Rocket fuel, or the fuel used for propulsion in rockets, is an essential part of the space industry. There are numerous synonyms for rocket fuels, such as propellants, fuels, boosters, and accelerants. Other terms that are frequently used include explosive, combustible, and reactive materials. Rocket fuels can also be classified based on their composition, such as solid, liquid, or hybrid fuels. Solid fuels are composed of a mixture of fuel and oxidizer, which ignites when a heat source is applied. Liquid fuels are made up of two or more substances that are mixed together just before ignition. Hybrid fuels combine both solid and liquid fuels to create a more stable and efficient propellant.