NUCLEAR, BIOLOGICAL AND CHEMICAL WEAPONS
November 30, 2006: The United States has begun replacing W62 nuclear warheads, on 300 Minuteman III missiles, with refurbished W87 warheads. The W87 was originally built for the Peacekeeper missile, which carried ten W87s each. But the last Peacekeeper was retired last year. The W87 warheads were checked over and reconfigured to work on the Minuteman. The W62 is a 1960s design that does not have as many safety or reliability features as the W87, and is more expensive to maintain. The W87 is a 1980s design. Each Minuteman now carries one warhead, although it was designed to carry three. But the START II treaty restricts the missiles to one.
It took about $250 million to modify the W87s to work on Minuteman. One missile a week is being converted, so it will take over five years to complete the work. Both warheads contain a hydrogen (fusion) bomb. The W62s has a yield of 170 kilotons, the W87 is 300 kilotons. Both weapons, with their Re-entry Vehicle equipment, weigh about 800 pounds each.