Propellante

Propellante is a term used to describe a substance or mixture that provides thrust in a propulsion system by expelling mass at high velocity. In rocketry and aerospace, propellants are designed to release energy through combustion or decomposition to produce controlled generation of hot gases and pressure that propel a vehicle. In consumer and industrial contexts, the word also covers gases used to expel contents from pressurized containers, such as aerosols, where the propellant itself is not intended to burn and serves primarily to lift or push the product out of the container.

Types and classifications

Propellants are commonly classified by phase and energetic content. Solid propellants consist of a fuel and oxidizer bound in a solid matrix and burn to generate gas. Liquid propellants use separate or combined liquid fuels and oxidizers to produce a controllable thrust over time. Monopropellants contain a single chemical species that decomposes to produce thrust without a separate oxidizer, while bipropellants pair a fuel with an oxidizer. Hybrid systems combine a solid or liquid propellant with a different enabling agent. Non-energetic propellants, such as nitrogen, helium, or carbon dioxide, are used primarily for pressurization and propelling contents in aerosols and other packaged products.

Applications

The primary use of propellants is propulsion in rockets, missiles, and spacecraft, including launch vehicles and attitude control thrusters. In everyday products, propellants enable the dispensing of aerosols, deodorants, paints, and other formulations by forcing the contents out of a container.

Safety and regulation

Propellants can be highly reactive, toxic, or flammable, requiring stringent handling, storage, and transport standards. Regulations cover formulation, performance, labeling, and environmental impact, with safety data sheets and compliance requirements guiding their use in both aerospace and consumer applications.