Liquid propellants are fuels used in rockets and spacecraft that are stored in liquid form. They typically consist of a fuel, like liquid hydrogen, and an oxidizer, such as liquid oxygen. When these two components are combined and ignited in a combustion chamber, they produce a high-speed exhaust that propels the rocket forward. This method allows for precise control over thrust and can be adjusted during flight. One of the main advantages of liquid propellants is their efficiency compared to solid propellants. They can be turned on and off, allowing for better maneuverability in space. This flexibility is crucial for missions involving satellites, like those launched by NASA or SpaceX, where precise positioning is essential.