Operation Igloo White was a covert United States joint military electronic warfare operation conducted from late January 1968 until February 1973, during the Vietnam War. These missions were carried out by the 553rd Reconnaissance Wing, a U.S. Air Force unit flying modified EC-121R Warning Star aircraft, and VO-67, a specialized U.S. Navy unit flying highly modified OP-2E Neptune aircraft. This state-of-the-art operation utilized electronic sensors, computers, and communications relay aircraft in an attempt to automate intelligence collection. The system would then assist in the direction of strike aircraft to their targets. The objective of those attacks was the logistical system of the People's Army of Vietnam (PAVN) that snaked through southeastern Laos and was known as the Ho Chi Minh Trail (the Truong Son Road to the North Vietnamese).
Establishment of Igloo White
The idea of a system to interdict North Vietnamese infiltration into South Vietnam had been proposed in the years before 1965 and finally led to the construction of a defensive barrier system including electronic sensors, which is best known as the McNamara Line, on January 13, 1967, when President Johnson authorized the construction. The defensive barrier system project had many cover name changes, such as Practice Nine until 14 June 1967, Illinois City (June 1967), Dye Marker (September 1967), Muscle Shoals (September 13, 1967) and finally Igloo White (June 1968). When the air-supported subsystem in eastern and central Laos was added in 1967, the project was named Muscle Shoals. In June 1968, when the program was renamed Igloo White, it consisted of three components:
- Munitions and sensing devices which were placed across and along suspected routes of infiltration to detect and impede enemy foot or vehicular movement;
- Orbiting aircraft which received signals from these sensors, amplified them, and retransmitted them;
- An Infiltration Surveillance Center (ISC) which received the transmitted signals from the aircraft and analyzed them to produce reliable tactical information for planning and interdiction operations.
The Igloo White system was originally expected to impede enemy infiltration through the use of minefields and aid in determining when mine reseeding was necessary. Sensors were also to be used along trails and roads to provide real-time target information for 3 tactical airstrikes. By July 1968, the munitions had proved to be relatively ineffective, and the use of sensors to obtain reconnaissance information was rapidly becoming the principal objective of the Igloo White system.
Effective implementation
Igloo White was rushed into service during the Battle of Khe Sanh and successfully passed its first operational test. Combined with Operation Commando Hunt in 1969, the system served as the keystone of the U.S. aerial interdiction effort of the Vietnam War.
Igloo White was a costly operation, with design and construction estimated at between $1 and $1.7 billion, and operating costs of approximately $1 billion per year over its five-year duration. It employed a range of advanced surveillance technologies, but its effectiveness remains subject to debate.
Development
As early as June 1961, General Maxwell D. Taylor, President John F. Kennedy's special military representative, had become interested in the prospect of erecting a physical barrier to halt the increasing infiltration of PAVN materiel (and later, manpower) through their Laotian logistical corridor and into the border regions of the Republic of Vietnam (South Vietnam). He then held talks with the deputy director of the Pentagon's Office of Special Operations, Edward G. Lansdale, who convinced him that a better solution to the infiltration dilemma would be the creation of mobile units to attack the infiltrators.
After the initiation of the strategic aerial bombardment of North Vietnam (Operation Rolling Thunder) in March 1965, Washington saw that program as its chief method of relaying signals to Hanoi to cease its support of the southern insurgency. When that failed as a strategy, the aerial effort was redirected to serve as an anti-infiltration campaign. After a million sorties were flown and more than three-quarters of a million tons of bombs were dropped, Rolling Thunder came to an end at the direction of President Lyndon B. Johnson on 11 November 1968.
As early as 1966 Secretary of Defense Robert S. McNamara had become disenchanted with Rolling Thunder. In January McNamara was presented with a working paper by the American academic Roger Fisher, who proposed a less costly physical and electronic barrier that would be located in South Vietnam. It was to consist of a 216-mile (348 km) long, 500-yard (460 m) wide barrier that would stretch from the South China Sea south of the Demilitarized Zone (DMZ), across the Laotian frontier and on to the border of Thailand. The physical barrier itself would be supported by electronic sensors and extensive minefields. Fisher estimated that it would take approximately five U.S. divisions to erect and defend the system.
The Joint Chiefs and CINCPAC turned down the concept, believing that it would consume the efforts of too many troops and create a logistical nightmare. McNamara, however, was intrigued. Ignoring the military chiefs, he approached the Institute for Defense Analyses and requested that it fund a study of the concept. The project was then handed over to the Jason Division (also referred to as the Jason Group or Jason Committee), a group of 67 scientists who were to study and develop the technology necessary to make the physical/electronic barrier feasible. The group concentrated its efforts in three key areas: communications; data processing and display; and sensor development. On 15 September 1966, McNamara made Army General Alfred D. Starbird the head of the newly formed Defense Communications Planning Group (DCPG), which was to oversee the implementation of the program. The barrier concept was then given the designation Practice Nine. The DCPG's original mission profile, as of September 1966, was simply to implement the anti-infiltration system devised by the Jason Division. The original plan foresaw the deployment of both a physical barrier in addition to an air-supported barrier using various electronic sensors.
