W87

Last updated
W87
W87 Peacekeeper warheads.png
The Mk21 Re-entry Vehicles shown here for the LGM-118A Peacekeeper contain W87 warheads.
Type Thermonuclear warhead
Service history
In service1986–present
Used byUnited States
Production history
Designer Lawrence Livermore National Laboratory
DesignedMod 0: February 1982
Mod 1: November 1986 to July 1988, March 2019 to 2030
ProducedMod 0: July 1986 to December 1988
Mod 1: 2030 onwards
No. built525
Variants2
Specifications
Mass400 to 600 pounds (180 to 270 kg)

Detonation
mechanism
Contact, airburst
Blast yield300 kt (W87-0)
475 kt (W87-1)
Exploded diagram of the Mk21 reentry vehicle for the W87 Mk21 Reentry vehicle.png
Exploded diagram of the Mk21 reentry vehicle for the W87

The W87 is an American thermonuclear missile warhead formerly deployed on the LGM-118A Peacekeeper ("MX") ICBM. 50 MX missiles were built, each carrying up to 10 W87 warheads in multiple independently targetable reentry vehicles (MIRV), and were deployed from 1986 to 2005. Starting in 2007, 250 of the W87 warheads from retired Peacekeeper missiles were retrofitted onto much older Minuteman III missiles, with one warhead per missile. [1]

Contents

Description

The W87 warhead. The secondary (top) is forward of the larger primary (bottom). W-87 warhead diagram.svg
The W87 warhead. The secondary (top) is forward of the larger primary (bottom).

Design of the W87 (now called the W87 Mod 0 or W87-0) started in February 1982 at Lawrence Livermore National Laboratory and production of the warhead began in July 1986 and ended in December 1988. [2] Its design is reportedly somewhat similar to the W88, though that warhead was designed at Los Alamos National Laboratory. The weapons are part of a National Nuclear Security Administration nuclear weapons lifecycle program. [3]

The W87 design includes all modern safety features, including the insensitive high explosives LX-17 and PBX-9502 (primary component TATB), a fire-resistant pit, and advanced arming and fuzing safety features. [4]

The original yield of the W87 was 300 kilotons, but it has the announced ability to be upgraded to a yield of 475 kilotons, presumably by using more highly enriched uranium (HEU) in the fusion secondary stage tamper. It is not known if that upgrade was completely tested and ready to implement, or merely designed. [4]

The exact dimensions of the W87 are classified, but it fits inside the Mk. 21 reentry vehicle, which is a cone with base diameter of 22 inches (56 cm) and a length of 69 inches (180 cm). The weight is believed to be between 440 and 600 pounds (200 and 270 kg). [4]

W87 mod 1

In addition to the higher yield upgrade option described above, a specific variant W87 mod 1 (W87-1) entered Phase 3 development engineering and was assigned its type designation in November 1988. [2] This variant was intended for the MGM-134 Midgetman small ICBM missile and was intended to have the full 475 kiloton yield. The W87-1 had a planned first production unit date of July 1997, [5] but Midgetman and W87-1 were canceled in January 1992.

In 2019, the W87 mod 1 was selected to replace the W78 warhead deployed on all Minuteman III missiles not currently carrying the W87 mod 0. The new warhead will not be deployed onto Minuteman III, but instead be deployed on Minuteman III's replacement ICBM system LGM-35A Sentinel (formerly Ground Based Strategic Deterrent or GBSD). It is not clear if the new W87 mod 1 program is a continuation of the previous W87 mod 1 program, or if it uses any of the physics package developed in the previous W87 mod 1 program. [6]

Information released by the Department of Energy (DoE) on the program states that it "has a similar primary design to the W87-0", which could be evidence that it is like the previous W87 mod 1 program in that it has a different or modified secondary to produce a higher yield. [6] The DoE states that the weapon is based on previously tested nuclear components, with a primary stage containing insensitive high explosives and advanced safety features, but that the weapon does not provide any new military capabilities. [7]

