Source: astronautix.com
10-21-2007 10:18
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The Long March 3 was a three-stage launch vehicle designed for delivery of satellites of 1,500 kg mass into geosynchronous transfer orbit. The first and second stages were based on the CZ-2C, and designed and manufactured by the Shanghai Academy of Spaceflight Technology. The majority of the technology and flight hardware used in the CZ-3 had been qualified and proven on the CZ-2C. The third stage, manufactured by CALT, was equipped with an LOX/LH2 cryogenic engine. Long March 3 was also capable of placing spacecraft into an elliptical or circular low earth orbit and sun synchronous orbit.
The third stage used the first Chinese liquid oxygen/liquid hydrogen engine. This had a vacuum thrust of 44 kN (4.5 tonnes thrust) and was capable of one restart. Development of the cryogenic third stage engine was a major technical achievement. This advanced in technology engine was superior in performance (vacuum specific impulse 50% more than that of a conventional propellant engine). Its combustion products were safe and non- toxic. But the boiling points of liquid hydrogen and liquid oxygen were low (-253 deg C and ?83 deg C respectively) and they were inflammable and explosive. Many problems in low temperature technology and multiple restarting of the engine in high vacuum and zero-G had to be solved. During development longitudinal coupling vibration was a knotty problem that took some time to cure. The problems were all surmounted under the leadership of Chief Designer Xie Guanxuan.
Manufacturer: CALT. Launches: 13. Failures: 2. Success Rate: 84.62%. First Launch Date: 1984-01-29. Last Launch Date: 2000-06-25. Launch data is: continuing. LEO Payload: 4,800 kg (10,500 lb). to: 200 km Orbit. at: 28.50 degrees. Payload: 1,400 kg (3,000 lb). to a: Geosynchronous transfer trajectory. Apogee: 40,000 km (24,000 mi). Associated Spacecraft: DFH-2, FY-2, HS 376. Liftoff Thrust: 2,960.000 kN (665,430 lbf). Total Mass: 204,000 kg (449,000 lb). Core Diameter: 3.35 m (10.99 ft). Total Length: 43.25 m (141.89 ft). Launch Price $: 40.000 million. in: 1999 price dollars.
Editor:Yang Jie