W87
Encyclopedia
LGM-118A Peacekeeper
The LGM-118A Peacekeeper, also known as the MX missile , was a land-based ICBM deployed by the United States starting in 1986. A total of 50 missiles were deployed. They have since been deactivated....
ICBM
Intercontinental ballistic missile
An intercontinental ballistic missile is a ballistic missile with a long range typically designed for nuclear weapons delivery...
, 50 of which, with up to 12 warhead
Warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...
s per missile, were deployed during the 1986-2005 period. Starting in 2007, 200 of the W87 warheads from now-retired MX/Peacekeeper missiles will be retrofitted onto much older Minuteman III missiles, with only one warhead on each missile.
Description
Design of the W87 started in February 1982 at Lawrence Livermore National LaboratoryLawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
and production of the warhead began in July 1986 and ended in December 1988.
Its design is reportedly somewhat similar to the W88
W88
The W88 is a United States thermonuclear warhead, with an estimated yield of 475 kiloton , and is small enough to fit on MIRVed missiles. The W88 was designed at the Los Alamos National Laboratory in the 1970s. In 1999 the director of Los Alamos who had presided over its design described it as...
, though that warhead was designed at Los Alamos National Laboratory
Los Alamos National Laboratory
Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...
.
The weapons were refurbished for an extended lifespan by the National Nuclear Security Administration
National Nuclear Security Administration
The United States National Nuclear Security Administration is part of the United States Department of Energy. It works to improve national security through the military application of nuclear energy...
's Life Extension Program.
The W87 design includes all modern safety features, including insensitive high explosives LX-17 and PBX-9502 (primary component TATB
TATB
TATB, or triaminotrinitrobenzene, is an aromatic explosive, based on the basic six-carbon benzene ring structure with three nitro functional groups and three amine groups attached, alternating around the ring....
), a fire resistant pit, and advanced arming and fuzing safety features.
The original yield
Nuclear weapon yield
The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...
of the W87 was 300 kilotons of TNT
TNT equivalent
TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...
, but has the announced ability to be upgraded to a yield of 475 kilotons, presumably by using more HEU
Enriched uranium
Enriched uranium is a kind of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711% of its weight...
in the fusion secondary stage tamper. It is not known if that upgrade was completely tested or merely designed and ready to implement.
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 (55 cm) and a length of 69 inches (175 cm). The weight is believed to be between 440 and 600 pounds (200 and 270 kilograms).
Variants
In addition to the higher yield upgrade option described above, a specific variant W87-1 entered Phase 3 development engineering and was assigned its type designation in November 1988.This variant was intended for the MGM-134 Midgetman
MGM-134 Midgetman
The MGM-134A Midgetman, also known as the Small Intercontinental Ballistic Missile , was an intercontinental ballistic missile developed by the United States of America.-Overview:...
small ICBM missile and was intended to have the full 475 kiloton yield. The Midgetman and W87-1 were cancelled in January 1992.