- W71
The W-71 nuclear warhead was a US thermonuclear warhead developed at
Lawrence Livermore National Laboratory in California and deployed on theLIM-49A Spartan Anti-ballistic missile. This was a component of anAnti-ballistic missile defense system briefly deployed by the US in the 1970s.The W-71 warhead had a yield of around 5 megatons optimized for the production of hard X-rays and minimal debris in an exoatmospheric detonation. The warhead package was roughly a cylinder, 42 inches in diameter and 101 inches long. The complete warhead weighed around 2,850 pounds. [ [http://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html Allbombs.html entry on W71] at [http://nuclearweaponarchive.org nuclearweaponarchive.org] , Accessed June 6, 2007]
A single W-71 prototype was successfully tested in Project CANNIKIN in the world's largest underground nuclear test, on
Amchitka Island in theAleutian Islands offAlaska . The W-71, mounted in a Spartan missile body, was lowered 6150 feet down a 90 inch diameter borehole into a man-made cavern 52 feet in diameter. A 264 foot long instrumentation system monitored the detonation. The full yield test was conducted at 11:00am local time November 6, 1971 and resulted in a vertical ground motion of more than 15 feet at a distance of 2000 feet from the borehole, equivalent to an earthquake of magnitude 7.0 on theRichter scale . A mile wide and 40 foot deep crater formed two days later.Film of the test has been declassified and can be seen in the third of the
Atomic Journeys documentariesWelcome To Ground Zero .30 units were produced in 1974 and 1975. The weapons went into service, but were then taken right back out of service in 1975 and the warheads stored until 1992 when they were dismantled.
External links
* [http://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html US nuclear weapons list at nuclearweaponarchive.org]
* [http://nuclearweaponarchive.org/Usa/Weapons/Spartanwarhd.jpgSpartan warhead image from nuclearweaponarchive.org]
* [http://www.globalsecurity.org/wmd/systems/w71.htm W-71 warhead information including at Globalsecurity.org]References
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