IDA had also found consistencies in the design parameters between the DUCC and a U.S. Air Force Strategic Air Command (SAC) proposal for a Deep Underground Support Center (DUSC). SAC had also explored the DUSC concept in 1962, the year after it began building the Cheyenne Mountain Air Force Station bunker complex under the mountain of the same name, which you can read about in more detail in this past War Zone story .

It's not entirely clear where the DUCC proposal first originated. A 1975 study of the evolution of U.S. strategic command, control, and early warning capabilities that the Institute for Defense Analysis (IDA) think tank had conducted for the Department of Defense, said it made "no attempt ... to track the origins and development of the idea." IDA's researchers did note they had located a document that personnel within the Office of the Assistant Secretary of Defense (Comptroller)'s Programming Office had prepared ahead of Hitch's memo to McNamara.

"The center could include an office where people, such as yourself, could conveniently spend a day every week or two to conduct business almost as usual and be in a position to assume National Command in the event of a no-warning attack on Washington," Hitch wrote to McNamara.

In January 1962, Charles Hitch, then the Assistant Secretary of Defense (Comptroller), sent a memorandum regarding a proposed Deep Underground Command Center (DUCC) to then-Secretary of Defense Robert McNamara. The plan was to construct "a 'superhard' command post easily accessible to the NCA [National Command Authority] and designed for minimum dislocation or interruption of official routines," according to an official U.S. military historical review of command and control architecture from 1960 to 1977. The National Command Authority refers to the highest possible source of orders for American forces, the only mechanism by which a nuclear strike can be ordered, which consists of the President and the Secretary of Defense, as well as the approved deputies that would take their place if either of them were to be killed or otherwise incapacitated.

The COVID-19 pandemic has thrust the topic of " continuity of government ," plans in place to ensure critical elements of the U.S. government can keep functioning in the midst of an extreme crisis, back into the general public consciousness. It has also sparked renewed interest in the hardened, underground facilities where those personnel would work, such as the U.S. military's "underground Pentagon" at Raven Rock, which you can read about more in this past War Zone feature . Had the U.S. government made different decisions during the Cold War, some of these teams might be sheltering inside a massive, very deeply buried bunker unlike any on earth, intended to shrug off direct impacts from nuclear bombs with huge yields of hundreds of megatons.

In the 1950s and the early 1960s, the U.S. government had built numerous other bunker complexes in addition to Raven Rock for continuity of government purposes, including the aforementioned Cheyenne Mountain facility, as well as the Mount Weather Emergency Operations Center in the Shenandoah Valley in Virginia. The White House and the Presidential retreat at Camp David both have underground bunkers and, until 1992, there was a bunker complex situated near the Greenbrier resort in West Virginia intended to house Congress. However, none of these were specifically associated with the NMCS infrastructure.

A satellite image of what can be seen of Raven Rock Mountain Complex from the air. Two entrances to the underground bunker complex are visible along the upper left portion of the snaking road.

In 1961, the U.S. military had already begun to implement the National Mission Command System (NMCS), which included two bunkers, a hardened National Military Command Center at the Pentagon and an Alternate National Military Command Center (ANMCC). The ANMCC would be an upgrade to the existing Alternate Joint Communications Center (AJCC), a facility technically part of Fort Ritchie in Maryland, but which was housed inside the Raven Rock Mountain Complex (RRMC), also referred to as Site R, across the border with Pennsylvania under the Appalachian Mountains near Blue Ridge Summit. The Department of Defense had finished building Raven Rock in 1953.

Whatever the actual source of the DUCC plan was, it is clear that the driving factor was the increasing capabilities of Soviet nuclear weapons, especially with regards to their yields. The Soviet Union had tested its first hydrogen bomb in 1953, years earlier than U.S. intelligence agencies had expected and raising concerns about the vulnerability of existing alternate command and control centers. Repeated hits in the same general area from nuclear weapons with yields in the hundreds of megatons range, or the simultaneous detonation of barrages of smaller weapons producing equivalent total yields, not to mention from potential bunker-buster designs able to penetrate dozens of feet down into the earth first, could pose a danger to hardened structures buried even hundreds of feet underground. McNamara and other proponents also pointed out that this made other above-ground strategic command and control nodes extremely vulnerable, as well.