Phase 6.2 Feasibility Study was halted in 2014 before being restarted in 2019. Phase 6.3 Development Engineering is planned to begin July 2022, with 6.4 Production Engineering planned for mid 2026 and 6.5 Initial Production planned for 2030. [7]

It is planned for the Sentinel missile to deploy in 2028, with W87-0 warheads initially being fitted to the system and W87-1 warheads being fitted from 2030 onward. This affords the air force a small amount of flexibility if the W87-1 is delayed. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Intercontinental ballistic missile</span> Ballistic missile with a range of more than 10,000 kilometres

An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than 10,000 kilometres (6,200 mi), primarily designed for nuclear weapons delivery. Conventional, chemical, and biological weapons can also be delivered with varying effectiveness, but have never been deployed on ICBMs. Most modern designs support multiple independently targetable reentry vehicle (MIRVs), allowing a single missile to carry several warheads, each of which can strike a different target. The United States, Russia, China, France, India, the United Kingdom, Israel, and North Korea are the only countries known to have operational ICBMs.

<span class="mw-page-title-main">LGM-30 Minuteman</span> American ICBM, in service

The LGM-30 Minuteman is an American land-based intercontinental ballistic missile (ICBM) in service with the Air Force Global Strike Command. As of 2023, the LGM-30G is the only land-based ICBM in service in the United States and represents the land leg of the U.S. nuclear triad, along with the Trident II submarine-launched ballistic missile (SLBM) and nuclear weapons carried by long-range strategic bombers.

<span class="mw-page-title-main">Multiple independently targetable reentry vehicle</span> Ballistic missile payload containing multiple warheads which are independently targetable

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 intercontinental ballistic missiles carrying thermonuclear warheads, even if not strictly being limited to them. An intermediate case is the multiple reentry vehicle (MRV) missile which carries several warheads which are dispersed but not individually aimed. Only the United States, the United Kingdom, France, Russia and China are currently confirmed to have deployed MIRV missile systems. Pakistan is developing MIRV missile systems. Israel is suspected to possess or be in the process of developing MIRVs.

<span class="mw-page-title-main">LGM-118 Peacekeeper</span> Intercontinental ballistic missile

The LGM-118 Peacekeeper, originally known as the MX for "Missile, Experimental", was a MIRV-capable intercontinental ballistic missile (ICBM) produced and deployed by the United States from 1985 to 2005. The missile could carry up to twelve Mark 21 reentry vehicles, each armed with a 300-kiloton W87 warhead. Initial plans called for building and deploying 100 MX ICBMs, but budgetary concerns limited the final procurement; only 50 entered service. Disarmament treaties signed after the Peacekeeper's development led to its withdrawal from service in 2005.

<span class="mw-page-title-main">R-36 (missile)</span> Type of intercontinental ballistic missile designed by the Soviet Union

The R-36 is a family of intercontinental ballistic missiles (ICBMs) and space launch vehicles (Tsyklon) designed by the Soviet Union during the Cold War. The original R-36 was deployed under the GRAU index 8K67 and was given the NATO reporting name SS-9 Scarp. It was able to carry three warheads and was the first Soviet MRV missile. The later version, the R-36M, also known as RS20, was produced under the GRAU designations 15A14 and 15A18 and was given the NATO reporting name SS-18 Satan. This missile was viewed by certain United States analysts as giving the Soviet Union first strike advantage over the U.S., particularly because of its rapid silo-reload ability, very heavy throw weight and extremely large number of re-entry vehicles. Some versions of the R-36M were deployed with 10 warheads and up to 40 penetration aids and the missile's high throw-weight made it theoretically capable of carrying more warheads or penetration aids. Contemporary U.S. missiles, such as the Minuteman III, carried up to three warheads at most.

<span class="mw-page-title-main">W76</span> US thermonuclear warhead of the 1970s

The W76 is an American thermonuclear warhead, designed for use on the UGM-96 Trident I submarine-launched ballistic missiles (SLBMs) and subsequently moved to the UGM-133 Trident II as Trident I was phased out of service. The first variant, the W76 mod 0 (W76-0) was manufactured from 1978 to 1987, and was gradually replaced by the W76 mod 1 (W76-1) between 2008 and 2018, completely replacing the Mod 0 in the active stockpile. In 2018 it was announced that some Mod 1 warheads would be converted to a new low-yield W76 mod 2 (W76-2) version. The first Mod 2 warheads were deployed in late 2019.

