Encyclopedia Astronautica
YF-25/23


Beijing Wan Yuan N2O4/UDMH rocket engine. 831 kN. In production. Cluster of YF-25 and 4 x YF-23 verniers. Isp=295s. First stage engine for CZ-2D, CZ-2E, CZ-2E(A), CZ-3A, CZ-3B, CZ-3C, CZ-4A. First flight 1988.

Thrust (sl): 732.400 kN (164,650 lbf). Thrust (sl): 74,685 kgf. Chamber Pressure: 71.00 bar. Area Ratio: 10.

Status: In production.
Diameter: 3.35 m (10.99 ft).
Thrust: 831.00 kN (186,816 lbf).
Specific impulse: 295 s.
Specific impulse sea level: 260 s.
Burn time: 295 s.
Number: 32 .

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Associated Countries
See also
Associated Launch Vehicles
  • CZ-4A Chinese orbital launch vehicle. The CZ-4 was developed and manufactured by the Shanghai Academy of Spaceflight Technology. Its first stage was essentially the same as that of the CZ-3 and the second stage was identical to that of the CZ-3. The CZ-4's third stage, however, was a development, featuring a thin wall common intertank bulkhead tankage and two-engine cluster with both engines gimbling about two perpendicular axes. The third stage engine cluster connected to the tank aft bulkhead through the engine bay. The CZ-4 had two payload fairing configurations: Type-A and Type-B. The CZ-4 was designed for launching satellites into polar and sun-synchronous orbits. More...
  • CZ-2E Chinese orbital launch vehicle. The CZ-2E added four liquid rocket booster strap-ons to the basic CZ-2 core to achieve a low earth orbit payload capability approaching the Russian Proton, US Titan, or European Ariane rockets. The Long March 2E had a maximum payload capability of 9,500 kg to low earth orbit. More...
  • CZ-2D Chinese orbital launch vehicle. The Long March 2D was a two-stage launch vehicle with storable propellants, suitable for launching a variety of low earth orbit satellites. Developed and manufactured by the Shanghai Academy of Spaceflight Technology, the CZ-2D had a typical payload capability of 3,500kg in a 200 km circular orbit. Its first stage was identical to that of the CZ-4. The second stage was essentially the same as that of the CZ-4, except for an improved vehicle equipment bay. More...
  • CZ-3A Chinese three-stage orbital launch vehicle. The Long March 3A, by incorporating the mature technologies of the CZ-3 and adding a more powerful cryogenic third stage and more capable control system, had a greater geosynchronous transfer orbit capability, greater flexibility for attitude control, and better adaptability to a variety of launch missions. More...
  • CZ-3B Chinese orbital launch vehicle. The Long March 3B was the most powerful Long March launch vehicle. It could inject a 5,000 kg payload into geosynchronous transfer orbit. The CZ-3B was developed on the basis of the CZ-3A, but had enlarged propellant tanks, larger fairing, and four boosters strapped onto the core stage. The CZ-3B boosters were identical to those of the CZ-3A. More...
  • CZ-2E(A) Planned upgrade of CZ-2E with enlarged liquid boosters. Probably intended for launch of Chinese space station modules in the 21st century. Fairing was 5.20 m in diameter and 12.39 m long. More...
  • CZ-3C Chinese orbital launch vehicle. Launch vehicle combining CZ-3B core with two boosters from CZ-2E. The standard fairing was 9.56 m long, 4.0 m in diameter. On August 23, 2001, the CZ-3C launcher passed its critical design review. CZ-3C development had begun in 1995 but was suspended in 1996-2000 due to the 1996 CZ-3B failure. First launch was in 2008. More...

Associated Manufacturers and Agencies
Associated Propellants
  • N2O4/UDMH Nitrogen tetroxide became the storable liquid propellant of choice from the late 1950's. Unsymmetrical Dimethylhydrazine ((CH3)2NNH2) became the storable liquid fuel of choice by the mid-1950's. Development of UDMH in the Soviet Union began in 1949. It is used in virtually all storable liquid rocket engines except for some orbital manoeuvring engines in the United States, where MMH has been preferred due to a slightly higher density and performance. More...

Associated Stages
  • CZ-2E-2 N2O4/UDMH propellant rocket stage. Loaded/empty mass 91,500/5,500 kg. Thrust 831.01 kN. Vacuum specific impulse 298 seconds. More...
  • CZ-3A-2 N2O4/UDMH propellant rocket stage. Loaded/empty mass 33,600/4,000 kg. Thrust 831.01 kN. Vacuum specific impulse 297 seconds. More...
  • CZ-4A-2 N2O4/UDMH propellant rocket stage. Loaded/empty mass 39,550/4,000 kg. Thrust 831.01 kN. Vacuum specific impulse 295 seconds. More...

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