In a fenced-off field near Langdon, North Dakota stands a strange and enigmatic object: a 24-metre high truncated concrete pyramid, looming over the prairie. Scattered around its base are other strange forms cast in concrete and steel, and a cluster of low, prefabricated buildings, now empty and slowly rusting away. These are the remains of the Stanley R. Mickelsen Safeguard Complex, a massive effort by the United States Military to defend its nuclear arsenal from missile attack. The culmination of 20 years of cutting-edge research, the complex took 6 years and $6 billion (about $60 billion today) to build. Yet only one day after the system came online, the United States Congress pulled the plug on the entire project. Within four months, the sprawling, high-tech complex was shuttered, decommissioned, and abandoned, becoming a crumbling monument to Cold War paranoia. This is the story of Project SAFEGUARD, the missile defence system that never was.

The roots of SAFEGUARD go back to the development of the Nike-Ajax and Nike-Hercules missiles in the early 1950s. These weapons were designed to shoot down Soviet Tu-95 and M-4 manned strategic bombers, which at the time were the only means of delivering nuclear weapons. But a new generation of nuclear weapons in the form of intermediate-range and intercontinental ballistic missiles were just around the corner. Missile-launched warheads were far smaller and faster than bombers, plunging down on their targets from outer space at speeds of 6 kilometres per second. It thus became clear that a new type of defense system would be needed to counter this coming threat: an anti-ballistic-missile or ABM. So, in 1955, the U.S. Army commissioned a research group composed of Western Electric, Bell Labs, and Douglas Aircraft to develop an anti-ballistic missile system known as Nike-Zeus.

Nike-Zeus consisted of six basic components. The first was the missile itself, developed from the older Nike-Hercules, which could travel at 4 times the speed of sound and reach a maximum altitude of 280 kilometres, allowing it to intercept enemy reentry vehicles above the atmosphere. Steering was via a set of moveable fins while inside the atmosphere, while exhaust gasses vented through the fins allowed for maneuvering in the vacuum of space. The missile was armed with 400-kiloton W50 enhanced-radiation nuclear warhead, which destroyed the target through a combination of blast and radiation effects.

But the most challenging aspect of Nike-Zeus development was the radar system, which detected and tracked incoming warheads and guided the anti-ballistic missiles to interception. This system comprised five basic components: the Acquisition Radar, which detected incoming warheads at long ranges and alerted the rest of the system; the Target Track Radar, which determined the warheads’ position and trajectory with greater accuracy; the Discrimination Radar, which separated out the warheads from the remains of the rocket booster and other clutter; the Missile Track Radar, which guided the Nike-Zeus missiles to interception; and the Data Processing Centre which tied the whole system together. These systems were marvels of 1950s electronics engineering, incorporating some of the first large-scale applications of the then-new technologies of transistors and modular architecture. The target-track radar was able to scan some 4 million cubic kilometres of space while keeping track of multiple different targets and interceptor missiles.

In 1958, testing of the Nike-Zeus system began at White Sands Missile Range in New Mexico and Kwajalein Atoll in the Pacific Proving Grounds. While initially the missiles suffered from a variety of issues, including excessive frictional heating of the guidance fins, these were eventually ironed out, and by 1963 the system had successfully performed 9 consecutive intercepts, both of Nike-Hercules missiles launched from Kwajalein and Atlas ICMBs launched from Vandenberg Air Force Base in California. Meanwhile, a prototype of the Target Track Radar tracked the Echo 1 communications satellite at an altitude of 3,600 kilometres and successfully received a signal bounced off the moon.

But just as the Nike-Zeus system was poised to enter service, it was abruptly cancelled by the Department of Defense. There were many reasons for this decision. Firstly, Nike-Zeus was developed under the assumption that Soviet ballistic missile deployment would remain relatively low. However, as the USSR continued to field ever greater numbers of increasingly advanced missiles, it became clear that an all-out attack would quickly overwhelm the Nike-Zeus system. Worse still, advancements in nuclear warhead miniaturization allowed missiles to carry multiple inflatable radar-reflector decoys, which would further clutter the radar image and overwhelm the system. Indeed, Army calculations predicted that at least 20 Nike-Zeus missiles would be needed to ensure the destruction of a single enemy warhead. Finally, experiments like Operation Fishbowl in 1962 had revealed that nuclear explosions in the upper atmosphere created large radio blackout zones, meaning the first few missile intercepts would effectively blind the whole system – and for more on this phenomenon, please check out our previous video Do Real EMP Weapons Actually Exist, or Are They Only a Thing in Movies?

There was also considerable skepticism as to the practicality of ABM systems in general, with Herbert York, head of the Advanced Research Projects Administration or ARPA, stating:

“The problem here is the usual problem between defense and offenses, measures, countermeasures, counter-counter measures, et cetera, in which it has been my judgment and still is that the battle is so heavily weighted in favor of the offense that it is hopeless against a determined offense and that incidentally applies to our position with regard to an anti-missile that they might build. I am convinced that we can continue to have a missile system that can penetrate any Soviet defense.”

