Back in Washington, deep inside the Pentagon’s inner ring, Jim Bradley had an idea. Bradley, a captain, was officially the assistant for undersea warfare in the Office of Naval Intelligence, but his real job was as the Navy’s chief underwater spy. A former submariner himself, Bradley oversaw the Navy’s growing clandestine efforts in undersea intelligence, where advanced technology was beginning to give the United States an advantage that it desperately needed to make up for a distinct gap in on-the-ground human espionage, which the intelligence community refers to as HUMINT.

For the better part of two weeks, the world has watched, in hope and horror, as 13 countries embarked on a frantic search for the ARA San Juan, the Argentine sub that went missing on Nov. 15 with a crew of 44 aboard. It’s almost certain now that all hands have been lost, and it could be weeks or months before we know what caused the sub to sink. The first challenge is to locate it.

The ARA San Juan is first submarine to be lost at sea since the Kursk, which sank after an accident in 2000, causing the loss of 100 Russian lives. The remarkable string of safe patrols in the years since helped us all forget that submarine duty is one of the most perilous peacetime jobs in the armed forces. It’s certainly not something that any submariner takes for granted.​

This article first appeared in 2017.

For as long as they’ve had submarines, the world’s navies have worried about losing them — and especially about how best to find them when they’re lost, ideally soon enough that a crew rescue is still possible.

Much of the technology and strategy deployed in sub search and rescue today can be traced back to 1963, when the USS Thresher was lost at sea during routine deep-diving tests off of Massachusetts. The loss of that state-of-the-art submarine, and her crew of 129, sent a shockwave through the US Navy’s submarine program, leading to the creation of numerous deep sea programs that continue to this day.

Many of them were put to the test in 1968, the worst-ever peacetime year in submarine history. Four boats were lost in 1968, including the USS Scorpion and the Soviet Union’s ballistic missile boomer K-129, which the Soviets never did locate — until the United States handed them the wreck’s location six years later.

How did the United States find it? Credit Project Azorian, a massive top-secret CIA mission to salvage the wreck. The six-year effort cost a half-billion dollars, and involved some of the U.S. Navy’s most impressive tools, many of them still classified. It was arguably the single most impressive feat of naval engineering in history.​

The hunt for the Soviet sub is the subject of journalist Josh Dean’s gripping new book, The Taking of K-129: How the CIA Used Howard Hughes to Steal a Russian Sub in the Most Daring Covert Operation in History. Here, an excerpt:

February 1968

The Soviet nuclear ballistic missile submarine K-129 left Petropavlovsk, on Russia’s remote, frigid Kamchatka peninsula, with a crew of ninety-eight after dark on February 24, 1968, for a routine but unexpected patrol. No external markings signified the sub’s name, and even its hull number was painted over so that it would be unrecognizable to any ship that happened to notice it when it surfaced to gulp air and run the diesel motors that recharged its onboard batteries.

The Golf-class sub, which the Soviets called by its side number, PL-574, was under the command of an ascendant thirty-eight-year-old Ukrainian captain first rank named Vladimir Kobzar, who was leading his final mission aboard the boat he’d commanded for four years. When the submarine returned to its home base, Kobzar would move to Soviet fleet headquarters, to assume a more senior position commanding multiple subs from a desk.

Kobzar was one of the most experienced captains in the fleet, a rigorous, demanding man so highly regarded that many in the submarine service thought he might one day command the entire fleet. He had been given the Order of the Red Star for excellent service and was being rewarded for his four years at sea with a promotion that was certain not to be his last. Kobzar was loved by his crew and respected by his superiors, who noted how he personally helped train watch officers, oversaw survival training, and could capably handle any job on the sub. He had a question he liked to repeat to men under his command: “Who is the most dangerous man on a submarine? The one who doesn’t know what he’s doing!”

Upon return to port, Kobzar’s second-in-command, Captain Third Rank Alexander Zhuravin, thirty-four, would take over the K-129. The two officers knew each other well, having served more than a year at sea together, and were comfortable working in unison.

