Cross Sectional Slice - Solid Rocket Propellant

Cross Sectional Slice - Solid Rocket Propellant

This is an example of what a cross sectional slice of a solid rocket motor looks like. In a solid rocket, the propellant is a mixture of fuel and oxidiser. It comes in the form of a grain which is packed into a casing, often with a hollow core. When the rocket is ignited, the exposed surface of the propellant burns. The hollow section serves as the combustion chamber. The combustion produces high temperature exhaust gas. High pressure forces the gas through a nozzle, which produces the thrust needed to launch the rocket.

The shape of the hollow core determines how the rocket will burn. For example, a greater surface area will increase thrust but reduce burn time. This is because more propellant is exposed to burn, so more exhaust gas will be produce at a time, but the propellant will be used up quicker. Different shapes are used to control changes in thrust, depending on the purpose of the rocket.