Staging

Staging is the technique of dividing a launch vehicle into multiple propulsive sections (stages), each of which is discarded after its propellant is exhausted. This dramatically improves performance because the rocket no longer wastes energy accelerating empty tanks and engines. Tsiolkovsky's rocket equation shows that staging is essential for reaching orbital velocity with chemical propulsion. Most modern rockets are two-stage (Falcon 9, Ariane 6, Long March 5). Historical vehicles like Saturn V used three stages. SpaceX's Starship uses two stages (Super Heavy booster + Starship upper stage), both designed for full reusability.