Zhuravin was sharp, polished, and ambitious, one of the youngest officers in the fleet at his level. He was tall for a submariner, at six foot two, and good-natured, fond of practical jokes and of occasionally fishing from atop the sub with the enlisted men when it wasn’t on war patrol. Alex was introduced to his wife, Irina, by her brother, while the two were cadets at the Leningrad Naval Academy. Irina was in high school at the time, back in Moscow, so their relationship began as a series of letters that she would sometimes read aloud in class, to impress her friends with the romantic notion that she was being wooed from afar by this handsome naval cadet. This went on for seven years, with Alex traveling to Moscow to continue his pursuit in person whenever his schedule allowed.

When Irina graduated from college, she finally agreed to marry him, making a commitment that came with an unfortunate asterisk: Alex was to join the Pacific Fleet, forty-two hundred miles away, on Kamchatka. Worse, he was to serve on submarines, leaving Russia for several months at a time, during which she would be home alone, unable to communicate with her husband for days and sometimes weeks. And yet, the marriage came with an upside, too. Being a Soviet naval officer was a prestigious job and Irina enjoyed some of the residual luster and of course the benefits—especially a nice house and a salary that was high for a young family in the Soviet Union. When Alex left port, his wife missed him, but she never feared he wouldn’t come back.

None of the sub’s officers expected to be at sea in February. The boat had completed a normal two-month combat patrol in the northeast Pacific on November 30, 1967, and upon return the crew was split into two for the duration in port, as was the custom. Half of the personnel went on vacation, while the other half were assigned to routine maintenance—cleaning, painting, repairs. Halfway through the break, they swapped roles.

What little rest the crew got during the break wasn’t just welcome; it was necessary. Autumn storms had rocked the boat almost incessantly for the entire time K-129 was at sea, making the previous mission a rough one, physically. And the men assumed, fairly, that they’d have at least a month or two to recover. Subs of this type typically did two combat patrols a year, but when two different sister ships experienced mechanical problems early in February and were deemed unfit for combat patrols, the Soviet Navy decided to send the K-129 back to sea so as to not disrupt the fleet’s scheduled activities.​

Telegrams from Central Command went out, ordering the crew to report to base between February 5 and February 8. When Division Commander Admiral V.A. Dygalo heard the news, he complained that the decision was cruel and potentially reckless. He filed a report stating his concerns to Rear Admiral Krivoruchko, commander of the Fifteenth Squadron, but Krivoruchko handed it right back, with a very clear message.

“You can take your report to the latrine,” he said. “Direct your energy to getting the sub ready for service.”

Dygalo was irritated enough that he didn’t heed the warning. Instead, he went up the chain of command, sending his report to the fleet commander, who had the same response.

“Comrade Dygalo, this order comes from the Supreme Commander,” he replied. “And nobody, not I, nor the Commander of the Navy will be asking him to postpone the mission by two weeks in hopes that [another] sub might be able to work through all its problems and report to active duty.”

Sufficiently chastened, Dygalo focused instead on trying to get his submarine ready for duty. Submarine K-129 wasn’t new; in fact, it had been in service since 1960, but it was outfitted to be as advanced as any of the forty subs stationed at the Soviet Navy’s Petropavlovsk-Kamchatka base. It was the first sub in the division to be given an award of excellence, and it sailed with the newest, most advanced navigation system in the Pacific Fleet.

Like all subs operating during the height of the Cold War, K-129 went to sea in full battle rattle. She was 328 feet long from nose to tail, propelled by three two-thousand-horsepower diesel engines when at the surface or in recharge mode, and three electric propulsion motors when cruising underwater, when the silence provided by electric motors is essential to mission success.

The sub carried three R-21 ballistic nuclear missiles—also known as SS-N-5 Serbs. Each R-21 had a white nose cone stuffed with a nuclear warhead and was loaded into one of the three vertical launch tubes that stood behind the sub’s conning tower. A single R-21 warhead carried one megaton of punch—more than sixty-five times the explosive power of Fat Man, the bomb that leveled Nagasaki—and had a range of 755 miles. It was also a historic weapon, the first Soviet missile that could be fired from a submerged submarine, giving the K-129 the ability to launch a preemptive nuclear strike from an undetectable position far from the American coastline if war were to break out.

Missile subs are relatively slow and vulnerable to attack. So to defend herself, K-129 carried two nuclear-tipped torpedoes loaded into the forward launch tubes, each one capable of sinking a US aircraft carrier, as well as a second set of conventional self-guided torpedoes in the stern bays to defend against attack from other submarines.

