At 10:49 on May 17, China successfully launched the 56th Beidou navigation satellite with the Long March 3B carrier rocket at the Xichang Satellite Launch Center. This satellite belongs to the geostationary orbit (GEO) satellite and is the first backup satellite of China's Beidou-3 project. After entering orbit and completing in orbit testing, it will be connected to the Beidou satellite navigation system. The launch of this satellite will further enhance the system's service performance, which is of great significance for promoting the unique services of the Beidou system and supporting its large-scale application. The satellite has realized on orbit hot backup of existing geostationary orbit satellites, which will enhance the availability and robustness of the system, increase the current regional short message communication capacity of the system by one-third, improve the satellite based enhancement and precision single point positioning service performance, and help users achieve fast and high-precision positioning. The satellites and supporting launch vehicles launched this time were jointly developed by the Fifth and First Research Institutes of China Aerospace Science and Technology Group. This is the 473rd launch of the Long March series of carrier rockets and the first mission after a thousand days of high-density networking of the Beidou-3 project. As a result, China's Beidou has taken a new and solid step, marking the beginning of a new stage in the development of China's navigation industry. In 2009, the Beidou-3 project was approved, inheriting the five major skills and having stronger capabilities. Different from foreign satellite navigation systems, the Beidou-3 system uses a hybrid constellation mode and consists of three satellites in the Earth's middle circular orbit (MEO), inclined geosynchronous orbit (IGSO), and geostationary orbit. On November 5, 2017, the first batch of Beidou-3 networking satellites were launched into orbit; On June 23, 2020, the 55th Beidou satellite successfully entered orbit, and the Beidou-3 system officially completed the construction of a hybrid constellation. The reporter learned from the Fifth Academy that although there are not many GEO satellites in the Beidou system, they bear the responsibility of providing enhanced services for the improvement of the technical indicators of the Beidou navigation system. The 56th Beidou satellite inherits the characteristics of the previous GEO satellite, and has five major capabilities: radio navigation, radio measurement, precise single point positioning, satellite based enhancement, time synchronization between stations and positioning. It can provide navigation and enhancement services for users in China and surrounding areas. At the same time, the development team upgraded and upgraded some of the single machines of the satellite, significantly enhancing the navigation signal power and information rate, further improving the continuity and stability of uplink injection. Feng Wenjing, the overall chief designer of the Beidou-3 satellite of the Fifth Academy, stated that with the launch of the satellite, the regional short message service of the Beidou system will expand from "three channels" to "four channels", greatly improving system capacity and service performance. In addition, the satellite will also conduct in orbit experiments to verify and optimize the high-precision system design scheme, laying the foundation for the continuous development of Beidou navigation in the new era. After three years of testing and stricter standards, the 56th Beidou satellite was designated as the "backup star" at the beginning of the development project. As a "little brother", although it was produced at the same stage as the "brothers and sisters", it has undergone more trials and tests. According to the overall requirements of the project, the overall strategy of "ground backup as the main approach and on-demand launch into orbit" is adopted. The Beidou-3 system has been operating steadily for the past three years, and the "in orbit satellite" is operating well, resulting in different launch requirements for the "backup satellite"