Expendable launch vehicles (ELVs) are rockets that carry satellites, people, and space probes but are not recovered or reused. These rockets are expendable, meaning that they are thrown away after their flights are completed. Expendable rockets can take many forms, but the most commonly used ones are powered by either liquid fuel or solid fuel and use multiple stages to propel their cargoes of spaceships, probes, or satellites into outer space.

The Soviet Soyuz spacecraft as photographed from the American Apollo spacecraft in Earth orbit in July 1975. The three major components of the Soyuz craft are easily visible: the Orbital Module (sphere-shaped), the Descent Vehicle (bell-shaped), and the Instrument Assembly Module (cylinder-shaped).

Each of the rocket's stages consists of a self-contained rocket engine or motor and the fuel such as hydrogen, kerosene, or a solid fuel that looks a lot like the eraser on...