Boats like the K-129 were particularly critical to the Soviet Navy’s mission. The Pacific Fleet was still young, and these diesel-powered ballistic missile subs of the Twenty-ninth Division provided the most direct threat to America’s major West Coast cities—a threat that the Americans couldn’t easily track. The sub’s role was to patrol the Pacific quietly and stand ready to act in the event of nuclear war.

The end result of the schedule change was that Kobzar and his men were yanked out of shore leave they had earned, tearing them away from neglected hobbies, upcoming anniversaries, and family birthdays they missed all too often in the course of serving the motherland. Zhuravin, his wife, and their two children had joined several other officers and their families at a spa resort, where the pristine air of the Kamchatka peninsula helped clear up the respiratory irritation he had developed on the previous mission. But the arrival of a telegram announcing orders to return to port could not be ignored, and though the young captain had reservations about returning to sea so soon, with the sub in need of repairs, he knew better than to express that sentiment aloud.

A Soviet submarine’s precise directives were never known to its captain upon departure, but Kobzar and his crew knew the broader plan: to follow a prescribed course to K-129’s station, a relatively small block of ocean well to the northwest of Hawaii, and more or less sit there—in a remote section of the Pacific, infamous for heaving seas and flotillas of flotsam and for being largely barren of nautical activity except for the silent passage of American hunter-killer subs that stalked Soviet ballistic missile subs. The K-129’s mission was to stay out of sight of these subs, or any other hostile American vessels, until returning to base on May 5 at no later than 1200 hours.

The sub slipped out of her bay, docked briefly alongside a floating barracks ship, then cruised on to the fleet weapons depot to pick up the ballistic missiles and nuclear-tipped torpedoes. Once loaded, the K-129 moved farther into the bay and anchored, to await the arrival of a large antisubmarine ship that escorted her as far as the booms, a standard procedure meant to signal loud and clear to any Americans watching that the sub leaving port was on a combat mission, carrying live nukes.

At twelve fifteen a.m. on February 25, the submarine passed the booms and headed into the open ocean. At one a.m., a monitoring station picked up a signal that the K-129 had submerged, and then it went quiet. After leaving Russian waters, the sub headed south until it reached 40 degrees latitude, then turned toward Japan, under orders to spend at least 90 percent of her time submerged, mostly at a depth of around one hundred feet, running on underwater diesel power (UDP). This was a hybrid stealth mode mandated by fleet command to keep Soviet subs hidden yet still within range of radio signals from shore. It was a far more risky (and noisy) position than cruising under battery power at a deeper and safer depth, but Soviet sub captains were under orders to operate according to UDP protocols as much as possible—and a mission’s success was in part judged by the percentage of time spent in this mode.

The K-129 cruised more or less in a straight line, with periodic zigs and zags to seek out and shake any American subs that might be trailing. Submarine warfare during the Cold War was a game of hide-and-seek. All captains of slower ballistic subs considered their vessels prey for attack subs and were trained to move evasively, making unpredictable course changes regularly. A sub might ascend or descend suddenly and would occasionally shut down all engines so the crew could just sit silently and listen for any external sounds that would indicate American hunter-killers lurking nearby.

At 180 degrees longitude, the K-129 was to turn again, toward the US coast. To prevent detection, especially considering the rising geopolitical tensions in the region, the K-129 traveled for two weeks in silent mode, running on battery power. As far as anyone back at command was concerned, she was proceeding as directed.

Vulnerable at snorkel depth, diesel-powered boats routinely and unavoidably traveled there. Golfs were the last generation of Soviet subs to have diesel power (all later generations had nuclear power, which eliminated the necessity to surface), and those noisy engines cranked up when a sub surfaced to charge the electric batteries that made cruising silently underwater possible. Ascend, charge, submerge. The pattern repeats over and over.

Inside, there was no fresh air. The caustic, bitter smell of diesel fuel permeated every inch of the submarine, seeping into clothes, mattresses, and sheets. And there was little freshwater. Each crewman was allowed a single liter per day, and that had to cover drinking, bathing, and—very occasionally—laundry. The entire crew shared three toilets and slept in bunks stacked so tightly that there was barely room for a man to lift his head.

