W71
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The W-71 nuclear warhead was a US thermonuclear warhead developed at Lawrence Livermore National Laboratory in California and deployed on the LIM-49A Spartan Anti-ballistic missile. This was a component of an Anti-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.[1]
A single W-71 prototype was successfully tested in Project CANNIKIN in the world's largest underground nuclear test, on Amchitka Island in the Aleutian Islands off Alaska. 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 the Richter 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 documentaries Welcome 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.
[edit] External links
- Photograph of the Spartan mille body containing the W-71 before lowering into the borehole
- US nuclear weapons list at nuclearweaponarchive.org
- Spartan warhead image from nuclearweaponarchive.org
- W-71 warhead information including at Globalsecurity.org
[edit] References
- ^ Allbombs.html entry on W71 at nuclearweaponarchive.org, Accessed June 6, 2007
