DFH-4

China announced in 1994 a plan to deploy a GEO data relay satellite later in this decade, although formal program approval was not granted at that time(Reference 252). subsequently the DFH-4 project was approved and is underway, though launch schedules and other technical details have not been publicly released. CASC's satellite R&D and manufacturing arm, CAST, has commenced work on the next generation communication satellite, the DFH-4, a direct broadcasting system which can transmit data to users without the need for ground station rebroadcasting.

The fielding of a direct broadcast satellite offers a capability for distributing information to the lowest echelon in a battlefield if this technology were adapted to military applications, potentially transmitting data (maps, pictures, and enemy deployments) on demand to small units, each using an 18-inch (or smaller) capability to receive orders and situational information. The DFH-4 could feasibly permit the transmission of tailored data to hundreds of units simultaneously.

In 2001 China started the Dongfanghong-IV project, the large-capacity and long-term static orbiting communications and broadcasting satellite. The designed life-span of the satellite is 15 years with 50 communication transmitters installed. Virtual load of the satellite will be designed mainly for broadcasting and communication. The whole project is to be finished in four years as planned.

The Project of Dongfanghong-IV Satellite is directed by Commission of Science Technology and Industry for National Defense (COSTIND) and developed by Chinese Academy of Space Technology of China Aerospace Science and Technology Corporation.

It is the third generation of communications satellite of China. The designed life-span of the satellite is 15 years with 50 communication transmitters installed. Virtual load of the satellite will be designed mainly for broadcasting and communication.

The Dongfanghong-IV platform will be first used to develop a satellite -- Sinosat-II -- for a Beijing-based operator, Sino Satellite Communications Co, to meet the country's mounting demands for communications and broadcasting, company president Cheng Guangren confirmed.

The developing of DFH-4 platform is an important program supported by the Chinese government. The program has gained significant breakthrough and progress. The DFH-4 platform inherited many from DFH-3 platform in both design and technology. At the same time the design and validation test of all critical technology and critical items such as large central cylinder, propellant tank, power control and management of satellite subsystem, OBDH subsystem (Onboard Date Handling), large solar array deployment mechanism etc., had been accomplished successfully. The pre-development phase ended in January 2001 and successfully passed the review organized by the government in early 2002. The flight model of SINOSAT-2 satellite was being developed and constructed at the time.

The new generation DFH-4 geostationary platform developed by CAST is comparable to A2100AX, HS601HP, FS1300 and SB4000 in both technology level and satellite capability, which means that CAST is capable of building large capacity telecommunications satellite as its international counterparts. The satellite can weigh up to 5100 Kg and can provide the 10 KW power due to the adoption of high efficiency GaAs/Ge solar cells. The satellite’s design lifetime is greater than 15 years and can meet all the requirements of telecommunications satellites of all kinds.