The U.S.-Canadian North American Aerospace Defense Command (NORAD) had also considered building extremely hardened Super Combat Centers in the late 1950s to house ground-controlled interception systems, known as the Semi-Automatic Ground Environment (SAGE), which you can read about more in-depth in this previous War Zone piece . NORAD had canceled those plans in 1960.

It's worth noting that the most powerful nuclear weapon ever built, the Soviet Union's Tsar Bomba, of which it only ever built one , had a yield of 50 megatons. However, it's clear that senior U.S. officials, such as McNamara, feared that this weapon, which the Soviets tested in 1961, was a prelude to the widespread use of such high-yield designs.

In contrast to the existing and planned components of the NMSC, the DUCC concept envisioned a bunker complex situated around 3,500 feet, or two-thirds of a mile, underground. Experts had judged this to be the necessary depth to survive multiple hits from nuclear weapons in the 100 to 200 megaton range bursting on the surface or from weapons with yields up to 100 megatons capable of penetrating between 70 and 100 feet down into the ground first. SAC's DUSC proposal had also called for a command and control center buried 3,500 feet below ground in order to withstand a 100 megaton weapon detonating on the surface anywhere within 0.5 nautical miles from the spot above ground directly above the center of the facility.

It's also important to remember that this memorandum came just over a year after the end of the Cuban Missile Crisis, where the United States and the Soviet Union had gotten worrying close to an actual nuclear exchange. This had served to highlight the concerns about the vulnerabilities within existing continuity of government plans that had prompted the DUCC proposal, to begin with.

"Studies indicate that the fixed facilities of this complex [the NMCS] and their communications could be eliminated with reasonably high probability by a small number (6-10) of 10 megaton weapons, resulting in only the aircraft and the ships surviving," according to a draft memorandum from McNamara's office meant for then-President John F. Kennedy on Nov. 7, 1963. "The aircraft, operating on ground alert at Andrews [Air Force Base outside Washington, D.C.], would require 10 to 15 minutes to become airborne and another 10 minutes to fly beyond the lethal range of a 50 MT weapon if airburst over Andrews. The ship is 30 to 60 minutes flying time from Washington. Both times are in excess of the upper limit of expected tactical warning."

The Navy did contribute ships for the NECPA fleet. The service heavily modified the Oregon City class heavy cruiser USS Northampton and the Saipan class light aircraft carrier USS Wright to serve as strategic command ships, which entered service in 1962 and 1963, respectively. These two vessels had then-state-of-the-art communications suites and The Washington Post once described Northampton specifically as a " floating White House ," where the President and their closet advisors could operate from for protracted periods of time. You will be able to read all about these ships in an upcoming War Zone feature.

The first NEACP aircraft were modified KC-135B aerial refueling tankers with expanded communication suites and were in service by 1963. These aircraft, which were eventually redesignated as EC-135Js, were similar, in concept, to SAC's EC-135A and EC-135C Looking Glass airborne command posts, which entered service around the same time. In 1962, the U.S. Navy had begun deploying smaller EC-130 Take Charge and Move Out ( TACAMO ) aircraft to serve as command posts to communicate with its ballistic missile submarines, in addition to land-based long-range communications sites, but these were not considered to be part of the high-level NMCS infrastructure.

The 1963 memorandum does not say where exactly the DUCC would be located, but, plans from McNamara's office showed it was to have been buried under the Potomac River, which lies roughly halfway between the Pentagon and the White House, according to Raven Rock: The U.S. Government's Secret Plan To Save Itself While The Rest Of Us Die. In something out of a James Bond movie, key personnel from the Pentagon, as well as the White House and State Department, would be able to enter it by way of elevators and an underground rapid transit system. The elevators would have discreet entrances, allowing designated individuals to make a break for the bunker undetected, straight from their offices. The elevators and transit system would allow personnel to get into the tunnel networks thousands of feet below within 10 minutes and into the actual DUCC itself within 15 minutes.

Google Maps A map showing the locations of, left to right, the Pentagon, the State Department's headquarters, and the White House. The DUCC would have been located underground somewhere between these buildings underneath the Potomac River.

