China opened its 2015 launch campaign on 30 March, with a next-generation Bei Dou (BD) navigation satellite lofted into orbit atop a modified Chang Zheng-3C (CZ-3C) rocket. The launch vehicle lifted off from Launch Complex 2 of the Xichang Satellite Launch Centre (XSLC) at 21:52 local time (13:52 GMT). This is the 17th Bei Dou navigation satellite launched since 1998.
The satellite, designated Beidou 3-I1-S, is the first of the 35 high- and medium-orbit Beidou navigation satellites to be launched over the coming years in order to establish a global satellite navigation system. It was designed and built by the Shanghai Engineering Centre for Microsatellites, an R&D institution formed jointed by the China Academy of Sciences and the local government of the Shanghai Municipality.
The launch marked the beginning of Phase-III of the Compass Navigation Satellite System (CNSS) programme, China’s indigenous dual-use satellite navigation system and the fourth of its kind in the world, after the U.S. Global Positioning System (GPS,), Russian GLONASS, and Europe’s Galileo. Phase-I of the programme established an experimental regional navigation network consisting of three geostationary satellites in 2000. Phase-II, completed in 2012, established an operational regional network to provide navigation and positioning services for both military and commercial users in China and East Asia. In Phase-III, the network is to be expanded into a constellation of 35 satellites to provide a global coverage.
The launch was also the first debut of the Chinese-developed Yuan Zheng-1 (“Expedition-1”) upper stage, which has been added to the three-stage CZ-3C rocket to provide the capability to directly insert the satellite into high orbits without the need to use the satellite’s own propulsion. This stretched the total length of the launch vehicle to 57.126 m, with the satellite and upper stage accommodated inside a enlarged payload fairings 4.2 m in diameter. The dual-engine cryogenic third-stage boosted the stack into a transfer orbit of 194 by 25,307 km inclined at 55°. After separation from the third stage that remained in this orbit, the liquid-fuelled YZ-1 upper stage began its first burn to raise the apogee of the orbit to 36,000 km, eventually reaching a geosynchronous orbit inclined at 55°, five hours 42 minute after lift-off.