<span class="mw-page-title-main">MGM-134 Midgetman</span> Intercontinental ballistic missile

The MGM-134A Midgetman, also known as the Small Intercontinental Ballistic Missile, was an intercontinental ballistic missile developed by the United States Air Force. The system was mobile and could be set up rapidly, allowing it to move to a new firing location after learning of an enemy missile launch. To attack the weapon, the enemy would have to blanket the area around its last known location with multiple warheads, using up a large percentage of their force for limited gains and no guarantee that all of the missiles would be destroyed. In such a scenario, the U.S. would retain enough of their forces for a successful counterstrike, thereby maintaining deterrence.

<span class="mw-page-title-main">W78</span> American thermonuclear warhead

The W78 is an American thermonuclear warhead with an estimated yield of 335–350 kilotonnes of TNT (1,400–1,460 TJ), deployed on the LGM-30G Minuteman III intercontinental ballistic missile (ICBM) and housed in the Mark 12A reentry vehicle. Minuteman III initially carried the older W62 warhead with a yield of 170 kilotonnes of TNT (710 TJ), but starting in December 1979 and ending in February 1982, some W62 were replaced with the W78. It is publicly estimated that 1083 warheads were manufactured.

<span class="mw-page-title-main">W50 (nuclear warhead)</span> Nuclear weapon

The W50 was an American thermonuclear warhead deployed on the MGM-31 Pershing theater ballistic missile. Initially developed for the LIM-49 Nike Zeus anti-ballistic missile, this application was cancelled before deployment. The W50 was developed by Los Alamos National Laboratory. The W50 was manufactured from 1963 through 1965, with a total of 280 being produced. They were retired from service starting in 1973 with the last units retired in 1991.

<span class="mw-page-title-main">W62</span> American thermonuclear warhead designed in the late 1960s

The W62 was an American thermonuclear warhead designed in the 1960s and manufactured from March 1970 to June 1976. Used on some Minuteman III ICBMs, it was partially replaced by the W78 starting in December 1979, and fully replaced by W87 warheads removed from MX Peacekeeper missiles and retired in 2010.

<span class="mw-page-title-main">W56</span> American thermonuclear warhead designed in the late 1950s/early 1960s

The W56 was an American thermonuclear warhead produced starting in 1963 which saw service until 1993, on the Minuteman I and II ICBMs.

<span class="mw-page-title-main">W59</span> American thermonuclear missile warhead

The W59 was an American thermonuclear warhead used on some Minuteman I ICBM missiles from 1962 to 1969, and planned to be used on the cancelled GAM-87 Skybolt air-launched ballistic missile.

The W67 was an American thermonuclear warhead developed from June 1966 but then cancelled prior to any production or service use approximately 18 months later.

<span class="mw-page-title-main">Nuclear triad</span> Set of three types of nuclear-strike weapons

A nuclear triad is a three-pronged military force structure of land-based intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and strategic bombers with nuclear bombs and missiles. Countries build nuclear triads to eliminate an enemy's ability to destroy a nation's nuclear forces in a first-strike attack, which preserves their own ability to launch a second strike and therefore increases their nuclear deterrence.

<span class="mw-page-title-main">Peacekeeper Rail Garrison</span> United States Air Force railcar-launched ICBM

The Peacekeeper Rail Garrison was a railcar-launched ICBM that was developed by the United States Air Force during the 1980s as part of a plan to place fifty MGM-118A Peacekeeper intercontinental ballistic missiles on the rail network of the United States. The railcars were intended, in case of increased threat of nuclear war, to be deployed onto the nation's rail network to avoid being destroyed by a first strike counterforce attack by the Soviet Union. However, the plan was canceled as part of defense cutbacks following the end of the Cold War, and the Peacekeeper missiles were installed in silo launchers as LGM-118s instead.

