Inderz World: Atomic Demolition Munitions

The Littlest Boy

Twenty years after Hiroshima, elite American troops trained to stop a Soviet invasion -- with nuclear weapons strapped to their backs.

BY ADAM RAWNSLEY AND DAVID BROWN | THE MAGAZINE

Sandia Laboratories Archive video

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As Capt. Tom Davis stands at the tailgate of the military cargo plane, the night air sweeps through the hold. His eyes search the black terrain 1,200 feet below. He grips the canvas of his reserve parachute and takes a deep breath.

Davis and the men who make up his Special Forces A-team are among the most highly trained soldiers in the U.S. Army. It's 1972, and Davis isn't far removed from a tour in Vietnam, where he operated along the Cambodian border. His communications sergeant served in Command and Control North, which was responsible for some of the most daring operations in the heart of North Vietnamese territory. But none of the men has ever been on a mission like this before.

Their plan: drop into Eastern Europe, make their way undetected through forested mountains, and destroy a heavy-water plant used in the manufacture of nuclear weapons.

Leading up to the operation, during four days of preparation, Army regional experts briefed them on routes of infiltration and anticipated enemy patrols. The team pored over aerial photographs and an elaborate mock-up of the target -- a large, slightly U-shaped building. It's situated in a wide, open area with a roving guard, but at least the team won't have to sneak inside.

Hanging awkwardly from the parachute harness of Davis's intelligence sergeant is a 58-pound nuclear bomb.

Hanging awkwardly from the parachute harness of Davis's intelligence sergeant is a 58-pound nuclear bomb. With a weapon this powerful, they can just lay it against a wall, crank the timers, and let fission do its work.

Davis had planned to follow in the footsteps of his family's prominent jurists -- his father was a lawyer; his grandfather a federal court judge -- until a notice from the draft board arrived during his first year of law school. Rather than be drafted, Davis signed up for officer candidate school and volunteered for Special Forces, graduating from the demanding "Q course" as a second lieutenant. From there, it was on to Vietnamese language school and off to the war in Southeast Asia, where he served as a civil affairs/psychological operations officer.

As a first lieutenant, Davis got his own A-team. His team sergeant suggested they volunteer for training with what the Army called Special Atomic Demolition Munitions -- tactical nukes designed to be used on the battlefield in a war with the Soviets. "What the hell. Why not?" he responded. Their company commander forwarded their names and the team was accepted for training.

A parachutist tests jumping into water with a SADM, which is attached to the line hanging below him.
Sandia National Laboratories archive photo

As the plane approaches the drop zone, the jump commands come quickly, shouted over the frigid, deafening wind. "Check static lines!" The men sound off for equipment check from the back of the chalk forward. "Stand by!" The light turns green, and each man is tapped out: "Go!" the soldiers, each carrying something on the order of 70 pounds of gear in addition to 30 pounds of parachute rigging, don't so much jump from the plane as waddle off the back of it and fall to the ground at about 20 feet per second.

At half-second intervals, their silhouettes emerge from the rear of the plane, their deflated parachutes streaming behind like comets' tails. Canopies catch air and expand, and the team speeds downward, fast enough to avoid being spotted (or shot at) but just slow enough not to be killed when the men collide with the ground. Once the team has landed and released and cached their parachutes, they skulk to a predetermined rally point hidden in trees and shadows, where they unseal the special jump container and assess its contents for damage, making sure their payload is intact and not leaking radiation. Then they slip the bomb into a rucksack, bury the container, and set out through the mountains, moving only at night so as not to be seen.

It takes them about two days to make their way to the target. On D-day, they set the device at the plant -- and run.
A diagram from an Army manual shows how ADMs could “assist in enemy entrapment.”
FP scan from FM 5-26 manual

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Capt. Davis's "mission" was, of course, an exercise. In reality, he and his men parachuted not into Eastern Europe, but near the White Mountain National Forest in New Hampshire. The heavy-water plant was actually a shuttered paper mill in the nearby town of Lincoln, and the bomb was a training dummy.

The mission wasn't real, but the job was.

