healthy operation of the satellite? To this end, the developers have equipped the satellite with a "big heart"-the power controller with the largest power in China. Compared with the first-generation power controller, its weight increased by more than 3 times and the power density increased by 2.5 times, but its weight only increased by 40%, realizing the domestic power controller from following and running to the leader. Of the leap.
With the increase of satellite Internet services, users' demand for large-capacity communication satellites is becoming more and more urgent. The high-throughput communication payload developed by the Fifth Academy of Aerospace Science and Technology Corporation carried on the No. 20 satellite covers Q/V frequency band payloads, broadband flexible transponders, etc. "The main way to increase the capacity of satellite communications is to increase the available frequency band bandwidth. If the geostationary orbit is compared to a highway in space, then this highway is the most congested on all space highways. However, the use of Q/V frequency bands is equivalent Yu has widened this highway by 4 to 5 times, which will greatly alleviate the current increasingly fierce international competition for geostationary orbit frequencies." said Li Feng, chief designer of the No.20 satellite of the Fifth Academy of Aerospace Science and Technology Group.
Large-capacity satellites play the leading role
From a set of numbers, we can see the "crossing" of Dongwu. Compared with the current "main products" Dongsan and Dongsi of the previous communication satellite family, the weight of Dongwu has been increased from 5.5 tons to 8 tons, the lifespan in orbit has increased from 15 years to 16 years, and the power of the whole satellite has increased from 10 kilowatts to 28 kilowatts. It is not difficult to see that the Dongwu platform is larger, higher and stronger, with the characteristics of "high load capacity, high power, high heat consumption, and high control accuracy", reaching the international leading level.
Through the sub-cabin modular design and digital development model, the Dongwu platform can greatly shorten the development cycle and improve production efficiency. For mature general-purpose payloads, the satellite development cycle does not exceed 36 months. At the same time, the single-machine localization rate of the Dongwu platform has reached 100%, which will strongly promote the development of my country's aerospace equipment.
As a public platform for large-scale satellites in my country’s geosynchronous orbit, the Dongwu platform can be widely used in high-orbit communications, microwave remote sensing, optical remote sensing, space scientific exploration, scientific experiments, and on-orbit services. Adaptive platform.
Therefore, the successful launch of the No.20 satellite in practice marks another step forward in the maturity of the Dongwu platform and has laid a solid foundation for the comprehensive promotion and application of the Dongwu platform. Especially at the moment, with the development of commercial satellite live broadcasting, emergency communications, mobile communications, Internet of Things and other services, as well as the steady development of conventional fixed satellite communications, the satellite communications industry has a rich demand and a broad market. The demand for emerging services represented by satellites is becoming increasingly urgent.
The industry predicts that by 2022, large-capacity (high-throughput) satellites will account for 50% of the global total satellite bandwidth; around 2022, my country's broadband satellite capacity demand will also reach more than 1TB. Facing the broad demand and serving the national "Belt and Road" and "Broadband China" strategies, my country will rely on the Dongwu platform to develop several communication satellites with a capacity of 100GB to 1TB, covering countries along the "Belt and Road" and surrounding areas.
Excerpt from [People's Daily Online]