Multistage Rocket

A multistage rocket is a launch vehicle built from two or more rocket stages, each carrying its own engines and propellant, stacked one on top of another or mounted side by side, so that a spent stage can be jettisoned once its propellant is used up. Discarding each stage in turn sheds dead mass and lets the remaining stages accelerate a lighter vehicle, which is why, by the logic of the rocket equation relating a vehicle's change in velocity to the ratio of its fuel to its dry mass, only multistage rockets have ever reached orbital speed; staging also lets each stage be tuned to the conditions it flies through, with lower stages shaped for thick atmosphere and upper stages for vacuum. The earliest known staged design is a fourteenth century Chinese weapon called the fire dragon issuing from the water, which released smaller rocket arrows from a larger carrier in flight, and the Austrian Conrad Haas is recorded testing multistage rockets as early as 1551. The concept was developed into its modern form independently by Konstantin Tsiolkovsky, Robert Goddard, Hermann Oberth and others in the early twentieth century.