For 25 years, during the latter half of the Cold War, the United States actually did deploy man-portable nuclear destruction in the form of the B-54 Special Atomic Demolition Munition (SADM).

Special Forces used the delivery container pictured above to protect bombs during parachute jumps. The container and the weapon inside were extremely heavy, adding 90 pounds to a paratrooper's load.
Sandia National Laboratories archive photo

Soldiers from elite Army engineer and Special Forces units, as well as Navy SEALs and select Marines, trained to use the bombs, known as "backpack nukes," on battlefronts from Eastern Europe to Korea to Iran -- part of the U.S. military's effort to ensure the containment and, if necessary, defeat of communist forces.

Throughout the standoff with the Soviet Union, the West had to wrestle with the fact that, in terms of sheer manpower and conventional armaments, Warsaw Pact forces had their NATO counterparts woefully outnumbered. For the United States, nuclear weapons were the great equalizer. In the 1950s, President Dwight Eisenhower went a step further, unveiling the "New Look," which sought to deter Soviet aggression on the cheap by threatening to respond to any attack with a nuclear onslaught of apocalyptic proportions -- a doctrine known as "massive retaliation." In this way, Ike thought he could hold back communism abroad and the military-industrial complex at home.

The strategy had a major flaw, however. Though massive retaliation was economical, it allowed the United States almost no flexibility in how it responded to enemy aggression. In the event that communist forces launched a limited, non-nuclear attack, the president would have to choose between defeat at the hands of a superior conventional force or a staggeringly disproportionate (and potentially suicidal) strategic nuclear exchange that would kill hundreds of millions of people.

To provide options between "red" and "dead," the United States soon embraced the concept of limited nuclear war.

To provide options between "red" and "dead," the United States soon embraced the concept of limited nuclear war, championing tactical atomic weapons designed for use in combat. If Warsaw Pact forces ever bolted from East Germany and Czechoslovakia toward Western Europe, the United States could resort to nukes to at least delay the communist advance long enough for reinforcements to arrive. These "small" weapons, many of them more powerful than the nuclear bomb dropped on Hiroshima, would have obliterated any battlefield and irradiated much of the surrounding area. But they provided options.

Cold War strategy was filled with oxymorons like "limited nuclear war," but the backpack nuke was perhaps the most darkly comic manifestation of an age struggling to deal with the all-too-real prospect of Armageddon. The SADM was a case of life imitating satire. After all, much like Slim Pickens1 in the iconic finale of Dr. Strangelove, American soldiers would strap on atomic bombs and jump out of airplanes as part of the opening act of World War III.

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Slim Pickens as Major "King" Kong rides into oblivion.
Archive photo via OpenNet

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The 1950s and '60s were a golden age of nuclear weapons design.Scientists and technicians at the Los Alamos and Sandia nuclear weapons laboratories succeeded in miniaturizing the so-called "physics packages" at the core of atomic bombs from the nearly 10,000-plus-pound behemoth used in the first-ever nuclear test to smaller warheads that could fit atop a missile. And their colleagues in rocketry surged ahead in developing land- and submarine-launched ballistic missiles that, together with bombers, soon made up the nuclear "triad" supporting strategic deterrence against the Soviets.

From the Army's perspective, the problem was that bombers and missiles were managed by the Air Force and the Navy, leaving the ground force out of arguably the most significant development in the history of war, even as its soldiers would be chiefly responsible for stopping a Soviet invasion of Western Europe. Fortunately for the Army, many U.S. strategists still saw nukes simply as bigger conventional bombs, and America's post-Hiroshima mastery of the cutting-edge science of atomic destruction had filled weapons designers more with a sense of the possible than the prudent. The result was a series of odd creations that made their way into the Army's arsenal, from atomic artillery to nuclear-tipped air-defense missiles.

