The W85 was a thermonuclear warhead developed by the United States of America to arm the Pershing II missile. It had a variable yield— often referred to as "dial-a-yield" — which could be set between 5 and 80 kilotons.
The Pershing Ia missile was armed with a 400 kiloton W50 warhead. By the early 1970s it was clear that this was far too large to allow the missile to be used as a tactical nuclear weapon — by this time 400 kt was larger than most strategic warheads. The Pershing II had a high accuracy maneuverable reentry vehicle (MARV), equipped with a radar terminal guidance system and carrying a low yield W85 warhead. Like many US nuclear weapons, it was a development of the B61 nuclear bomb - in this case, a modification of the Mod 3/4 design.
After the Pershing missiles were scrapped, all 120 of the W85 warheads produced were modified into B61 bombs, in this case the B61-10 free-fall weapon.
- http://www.nuclearweaponarchive.org/Usa/Weapons/Allbombs.html, accessed Oct 2, 2006
- http://www.nuclearweaponarchive.org/Usa/Weapons/B61.html, accessed Oct 2, 2006
- http://www.globalsecurity.org/wmd/systems/b61.htm, accessed Oct 2, 2006
- The B61 family of bombs, Robert Norris The Bulletin of the Atomic Scientists