US ABM Programs 1950s-1970s
Still a political and technical “hot potato” in the beginning years of the 21st century, Anti-Ballistic Missile (ABM) defenses, or at least the planning for them, has been a concern of military planners since World War II. No defense against the German V-2 proved possible, aside from the active measures of attacking launchers and the system’s infrastructure before firings took place. Anti-aircraft artillery and fighters could not hope to shot a V-2 down, and since the missile was inertially guided it was impossible to jam.
The collapse of Germany ended the immediate missile threat, but ABM interest did not die, as the Soviets were soon known to be have V-2 copies of their own, as well as longer-range derivatives, and they were continuing to work towards an intercontinental-range missile capability. By the mid-1950s, both the Army and USAF were seriously looking at building ABM systems to defend against Soviet ICBMs; the Air Force began work on the Wizard program, which would be aimed at providing a comprehensive ABM defense of the entire continental US, using large interceptor missiles to hit incoming warheads at least a thousand miles out. Although the Army was still in the process of developing its Nike-Hercules SAM, it also instituted the Nike-Zeus program, a much more ambitious follow-on. Nike-Zeus would have a much shorter range than the Wizard interceptors, but the Army plan was nonetheless selected for development in January 1958, while Wizard was canceled.
The scope of and the rational for a US ABM deployment would be continuously under review, even as the hardware evolved. Many believed that ABMs would only heighten the arms race by forcing the Soviets to increase their numbers of missiles and warheads, while even ABM proponents argued whether the goal should be to primarily defend cities, military installations (in particular, missile and bomber bases) or both.
Nike-Zeus was intended for area defense, essentially paralleling the Nike-Hercules anti-bomber deployment by ringing target cities with interceptor batteries. The initial configuration was really a test article combining a Nike-Hercules type upper stage with an entirely new booster. Operational missiles would be armed with W50 warheads. Controlling the actual missile engagements would be a series of radars; separate acquisition, discrimination, and target-tracking radars would focus on the incoming warheads, while a missile tracking radar would follow the Nike-Zeus interceptor itself.
The Nike-Zeus system was judged as not practical for countering a massed attack that could consist of many warheads, decoy balloons, and other penetration aids, as the radars had little discrimination capability. This meant that the system would certainly miss some warheads outside the atmosphere by attacking other objects. The atmosphere has a filtering effect as decoys and debris behave differently during reentry, but the Nike-Zeus mechanically-steered radars did not have the capability to engage extremely fast endoatmospheric targets in sufficient time to kill them at a safe distance. Political pressure to deploy an interim Nike-Zeus system continued into the early 1960s, but although work continued, it was evident that a more capable defense plan using the basic Zeus missile would be needed to meet the threats of the late 1960s and early 1970s.
While the future of the system was hashed out, technical progress continued. The first attempt at a Nike Zeus flight took place on August 28, 1959, but the missile was destroyed shortly after launch. A successful test was conducted on October 14 of that same year. In September 1960, Nike-Zeus showed that it could indeed knock down other missiles in flight, although the first target used, a Nike-Hercules, had nothing like the terminal speed of an ICBM warhead. This test was conducted over the White Sands Missile Range; the Hercules was not actually destroyed, as the Zeus was unarmed, but the interceptor did pass within lethal range of the target. Tests against Atlas RVs were subsequently carried out over the Pacific. While White Sands was adequate for test firings and intercepts of ICBM warheads dictated that a Nike-Zeus installation be constructed within the Western Missile Range. Kwajalein Atoll would be the site selected, and the atoll remains an ABM testing center to this day.
In a postscript, Nike-Zeus actually did see service of a sort, albeit short-lived, and not in the role it was primarily designed for. A missile with high-altitude ABM capability, would, by virtue of necessity, also have some ability to attack low-orbit satellites, and by the mid-1960s a great deal of concern was being expressed over countering Soviet orbiters. Attacking another nation’s space vehicles has always been a touchy topic, and early on in the space age there was considerable debate over where a nation’s territorial airspace ended and space began. Despite such concerns, the Army’s Project 505/Mudflap of the early 1960s proposed using the Nike-Zeus for the ASAT mission. Mudflap would have complimented the USAF’s Thor ASAT system, as the ABM-derived missile was faster, although it did not have the reach of the converted IRBMs.
