HELSINKI — China launched the last pair of backup satellites for its Beidou navigation system late Wednesday, with an eye on a future, upgraded system.
A Long March 3B rocket equipped with a Yuanzheng-1 upper stage lifted off from the Xichang Satellite Launch Center at 9:14 p.m. Eastern Sept. 18 (0114 UTC Sept. 19). Two backup Beidou positioning, navigation and timing (PNT) satellites were successfully inserted into medium Earth orbits (MEO).
These satellites are the 59th and 60th launched for China’s Beidou global navigation satellite system (GNSS). The new satellites were provided by the Innovation Academy for Microsatellites under the Chinese Academy of Sciences (IAMCAS). The China Academy of Space Technology (CAST) has also developed and manufactured Beidou satellites.
The new pair will join existing Beidou MEO orbital planes as backups. This will allow maintenance and management of satellites while maintaining full operation of the system.
Additionally, the pair will conduct experiments for the future Beidou-4 next-generation navigation satellite technology. They feature improvements over earlier Beidou satellites in areas including autonomous integrity monitoring and atomic clock technology.
“The two satellites represent the final group of Beidou-3, serving as a bridge between the current and future generations. Aside from fulfilling their routine tasks as satellites of the constellation, they will also be engaged in technical validation and exploration projects,” Liu Yingchun, chief designer of the Beidou-3 system, told CCTV.
Beidou-3 refers to the global phase of the three-step Beidou program, which began with Beidou-1 and Beidou-2 satellites providing regional positioning services.
The system has 24 satellites in MEO, with eight in each plane, excluding backups. Additionally there are three Beidou satellites in inclined geosynchronous orbits and three satellites in geostationary orbits. Beidou is used for both military and civilian purposes.
Beidou-4 refers to a planned upgrade. China aims to build a more ubiquitous, integrated and intelligent comprehensive PNT system by 2035.
Though details are few, Beidou-4 will be designed to address technical challenges such as weak satellite navigation signals and interference, and aim to support underwater, indoor and deep space navigation.
Beidou and its supporting ground infrastructure is considered to provide the most accessible and accurate PNT data of any operating GNSS constellation in some regions, including the U.S. Global Positioning System (GPS), according to a Belfer Center report.
Meanwhile, a Government Accountability Office (GAO) report earlier this month reveals that the U.S. Space Force is facing technical hurdles in developing its next-generation GPS satellites and ground systems.
The launch was China’s 41st of 2024. It comes after a two-week break in Chinese launch activities following a Long March 6 launch Sept. 5 which sent 10 Geely satellites into orbit for the carmaker’s “Future Mobility Constellation.”
Main state contractor CASC stated early this year that it targeted launching around 70 times across 2024. A further 30 launches were planned by commercial actors, however only six have so far been conducted. Kuaizhou-1A (Expace) and Lijian-1 (CAS Space) solid rocket launches are expected within the next week, along with more Long March launches.
The debut of the new Long March 12 launcher is expected from a new commercial pad is expected in the near future. The area was hit by Typhoon Yagi in early September, affecting launch infrastructure.