<span class="mw-page-title-main">Francis E. Warren Air Force Base</span> US Air Force base near Cheyenne, Wyoming, United States

Francis E. Warren Air Force Base, shortened as F.E. Warren AFB is a United States Air Force base (AFB) located approximately 3 miles (4.8 km) west of Cheyenne, Wyoming. It is one of three strategic-missile bases in the U.S. It was named in honor of Francis E. Warren in 1930. Warren AFB is home of the 90th Missile Wing, assigned to the Twentieth Air Force, Air Force Global Strike Command. The 90 MW operates the LGM-30G Minuteman III ICBM. It is also the home of Twentieth Air Force, which commands all U.S. Air Force ICBMs.

<span class="mw-page-title-main">STRAT-X</span> U.S. government-sponsored study

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 significant strides in nuclear weapons delivery, and also constructing anti-ballistic missile defenses to protect strategic facilities. To address a potential technological gap between the two superpowers, U.S. Secretary of Defense Robert McNamara entrusted the classified STRAT-X study to the Institute for Defense Analyses, which compiled a twenty-volume report in nine months. The report looked into more than one hundred different weapons systems, ultimately resulting in the MGM-134 Midgetman and LGM-118 Peacekeeper intercontinental ballistic missiles, the Ohio-class submarines, and the Trident submarine-launched ballistic missiles, among others. Journalists have regarded STRAT-X as a major influence on the course of U.S. nuclear policy.

<span class="mw-page-title-main">LGM-35 Sentinel</span> Intercontinental ballistic missile

The LGM-35 Sentinel, also known as the Ground Based Strategic Deterrent (GBSD), is a future American land-based intercontinental ballistic missile system (ICBM) currently in the early stages of development. It is slated to replace Minuteman III missiles, currently stationed in North Dakota, Wyoming, Montana, and Nebraska from 2029 through 2075. In 2020 the Department of the Air Force awarded defense contractor Northrop Grumman a $13.3 billion sole-source contract for development of the LGM-35 after Boeing withdrew its proposal. Northrop Grumman's subcontractors on the LGM-35 include Lockheed Martin, General Dynamics, Bechtel, Honeywell, Aerojet Rocketdyne, Parsons, Textron, and others.

References

  1. Kristensen, Hans M.; Norris, Robert S. (January 18, 2015). "US nuclear forces, 2015". Bulletin of the Atomic Scientists. 71 (2): 107–119. Bibcode:2015BuAtS..71b.107K. doi: 10.1177/0096340215571913 . S2CID   145260117.
  2. 1 2 Nuclear weapons labs (status report), University of California, 1989, archived from the original on 2006-05-18, retrieved 2006-04-15.
  3. "Fact Sheet: W87-1 Modification Program" (PDF). National Nuclear Security Administration. March 2019. Archived (PDF) from the original on 2019-12-31. Retrieved 2020-03-07.
  4. 1 2 3 Sublette, Carey (1 September 2001). "The W87 Warhead". Nuclear Weapon Archive. Retrieved 14 April 2023.
  5. Terry Michael Josserand (1 March 2017). R&A for UUR_Weapon_History_Phases_20170206 (Report). Sandia National Labs. OSTI   1429158. Archived from the original on 30 August 2021. Retrieved 30 August 2021.
  6. 1 2 "W87-1 Modification Program" (PDF). March 2019. Archived (PDF) from the original on 2019-12-31. Retrieved 2020-03-08.
  7. 1 2 National Nuclear Security Administration (1 Feb 2022). W87-1 MODIFICATION PROGRAM (PDF) (Report). Archived (PDF) from the original on 30 March 2022. Retrieved 30 March 2022.
  8. Frank G. Klotz, Alexandra T. Evans (2022). Modernizing the U.S. Nuclear Triad: The Rationale for a New Intercontinental Ballistic Missile (PDF) (Report). RAND. p. 21. Archived (PDF) from the original on 6 February 2022. Retrieved 30 March 2022.