When a sub is on or near the surface, all personnel stand at the ready, with key officers manning the boat’s two periscopes: the sky-search scope, which points straight up to spot sub-hunter planes; and the attack scope, which scans the ocean surface in search of foreign vessels. At prearranged times, the K-129 would also use these opportunities to send word back to Kamchatka, in the form of encoded burst communications that told superiors back at base that the mission was continuing as planned and that no problems had arisen en route.

A submarine’s most important attribute is stealth, and what made subs so important during the Cold War was that they enabled both sides to move nuclear missiles from land—where their fixed positions were easily located and, in theory, destroyed if a war were to break out—to sea, where on these silent, mobile launch platforms they would remain capable of striking and prolonging a war even if the homeland’s nuclear arsenal had been eliminated. Locating Soviet subs, then, was a huge priority for the US Navy, which had an almost unlimited budget for intelligence and antisubmarine warfare tactics—a line item so important that it required no congressional oversight.

The Soviets were aware that any radio transmissions sent between the subs and the mainland were intercepted by a network of land-based installations. What frustrated US Naval Intelligence was that analysts could not unlock these communications—typically short bursts of code sent at prearranged times and from specific locations—so while they could hear when and from where a particular burst originated, analysts had no idea what specific information was being transmitted.

Like any Soviet captain, Kobzar did not learn his official orders until the sub was in the open ocean. They were contained in a packet handed to him by his commander just before departure. The envelope was marked with clear directions: “To be opened on the third day after leaving base.” Kobzar bore a heavy burden—he was in a position to start a war if necessary, and should that happen, he would be asked to target and destroy three of the most critical US military installations in the Pacific: Pearl Harbor, Hickam Air Force Base, and US Pacific Command Headquarters, in Oahu.

Nothing about this was new, and there was nothing new about the mission either. It was a routine combat patrol, hopefully doing very little. Only in the event of combat was Kobzar allowed to think freely and react, and even then, very specific instructions for handling himself and the precious ballistic load on board had been drilled into his head.

Pacific Fleet command expected to hear from all deployed subs at prearranged times, but the K-129 was to travel in silent mode for the first two weeks at sea, so until March 8, there was no reason for anyone back in Kamchatka to worry. On the eighth, however, a watch officer at Soviet Navy Central Command noticed that the sub failed to transmit a radio message as scheduled, and he brought the matter to his superiors. An alert was declared.

Rear Admiral Dygalo was at the home of one of his captains that night when the phone rang at ten o’clock. It was the squadron commander, who wanted to see Dygalo immediately. A quarter of an hour later, he arrived at headquarters to find Krivoruchko pacing frantically while smoking a cigarette as if he were in a race to finish it. His previous cigarette was still smoking in an ashtray.

There has been no communication from the K-129, Krivoruchko said. The fleet commander was already on a plane from Moscow and would be at headquarters in the morning expecting a full report with explanations for the apparent disappearance of a submarine carrying ninety-eight men and three ballistic nuclear missiles.

“When ready, report to me on the possible reasons for Kobzar’s silence, and on the forces necessary for the search operation,” Krivoruchko told Dygalo.

A failure to communicate didn’t necessarily indicate disaster. Radio transmitters are not infallible, and Soviet submarines were notorious for equipment failure. Weather can also be an issue. And if a sub’s commander felt his boat was under threat of discovery or attack by American vessels, he might also choose to remain silent. Thus, Soviet admirals didn’t automatically assume the worst when a sub failed to communicate. But it was rare for one to go completely dark for more than a full day, and when the K-129 missed a scheduled communication for the second consecutive day, fleet command began to panic.

Although the Soviet Union had never lost a submarine with nuclear missiles on board, the idea of it happening was a nightmare for command. The crew of officers that Dygalo assembled offered a number of possibilities for the silence—damage to the ship’s antennas, a collision with another vessel, a sudden loss of buoyancy caused by a leak or massive water intake through the snorkel while under diesel power, or a catastrophic fire caused by a leak of rocket fuel or oxidizer from the ballistic missiles. In some rare cases, they noted, freakish ocean conditions—a zone of higher-temperature or low-salinity ocean water, or a run-in with subsurface waves—can even push a sub suddenly toward its depth limit, the point at which its hull collapses.

