Nike Zeus
Nike Zeus was an anti-ballistic missile (ABM) system developed by the US Army during the late 1950s and early 1960s that was designed to destroy incoming Soviet intercontinental ballistic missile warheads before they could hit their targets. It was designed by Bell Labs' Nike team, and was initially based on the earlier Nike Hercules anti-aircraft missile. The original, Zeus A, was designed to intercept warheads in the upper atmosphere, mounting a 25 kiloton W31 nuclear warhead. During development, the concept changed to protect a much larger area and intercept the warheads at higher altitudes. This required the missile to be greatly enlarged into the totally new design, Zeus B, given the tri-service identifier XLIM-49, mounting a 400 kiloton W50 warhead. In several successful tests, the B model proved itself able to intercept warheads, and even satellites. The nature of the strategic threat changed dramatically during the period that Zeus was being developed. Originally expected to face only a few dozen ICBMs, a nationwide defense was feasible, although expensive. When the Soviets claimed to be building hundreds of missiles, the US faced the problem of building enough Zeus missiles to match them. The Air Force argued they close this missile gap