China launches twin BeiDou-3 navigation satellites into space
China has successfully sent pair of twin Beidou-3MEO satellites – Beidou-30 and Beidou-31 –into space as part of its third and final stage of launching its domestic Beidou (Compass) satellite navigation system.
They were launched on board Long March-3B carrier rocket from Xichang Satellite Launch Center in southwest China’s Sichuan Province. It was 269th mission for the Long March rocket family.
The twin satellites are MEO satellites i.e. Medium Earth Orbit component of the third phase of Beidou satellite navigation system. They will work together with six previously launched BeiDou-3 satellites once they pass series of tests. They were developed by the Innovation Academy for Microsatellites at Chinese Academy of Sciences and China Academy of Launch Vehicle Technology, respectively. These satellites are part of fleet of Beidou satellites that will expand the system to global navigation coverage. These satellites reside in 21,500 – 21,400 km nominal orbit at 55.5 degrees. These satellites are using new bus that features phased array antenna for navigation signals and laser retroreflector.
BeiDou is 2nd generation of Chinese homegrown navigational system seen as rival to US’s Global Positioning System (GPS). It was named after Chinese term for plough or Big Dipper constellation. It comprises constellation of total 35 satellites including 27 MEO (21,500 km orbits) satellites, 3 IGSO satellites and 5 GSO satellites.
The first BeiDou satellite was sent into space in 2000. The system became operational in December 2011, with constellation of 10 satellites providing services in China only. In December 2012, it began offering services to customers in Asia-Pacific region. On its completion in 2020, it will provide services to global customers. Currently it used for civilian services in field of navigation, messaging, transportation and weather forecasting sectors. It also has military applications.