propelant

Propellant is a substance that is expended to produce thrust in a rocket or jet engine. It is the working fluid that is expelled at high velocity to generate the reaction force that propels the vehicle forward. Propellants can be broadly categorized into solid propellants and liquid propellants, with some hybrid systems also in use. Solid propellants are typically a homogeneous mixture of fuel and oxidizer cast into a solid grain. Once ignited, they burn continuously until depleted. Liquid propellants consist of separate fuel and oxidizer components that are stored in tanks and pumped into a combustion chamber where they mix and burn. The performance of a propellant is often measured by its specific impulse, which is a figure of merit representing the efficiency of the propellant. Higher specific impulse means more thrust is generated for a given mass of propellant. The selection of a propellant depends on the specific mission requirements, such as desired thrust, burn time, cost, and safety considerations.