The Nike-X, developed during the mid-1960s, was an anti-ballistic missile system designed to correct deficiencies of the older Nike-Zeus system, most notably through its two phased-array radars. The Nike-X was the basis for the Sprint interceptor missile, a component of the proposed Sentinel project, and deployed in 1975 as part of the Safeguard system.
During the late 1950s, the Nike-Zeus system was the primary U.S. anti-ballistic missile development project. The system, however, suffered several drawbacks. It was vulnerable to decoys and countermeasures, unable to discriminate between targets, and relatively slow compared to the incoming ICBMs. In addition, each interceptor cost $1 million, which meant that it would cost the U.S. military more to offset the Soviet ICBMs than it would cost the Soviets to deploy them.
For these reasons, in 1963 the Kennedy administration canceled Nike-Zeus in favor of a new project known as Nike-X. Based on the Nike-Zeus model, the Nike-X was designed to intercept incoming reentry vehicles just after they entered the atmosphere, thus making it easier to sort out warheads from countermeasures and decoys. To accomplish this, the new system was to incorporate faster burning rockets, new computers, and two electronically steered phased-array radars.1
The phased-array radars, in particular, were a significant improvement over the Nike-Zeus, whose mechanically steered radars were cumbersome and vulnerable. By contrast, the phased-array radars steered their beams electronically by shifting the phases of radiating elements, as opposed to mechanically rotating the entire surface of the radar. This made it possible for the new radar system to maintain its track on known targets while continuing to scan for others.
Nike-X included two phased-array radars, working in conjunction. The first radar was known as the Perimeter Acquisition Radar (PAR). It was able to detect incoming warheads outside the atmosphere and determine their trajectory within three seconds. The second was known as the Missile Site Radar (MSR). It was designed to track the incoming warheads and guide the missiles to their assigned targets. When combined, the PAR and the MSR formed a layered radar shield, an approach that was carried over into future radar designs.2
In 1966, the U.S. Army attempted to acquire funding to produce the Nike-X, but was told that funding would not be available until 1968. In June 1967, however, China exploded its first thermo-nuclear device. The Johnson administration decided to reprioritize its anti-ballistic missile projects: away from the threat of large scale Soviet ICBMs and towards the emerging threat of a smaller Chinese attack.
On September 18, 1967, the Nike-X project was replaced by the Sentinel project. Yet the Nike-X missile would continue to play a role: it would later become the basis for the Sprint interceptor, originally envisioned as part of Sentinel and later deployed in 1975 as part of the Safeguard system.3
- Donald R. Baucom, The Origins of SDI, 1944-1983 (Lawrence, KS: University Press of Kansas, 1992), 17, 19-20, 25-26; Bradley Graham, Hit to Kill: The New Battle Over Shielding America from Missile Attack(New York: Public Affairs, 2001), 5-8; Stephen P. Moeller, “Vigilant and Invincible,” Air Defense Artillery Magazine (May-June 1995). (Back) ↩
- Gregory H. Canavan, Missile Defense for the 21st Century (Washington, DC: The Heritage Foundation, 2003); U.S. Congress, Office of Technology Assessment, Ballistic Missile Defense Technologies, OTA-ISC-254 (Washington, DC: U.S. Government Printing Office, September 1985). ↩
- GlobalSecurity.org, “Nike-X Description,” available at http://www.globalsecurity.org/space/systems/nike_x.htm, accessed on 10 January 2005. ↩