China launches last pair of backup satellites for BeiDou-3 system

China launched the last pair of backup satellites for the BeiDou-3 Navigation Satellite System (BDS-3) on Thursday.

The satellites, the 59th and 60th in the family of BeiDou, were launched at 9:14 a.m. (Beijing Time) and sent into orbit by a Long March-3B rocket from the Xichang Satellite Launch Center in southwest China's Sichuan Province.

The two medium Earth orbit (MEO) satellites will enhance the system's reliability and improve services of positioning, navigation, timing as well as short message communication for global users, as reported by China Media Group (CMG).

In addition to backup satellites, BDS-3 now operates a total of 30 networking satellites in orbit, most of which have been in service for six years. With most of these satellites designed for a lifespan of 10 years, researchers are planning an upgrade for the deployment of new satellites.

"We will enter the deployment of BDS-4, with the two satellites serving as the last additions to BDS-3," Liu Yingchun, chief designer of BDS-3, told CMG.

Therefore, they will also conduct technical verification and exploration besides the regular operations in the constellation, said Liu.

A coverage from deep sea to space

China has set a three-step development strategy for its BeiDou navigation system, with the first step to provide services to domestic users, the second to expand services to the Asia-Pacific region, and the third to provide services globally.

The construction of BDS-1 and BDS-2 was completed in 2000 and 2012, respectively, and China became the third country to have an independent global navigation satellite system when BDS-3 was completed and put into service in July 2020.

The completion of the three-step strategy is not the end. The country is scheduled to build a more ubiquitous, integrated and intelligent, and comprehensive system with positioning, navigation and timing capabilities by 2035, which refers to a stronger, safer and more reliable system with BDS as its core and foundation, covering indoor to outdoor, from deep sea to deep space.

To build such a system, China plans to first build a low-orbit constellation system relying on BDS by 2025 in a bid to realize the global sharing of centimeter-level positioning services. Meanwhile, it needs to address technical problems related to navigation signals and interference to realize underwater, indoor and deep space navigation.

(Cover: A Long March-3B rocket, carrying two new BeiDou satellites, blasts off from the Xichang Satellite Launch Center in southwest China's Sichuan Province, September 19, 2024. /CFP)