In June 1967 the barrier project, by then referred to as the Strong Point Obstacle System (or SPOS) was renamed Illinois City, which lasted for a month before the program was redesignated Dyemarker. On 6 July, groundbreaking ceremonies were conducted for the command center of the operation. Construction work was completed three months later. The new Infiltration Surveillance Center (ISC) was located at Nakhon Phanom, Thailand, nine miles (14 km) west of Nakhon Phanom city on the banks of the Mekong River. The first commander of the unit was Air Force Brigadier General William P. McBride, whose superior was the deputy commander of the Seventh/Thirteenth Air Force at Udon Thani, Thailand. From its creation the ISC (and the operations conducted from it) was known as Task Force Alpha.
On 8 September 1967, the electronic portion of Dyemarker was divided and the aerial, sensor-based portion was designated Muscle Shoals. On 1 June 1968, the aerial portion was redesignated Igloo White. That name became the most associated with the program though various elements received a number of separate codenames. All resources for Dyemarker/Muscle Shoals were redesignated Duck Blind in April 1968, and in June 1968 Muscle Shoals outright became Duel Blade. In October 1968 Duck Blind was changed to Duffel Bag.
In mid-1968, the physical barrier concept was pushed aside after the North Vietnamese overran the Lang Vei Special Forces camp and besieged Khe Sanh. The barrier concept was reduced to an aerial, sensor-based electronic interdiction program that was to be conducted in Laos.
Sensors and Weapons
The Defense Communications Planning Group's research and development program created an advanced technological system. Muscle Shoals would consist of three interdependent parts. First, there were air-dropped, battery-powered acoustic and seismic sensors. The camouflaged sensors were to be dropped in strings at predetermined geographical points along the PAVN logistical network. Once emplaced, they would serve as tripwires to any movement or activity along the system.
The first sensors utilized by the program were Air-Delivered Seismic Intrusion Detector (ADSID), which had been developed from devices then in use in underground mapping for the oil industry. The device could sense vertical earth motion by the use of an internal geophone and could determine whether a man or a vehicle was in motion at a range of 33 and 109 yards (30 and 100 m) respectively. The first acoustic sensors were developed from the U.S. Navy's Project Jezebel anti-submarine warfare sonobuoys, which recorded and processed sound by the utilization of an audio spectrum analyzer. The first model of seismic detectors (Phase I) outshone their contemporary acoustic types in the quality and quantity of the information they reported. The Phase I models of both the acoustic and seismic sensors were only available for operation in a continuous mode, which meant that under normal conditions, their lithium batteries would function for approximately 30 days.
The Acoustic Seismic Intrusion Detector (ACOUSID), combined the operations of both seismic and acoustic devices, with the added ability to transmit sound from a built-in microphone. The ACOUSID had three switchable detection modes: in the C mode, a line spectrum detector determined the presence of enemy vehicles and had an effective range of 1,094 yards (1,000 m); an I Mode which was activated by sounds picked up by its internal microphone and could detect personnel at a range of 438 yards (401 m); and a B Mode that combined both of the above abilities and operated in a continuous real-time mode of 40 activations per hour with a battery life of 30 days.
The sensors reported their data via radio frequency channels ranging upward from 162 megahertz (MHz) to 174 MHz on the very high frequency band. 31 channels were assigned to each type of sensor with a 375 kHz separation between each channel. Every channel contained 27 identification codes or addresses which could be set in the field prior to emplacement. Thus, a total of 837 individual sensors (27×31) could be deployed at any one time without signal duplication in a single operational zone.
The deployment of gravel mines and the Wide-Area Anti-Personnel Mine System became integral parts of the operation. Other weapons were specifically developed or otherwise became associated with the campaign as well. These notably included the BLU-31/B and Mk 36 air-dropped mines, BLU-43/B and BLU-44/B landmine system (Dragontooth), the BLU-72/B fuel-air explosive (Pave Pat), and the BLU-52/A chemical bomb (filled with bulk CS-2 powder). Anti-vehicle operations in support of Muscle Shoals/Igloo White were designated Mud River, while anti-personnel operations received the codename Dump Truck.
PAVN personnel moving on foot through the trail system would be detected by the detonation of air-sown, aspirin-sized, wide-area gravel mines, which would activate the sensors. Subsequent bomb damage assessment missions and hand emplacement of sensors and mines in support of Muscle Shoals would be carried out by the reconnaissance teams of the highly classified Military Assistance Command, Vietnam Studies and Observations Group (SOG). A number of hand emplaced units were developed for this role, including the MICROSID and MINISID, and a device designed to work with either called MAGID, a magnetic detector, designed to be triggered by amounts of metal as small as an infantry rifle.
The sensors were designed for air deployment by either of two means. The first was by parachute, which would hang the devices in trees, where they appeared to be part of the foliage. The second method was the use of gravity, which would drive the spike-shaped device into the ground like a lawn dart, burying all but their antennae, which were designed to appear as weeds. Surprisingly, approximately 80 percent of the air-dropped sensors were found to be operational after delivery.
The second phase of sensor development improved the older models by providing for non-continuous operation as directed by the ISC. They also had the capability of carrying out three separate reporting functions: to report current information (transmitting noises or earth tremors); to keep silent, but to count impulses and respond when queried; or to remain in constant operation like the Phase I models. Their batteries also provided the ability to operate for approximately 15 days longer than the Phase I models (45 days).