"It would have the potential of reducing significantly the problems of transition from peace to war," McNamara wrote of the DUCC plan. "The very existence of a DUCC would also contribute in a major way to the broad objective of deterrence of enemy attack by making a survivable control posture credible and by creating the impression of a strong will to fight." The DUCC would also be self-sufficient, with individuals inside being able to live there for at least 30 days after a massive nuclear strike. The design would be scalable, with an initial "austere size" of 10,000 square feet capable of supporting 50 individuals and the ability to expand that to "moderate" dimensions of 100,000 square feet to accommodate 300 personnel. SAC's DUSC plan had called for a 40,000-square-foot complex capable of supporting 213 people for a similar amount of time. "The DUCC proposal was controversial and raised many questions, including the technical-engineering feasibility and costs, the elements of the NMCS that it might displace, and the command authorities who might be included in it (the JCS [Joint Chiefs of Staff] were among those scheduled to be included if it ever came to pass)," according to IDA's 1975 study. In 1963, McNamara's office had estimated that the "austere" DUCC would cost $110 million, almost $928 million in 2020 dollars, between the 1965 and 1969 Fiscal Years, almost $760 million of which would be for construction alone. The cost of the full 300-person bunker complex was pegged at $310 million, or around $2.6 billion in 2020 dollars.

DOD A breakdown of basic details about the "austere" and "moderate size" DUCC concepts, including cost, as of November 1963.

DOD A more detailed breakdown of the costs associated with the "austere" DUCC plan.

Beyond that, "order-of-magnitude estimates of 5,000-10,000 psi [pounds per square inch of pressure] hardening against 100-megaton weapons, for example, were based on theoretical calculations and were received in some quarters as speculations," IDA's researchers noted. "Even if the basic DUCC capsule could be built to survive direct hits, questions of communications coupling and lifeline logistics remained formidable." Even if the DUCC bunker itself was feasible, there were questions about whether associated communications infrastructure could ever be robust enough to ensure that it would function as intended in the aftermath of a massive Soviet nuclear strike. While the complex itself might be able to survive repeated hits from weapons with yields of hundreds of megatons, it would still need some sort of links to the outside world. Its depth would preclude direct wireless communications to other command and control nodes and force it to rely on cable networks to at least reach transmitters on the surface, or at least close to it. Extremely low-frequency communications arrays, which you can read about in more detail in this past War Zone piece, which are themselves largely buried underground, might have provided a more hardened option, and remain in service in the United States and elsewhere for this very reason. Unfortunately, they have extremely limited bandwidth, inherently preventing them from sending any sort of complex message. It's not entirely clear how it happened exactly, but the DUCCs proposal did not come to fruition. Less than two weeks after the Office of the Secretary of Defense completed its final draft of the plan to send to the White House, Lee Harvey Oswald assassinated President Kennedy during a visit to Dallas, Texas. Under President Lyndon Johnson, McNamara, with support from National Security Advisor McGeorge Bundy and the State Department, continued to plan for the bunker complex as part of planning for the Fiscal Year 1965 budget. However, the House Armed Services Committee refused to fund the Pentagon's entire DUCC request for that fiscal cycle, according to the book Raven Rock. The more pressing needs of the Vietnam War were also a contributing factor. Before the end of 1965, Johnson finally shot the entire project down, according to Spurgeon Keeny, Jr, who served as the President's Science Adviser under Dwight Eisenhower, as well as Kennedy and Johnson. He was also a member of the National Security Council during the Kennedy and Johnson administrations. Johnson's "view of nuclear war was brought home to me by his reaction at the final meeting in 1965 on the military budget to an item listed as DUCCS. In response to his question as to what this was, he was told it stood for Deep Underground Command and Control Site, a facility that would be located several thousand feet underground, between the White House and the Pentagon, designed to survive a ground burst of a 20-megaton bomb and sustain the president and key advisers for several months until it would be safe to exit through tunnels emerging many miles outside Washington," wrote in an article in the October 2006 edition of the Arms Control Association's Arms Control Today magazine. "After a brief puzzled expression, Johnson let loose with a string of Johnsonian expletives making clear he thought this was the stupidest idea he had ever heard and that he had no intention of hiding in an expensive hole while the rest of Washington and probably the United States were burned to a crisp. That was the last I ever heard of DUCCS."

National Archives President Lyndon Johnson, at left, and Secretary of Defense Robert McNamara, at right, during a cabinet meeting in 1968.