In January 1963, the existence of a Nike-Zeus successor system, Nike-X, was formally disclosed. Significantly, this was to have two tiers, the upper consisting of the Douglas Spartan missile, which could hit exoatmospheric targets nearly five hundred miles out. The ultimate example of the Nike-Zeus series, Spartan was evolved out of the Nike-Zeus B. A much larger warhead, the 5-megaton yield W71 was fitted; as Spartan would encounter RVs above the atmosphere, radiation yield rather than blast effects would destroy the targets. The W71 was test-fired on November 6, 1971; codenamed Cannikin, this test would be the largest American underground nuclear detonation, and was staged more than a mile under the Alaskan island of Amchitka.
In order to deal with RVs that had made it through the atmosphere, a second type of interceptor would be fielded. The endoatmospheric Sprint missile, developed by Martin, would be a two-stage weapon with a conical airframe. In order to intercept extremely fast targets, Sprint had to have tremendous acceleration. Launching of operational missiles would be done from silos, with a piston arrangement ramming the missile into the air - once clear, the Hercules solid motor fired, producing 650,000lbs of thrust. The airframe and systems thus had to be engineered to withstand the tremendous g-loading that came from such a flight profile, and as Sprint would operate in the densest part of the atmosphere, the missile had to be coated with ablative material to counter the friction-induced heat. The warhead would be a W66 device that was to kill RVs via neutron bombardment. Prior to the arrival of the first Sprints, Martin conducted tests using Squirt demonstrator vehicles, which had first stages powered by clustered Recruit-type solid motors.
The radar architecture for Nike-X and succeeding schemes would be much changed from that of Nike-Zeus. A new Multifunction Radar with phased array antennas would replace the distinct acquisition, discrimination, and tracking sets of the older system. A missile site radar, also of phased array design and hardened construction would also help control engagements.
By 1967, Nike-X had in turn given way to a system known as Sentinel; the more comprehensive earlier plan having been rejected due both to technical complexity and its potentially destabilizing effect on the arms race. Sentinel was aimed at countering an accidental strike by a few Soviet missiles, or a deliberate attack by Communist China’s small ICBM force, which was expected at the time to be in place by the early 1970s.
Ironically, Sentinel would ignite protests from the very people that the system was designed. Demonstrators, fueled by the anti-military sentiment of the day and the idea of nuclear weapons (even defensive ones) placed near their communities railed against Sentinel. There were also questions as to whether the Chinese threat would in fact materialize as projected. In fact, it did not; some analysts thought that the PRC would have well over one hundred ICBMs by the late 1970s, but the Chinese did not in fact field intercontinental-range missiles until the 1980s, and then only in small numbers.
By late March 1968, the new Nixon Administration had decided on yet another ABM plan. Called Safeguard, and again using interceptors evolved for Nike-X, this would abandon city defense as the prime goal, reasoning that an imperfect defense (which was what could be expected) would still bolster the deterrent force’s stability if the interceptors were to defend Minuteman silos, while a system dedicated to defending the populace had to be foolproof to be effective.
Even this limited deployment would be just barely approved, with the project’s initial phase calling for Safeguard installations to be constructed at Grand Forks and Malmstrom to protect the associated Minuteman fields. Planning was underway by 1970 for a second phase of Safeguard with much greater coverage, able to defend both populated areas and missile fields. Additional radars would be emplaced at Warren and Whiteman as well as other locations.
However, the 1972 ABM Treaty put an end to plans for a nationwide system, as under the agreement’s terms the US and USSR could only have two ABM complexes. A further restriction to Safeguard deployment came in 1974, when the treaty was amended to allow each side only a single site. The North Dakota facility, which was nearing completion, was chosen to be the US site. The main “missile farm” of the system would be located with the Missile Site Radar, and would have thirty silos for Spartans and sixteen for Sprints. An additional four satellite farms in the vicinity held more Sprint silos. Unlike the earlier, more comprehensive plans that would have installed Perimeter Acquisition Radars around the borders of the US to provide long-range detection of incoming RVs, Safeguard as deployed would have only one PAR.
Even as Safeguard was nearing completion, the Army was looking towards the ABM needs of the next decade, particularly the requirement to defend Minuteman silos against attack from greater numbers of more accurate Soviet missiles. Under the Site Defense plan, farms of silos for improved Sprints would be situated around Minuteman sites, along with small missile site radars. The interceptors would have better electronics and motors, and would be further hardened against nuclear effects.
Safeguard was partially operational by April 1975, and on October 1 of that year the system was fully online. Ironically, despite the fact that nearly twenty years and billions of dollars had been spent to achieve an operational ABM defense, the very next day Congress voted to deactivate Safeguard on budgetary grounds, and this was carried out by early 1976, although the PAR remained in service for surveillance work, and the remaining Safeguard infrastructure was proposed for use in later national missile defense schemes.