Nonetheless, the Department of Defense directed the Nike-Zeus’ team to develop an even more advanced anti-ballistic-missile system, which became known as Nike X. The Nike X system incorporated a number of advances over Nike-Zeus. Firstly, instead of traditional rotating-antenna radars, the system incorporated the new technology of phased arrays, which allowed the radar beam to be steered electronically instead of mechanically, vastly increasing speed and accuracy. And instead of four radars, the system only used two: a Perimeter Acquisition Radar or PAR to detect incoming warheads at long ranges, and a Missile Site Radar or MSR to track the targets and guide the interceptor missiles. The system could track up to 40 objects simultaneously and detect objects as small as a baseball. Even more important to future technological development, the data processing system for these radars made extensive use of another major advancement in electronics: the integrated circuit.

Secondly, the Nike-X system used not one but two different interceptor missiles. The first of these was the Spartan, an upgraded version of the Nike-Zeus designed for greater speed and altitude and armed with a 5-megaton W71 warhead. This was designed to intercept warheads shortly after they were detected by the PAR, while they were still above the atmosphere. However, thanks to the deployment of radar-reflective decoys and other countermeasures, at least a few warheads were expected to get through this initial defence. Thankfully, these countermeasures would be quickly slowed down by atmospheric friction, causing the real warheads to become decluttered – that is, separated from their decoys and easier to detect. Unfortunately, due to their tremendous speed, the time between the warheads entering the atmosphere and reaching the ground was measured in seconds, creating a very narrow interception window. This secondary, low-altitude interception was performed by a second type of missile, the Martin-Marietta Sprint. Measuring 8 metres long and weighing 3,500 kilograms, the cone-shaped Sprint was one of the most impressive weapons ever developed. Gas-launched from an underground silo, the two-stage missile accelerated at a whopping 100 Gs, going from 0 to Mach 10 in less than 5 seconds. So fast was the Sprint that within seconds of launch, atmospheric friction made its casing glow white-hot. This blistering performance allowed the missile to intercept incoming warheads at altitudes of up to 30 kilometres within 15 seconds.

As with Nike-Zeus, the components of Nike-X were tested at White Sands and Kwajalein, where they performed practice intercepts on Polaris intermediate-range missiles launched from Navy ships and Minuteman intercontinental ballistic missiles launched from Vandenberg. Between 1963 and 1975, 150 test intercepts were conducted from Kwajalein with a 90% success rate, the last 21 intercepts being complete successes. As the system was expected to be able to survive a nuclear strike, all the major components – especially the above-ground radar antennas – had to be hardened against the effects of blast and radiation. Much of this research was carried out at Canadian Forces Base Suffield in Alberta, Canada, where in 1964 large piles of conventional explosives were used to simulate the blast wave from a nuclear weapon. Components were also exposed to underground nuclear detonations to test their radiation resistance.

While Nike-X was being developed, world events were making the system’s deployment increasingly urgent. On October 16, 1964, the People’s Republic of China successfully detonated its first atomic bomb, while on June 17, 1967 it tested its first thermonuclear or hydrogen bomb. Suddenly, the bi-polar nuclear contest between the United States and Soviet Union had become a tri-polar one. In response to this new threat, on September 18, 1967, U.S. Secretary of Defense Robert McNamara announced the creation of Project SENTINEL, a system of 17 Nike-X sites scattered around the United States to defend the country against the small anticipated Chinese ICBM fleet or a limited strike by the Soviets. To ensure an adequate workforce for construction and easy access to utilities and other resources, the sites would be built just outside major metropolitan areas, with the whole system coordinated from NORAD headquarters in Cheyenne Mountain, Colorado via a system of hardened microwave-tower links.

Construction soon began on the first Perimeter Acquisition Radar site at Sharpner’s Pond, just outside of Boston. But almost immediately, the entire project became mired in controversy, receiving fierce opposition from multiple sectors. Predictably, residents of communities where Sentinel sites were planned feared that the installations would turn their homes into targets, and mass protests were held in several cities to oppose their construction. Meanwhile, government scientists continued to question the wisdom of ABS systems – not only because they might be ineffective, but because they might paradoxically increase the risk of nuclear war. This argument was based on the prevailing nuclear doctrine at the time: Mutually-Assured Destruction or MAD, which depended on the ability of both superpowers to annihilate the other to deter either from launching a first strike. An effective ABM system would dramatically shift this delicate balance of power, allowing one power to destroy the other while remaining impervious to counter-attack. This in turn, the scientists argued, might provoke the other power – in this case, the Soviet Union – into launching a first strike before the ABM system became operational. Many politicians also opposed Sentinel on the basis of cost, including Pennsylvania Democratic representative Daniel Flood, who argued that fallout shelters would be more effective than ABMs at saving American lives:

“It is estimated that a shelter system at a cost of $2 billion would save 48.5 million lives. The cost per life saved would be about $40.00. An active ballistic missile defense system would cost about $18 billion and would save an estimated 27.8 million lives. The cost per life saved in this case would be about $700….I personally will never recommend an anti-ICBM program unless a fallout program does accompany it. I believe that even if we do not have an anti-ICBM program, we nonetheless should proceed with the fallout shelter program.^”

