It was not until January 1963 that development started on a redesigned Nike Zeus system called Nike X. Compared to Nike Zeus, this system consisted of two missiles, phased array radars and higher capacity data processing systems. The Nike EX missile, which was a longer and heavier version of the Nike Zeus B missile, performed an exo-atmospheric interception of the RV. Another shorter range missile also was required, which was called Sprint, which provided a last ditch defence against warheads that had either evaded the Nike EX or which had been let through. The use of phased array radars combined with higher performance data processing systems (computers) allowed the system to track and intercept many targets at once. These basic design requirements overcame many of the short comings of the Nike Zeus system.

By October 1965 the design for Nike X had been completed and contracts were let. The Prime contractor for Nike EX was Western Electric Company which was under direction of Huntsville Alabama. Bell Telephone Laboratories had research and development responsibility while McDonnell Douglas Astronautics, under direction from Bell, were responsible for missile development.

This system was essentially the system that went operational despite numerous changes in name of the program. With each change of program name came with it a change in deployment, rather than a change in hardware.

To assist the two missiles, two radars were required, both Phased Array radars which sweep the radar beam electronically rather than via mechanical means. As a result, the major limitation of the Nike Zeus system had been overcome. The first radar was the Perimeter Acquisition Radar (PAR). It would detect incoming warheads and within 3 seconds of detection, determine their trajectory.

The other radar involved in the system initially was the Multi-Function Array Radar (MAR) which was also a phased array radar that was used to track the incoming warheads and guide the missiles to their assigned targets. This radar was tested at White Sands Missile Range in July 1964 with separate transmitter and receiver arrays, but was soon superseded by Raytheon's Missile Site Radar (MSR) with an integrated array.

When operating, both radars combined to form an integrated layered defence. Incoming targets were acquired and tracked by the PAR and their computed impact point was determined. Once it had detected an incoming RV, it only had 6 minutes to destroy it. Based on the computed impact point, the target information was handed over to the MSR which then tracked the RV target once within range. Powerful computer systems (for the day) then determined which warheads were to be intercepted. The appropriate missiles were launched (which were co-located with the MSR), with the MSR tracking both missile and target with the associated ground based computers guiding the missile to an intercept. Warheads on the missiles were detonated by ground command.

An effort was made by the Army in 1966 to acquire production funding but such funding was not actually forthcoming until 1968. In the meantime, McNamarra was forced into a corner. All the objections that he had raised over the years against an ABM system had been resolved and he found himself in a position where his reasons for non-deployment were no longer valid, and he could no longer deny funding. So he started questioning the deployment.

In June 1967 China exploded their first thermo-nuclear device and so a new threat was perceived to exist to the USA. It was felt that they would have missiles with a range capable of reaching the continental US within a number of years. It was also during this time that the USA and the Soviets were having talks regarding arms limitation. From a political perspective, it was felt not advisable to deploy an ABM system designed to intercept Soviet ICBMs. So Johnson and McNamara re-orientated the ABM system to counter the perceived Chinese threat instead. Nike-X died and Sentinel was born.

Last Modified: 22-Aug-2002