“Lack of Interest Stalls Missile Defense Programs” Aviation Week October 7, 1957 p.29
“Wizard Reactivated” Aviation Week April 7, 1958 p.27
[Photo: “Douglas Nike Zeus Firing”] Aviation Week February 29, 1960 cover
“Douglas Nike Zeus Missile Fired Successfully at White Sand Proving Ground” Aviation Week February 29, 1960 p.54-55 6 illustrations
“Army Mounts Major Budget Fight For Acceleration of Zeus Project” Aviation Week November 14, 1960 p.27-28
Max S. Johnson “Danger: Antimissile Gap” U.S. News & World Report November 14, 1960 p.67 1 illustration (Nike-Zeus)
[Photo: Nike-Zeus] Aviation Week March 13, 1961 p.83
[Photo: Nike-Zeus] U.S. News & World Report May 29, 1961 p.65
Russell Hawkes “Nike Zeus Second Stage Explodes On First Launch From Pt. Mugu” Aviation Week & Space Technology September 18, 1961 2 illustrations
“Department of Defense Restricts Nike Zeus Testing Information” Aviation Week & Space Technology February 5, 1962 p.32-33 1 illustration
[Photo: “Nike Zeus Launching”] Aviation Week & Space Technology March 12, 1962 p.139
“Nike Zeus Tested” Aviation Week & Space Technology April 30, 1962 p.31 1 illustration
“Missile vs. Missile” Newsweek July 30, 1962 p.47 1 illustration (Nike-Zeus)
“A Dramatic New ‘First’ For America” U.S. News & World Report July 30, 1962 p.6 2 illustrations
“Four Radars Comprise Army Nike Zeus System” Aviation Week & Space Technology September 24, 1962 p.69 5 illustrations
“Nike X Multi-Array Radar Installation Shown” Aviation Week & Space Technology July 27, 1964 p.25 3 illustrations
“Decision Time Grows Shorter for Nike-X” Aviation Week March 15, 1965 p.147-151 2 illustrations
“Nike Zeus Improvement Seen Probable” Aviation Week & Space Technology August 23, 1965 p.71
[Photo: Sprint model] advertisement Aviation Week & Space Technology April 18, 1966 p.110
“DOD Halves Nike-X Cost Estimate For Area Defense Against China” Aviation Week & Space Technology July 4, 1966 p.77
“Doubts Rise Over Nike-X Production Commitment Now” Aviation Week & Space Technology March 6, 1967 p.112-115 1 illustration
“Nike-X Contracts Expected by Early 1968” Aviation Week & Space Technology September 25, 1967 p.16-18
“Quick-Reaction Sprint Launch” Aviation Week & Space Technology October 23, 1967 p.63 2 illustrations
“Nike Gets New Anti-Satellite Role” Aviation Week & Space Technology October 23, 1967 p.62-67 3 illustrations
“Nike-X Go-Ahead Followed Fierce Struggle” Aviation Week & Space Technology October 23, 1967 p.70-75 2 illustrations
Philip J. Klass “Soviet Payloads Overfly Nike-X Test Site” Aviation Week & Space Technology December 11, 1967 p.81-85
“Safeguard Extension Aimed At Urban Area Protection” Aviation Week & Space Technology February 9, 1970 p.22-23
“Military Buildup by Soviet Spurs Safeguard Growth” Aviation Week & Space Technology February 23, 1970 p.17-18
“Nixon Stresses Strategic Buildup” Aviation Week & Space Technology March 9, 1970 p.21-25
Clarence A. Robinson, Jr. “Army Spurs Missile Defense Technology” Aviation Week & Space Technology April 22, 1974 P.12-13+ 2 illustrations
“Army Widens Ballistic Missile Research” Aviation Week & Space Technology December 8, 1975 p.17-18
“Test Flight Made By Missile Killer” The New York Times October 15, 1959 p.17 c.1
John D. Morris “Senators Meet in Secret, Then Bar Nike Speed-Up” The New York Times April 12, 1963 p.1
William Beecher “Now an Anti-anti-missile Missile?” The New York Times June 26, 1966 IV p.3 c.5 1 illustration (Sprint launch)
William Beecher “The Antimissile Issue” The New York Times November 11, 1966 p.19
William Beecher “U.S. Will Deploy Missile Defense Around Nation” The New York Times September 16, 1967 p.1 c.8
copyright 2003-2010 C. Reed
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- An interesting look at the never completed Sentinel PAR site near Boston.
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History of the first US ICBM, the Convair Atlas