A reusable launch vehicle (RLV) is a craft designed to place payloads or crews into Earth orbit, and then return to Earth for subsequent launches. RLVs are designed to reduce launch costs by reusing the most expensive components of the vehicle rather than discarding them and building new ones for each mission (as is the case with expendable launch vehicles, known as ELVs). The definition of RLVs does not include reusable craft launched from expendable launch vehicles. As of 2001, the only operational RLV was the U.S. space shuttle. A number of concepts were being developed or studied. Some were partially reusable. Most employed rockets, while others used jet engines, aircraft, or high-speed rail systems.

The aim of the X-34 program was the development of low-cost space access through reusable launch vehicles.

RLVs may be categorized by whether the vehicle takes off horizontally or...