Dygalo recalled one such rare case. In March 1965, the sub K-163 was on patrol in the North Pacific when, in less than two minutes, it plummeted from forty meters nearly to its crush depth—the point at which the integrity of its steel hull is compromised—and was saved only because the watch officer noticed the change immediately and ordered the engine room to go full power toward the surface. This slowed but did not stop the sub’s plunge, and it kept descending right up to the precipice of its crush depth again, when the sub, its steel hull groaning violently from the ever-growing water pressure, finally stabilized and began to rise.

There were plans for rescuing vessels in distress, and the Soviet Navy put them into effect on March 9, dispatching a flotilla of ships, from various ports, out to sea. A damaged submarine will always surface, if possible, so the fleet’s reflex is to commence a rapid search for a crippled sub somewhere inside a predetermined area, in this case one measuring about 854,000 square miles. Searchers were to look for a submarine bobbing on the surface, probably without power or communication. Provided the sub’s structural integrity hadn’t been compromised, it would be safe there. Every sub in the fleet carried enough provisions on board to keep a crew alive for three months.

The US Navy maintained a constant presence off the Kamchatka Coast, and the USS Barb was sitting quietly in radio silence near Vladivostok when the Soviet Navy’s mobilization began. The Barb’s captain, Bernard “Bud” Kauderer, was initially confused by the frantic reaction. It was unlike anything he’d ever seen—an entire sub group racing out of port, with active sonar going full bore, and no apparent worry about detection. Kauderer ordered the Barb to follow the group from a safe distance, observing as these Soviet subs dove, resurfaced, then dove again, talking openly over the radio channels to fleet command and calling out, again and again, for a boat that never called back. “Red Star, come in. Red Star, come in. Red Star.”

Kauderer reported back to US Fleet Command and asked for orders.

“Stay on station,” he was told.

The search intensified. Two destroyers, three frigates, three minesweepers, two mother ships, and ten support vessels—in addition to the four submarines—participated in a methodical search led by planes that circled overhead. In total, thirty-six flagged vessels participated in the hunt for K-129, working day and night, using echo and sonar sounders and dragging photographic equipment that scanned the depths far below the surface. All the while, surveillance planes flew ahead—at least fifty-three took part—tracking the sub’s intended path, looking for any wreckage on the surface that could help narrow the search area. Over the next seventy-three days, Soviet planes would make a total of 286 flights over the zone.

Weather made matters worse. Winters can be brutal in the North Pacific, and the Soviet fleet ran smack into violent storms, with heavy snow, gale-force winds, and waves cresting as high as forty-five feet. During the early days of the search, the ocean was as wicked as it could be, with conditions registering at or near a 9 on the Douglas Sea Scale—a scale designed to express the sea’s roughness for navigation that only goes as high as 9. At that level, waves can reach fifty feet and the sea is described, bleakly, as “phenomenal.”

Dygalo joined the search personally, aboard a nuclear sub, and at snorkel depth, his watch officer wore a full diving suit over a fur coat and pants and was strapped using a harness and chain to an iron brace on the bridge. There, Dygalo recalled, “he bobbed up and down like a cork in waters foaming about his chin whenever the sub plowed into an oncoming wave.” On the downside of waves, the sub would nearly roll onto its side. “To make anything out in those seething waters, in those conditions, was highly improbable,” Dygalo later said.

All the while, American Orion-class antisubmarine planes circled overhead, constantly audible to the Soviet watchmen but visible through sky scopes only on the rare occasion when the weather broke and the clouds parted.

The biggest problem was that the Soviets didn’t actually know where to look; they knew only where the K-129 had been last—on March 7—and where it was headed—to the Hawaii station—so they focused the search along that line, looking for oil slicks, debris, or anything else on the surface that could indicate a disaster. The initial search zone was vast, more than eight hundred thousand square miles, and got bigger as the search failed to locate any signs of the sub, growing to 1 million square miles, an almost impossibly large area, especially considering another factor: the ocean’s depth. In that area of the Pacific, the bottom was nearly four miles below, and because all signs pointed to a catastrophic loss, the K-129 wasn’t likely to be found on the surface. In all likelihood, it lay shattered on the bottom, more than three miles below.​