In a 1969 study, the U.S. Army tows an M-60 tank from a crater created by a simulated half-kiloton ADM blast to test the difficulty the weapons would pose to the movement of enemy forces.
Photo from 1969 Army study "Project Tank Trap"

The Army began rolling out atomic demolition munitions (ADMs) in 1954. The early iterations were cumbersome weapons, weighing hundreds of pounds and requiring several men to carry them with the help of trucks and helicopters. They were intended mostly for what you might call nuclear landscaping -- to create irradiated, impassible craters or to collapse mountainsides into narrow passes in order to obstruct likely invasion routes and bottleneck enemy forces. One engineer recalls setting up an ADM in the middle of a forest: "The idea was to blow these trees across a valley to create a radioactive physical obstacle for vehicles and troops to get by," he said.

The Army's countermobility field manual taught soldiers to use ADMs for "stream cratering," in which atomic explosions near small waterways would "form a temporary dam, create a lake, cause overbank flooding, and produce an effective water obstacle" for enemy forces.2

An Army field manual for the Employment of Atomic Demolition Munitions.
FP scans from FM 5-26 manual

If worst came to worst, the Army's atomic engineers planned to deny advancing forces the use of friendly infrastructure by destroying allied bridges, tunnels, and dams. Railroad yards, power plants, airports -- all were ripe targets for preemptive nuclear destruction.

But the Army wanted a more proactive nuclear role as well. Army partisans argued that the doctrine of massive retaliation left America unprepared for the full spectrum of conflict. Documents from the Atomic Energy Commission (AEC) show that America's nuclear weapons developers were happy to support the Army's quest for tactical nukes. In 1957, according to an AEC history, Sandia Corporation President James McRae lamented that "indiscriminate use of high-yield nuclear weapons inevitably created adverse public opinion." Since the future of war lay in an "unending succession of brushfire wars, rather than large-scale conflicts," McRae recommended that "greater emphasis should be placed on small atomic weapons," which could be used in "local ground combat."

McRae's urgings paved the way for the development of the Davy Crockett, a sub-kiloton-yield nuclear rocket that could fit on the back of a jeep. In 1958, when the Army came knocking for an atomic demolition munition that could be carried by a single soldier, the AEC looked to the Crockett's lightweight Mark 54 warhead for its solution. The resulting weapon would be a smaller, more mobile version of the ADMs. The Army, though, would have to share the device with the Navy and Marine Corps.

The AEC's final product -- the B-54 Special Atomic Demolition Munition -- entered the U.S. arsenal in 1964. It stood 18 inches tall, encased in an aluminum and fiberglass frame. It rounded to a bullet shape on one end and had a 12-inch-diameter control panel on the other. According to an Army manual, the weapon's maximum explosive yield was less than 1 kiloton -- that is, the equivalent of a thousand tons of TNT. To protect the bomb from unauthorized use, the SADM's control panel was sealed by a cover plate secured by a combination lock. Glow-in-the-dark paint applied to the lock allowed troops to unlock the bomb at night.

As Soviet forces advanced into such countries as West Germany, the SADMwould allow Special Forces units (dubbed "Green Light" teams) to deploy behind enemy lines to destroy infrastructure and matériel. But their mission wouldn't have been limited to NATO countries alone. What many nuclear historians don't realize is that Special Forces Green Light teams were also prepared to use SADMs on territory of the Warsaw Pact itself in order to thwart an invasion. The teams prepared to destroy enemy airfields, tank depots, nodes in the anti-aircraft grid, and any potentially useful transportation infrastructure in order to mitigate the flood of enemy armor and to allow allied air power to punch through. According to an internal report, the Army also considered burying SADMs next to enemy bunkers "to destroy critical field command and communications installations."

Navy SEALs and Army Special Forces were trained to reach their targets by air, land, and sea. They could parachute behind enemy lines from cargo planes or helicopters.

Teams specializing in scuba missions could swim the bomb to its destination if necessary.

Teams specializing in scuba missions could swim the bomb to its destination if necessary3. (TheAEC built an airtight, pressurized case that allowed divers to submerge the bomb to depths of up to 200 feet.) One Special Forces team even trained to ski with the weapon in the Bavarian Alps, though not without some difficulty. "It skied down the mountain; you did not," said Bill Flavin, who commanded a Special Forces SADM team. "If it shifted just a little bit, that was it. You were out of control on the slopes with that thing."

