Chemical propulsion is a method of generating thrust by burning fuel and oxidizer to produce hot gases. This process occurs in engines, such as those used in rockets and spacecraft, where the rapid expansion of gases is directed out of a nozzle, propelling the vehicle forward. The most common types of chemical propulsion systems include liquid rocket engines and solid rocket boosters. These systems are essential for launching satellites, space probes, and crewed missions, as they provide the necessary force to overcome Earth's gravity and reach space.