The K-129’s return to port had been scheduled for May 5, and when that date came and went, the wives and parents back in Petropavlovsk, who’d been told almost nothing by the fleet leadership, began to accept that their husbands and sons weren’t coming home. They gathered in a square next to a monument erected for another lost sub, wearing black. Irina Zhuravina, wife of the submarine’s second-in-command, had been clinging to faint hope. “He loved life so much that he simply couldn’t die,” she told herself, and the friends from the fleet who fished with her husband and made caviar in their home kept coming by. “Sasha can’t die,” they told her. “He’ll come up. He’ll figure out a way.” For weeks, her eight-year-old son, Misha, kept asking the same question: “Where is Daddy? He’s never gone this long.” “Daddy’s at sea,” she told him.

Officially, the families were told very little. It wasn’t until September 12, six months after the K-129’s disappearance, that the supreme commander of the Soviet Navy issued an order stating that the sub had been lost while on duty in the Pacific and that all the men on board were “presumed dead.” That description wasn’t just insulting; it was financially cruel, because instead of the full salary and pension awarded to military men lost in the line of duty, it meant the families were awarded only a single lump-sum payment of fifteen hundred rubles plus a partial pension—the same pitiful amount they’d have been given if the men had died accidentally by slipping and falling.

Many within the fleet, including Admiral Dygalo, were ashamed of the Soviet response. Dygalo suffered a heart attack while writing personal letters to each of the families and was hospitalized for a month. “By the order of the Minister of Defense, K-129 was removed from the register of naval vessels, as though it never existed,” he later wrote. “Moscow decided that it was the end of the story.”

Back in Washington, deep inside the Pentagon’s inner ring, Jim Bradley had an idea. Bradley, a captain, was officially the assistant for undersea warfare in the Office of Naval Intelligence, but his real job was as the Navy’s chief underwater spy. A former submariner himself, Bradley oversaw the Navy’s growing clandestine efforts in undersea intelligence, where advanced technology was beginning to give the United States an advantage that it desperately needed to make up for a distinct gap in on-the-ground human espionage, which the intelligence community refers to as HUMINT.

Bradley, forty-seven, was an enigma even to most people in his own branch. If you looked him up in the Pentagon’s official record, you’d see his assignment as “Naval Operations, Navy Department,” a designation about as specific as referring to a professor of chemistry as “Faculty, University.” In reality, Bradley oversaw highly compartmentalized black programs from an unmarked bunker on the fifth floor of the Pentagon, hidden behind three sets of locked doors. There, Bradley considered ways to use some of the Navy’s most sophisticated and secret tools to unlock mysteries of the Soviet arsenal, in particular its submarine, encoded communications, and ballistic missile programs.

It was obvious to Bradley and anyone else who had been told about the Soviets’ vast and fruitless search of the North Pacific that they’d lost a sub—a sub the Navy suspected with some confidence to be the K-129. This presented a tantalizing thought: If the US Navy could locate the sub’s precise location, it might be able to access the wreck and mine it for a host of valuable intelligence—including communication codes, code-breaking machinery, and most compelling of all, the nuclear warheads atop the ballistic missiles. Any combination of these things would provide the single most important intelligence haul of the Cold War to date.

Both the United States and the Soviet Union knew basically what the other side was packing, but when it came to the specifics of those atomic missiles and warheads, the two adversaries were guessing. Getting their hands on an actual Soviet missile, intact, would allow US nuclear analysts to unlock any number of secrets about the enemy’s arsenal, in particular the makeup of the warheads and the design of the guidance system, which could enable the United States to build better antimissile defenses specially calibrated to the Soviet design.

While the idea of finding a missing submarine in the Pacific Ocean, even when they had a general idea of where to search, proved so daunting to the Soviets that they’d ultimately given up looking, Bradley was fairly optimistic. He had a better way of locating it.

The story of the missing sub and its eventual recovery by American forces is one of the most fascinating chapters of the Cold War. Josh Dean’s new book, The Taking of K-129: How the CIA Used Howard Hughes to Steal a Russian Sub in the Most Daring Covert Operation in History, is available from Amazon and bookstores everywhere.

This article by Task and Purpose originally appeared at Task & Purpose. Follow Task & Purpose on Twitter. This article first appeared in 2017.