Rocket staging

Rocket staging

The use of successive rocket sections, each having its own engine or engines. One way to minimize the weight of large missiles, or space vehicles, is to use multiple stages. The first or initial stage is usually the heaviest and biggest and often called the booster; the next few stages are successively smaller and are generally called sustainers. Each stage is a complete vehicle in itself and carries its own propellant (either solid or liquid; both fuel and oxidizer), its own propulsion system, and has its own tankage and control system.

Once the propellant of a given stage is expended, the dead weight of that stage including empty tanks, rocket engine, and controls is no longer useful in contributing additional kinetic energy to the succeeding stages. By dropping off this useless weight, the mass that remains to be accelerated is made smaller; therefore it is possible to accelerate the payload to higher velocity than would be attainable if multiple staging were not used.

It is quite possible to employ different types of power plants, different types of propellants, and entirely different configurations in successive stages of any one multistage vehicle (see illustration). Because staging adds complications, it is impractical to have more than four to seven stages in any one vehicle. See Rocket propulsion