NAPLES, Italy — The Chinese Academy of Space Technology plans to introduce its two new versions of China’s DFH-4 telecommunications satellite platform starting next year, both featuring lithium-ion batteries and the option of ion-electric propulsion, an academy official said Oct. 4.
Both versions are intended to strengthen China’s position in the global market for telecommunications platforms.
In a presentation here to the 63rd International Astronautical Congress, Yongxuan Xiao said that “with great support from [China’s] native satellite operator,” the first small-class version of DFH-4, called the 4S, will make its qualification flight as part of a commercial mission operated by China Satellite Communications Co. Ltd.
The DFH-4S is designed to be small enough to fit onto a Chinese Long March 3C rocket, which is less expensive than the Long March 3B vehicle that currently orbits China’s telecommunications satellites.
At 3.2 meters tall and with a maximum launch weight of 3,800 kilograms, the DHF-4S is smaller than the standard-version DFH-4 now being flown, and considerably smaller than the DFH-4E, which is also scheduled to be ready for flight in the next two years.
DFH-4E will weigh up to 6,000 kilograms at launch and deliver between 9 and 11 kilowatts of power to its payload. Xiao said qualification tests of the satellite’s principal subsystems will be completed in late 2012, and that it will be ready for sale to the market in 2013.
DFH-4 was introduced in 2006. After solar-array drive mechanism issues sharply reduced the life and functionality of two early versions, seven most recently launched models have worked well, with Venezuela’s Venesat-1 having accumulated more than three years of in-orbit service life.
Xiao said the ion-electric thrusters, which at the customer’s option may be used to replace conventional propellant to assure the satellite’s in-orbit stability, have accumulated more than 3,700 hours of lifetime tests. Electric propulsion offers substantial weight savings over conventional propulsion, which can be used to purchase a less-expensive rocket or to add more payload capacity.
Xiao said that for the moment, the electric propulsion designs for DFH-4S and the larger DFH-4E call for electric propulsion to be used only for station-keeping, and not in “full electric” mode to power the satellite from its transfer orbit after separation from its launch vehicle to final geostationary position.
Up to now, China has sold telecommunications satellites mainly as part of package deals that include a launch aboard a Chinese Long March rocket and insurance coverage. Xiao said the Chinese Academy of Space Technology’s goal is to break into export markets for the satellites themselves, with or without a Chinese rocket.
