Why Are Rockets Built in Stages?

A rocket must initially lift not only its payload, but also the weight of its propellant--the fuel and the oxygen (or other oxidizer) needed to burn the fuel. In fact, most of the mass of a rocket before launch is propellant. Much of the rest-- supporting structure, tanks, pumps, engines, and more--is useless once the fuel has burned. To avoid having to carry all that excess weight into space, rockets often have several stages, or sections, each of which drops away after use.

Rocketing Across the U.S.A.

(Rev. 01/03/97)