Liquid propellant refers to a type of fuel used in rockets and spacecraft that is in liquid form. It typically consists of a fuel and an oxidizer, which are combined in a combustion chamber to produce thrust. This method of propulsion is efficient and allows for precise control over the rocket's speed and direction, making it ideal for space exploration and satellite launches. One of the most common examples of liquid propellant is the combination of liquid oxygen and liquid hydrogen. This mixture burns cleanly and produces a high amount of energy, which is why it is used in many space missions, including those by NASA and other space agencies around the world.