The Atlas E/F was an American expendable launch system and sounding rocket built using parts of decommissioned SM-65 Atlas missiles. It was a member of the Atlas family of rockets.
Launch of Atlas E/F X4 with a U.S. Navy payload
Atlas is a family of US missiles and space launch vehicles that originated with the SM-65 Atlas. The Atlas intercontinental ballistic missile (ICBM) program was initiated in the late 1950s under the Convair Division of General Dynamics. Atlas was a liquid propellant rocket burning RP-1 kerosene fuel with liquid oxygen in three engines configured in an unusual "stage-and-a-half" or "parallel staging" design: two outboard booster engines were jettisoned along with supporting structures during ascent, while the center sustainer engine, propellant tanks and other structural elements remained connected through propellant depletion and engine shutdown.
SM-65A Atlas missile, 1958
Atlas-B with SCORE payload, at LC-11, 1958
Mercury-Atlas 9 at Launch Complex 14
2005 Launch of Mars Reconnaissance Orbiter