solid-propellant motor

A solid-propellant motor, often called an SRM, is a type of chemical rocket propulsion system where the fuel and oxidizer are combined into a solid mixture. This solid propellant is housed directly within the motor's casing, which also serves as the combustion chamber.1

When ignited, the solid propellant burns on its exposed inner surfaces, generating hot gases that are expelled through a nozzle at high velocity. This expulsion creates thrust, propelling the rocket forward. SRMs are known for their simplicity in design, resembling large fireworks, and are often used to provide extra thrust during liftoff for launch vehicles. Unlike liquid-fueled rockets, once ignited, SRMs burn until their propellant is completely exhausted and cannot be shut off or restarted.12