EELV (Evolved Expendable Launch Vehicle)

The EELV (Evolved Expendable Launch Vehicle) was a 1995 US Air Force specification for a new generation of American medium- to heavy-lift launch vehicles intended to reduce the cost of placing large payloads in orbit by at least 25% over then-existing Delta, Atlas, and Titan rockets. Contracts for the EELV were eventually awarded to Boeing for the Delta IV and Lockheed Martin for the Atlas V.