Atlas V Phase 1

EELV Phase 1

Mission Profile

The Atlas V Phase 1 was an early design concept for the Atlas V launch vehicle, studied as part of the U.S. Air Force's Evolved Expendable Launch Vehicle (EELV) competition in the late 1990s. Proposed with a 3.8 m diameter core stage and a two-stage configuration, this conceptual vehicle was designed to carry both military national security payloads and commercial satellites. Though the final Atlas V evolved significantly from this initial concept, Phase 1 studies established the technical foundation for what would become one of the most reliable American launch vehicles, completing 100 consecutive successful missions before retirement.