What are the three primary types of rocket propulsion?

The three primary types of rocket propulsion are solid, liquid, and hybrid.

Solid propulsion systems use a fuel that is in a solid state. The propellant is pre-loaded into the rocket motor, and once ignited, it burns at a controlled rate to produce thrust. This type of propulsion is known for its simplicity, reliability, and relatively low cost, which makes it popular for many types of rocketry, especially in hobby and commercial launch vehicles.

Liquid propulsion systems, on the other hand, utilize fuel and oxidizer in liquid form. This allows for the ability to throttle and shut down the engine as needed, providing greater control over the thrust produced. Liquid engines typically offer higher performance in terms of specific impulse compared to solid engines, but they are more complex due to the necessary fuel handling and injector systems.

Hybrid propulsion systems combine features from both solid and liquid systems. In a hybrid engine, the fuel is usually in a solid state, while the oxidizer is in a gaseous or liquid form. This design offers some advantages over pure solid or liquid engines, providing a balance of performance and control.

The other choices present propulsion types that are not considered primary categories. Electric propulsion utilizes electric or electromagnetic means to produce thrust, nuclear propulsion involves the