The ZBGM-75 Advanced Intercontinental Ballistic Missile, also known as Weapons System 120A (WS-120A), was a program to develop an
intercontinental ballistic missile
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons ...
(ICBM), proposed by the
United States Air Force
The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
in the 1960s as a replacement for the
LGM-30 Minuteman
The LGM-30 Minuteman is an American land-based intercontinental ballistic missile (ICBM) in service with the Air Force Global Strike Command. , the LGM-30G Minuteman III version is the only land-based ICBM in service in the United States and r ...
as the Air Force's standard ICBM. Funding was not allocated for the program and the project was cancelled in 1967.
Background
The Department of Defense began the
STRAT-X
STRAT-X, or Strategic-Experimental, was a U.S. government-sponsored study conducted during 1966 and 1967 that comprehensively analyzed the potential future of the U.S. nuclear deterrent force. At the time, the Soviet Union was making significan ...
study on 1 November 1966 to evaluate a new ballistic missile proposal from the Air Force, which was designated the Advanced Intercontinental Ballistic Missile (AICBM). The project was intended to provide a successor to the
LGM-30 Minuteman
The LGM-30 Minuteman is an American land-based intercontinental ballistic missile (ICBM) in service with the Air Force Global Strike Command. , the LGM-30G Minuteman III version is the only land-based ICBM in service in the United States and r ...
ICBM then in
United States Air Force
The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...
service.
[Parsch 2003] The program was officially launched in April 1966, and in June the project received the
designation
Designation may refer to:
* Designation (law), the process of determining an incumbent's successor
* Professional certification
* Designation (landmarks), an official classification determined by a government agency or historical society
* Desig ...
ZBGM-75,
the "Z" prefix indicating a project in the planning stage.
The specifications for the ZBGM-75 called for a large
solid-fuel-powered missile, which would be fitted with between 10 and 20
multiple independently targetable reentry vehicle
A multiple independently targetable reentry vehicle (MIRV) is an exoatmospheric ballistic missile payload containing several warheads, each capable of being aimed to hit a different target. The concept is almost invariably associated with int ...
s (MIRVs).
The missiles would be based in
silo
A silo (from the Greek σιρός – ''siros'', "pit for holding grain") is a structure for storing bulk materials. Silos are used in agriculture to store fermented feed known as silage, not to be confused with a grain bin, which is used t ...
launchers, which were specified to be hardened by a factor of 10 over the existing silos used by Minuteman missiles.
[Hartunian 2003] In addition, there was also a plan to develop a
railroad-based deployment system for the AICBM.
Improvements in accuracy over existing missiles, combined with
penetration aid
A penetration aid (or "penaid") is a device or tactic used to increase an intercontinental ballistic missile (ICBM) warhead's chances of penetrating a target's defenses.
These can consist of both ''physical devices'' carried within the ICBM (as p ...
s under development to enhance the effectiveness of each missile, were expected to make the AICBM capable of defeating existing and projected
Soviet
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
anti-ballistic missile
An anti-ballistic missile (ABM) is a surface-to-air missile designed to counter ballistic missiles (missile defense). Ballistic missiles are used to deliver nuclear, chemical, biological, or conventional warheads in a ballistic flight traje ...
systems.
[Auten 2008, pp.42–43.]
Cancellation
Ultimately, the Navy won the STRAT-X competition with the design that would become the
ballistic missile submarine
A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. The United States Navy's hull classification symbols for ballistic missile submarines are SSB and SSBN – t ...
s. Nevertheless, the final report, issued in August 1967, recommended that the ZBGM-75 also be developed. Accordingly, the Joint Chiefs of Staff recommended to
Secretary of Defense Robert McNamara
Robert Strange McNamara (; June 9, 1916 – July 6, 2009) was an American business executive and the eighth United States Secretary of Defense, serving from 1961 to 1968 under Presidents John F. Kennedy and Lyndon B. Johnson. He remains the ...
that the ZBGM-75 be funded starting in Fiscal Year (FY) 1969, with a projected entry into service by 1973. This recommendation came after the Air Force had completed the preliminary studies on the missiles and the new, hardened silos. McNamara instead kept the missile in "advanced development", which stopped all work on the project. Only development of the new super-hardened silos was approved for funding; these would be used by the Minuteman missiles.
As a result, the missile's development was cancelled.
McNamara's rationale for cancelling the program was the destabilizing influence of the new missile, which could have rendered existing Soviet anti-ballistic missile defenses ineffective. McNamara saw relative parity between the two powers—the strategic basis for
mutually assured destruction
Mutual assured destruction (MAD) is a doctrine of military strategy and national security policy which posits that a full-scale use of nuclear weapons by an attacker on a nuclear-armed defender with second-strike capabilities would cause the ...
—as the best method to keep the Soviet Union in a position where it must negotiate with the United States.
After the cancellation of WS-120A, the Air Force made no further development of new ICBMs until 1972. In that year the MX project was begun, which resulted in the development of the
LGM-118 Peacekeeper.
The Peacekeeper entered service in the mid-1980s and served until 2005; the Minuteman III is still in service, and has outlasted both of its planned replacements.
See also
*
BGM-109G Ground Launched Cruise Missile
The Ground Launched Cruise Missile, or GLCM, (officially designated BGM-109G Gryphon) was a ground-launched cruise missile developed by the United States Air Force in the last decade of the Cold War and disarmed under the INF Treaty.
Overview
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References
Notes
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{{Use dmy dates, date=June 2017
BGM-075
Cold War weapons of the United States
Proposed weapons of the United States
Abandoned military rocket and missile projects of the United States