On Oct. 7, 2001, a U.S. Air Force MQ-1 Predator drone flying over Afghanistan fired a missile at a building CIA analysts suspected of housing Taliban leader Mullah Omar. The Predator missed and instead struck a vehicle, killing several of the mullah's bodyguards.
The botched Predator strike was hardly the first time U.S. military and intelligence agencies had sent aerial robots into battle. As early as World War II, the military tinkered with remote-controlled bombers.
And drones played an important—and today largely unheralded—role in the bloody, two-decade U.S. air war over Vietnam and surrounding countries in the 1960s and ’70s. Drone aircraft spotted targets for manned U.S. bombers, jammed North Vietnamese radars, and scattered propaganda leaflets, among other missions.
My new nonfiction book Drone War: Vietnam explores that obscure chapter of history. Drone War: Vietnam is based on military records, official histories, and published firsthand accounts from early drone operators, as well as a survey of existing scholarship.
The Ryan Aeronautical Model 147 Lightning Bug subsonic drone, a mainstay of the Vietnam air war, launched in mid-air from a DC-130 motherplane, navigated along preprogrammed checkpoints while snapping photos and, at the end of its mission, popped a parachute and floated toward the ground. A helicopter buzzed in to retrieve it.
The Model 147s were crude, unreliable, and vulnerable to enemy air-defenses and espionage. In 1967 the North Vietnamese began intercepting the drone operators' radio signals and exploited the resulting intelligence to set aerial ambushes for drones and manned warplanes. Spiking losses forced the Air Force and the National Security Agency to equip the motherships with new radio encryption.
The Lightning Bug evolved. By the end of the war, the Model 147 was more effective, more reliable, and more survivable than early models were. And it inspired totally new drone designs that further improved on the basic concept of unmanned aerial reconnaissance.
In perhaps the ultimate expression of robotic recon up to that point, the CIA deployed supersonic drones to spy on Vietnam's neighbors. After many failures, the powerful D-21 drone—in essence a pilotless miniature of the Mach-3 SR-71 manned spy plane—photographed China’s Lop Nor nuclear test site between 1969 and 1971.
After Saigon fell to North Vietnamese forces in 1975, the Pentagon quickly cooled on drones. The advent of more-capable and more-reliable satellites arguably rendered obsolete the drones that flew over Vietnam and its neighbors. For four decades, fast and dumb spy drones with their volatile engines, self-contained navigation systems, and general lack of real-time data-link to their operators were… historical curiosities.
Then history began to loop back on itself. The high cost and inherent limitations of spy satellites in the 1990s spurred the development of a new generation of combat drone. The Predator that fired on Mullah Omar in October 2001 dramatically announced what appeared to many to be a whole new kind of warfare.
But it wasn’t actually new. In their fledgling efforts to send robots instead of human beings on the most dangerous aerial missions, U.S. operators in Southeast Asia in the 1960s and ’70s wrote the first chapter in the continuing tale of autonomous warfare.
Between 1964 and 1975, the Air Force flew 1,106 Model 147s on 3,435 operational missions over Southeast Asia. Almost all of the drones flew until they were shot down or crashed. A few dozen survived to return to the United States. Historian William Wagner estimated that, in substituting for manned recon planes, the drones saved the lives of “scores” of pilots.
The drones managed to inspire some of the pilots they couldn’t prevent from getting shot down. On July 9, 1967, U.S. Navy commander Edward Martin was in the cockpit of his A-4C attack plane speeding toward Hanoi. Fifteen miles from the city center, S-75 surface-to-air missile batteries opened fire. A V-750 missile exploded just 250 feet in front of the compact, single-engine fighter.
Martin flew directly into the blast. “That was the start of my five-and-a-half years as an unwilling guest of the North Vietnamese,” Martin said later. A week later he was in his cell at Hoa Lo Prison in Hanoi, in his own words a “crumbling heap of humanity tied up in ropes and lying near unconsciousness on the floor.”
An air-raid siren wailed. Anti-aircraft gunners opened up. Prison guards and interrogators raced for cover. After 20 minutes, calm returned. The prison staff resumed their work. Martin’s own guards were “more than a little angry” when they returned.
That’s when Martin heard the distinctive whine of a Model 147 drone. He knew the sound because he’d shot at Q-2C targets, on which the recon drones were based, in training in 1959. During a mission over the Gulf of Tonkin prior to his shoot-down and capture, he’d seen, although obviously not heard, Lightning Bugs going about their secretive business.
The North Vietnamese gunners opened fire again. Martin’s interrogator later claimed, without proof, that the gunners had shot down the drone. Martin wasn’t convinced.
Over the following years Martin had many encounters with Lightning Bugs as they flew ahead of manned bombers in order to spot targets, or followed behind the bombers to assess the effectiveness of a raid.
“One thing that impressed me most about the pilotless recce aircraft was the relative degree of impunity with which they intruded upon North Vietnamese air space,” Martin recalled. “When a strike force of bombers and attack planes came in, there was always an alert, but when a single 147… came in fast and low they wouldn’t draw an alert.”
More than once, Martin and his fellow prisoners were outside bathing and washing their clothes when a Lightning Bug appeared overhead. The guards excitedly would usher the prisoners inside then open fire with their small arms, never hitting the speedy little drones.
In the spring of 1968, after the North Vietnamese had moved Martin to a different prison, one known as “The Zoo,” a Model 147 approached the prison complex at high speed. Radar-aimed anti-aircraft guns opened fire and scored multiple hits on the drone but failed to destroy it.
Martin said his guard was “absolutely horrified.” The guard tried to shoo Martin inside but he and his fellow prisoners refused to go. “I remember we were all elated, so much so that they dragged me out for special treatment as I was the senior officer at The Zoo. They reprimanded me for my bad attitude because I had smiled when one of the ‘spy planes,’ as they called them, intruded upon the Vietnamese people.”
