Bipropellant rocket

A bipropellant rocket is a rocket that uses separate fuel and oxidizer[?] propellants. Bipropellant systems are more efficient than monopropellant systems, but they tend to be more complicated because of the extra hardware components needed to make sure the right amount of fuel gets mixed with the right amount of oxidizer (this is known as the mixture ratio.)

Thousands of combinations of fuels and oxidizers have been tried over the years. Some of the more common and practical ones are:

• liquid oxygen and liquid hydrogen - Space Shuttle main engines
• liquid oxygen and kerosene or RP-1[?] - Saturn V booster, various Soviet boosters
• hydrogen peroxide and kerosene - ???
• hydrazine and red fuming nitric acid - Nike Ajax Antiaircraft Rocket
• dimethylhydrazine and dinitrogen tetroxide - some USSR rockets and Apollo lander

The best mixture oxygen and hydrogen suffer from the deep temperature which is needed to store the fuel. For intercontinental rockets or a space craft the cooling is an unsolvable problem. Because of this the mixtures of hydrazine and its derivatives in combination with nitrogenoxides are used for these rokets.

see also: spacecraft propulsion