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 (LOX) and liquid hydrogen (LH2,LH₂)- Space Shuttle main engines
liquid oxygen (LOX) and kerosene or RP-1 - Saturn V booster, various Soviet boosters
liquid oxygen (LOX) and alcohol (Ethanol,C2H5OH,C₂H₅OH) - early liquid fueled rockets, like German (WW2) A-4 , aka V-2
T-Stoff (80% Hydrogen Peroxide) and C-Stoff (Methanol,Hydrazinehydrate) - Walter Werke HWK 109-509 engine used on Messerschmitt Me 163B Komet a rocket fighterplane of (WW2)
nitric acid and kerosene - Russian (USSR) SCUD-A, aka SS-1
IRFNA and UDMH Russian (USSR) SCUD-B,-C,-D, aka SS-1-c,-d,-e
nitric acid 73% with dinitrogen tetroxide 27% (=AK27) and kerosene/gasoline mixture - various Russian (USSR) cold war ballistic missiles, Iran: Shahab-5, North Korea: Taep'o-dong-2
hydrogen peroxide and kerosene - UK (1970's) Black Arrow, USA Development (or study): BA-3200
hydrazine and red fuming nitric acid - Nike Ajax Antiaircraft Rocket
dimethylhydrazine and dinitrogen tetroxide - many USSR rockets and Apollo Lunar Module
monomethylhydrazine (MMH) and dinitrogen tetroxide - Space Shuttle Orbital Maneuvering System OMS

The best mixture oxygen and hydrogen suffer from the deep temperature (20K (-253�C)) which is needed to store the fuel. Also the low density (70 kg/m³), which makes the need for large and heavy tanks, is a disadvantage. The use of lightweight foam, to insulate the cyrogenic tank, proved do be dangerous as seen in the Columbia (STS-107) accident. For storable intercontinental rockets or interplanetary space crafts the cooling is an unsolvable problem. Because of this the mixtures of hydrazine and its derivatives in combination with nitrogenoxides are used for these rockets.