Lightning Bug missions continued even after President Lyndon Johnson ordered a second halt to bombing in North Vietnam starting in April 1968. Johnson hoped the pause would bring the North Vietnamese to the negotiating table and also give Vice President Hubert Humphrey an electoral boost in that fall’s presidential election.
The bombing pause didn’t work on either count. Republican Richard Nixon, a former vice president, defeated Humphrey.
And although Nixon extended the bombing pause, allowing only infrequent retaliatory raids, there were no diplomatic breakthroughs. For four years, drones and a few manned recce planes were the only American aircraft Martin heard over his prison. “They were about the only thing that did lift our morale during those years,” Martin said.
The North Vietnamese released Martin in 1973. In April of that year, he dropped by Ryan Aeronautical in San Diego to tell company workers all about the years he spent staring into the sky at passing Lightning Bugs—a meeting Wagner documented in detail.
Nixon resumed major bombing of North Vietnam in April 1972 in response to a series of North Vietnamese offensives. American air power in South Vietnam had atrophied during the four-year bombing pause. Now it quickly bulked up.
The Navy surged five aircraft carriers to the Gulf of Tonkin. Strategic Air Command deployed 152 eight-engine B-52D and B-52G bombers to Guam and another 54 to U Tapao airfield in Thailand, then the main Lightning Bug base, to complement a huge force of fighter-bombers flying from South Vietnam and Thailand.
Model 147s had never stopped flying during the four-year bombing pause, of course. But the resumption of air raids did alter the demand signal for unmanned operations. Model 147s would fly bomb-damage assessment missions to photograph the devastation that mass formations of B-52s sowed across North Vietnam.
The Air Force also revived the Navy’s concept for an armed drone. Ryan Aeronautical actually had been tinkering with the armed Model 234A since at least 1970, spurred by the Pentagon’s alarm over the rapid advancement of Soviet air-defense networks. The Air Force hoped that drones firing guided missiles or dropping guided bombs could help clear a path through the air-defenses to allow manned aircraft safely to pass.
The Model 234A in fact was a Model 147S with the latest altitude-control system plus a TV camera in the nose. The camera fed live video to a remote operator who could control the vehicle via a joystick linked to the drone’s flight-control surfaces. The front-line drone wing would operate TV-equipped Model 147SC/TVs starting in June 1972.
Tests of the Model 234A focused on the drone’s ability to carry and fire the TV-guided AGM-65 Maverick anti-tank missile. The missile itself relayed to the drone controller the image from its nose-mounted camera. So in effect the same control team separately could steer the missile-carrying drone and (once launched) the missile itself.
An October 1971 test was a smashing success. The drone approached within three miles of the target, at which point the Maverick’s own seeker clearly could see the aimpoint. The operators launched the missile. Nine seconds later it scored a direct hit.
At that moment, the Air Force in theory possessed an armed drone that was capable of striking targets with high precision while under remote control. Notably, this achievement came 30 years to the month before the service’s historic first lethal drone strike in Afghanistan, using a decidedly less survivable propeller-driven platform firing the same basic type of missile that the Model 234A carried in 1971.
With the resumption of bombing in Vietnam, the Air Force wanted to deploy armed drones as soon as possible. “Everyone wanted to cut down the number of guests at the Hanoi Hilton,” Ryan Aeronautical employee Bill Helmich told Wagner.
In fact, the Vietnam War would end before the armed Lightning Bugs could join the action. But Model 147s participated in other ways in the belated escalation that preceded the abrupt and bloody end of the conflict for the United States.
The Air Force wanted to complement its lethal raids in 1972 with intensive propaganda efforts. The service for years had been scattering paper leaflets—millions of them—across North Vietnam in an effort to win hearts and change minds.
Some of the early leaflets were just long statements from President Johnson extolling the reader to choose peace. Others depicted American warplanes and the damage they could inflict. Some mocked communist leaders. Some included photos of North Vietnamese dead.
Operation Field Goal, which ran between July 1972 and January 1973, involved F-4 fighters, C-130 transports, B-52 bombers, and Model 147 drones dropping 94 million leaflets per month for a grand total of 661 million scraps of paper.
Tactical Air Command’s chaff-dispensing Model 147NCs were perfect for the role. The command simply swapped out radar-foiling metal strips for paper leaflets. But TAC wasn’t ready to set up its own drone operation in Southeast Asia. The command transferred at least three Model 147NCs to U Tapao.
The “bullshit bombers,” as the Lightning Bug team called the leaflet-dispensers, flew 29 missions between July and December 1972.
But the most important missions the Lightning Bug force flew in mid-1972 aimed to duplicate the accomplishments of 1965 and ’66, when Model 147Es captured the radar and fuzing signals from North Vietnamese S-75 batteries.
Those helped the Air Force to develop radar-jammers specifically for defeating the S-75. Six years later North Vietnam had acquired new Fan Song fire-control radars for its deadly missiles. The upgraded Fan Songs boasted more and better antennas for more precise and jam-proof control of the V-750 missile.
The Air Force needed to update its jammers. It again turned to drones to capture the signals.
The task was urgent. Strategic Air Command was spooling up its B-52 wings for mass attacks on North Vietnamese targets, including military and industrial sites in and around Hanoi that enjoyed the protection of what was then the world’s densest air-defense network, which at the time included no fewer than 21 S-75 sites.
The command called the operation “Linebacker II.” It was America’s last desperate offensive in Vietnam—and the swan song for that first generation of combat drones.
Reprinted with permission of Pen & Sword Books. Copyright David Axe.
Drone War: Vietnam is available wherever you buy books.