The debate over Sentinel reached its peak in 1969 with the election of President Richard Nixon, who agreed to hold a thorough review of the system. This culminated in the Senate authorizing the construction of Sentinel on August 7, 1969, the resolution passing by only a single voice. However, the scope of the system was considerably narrowed, with the number of missile sites being reduced from 17 to 12 and the system’s mission shifted from protecting the U.S. population to defending the nation’s offensive weapons installations. In this new guise, Sentinel was re-named SAFEGUARD. Construction of the Sharpner’s Pond PAR site was halted, and development efforts refocused on a pair of sites in North Dakota and Montana to defend the area’s 1,000 Minuteman ICBM sites – a strategy known as counterforce defense. According to Secretary of Defense Melvin Laird, this strategy minimized many of the system’s potential shortcomings:

“When you are looking toward city defense, it needs to be a perfect or near perfect system because, as I examined the possibility of even a thick defense of cities, I have found that even the most optimistic projections, considering the highest development of the art, would mean that we would still lose 30 million to 40 million lives…[but] when you are talking about protecting your deterrent, it need not be perfect. It is necessary only to protect enough of the deterrent that the retaliatory second strike will be of such magnitude that the enemy would think twice about launching a first strike.”

But just as construction was getting underway, world events once again intervened to change the fortunes of SAFEGUARD. On May 26, 1972, President Nixon and Soviet Premier Leonid Brezhnev signed the Strategic Arms Limitation Treaty or SALT, which reduced the number of nuclear weapons systems both nations were allowed to field. Under the terms of the treaty, the US and USSR could deploy two ABM systems each with a total of 100 interceptor missiles to defend ballistic missile sites and strategic command headquarters. Consequently, construction was halted on the Montana SAFEGUARD site and the completed infrastructure demolished. For budgetary reasons it was also decided to abandon the site defending Washington, DC. This left a single ABM site in North Dakota, which was named after Lt. General Stanley R. Mickelsen, the first commander of Army Air Defence Command. The entire complex consisted of six separate sites spread out over an area of some 400 square miles. The Perimeter Acquisition Radar, housed in a large concrete cube, was located outside the town of Cavalier, its single radar antenna facing north to detect missiles coming over the North Pole. The pyramid-like Missile Site Radar, with a radar antenna in each of its four faces for 360-degree coverage, was located near the town of Langdon. This site also housed silos for 30 Spartan long-range missiles and 16 Sprint short-range missiles. Finally, scattered around the surrounding countryside were four Remote Sprint Launch or RSL sites with 16 Sprint missiles each. The site finally became operational on October 1, 1975 – just 3 days ahead of the projected deadline. At its peak, the facility employed 500 military and 1,200 civilian personnel, with the Army carrying out major improvements to housing, utilities, and other services in neighbouring towns to accommodate the large influx of people.

But this hyper-advanced shield against a counter-force strike was not to be, for only one day after the SAFEGUARD system became operational, the U.S. House of Representatives voted to shut it down. The reasons given for the cancellation were familiar ones: advances in countermeasures technology and the use of Multiple Independent Reentry Vehicles or MIRVs would overwhelm SAFEGUARD; the system was too expensive; ABMs destabilized the global balance of power. Furthermore, the Chinese ballistic missile force the system was intended to defend against never materialized. The general consensus was that SAFEGUARD was a “system in search of a mission”, while Texas Democratic representative George Mahon stated:

“We have spent $5.7 billion preparing to defend ourselves against the intercontinental ballistic missile. The Safeguard system has not been effective, except perhaps from a cosmetic standpoint. If we had done nothing, it would have been the same.”

Yet contrary to a popular myth, SAFEGUARD did not shut down immediately. It remained active until November, while decommissioning officially began on February 10, 1976. The only part of the system to remain active was the PAR, which is operated by what is now Cavalier Space Force Station. Upgraded and re-designated the Enhanced Perimeter Acquisition Attack Characterization System or PARCS, it is used to track satellites and other objects in earth orbit. The other system sites were stripped of their missiles and electronic equipment and sold to private owners. The MSR site is now owned by the Cavalier County Job Development Authority, which plans to renovate the property and develop an interpretive centre; while the concrete pyramid itself was acquired in 2022 by Bitzero Blockchain Inc, who plan to convert it into a data centre. Finally, one of the three Remote Sprint Launch sites, RSL #3 near Cavalier, is open for private tours.

The SAFEGUARD system was the product of 20 years and $20 billion in research and development – 6 years and $6 billion of which was spent on constructing the Mickelsen complex itself. While the system’s abrupt cancellation after only a day of operation may seem like a colossal waste of money and effort, the project was not without its benefits. Many of the advancements in radar in computer technology developed for SAFEGUARD are still in use today, while the project was a major boost to the local economies and public infrastructure of North Dakota counties surrounding the radar and missile sites. But most importantly, ABM projects like SAFEGUARD served as key bargaining chips in Cold War diplomacy, convincing the Soviets to sign arms limitations treaties like SALT and START. These treaties have arguably done more to secure world peace in a nuclear world than defence systems like SAFEGUARD ever could.

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