The YF-77 is currently China's most powerful cryogenic rocket engine using liquid hydrogen (LH2) fuel and liquid oxygen (LOX) oxidizer. Engine development began in the 2000s, with testing directed by the China National Space Administration (CNSA) commencing in 2005. The engine has been successfully tested by mid-2007.

Specifications

• Vacuum thrust: 673 kN
• Vacuum specific impulse: 438 s
• Sea Level thrust: 550 kN
• Sea Level specific impulse: 333 s
• Burn time: 500 s (estimated)
• Engine weight: TBA
• Exit to Throat Area ratio: TBA
• Propellants: LOX
  Lox
  Lox is salmon fillet that has been cured. In its most popular form, it is thinly sliced—less than in thickness—and, typically, served on a bagel, often with cream cheese, onion, tomato, cucumber and capers...
  
   & LH2
• Mixture ratio: 5.45

• Design: TBA
• Diameter: TBA
• Chambers: TBA
• Chamber Pressure: TBA
• Thrust to Weight Ratio: TBA
• Restartable: TBA

• Contractor: China Academy of Aerospace Liquid Propulsion Technology
• Vehicle Application: Long March
  Long March rocket
  A Long March rocket or Chang Zheng rocket as in Chinese pinyin is any rocket in a family of expendable launch systems operated by the People's Republic of China. Development and design falls under the auspices of the China Academy of Launch Vehicle Technology...
  
    / CZ-5
• Status: in Development