Special Forces thus turned to teams trained in special high-altitude parachute jumps and scuba diving to deliver the weapon. Team leaders were allowed to choose which of their men would receive training on the weapon in order to make sure their units could pass the Army's periodic, demanding nuclear surety inspections. "The people with the best records, the people with the most experience, usually ended up on the SADM team because they had to pass the surety inspection," said Flavin. To receive SADM qualification, soldiers also had to be screened through the Defense Department's personnel reliability program to make sure they were trustworthy and mentally stable.

Some men approached for the mission were gung-ho; others were less so.

Colonel Tom Davis (ret.) led a SADM team while serving in the 10th Special Forces Group (Airborne).
Photo courtesy of Tom Davis

"Of course everybody would volunteer. That wasn't a problem," said Capt. Davis. "We did it because, hey, it was gee-whiz. It was a neat thing to do, and I wanted to learn about it." But when Green Light team member Ken Richter began interviewing potential candidates, he said, not everyone was as enthusiastic: "I had a lot of people that I interviewed for our team. Once they found out what the mission was, they said, 'No, thanks. I'd rather go back to Vietnam.'"

When he was introduced to the weapon, Richter could hardly believe what the AEChad come up with. "I think that my first reaction was that I didn't believe it," he said. "Because everything that I'd seen prior to that, World War II, showed this huge weapon. And we were going to put it on our backs and carry it? I thought they were joking."

Soldiers receive classroom instruction in the use of Medium Atomic Demolition Munitions or "MADMs." MADM -- SADM's big sister -- weighed in at a hefty 400 pounds and required a team of engineers to carry it with the help of a help of a helicopter or truck. The MADM had a larger, variable yield of 1-15 kilotons and could be triggered by timers, wire, or radio.
From the Collection of Larry Fukalek, retired ADM engineer, 2th Engineer Battalion, 7th Infantry Division

They were not. Special Forces SADM teams like Davis's were given a weeklong course comprising eight to 12 hours of instruction each day in a cinder-block classroom at Fort Benning, Ga. The teams would also receive periodic refresher training from the Special Forces SADM committee, composed ofSADM-qualified senior noncommissioned officers, and they were subject to regular inspections to evaluate their fitness in handling nuclear weapons. But given the stakes, the training did not always inspire tremendous confidence.

For a nuclear weapon, the bomb was compact and light, but as infantry equipment went, it was still heavy and ungainly, its weight often suddenly shifting against a carrier's back. "When [the jumpmaster] said, 'Go,' they kinda tossed me out of the airplane with it on me," recalled Danny Powers, a communications sergeant with a SADM team.

When hauling the weapons on foot, things were even more difficult. Dan Dawson, an ADM engineer, remembers how difficult it was to run with a backpack nuke. During a training exercise, his unit simulated a mission to blow up a railroad tunnel but found it difficult to move a SADM across a patch of open ground. "To get [the SADM backpacker] across this open area in a hurry, two of us, one on each side, had to support him under his arms and trot with him across this open area. You could carry it, but you couldn't run with it."

In addition, the two-man rule, which to this day dictates that no individual service member have the ability to arm a nuclear weapon, demanded that Green Light teams divide the code that unlocked the cover plate. But that could present a challenge if the wrong man got killed en route to the target. "Here you were with this hunk of shit in your bag and no good place to go," Flavin said. "So we said, 'Eh, I don't think we can allow that to happen,'" and his men agreed to share the code in the event of a real mission.

It was not as if the men could leave the SADM behind if a mission went bad. The weapon's unique power meant that it could not be allowed to fall into enemy hands, and the cover plates, secured by a single combination lock, didn't provide much protection if enemy forces captured a SADM team. "A crowbar can pop that thing off," said Flavin. So the teams trained to scuttle the weapon. "We always had to carry the appropriate amount of explosives so we could destroy it without it going off," Powers explained. "It might scatter nuclear waste, but it would not go up like a real mushroom cloud."

If the team reached the target, the men would remove the lock-secured cover plate and set the timers. They would then reach into the safe well -- a small compartment in the top left of the control panel -- and pull out a hand-sized explosive charge used to trigger the bomb's nuclear chain reaction. After placing the charge in the armed position and flipping the switch, they would beat a hasty retreat.

