DFH-2

The DFH-2 was a spin-stabilized, drum-shaped military communications satellite with a despun antenna, a diameter of 2.1 m, and a height of 3.1 m. The communications payload consisted of only two C-band 6/4 GHz transponders, each having a saturated power output 7.3 dBW (10 W).

The global coverage horn antenna had a receive/transmit gain of 19.5 dB/16.5 dB, using circular polarization. The total electrical power capacity was 300 W. Also known as STW-1, the satellites were the technological equivalent of the 1960's Intelsat-3 and used a solid apogee kick motor to insert the satellites into geostationary orbit. Design life was four years, mass including the apogee kick motor propellant was about 900 kg and on-orbit mass was 441 kg. Two prototypes had an on-orbit mass of 433 kg and power of 284 W. The improved version DFH-2A was similar to DFH-2, but had four C-band transponders, and more precise position and attitude controls. China successfully launched three DFH-2A's (STW-3 on March 7, 1988, STW-4 on December 22, 1988, STW-55 on February 4, 1990). They were used for both military and domestic satellite telecommunication services and television broadcast program distribution.

Length: 3.10 m (10.10 ft). Maximum Diameter: 2.10 m (6.80 ft). Mass: 1,025 kg (2,259 lb). Main Engine: DFH-2 AKM. Main Engine Propellants: Solid. Main Engine Propellants: 584 kg (1,287 lb). Associated Launch Vehicle: CZ-3.

• 1984 April 8 - STTW-T2 - Launch Site: Xichang. Launch Vehicle: CZ-3. Mass: 900 kg (1,980 lb). Perigee: 35,733 km (22,203 mi). Apogee: 35,796 km (22,242 mi). Inclination: 6.10 deg. Period: 1,435.00 min.

  Prototype of DFH-2 communications satellite. After on-orbit testing and check out of the satellite and the ground stations, the satellite system was declared operational, and was used experimentally for the transmission of television, telephone, and data messages with good results. It stayed in operation for more than four years, exceeding the design life of three years by a comfortable margin. Operated in geosynchronous orbit at 125 deg E in 1984-1988. As of 4 September 2001 located at 40.81 deg E drifting at 0.320 deg W per day. As of 2007 Feb 27 located at 133.57E drifting at 0.079W degrees per day.

• 1984 January 29 - STTW-T1 - Launch Site: Xichang. Launch Vehicle: CZ-3. FAILURE: Third stage failed to ignite. Mass: 900 kg (1,980 lb). Perigee: 484 km (300 mi). Apogee: 6,446 km (4,005 mi). Inclination: 36.10 deg. Period: 162.00 min.

  First launch of a prototype DFH-2 communications satellite. Payload stranded in low earth orbit, but all subsystems including the communications payload were completely checked and tested.

• 1986 February 1 - STTW 1 - Launch Site: Xichang. Launch Vehicle: CZ-3. Mass: 1,024 kg (2,257 lb). Perigee: 35,774 km (22,228 mi). Apogee: 35,819 km (22,256 mi). Inclination: 9.80 deg. Period: 1,436.60 min.

  Second successful DFH-2 launch. Also designated STW-2, the satellite was positioned at 103 deg E. In comparison to the first two DFH-2's, a parabolic antenna reflector replaced the horn antenna. Operated in geosynchronous orbit at 103 deg E in 1986-1990. As of 3 September 2001 located at 102.75 deg E drifting at 0.030 deg W per day. As of 2007 Mar 10 located at 46.50E drifting at 0.019E degrees per day.

• 1988 December 22 - Zhongxing-2 - Launch Site: Xichang. Launch Vehicle: CZ-3. Mass: 1,024 kg (2,257 lb). Perigee: 35,787 km (22,236 mi). Apogee: 35,791 km (22,239 mi). Inclination: 0.10 deg. Period: 1,436.20 min.

  Operated in geosynchronous orbit at 110 deg E in 1989-1999. As of 27 August 2001 located at 91.92 deg E drifting at 0.244 deg E per day. As of 2007 Mar 10 located at 83.40E drifting at 0.283W degrees per day.

• 1988 March 7 - Zhongxing-1 - Launch Site: Xichang. Launch Vehicle: CZ-3. Mass: 1,024 kg (2,257 lb). Perigee: 35,786 km (22,236 mi). Apogee: 35,789 km (22,238 mi). Inclination: 0.50 deg. Period: 1,436.20 min.

  Operated in geosynchronous orbit at 87 deg E in 1988-1997. As of 28 August 2001 located at 87.94 deg E drifting at 0.038 deg E per day. As of 2007 Mar 11 located at 64.00E drifting at 0.067E degrees per day.

• 1990 February 4 - Zhongxing-3 - Launch Site: Xichang. Launch Vehicle: CZ-3. Mass: 1,024 kg (2,257 lb). Perigee: 35,783 km (22,234 mi). Apogee: 35,795 km (22,241 mi). Inclination: 0.00 deg. Period: 1,436.30 min.

  National operational communications satellite. Designation 1990-2. Operated in geosynchronous orbit at 98 deg E in 1990-1998. As of 4 September 2001 located at 52.36 deg E drifting at 0.045 deg W per day. As of 2007 Mar 10 located at 96.88E drifting at 0.061W degrees per day.

• 1991 December 28 - Zhongxing-4 - Launch Site: Xichang. Launch Vehicle: CZ-3. FAILURE: Third stage failed to ignite. Partial Failure. Mass: 1,025 kg (2,259 lb). Perigee: 2,023 km (1,257 mi). Apogee: 34,041 km (21,152 mi). Inclination: 32.30 deg. Period: 632.60 min.

  Third stage failure; unusable orbit. DFH-2 operational communications satellite.

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