China orbited its first geostationary communications satellite in 1984. Current communications satellites for military and commercial uses are based on the third-generation DFH-4 satellite bus. The PLA has obtained the communications-on-the-move (COTM) capability since 2000, which enables military users to send and receive communications and maintain situational awareness whilst in motion on land, in the air and at sea.
PLA command vehicles with SATCOM
DFH-2 (Dong Fang Hong 2) was China’s first geostationary communications satellite. The development of the satellite was initiated in 1975 under the code name “Project 331”. The satellite was cylinder-shaped, spin-stabilised with a despun antenna. The satellite’s communications payload consisted of two C-band 6/4 GHz transponders. The satellite was launched by a CZ-3 rocket launcher to a highly elliptical geostationary transfer orbit (GTO), where it then fired its solid apogee kick motor to moves to its intended location on the Geostationary Earth Orbit (GEO). The improved DFH-2A was similar to DFH-2, but had four C-band transponders, and more precise position and attitude controls.
Between 1984 and 1991, a total of seven launches were made, of which six were successful. These included four operational communications satellites (ChinaSat 1/2/3/4) for both military and civilian uses.
DFH-3 (Dong Fang Hong 3) was a medium-capacity, geostationary communications satellite bus developed by the China Academy of Space Technology (CAST) in the 1990s. The development of the 2nd-generation satellite with improved capacity and reliability began in the early 1980s to meet the growing demands for larger-capacity communications and broadcasting satellites from both military and civilian sectors. The programme was officially given go-ahead by the State Council in March 1986. The Ministry of Astronautics signed a contract in 1987 to co-develop the DFH-3 with Deutsche Aerospace AG (DASA, now Airbus Defence and Space), the first high-profile space technology co-operation project between China and the West.
The development of the DFH-3 took over eight years to complete. DASA provided overall design guidance, as well as contributed the apogee kick stage and components for the communications antennas and solar array mechanism. The DFH-3 was too heavy for the 1,400 kg-payload CZ-3 launcher and as a result the CZ-3A launcher with a GTO payload capability of 2,600 kg was introduced.
A total of nine DFH-3 communications satellites have been launched between 1997 and 2012, including two commercial telecommunications satellites (ChinaSat 5/6), two tactical military communications satellites (ChinsSat 22/22A), two strategic military communications satellite (ChinaSat 20/20A), as well as three tracking and data relay satellites (Tianlian 1A/1B/1C).
The DFH-3 was a geostationary, three-axis-stabilised satellite, with two large solar panels. It had a power supply of 2 kW and a designed lifespan of eight years. The telemetry system was in the C-band. The box-shaped DFH-3 bore some resemblance to the GE Astro Space 5000 series spacecraft. The 2,200 kg satellite consisted of service section, propulsion section, and communications section, and could be equipped with a variety of payloads for different purposes. When used for communications, the satellite could carry 24 C-band transponders, providing 6 television channels and 18 communications transmission channels.
- Gross mass: 2,230 kg
- Empty mass: 1,130 kg
- Height: 1.7 m
- Solar panel wingspan: 18.10 m
The Fenghuo (“Beacon”) series tactical communications satellites was designed provide secured digital data and voice communications for military users from geostationary orbit. The first-generation Fenghuo 1 satellites were based on the DFH-3A satellite bus, carrying Ku- and Ka-band transponders for VHF data and voice communications. The ground sections consisted of central stations, regional stations, base stations, and mobile vehicle stations.
Fenghuo 1 was designed to provide Communications-on-the-Move (COTM) capability, which enables military users to send and receive communications and maintain situational awareness whilst in motion on land, in the air and at sea. Traditional satellite communications required the user to be stationary so that the antenna could be pointed towards the satellite, which can be a huge disadvantage in the battlefield. COTM eliminates this need to pause by having the antenna automatically tracking the satellite in motion.
The first satellite Fenghuo 1, under the cover name ChinaSat 22, was launched in January 2000 and positioned at 98ºE on the Geostationary Earth Orbit (GEO). The satellite was succeeded by Fenghuo 1A (ChinaSat 22A) launched in September 2009.
The Shentong series geostationary military communication satellite was designed to provide secured voice/data communications services for miltiary users in Ku-band. Shentong 1 was based on the DFH-3A satellite bus , with heavier payload, increased power supply, and improved better reliability. The satellite carries 4 Ku-band and 8 C-band transponders.
