Kerosene

Kerosene is obtained from the fractional distillation of petroleum at 150°C and 275°C (carbon chains from the C12 to C15 range).

RP-1 is a highly refined form of kerosene similar to jet fuel, used in the United States as a rocket fuel. RP-1 is typically burned with LOX (liquid oxygen) as the oxidizer. Although having a lower specific impulse than liquid hydrogen and thus thrust per mass, RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far more dense (a given volume of RP-1 is significantly more powerful than a similar volume of LH2) and more practical for many uses.

RP-1 is the fuel in the first-stage boosters of the Delta and Atlas rockets. It also powered the first stages of the Titan I, Saturn IB and Saturn V.

RP-1 is a refined fraction of kerosene, which is subjected to further treatment to remove unsaturated substances which polymerise when the fuel is stored, as well as sulphur-containing hydrocarbons which reduce the efficiency of combustion. Furthermore, in order to meet specific requirements of density, heat of combustion, and aromatic content, the kerosene must be obtained from crudes with a high naphthalene content.

Russian rocket-grade kerosene is of very similar standard as RP-1 and is designated T-1 and RG-1. Russian rocket grade kerosene is formulated for higher densities though (0.82 to 0.85 g/ml) compared to American RP-1 at 0.81 g/ml, and the Russians achieved even higher densities by super-chilling the kerosene in a rocket’s fuel tanks, but this partially defeats the purpose of using kerosene over other fuels.