2010-11-25 (China Military News cited from nasaspaceflight.com) — China launched the second Shen Tong-1 military communications satellite via a CZ-3A Chang Zheng-3A (Y19) launch vehicle, providing secured voice/data communications services for PLA ground users in Ku-band. Receiving the designation ZX-20A ZhongZhing-20A, the satellite was launched from the Xi Chang Satellite Launch Center, in Sichuan Province at 00:09 loca time on Friday.
The first Shen Tong strategic communications satellite was launched on November 14, 2003 by a CZ-3A Chang Zheng-3A launch vehicle from Xi Chang.
Shen Tong satellites are based on the Dong Fang Hong 3 (DFH-3) satellite bus developed by the China Academy of Space Technology, and have a heavier payload, increased power supply, better reliability, being three-axis stabilized satellite – weighing in at 2,300kg.
The spacecraft features a number of new technologies, providing Ku-band communication and utilizing the advanced multiple steerable spot beam antenna technology to enable ground users to communicate whilst on the move. These satellites are the first to use secured uplink transmission for satellite antenna control and have the most powerful onboard data processing capability.
China used a CZ-3A Chang Zheng-3A launch vehicle for the mission to carry the bird into its transfer orbit.
The CZ-3A is a large-scale three-stage liquid launch vehicle, which has inherited the mature technology of the CZ-3 Chang Zheng-3. An upgraded liquid hydrogen and liquid oxygen cryogenic third stage has been developed to enable CZ-3A performing greater geostationary transfer orbit (GTO) capability.
The CZ-3A is equipped with a more flexible and sophisticated control system which supports substantial attitude adjustments to orient the payloads before spacecraft separation and provides adjustable satellite spin-up rotation rate. It has paved the way for the development of CZ-3B Chang Zheng-3B and CZ-3C Chang Zheng-3C.