Of course, in the hours or minutes before detonation, the bomb would be exposed to discovery and tampering from enemy troops, so some Special Forces teams were told they had to keep eyes on the weapon until just minutes before it detonated. The "proper" distance to ensure both the security of the weapon and the safety of the team varied by nuclear surety inspector, recalled Frank Antenori, who served as an Army nuclear weapons maintenance technician for a Special Forces team before earning decorations for valor as a Green Beret in Iraq and Afghanistan. Some inspectors told teams to get out of the area as soon as the weapon was in place; others insisted that the team had to stay within visual range of the weapon until it blew.

Even at a "safe" distance, SADM teams would still find themselves uncomfortably close to a detonation. "We're outside the vaporization range," said Antenori, "but well within the 'I will feel the wonderful warm wind that will blow by when it goes off in a second' range."

Heightening the absurdity of intentionally huddling near a nuclear weapon that was about to explode was the fact that the men could not know exactlywhen it would explode. Probably to make the weapon resistant to electromagnetic pulses from any nearby nuclear explosions, as one might expect at the outset of war with the Soviets, the AEC had fashioned the SADMlargely devoid of electronics. Instead, the device relied on two mechanical timers that, unfortunately, became less accurate the longer they were set for, potentially going off as early as eight minutes ahead of schedule or as many as 13 behind. Army field manuals warned that it was "not possible to state that [the timers] will fire at a specific time," so SADM teams were trained to predict the general window in which the weapon would go off.

Nevertheless, Powers said, "we always figured we'd go through all these meticulous procedures on this device, set the timer for several hours to get away, but really when we turned that button, we were going to disappear."

If the Green Light teams were lucky enough to be alive after the weapon detonated, the odds were still heavily stacked against their survival. Behind enemy lines and cut off from support at the start of the Third World War, they would have to rely on their wits and their escape and evasion training to avoid being captured or killed. Some provisions were made for them: Special Forces fleeing a SADM detonation could seek out weapons and supply caches hidden across Eastern Europe and marked on special maps. "When the [Berlin] Wall came down, we serviced and pulled some of those [caches] out," recalled Flavin. "I was surprised; the weapons and everything were still good to go."

Julius Reinitzer, known to his colleagues as "The Bear." A Czechoslovak-born Special Forces sergeant, Reinitzer advised SADM troops about how to stay alive behind enemy lines.
Photo courtesy of Ilona Reinitzer

In addition to their caches, some SADMteams had access to another secret weapon to help them get home: a Czechoslovak-born Special Forces sergeant by the name of Julius Reinitzer. As a teenager, Reinitzer twice busted out of a Nazi labor camp in Poland. He would later link up with U.S. military intelligence, hopping across the Czechoslovak border to set up resistance networks. After his arrest and imprisonment in communist Czechoslovakia for espionage, again he escaped. Back in the free world, Reinitzer joined the U.S. Army, earning American citizenship and becoming a Green Beret. "The Bear," as he was known, grew to be an in-demand tutor to Special Forces teams, including Flavin and his men, who were looking for a master class in the delicate art of living life on the run behind the Iron Curtain.

Still, the notion that Green Light missions were in all likelihood one-way trips didn't escape members of the Special Forces world. Flying through enemy airspace, operating covertly behind the lines, sneaking up on hostile forces with a nuclear weapon, and waiting uncomfortably close to the bomb before it exploded -- the missions were nothing short of preposterous. As Flavin put it: "There were real issues with the operational wisdom of the program, and those who were to conduct the mission were sure that whomever thought this up was using bad hemp."

Humor cushioned the grim realities of working with atomic demolition munitions. The ADM engineer units created patches and logos adorned with mushroom clouds. An unofficial motto sprung up among them: "Nuke 'em 'til they glow, and shoot 'em in the dark." The joking was made easier by the fact that some thought that the chances of the chain of command authorizing a mission were slim.

"In our hearts, we knew nobody was going to give control of these to a bunch of big old boys running around the countryside. We just didn't believe it was ever going to happen."

