Tiantong 1-01 (Tiantong =”Sky Communications”) communications satellite was launched into orbit by a Chang Zheng-3B (CZ-3B) launch vehicle on 6 August. The launch took place at 00:22 CST (16:22 UTC on 5 August) from Launch Complex 3 of the Xichang Satellite Launch Centre (CSLC), in Sichuan Province.
After about 20 minutes of flight, the satellite was separated from the third-stage of the launch vehicle and entered a highly elliptical Geostationary Transfer Orbit, where the satellite then used its own Apogee Kick Motor (AKM) to move to its intended position on geostationary orbit.
The mission was China’s 10th orbital launch this year, and the 232nd flight of the Chang Zheng family of launch vehicles.
Tiantong 1-01 is the first of a mobile satellite communications (SATCOM) constellation, similar to the Iridium, Thuraya, and Inmarsat networks. The system is designed to offer mobile communications services in S- and Ku-band for commercial, maritime, enterprise, government and military users. It also enables mobile user terminals to be connected into public landline and mobile phone networks, as well as the Internet. The network will initially serve users in East Asia, the Middle East, North Africa, and the Indian Ocean, but will be expanded to provide a global coverage by 2020.
Tiantong 1-01 was developed by China Academy of Space Technology (CAST), and is owned and operated by China Satellite Communications Corporation (China Satcom). The ground section of the network is operated by China Telecommunications Corporation (China Telecom).
Tiantong 1 is equipped with transponders in S- and Ku-band. The satellite’s Ku-band beams will provide connectivity services for ground base stations, while the S-band beams will provide 24/7 communications services directly to mobile user terminals including vehicle-mounted, shipborne, and airborne terminals, as well as handheld devices. The services will consist of standard services for commercial users, and encrypted secure communication for military users.
The ground section includes central control station and a number of exchange stations, connecting the satellite communications network with the public switched telephone network (PSTN), public land mobile network (PLMN), and the Internet.
The satellite was based on the DFH-4 satellite bus developed by CAST. First introduced in 2006, the DFH-4 is China’s third-generation high-capacity, long-endurance geostationary telecommunications satellite. It is a three-axis stabilised spacecraft, capable of carrying 600 to 800 kg of mission payload and 3,100 kg of fuel. It is also equipped with advanced station-keeping subsystems, solar arrays and batteries, and command and control subsystems.
The CZ-3B is a three-stage launch vehicle designed for geostationary satellite launch missions. The launcher made its maiden flight successfully in 1997, and remained the most capable launch vehicle in China’s Chang Zheng launch vehicle family until the introduction of the CZ-7 in June this year. The launch vehicle’s first-stage is powered by a cluster of 4 DAFY6-2 liquid engines, assisted by four strap-on boosters each powered by a single DAFY5-1 engine, all burning the UDMH/N2O4 bi-propellant, producing a total thrust of 5,923.2 kN at lift-off.
The second-stage is powered by a DAFY21-1 main engine and four YF-23B veering thrusters, also burning the UDMH/N2O4 bi-propellant. The third-stage is powered by a single YF-75 liquid engine burning the LH2/LOX bi-propellant. The launcher can also be fitted with a Yuanzheng 1 (YZ-1) upper stage to further enhance its payload capacity and orbit insertion accuracy.