Design began in April 1966 as WS-120A. The BGM-75 AICBM was to be a solid-propellant missile designed for use in fixed silo and mobile train configurations. AICBM was not approved for development and cancelled in 1967.
Historical Essay © Andreas Parsch
In 1966, the U.S. Air Force began studies for a successor to the LGM-30 Minuteman ICBM. In April 1966, the new ICBM program was officially started as Weapons System 120A AICBM (Advanced Intercontinental Ballistic Missile), and in July that year the designation ZBGM-75A was allocated to the missile. The BGM-75 was to be a solid-rocket powered missile, to be used with both hardended (silo) and mobile (train) basing schemes. However, the AICBM program was not approved by the Secretary of Defense and cancelled in 1967. It was not until 1972 that the Air Force began another ICBM program, the then planned to be mobile MX (later LGM-118 Peacekeeper). Specifications
The BGM-75 program was cancelled before any design work was done.Main Sources
 James N. Gibson: "Nuclear Weapons of the United States", Schiffer Publishing Ltd, 1996
 Department of Defense Missile Nomenclature Records
Status: Cancelled 1967.