"In our hearts, we knew nobody was going to give control of these to a bunch of big old boys running around the countryside," said Davis. "We just didn't believe it was ever going to happen."

Aside from the "operational wisdom" of the program, as Flavin dryly put it, some Special Forces teams questioned whether their delivery aircraft, much less the weapon itself, would even reach them in the chaos and destruction of the Third World War's opening act. The SADM units rarely, if ever, had access to the live weapons themselves, which were held in tightly controlled storage depots, like the Army's facility in Miesau, West Germany. In the event of war, the weapons would be flown from their storage depots to nearby airfields and the Special Forces SADM teams waiting for them there. Flavin summed up the challenges well: "So you had to get us somewhere. You had to get the weapon somewhere. You had to get the airplane somewhere. And all of this had to be done when? Supposedly before the other side knew that they were going to attack, I guess."

Political sensitivities posed an obstacle as well. NATO allies, particularly West Germany, were understandably apprehensive about the idea of U.S. forces lighting off scores of small nuclear weapons on their territory. Engineers were supposed to use the weapons only after local populations had been evacuated, but that requirement didn't settle nerves. Burying the weapons underground would help limit radioactive fallout, but the Federal Republic publicly balked when the United States asked for permission to pre-dig emplacement holes for nuclear weapons near its transportation infrastructure.

A How-To Guide to the Backpack Nuke
Images from an Army field manual on employment of Atomic Demolition Munitions

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Watch: This 1969 film reel shows a Navy Underwater Demolition Team in Key West practicing anchoring a SADM training device to the seafloor.Video obtained by the authors from the National Archives and Records Administration

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Watch: This Sandia Laboratories training film shows how to unlock a SADM, set its timers, and arm the weapon.Video obtained by the authors through a Freedom of Information Act request
Archive photos via OpenNet

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In the end, none of the doubts about the SADM were ever answered. In 1984, 20 years after the weapon's creation, the public got a sense of the bomb and its capabilities when William Arkin and colleagues sketched out a description of the SADM from military documents and manuals for the Natural Resources Defense Council. His revelations provoked some outrage in Congress and shock in the media, but the weapon's days were already numbered.

As Cold War tensions abated, the United States began recalling SADMs to the continental United States. The weapon was officially retired in 1989, with the departments of Defense and Energy declaring that it was "obsolete" and that "there was no longer an operational requirement" for it. With the demise of the Soviet Union in 1991, George H.W. Bush made deep cuts to nonstrategic nuclear weapons across all the services.

Six years later, some details about the weapon were officially declassified. But the operational details of how the U.S. military intended to use backpack nukes -- including missions on Warsaw Pact territory, the demands the weapons put on the men tasked with deploying them, and the risks that their missions entailed -- have only now come to light through interviews, documents declassified through Freedom of Information Act requests, and newly obtained military manuals.

What was once a top-secret weapon is now a draw for tourists.

What was once a top-secret weapon is now a draw for tourists. Today, visitors to the U.S. government's National Museum of Nuclear Science and History in Albuquerque, N.M., can get their picture taken in front of a SADMparachute container. The Special Atomic Demolition Munition has gone from being a deadly serious, if eccentric, weapon to an item of Cold War kitsch.

SADM control panel.
Archive scan via OpenNet

In the light of historical distance, it's tempting to dismiss the SADM as an aberration born of Cold War hysteria. But the United States still keeps tactical nuclear weapons in Europe, albeit in the form of the less adventurous B61 air-dropped bomb. More frighteningly, other countries are increasingly embracing them as instruments of national defense. Pakistan, for example, reportedly keeps nuclear weapons forward deployed, and authority for their use pre-delegated to troops in the field -- an effort to compensate for India's much larger army. And in a reversal of fortune, now that Russia finds itself in a position of conventional inferiority vis-à-visNATO, Moscow has elevated the role of tactical nuclear weapons in its strategic doctrine.

For the Army's SADM veterans, however, their nuclear past is long behind them. Some had doubts about the mission; others embraced it. Regardless, they each bore the burden of the Cold War's worst nightmares -- on their backs.