RP-1

thumb|alt=Photo of person holding flask containing reddish liquid|An Erlenmeyer flask containing about of RP-1

RP-1 (Rocket Propellant-1 or Refined Petroleum-1) and similar fuels like RG-1 and T-1 are highly refined kerosene formulations used as rocket fuel. Liquid-fueled rockets that use RP-1 as fuel are known as kerolox rockets. In their engines, RP-1 is atomized, mixed with liquid oxygen (LOX), and ignited to produce thrust. Developed in the 1950s, RP-1 is outwardly similar to other kerosene-based fuels like Jet A and JP-8 used in turbine engines but is manufactured to stricter standards. While RP-1 is widely used globally, the primary rocket kerosene formulations in Russia and other former Soviet countries are RG-1 and T-1, which have slightly higher densities.