The three-axis stabilised Shentong 1 weights 2,300 kg. It features a number of new technologies, including the first Chinese satellite to provide the Ku-band communication; the first to use the advanced multiple steerable spot beam antenna technology to enable ground users to communicate while on the move; the first to use secured uplink transmission for satellite antenna control; and the most powerful onboard data processing capability.
The first satellite Shentong 1, under the cover name ChinaSat 20, was launched in November 2003. The satellite was positioned at 103ºE on the GEO. The satellite was succeeded by Shentong 1A (ChinaSat 20A) launched in November 2010.
Tianlian (“Sky Link”) was a data relay satellite was developed by CAST to satisfy the requirement for long-duration, high-coverage space-to-ground voice and data communications, similar in concept to the NASA Tracking and Data Relay Satellite System (TDRSS).
Tianlian 1, based on the DFH-3A bus, operated on the geostationary orbit to provide low-, medium-, and high-speed data communications between the orbiting spacecraft and ground terminals in Ka- and S-band. The satellite was intended to support China’s manned spaceflight missions, including the Space Laboratory and Space Station. Furthermore, it could also be used for communications to and from other orbiting spacecraft such as the Yaogan reconnaissance satellite.
The first experimental satellite Tianlian 1A was launched on 25 April 2008. The system was tested during the Shenzhou 7 human space flight mission. A second satellite Tianlian 1B was launched in July 2011 prior to China’s first rendezvous docking operation between Tiangong 1 and Shenzhou 8. Tianlian 1C was launched in July 2012. The three satellites are positioned at 77°E, 176.77°E, and 20°E respectively.
DFH-4 (Dongfanghong) is China’s 3rd-generation geostationary telecommunications satellite, designed to provide a high-capacity, long-endurance platform for TV broadcasts, voice and data communications, tracking and data relay, and regional mobile communications satellites. It could also be used for navigation and deep space exploration missions. The satellite had a mission payload capacity of 595 kg, and a designed operational life of 15 years, making it in the same class as the Lockheed Martin A2100AX and Space Systems/Loral FS1300.
High-capacity and long-endurance communications satellite for both military and commercial users was a key project in China’s 10th five-year plan (2001-2005). Preliminary concept development of the 3rd-generation communications satellite began in the late 1990s and the Dongfanghong 4 programme was approved by the Chinese government in October 2001. Engineering development of the satellite began in January 2002, with CAST being the primary contractor.
In its early years the DFH-4 suffered from some design flaws, with the first two satellites (SINOSAT 2 and Nigcomsat-1) both failing to deploy their solar wings. After replacing the original two-stage solar wing deployment method to a less complex single-stage deployment method (at a cost of lower output), subsequent missions were all successful.
The DFH-4 is a three-axis stabilised spacecraft, with a designed lifespan of 15 years. The satellite weighs 5,100-5,400 kg at launch and can carry 600-800 kg payload and 3,100 kg fuel. The satellite consists of mission payload and service section. It was fitted with two solar wings each made of four solar panels, which can provide 6-8 kW electrical power for the onboard mission payload. The satellite was launched onboard the CZ-3B launch vehicle from the Xichang Satellite Launch Centre, but could also be adapted to a European or Russian rocket.
- Dimensions: 2.36 m x 2.10 m x 3.60 m
- Launch mass: 5,100 kg
- Payload mass: 600 kg
- Fuel mass: 3,100 kg
- Solar panel power: 10,500 kW
- Payload power: 8 kW
- Designed life: 15 years
Fenghuo 2 was the 2nd-generation tactical military communications satellite developed for the PLA. The satellite has a mass of 5,320 kg and an orbital life of 11 years. The first satellite Fenghuo 2A, debuted ChinaSat 1A in its cover name, was launched in September 2011 by a CZ-3B launcher from Xichang. The satellite was positioned at 130ºE on the GEO. A second satellite Fenghuo 2C (ChinaSat 1C) launched in December 2015 was positioned at 81.5ºE on the GEO.
Shentong 2 was the 2nd-generation strategic military communications satellite based on the DFH-4 bus. The first satellite Shentong 2A, under the cover name ChinaSat 2A, was launched in May 2012 and is positioned at 98ºE on the GEO. The second satellite Shentong 2C (ChinaSat 2C) was launched in November 2015, and is positioned at 103ºE on the GEO.