Opération igloo white

Opération Igloo White
Informations générales
Date	Janvier 1968 - Février 1973
Lieu	Piste Ho Chi Minh, Sud du Laos
Issue	Défaite de la stratégie américaine
Belligérants
États-Unis	Nord Viêt Nam
Guerre du Viêt Nam
Batailles
Opération Ranch Hand – Incidents du golfe du Tonkin – Bataille de la Drang – Offensive du Tết – Lang Vei (Tết) – Khe Sanh (Tết) – Huế (Tết) – Saïgon (Tết) – Opération Igloo White – Hamburger Hill – raid de Son Tay – Incident du Mayagüez –

L’opération Igloo White était une opération de guerre électronique secrète conduite par l’USAF de fin janvier 1968 à février 1973 pendant la guerre du Viêt Nam. Cette opération sophistiquée utilisait des capteurs électroniques, des ordinateurs et des relais de communication aéroportés dans une tentative d'automatiser la collecte de renseignements. Le système était utilisé pour guider les bombardiers sur leurs cibles. L'objectif de ces attaques était le réseau logistique de l'armée Nord Vietnamienne qui serpentait à travers le sud-est du Laos et qui était connu sous le nom de piste Ho Chi Minh (la route Truong Son pour les nords-vietnamiens).

Conçue en remplacement de l'opération Rolling Thunder qui avait échoué, l'opération Igloo White a démarré pendant la bataille de Khe Sanh et passa son premier test opérationnel avec succès. En combinaison avec l'opération Commando Hunt en 1969, l'opération a été la clé de voûte de la plus vaste opération aérienne d'interdiction de la guerre du Viêt Nam. Durant quatre ans, les deux opérations ont été menées de concert pour stopper l'infiltration de soldats et de matériels Nord Vietnamiens vers les champs de bataille du sud.

L'opération Igloo White a couté entre 1 et 1,7 milliards de dollars pour sa conception et sa réalisation (auquel il faut ajouter un milliard de dollars par an durant les cinq années de sa durée) et a mis en œuvre certaines des technologies les plus avancées sur le théâtre sud-est asiatique. Cependant, son efficacité est toujours l'objet de discussions. Ceci est du en partie à la surestimation de l'efficacité des campagnes de bombardement qu'elle a dirigées, à la déficience de l'évaluation des dommages des bombardements au Laos et à la pénurie des sources historiques en République socialiste du Viet Nam.

Sommaire 1 Développement 2 Sensors 3 Pinball wizards 4 Operations 5 Conclusion 6 Notes 7 References

Développement

Pour plus de détails sur la campagne aérienne américaine contre le Nord Viêt Nam, consulter l'article Opération Rolling Thunder.

Pour plus de détails sur la logistique de l'armée Nord Vietnamienne, consulter l'article Piste Hô Chi Minh.

Dès juin 1961, le général Maxwell D. Taylor, le représentant spécial du président John F. Kennedy pour les affaires militaires, s’était intéressé à la proposition d’ériger une barrière physique pour stopper les infiltrations en nombres croissants de matériel de l’armée Nord Vietnamienne (et plus tard d’hommes) par le corridor laotien et par les régions frontalières du de la république du Vietnam (Sud Viêt Nam) ^[1]. Il s’entretint donc avec le directeur des opérations spéciales au Pentagone, Edward G. Lansdal, qui le convainc que la meilleure solution à ce problème d’infiltration serait la création d’unité mobile pour attaquer les infiltrés.^[2]

Après les débuts de la stratégie de bombardement aérien du Nord Viêt Nam (Opération Rolling Thunder) en mars 1965, Washington concevait ce programme comme la meilleure méthode pour envoyer un signal clair à Hanoï pour que le Nord Viêt Nam cesse son soutien aux insurgés du Sud. ^[3] Lorsque cette stratégie s’avéra défaillante, l’effort aérien a été redirigé pour servir la stratégie anti-infiltration. .^[4] Après un million de sorties aériennes et plus de 750 000 tonnes de bombes lancées, Rolling Thunder pris fin sur ordre du président Lyndon B. Johnson, le 11 novembre 1968. ^[5]

Dès 1966, le secrétaire à la défense Robert S. McNamara a été déçu par l’opération Rolling Thunder, car elle manquait manifestement ses deux buts initiaux. ^[6] “Rolling Thunder” était également une opération coûteuse et pas seulement financièrement. L’accroissement de la densité de l’artillerie antiaérienne, des missiles et des appareils de défense aérienne Nord Vietnamienne rendait la campagne coûteuse en avions et en équipages abattus au Nord Viêt Nam.^[7]

En janvier 1966, un académicien américain Roger Fisher présenta un document de travail à McNamara, qui proposait une barrière physique et électronique moins coûteuse qui serait localisée au Sud Viêt Nam. ^[8] La barrière avait une longueur de 216 miles (350 km) et une largeur de 500 m qui se serait étendue du sud de la mer de Chine au sud de la zone démilitarisée, en passant au travers de la frontière avec le Laos et le long de la frontière avec la Thaïlande.^[9]. La barrière physique aurait été munie de capteurs électroniques et de larges champs de mines. Fisher estimait que cela nécessiterait approximativement cinq divisions américaines pour ériger et défendre ce système.^[10]

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.^[11] McNamara, however, was intrigued. Ignoring the military chiefs, he approached the Institute for Defense Analysis and requested that it fund an independent study of the concept.^[12] The project was then handed over to the Jason Division, a group of 47 scientists who were to study and develop the technology necessary to make the physical/electronic barrier feasible.^[13] The group concentrated its efforts in three key areas: communications; data processing and display; and sensor development. On 15 septembre 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.^[14]

During the ensuing two years the physical barrier concept was pushed aside (although construction on the project would continue until late 1968 in favor of an aerial, sensor-based electronic interdiction program that was to be conducted in Laos.^[15] In juin 1967 the barrier project was renamed Dyemarker, and, on 6 juillet, groundbreaking ceremonies were conducted for the command center of the operation. Construction work was completed three months later.^[16] The new Infiltration Surveillance Center (ISC) was located at Nakhon Phanom, Thailand, nine miles 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. On 8 septembre the electronic portion of Dyemarker was divided and the aerial, sensor-based portion was designated Muscle Shoals. From its creation the ISC (and the operations conducted from it) was known as Task Force Alpha.

Sensors

The Defense Communications Planning Group's extensive research and development program created what was without doubt the most advanced technological system that would be fielded by the U.S. in Southeast Asia. Muscle Shoals would consist of three interdependent parts. First, there were air-dropped, battery-powered acoustic and seismic sensors.^[17] 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 respectively.^[18]

The first acoustic sensors were developed from the U.S. Navy's Project Jezebel anti-submarine warfare sonobouys, 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.^[19] 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.^[20]

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; an I Mode which was activated by sounds picked up by its internal microphone and could detect personnel at a range of 438 yards; 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.^[18]

The sensors reported their data via radio frequency channels ranging upward from 162.5 megahertz (MHz) to 133,5 MHz on the very high frequency band. 31 channels were assigned to each type of sensor with a 375 MHz 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 (27x31) could be deployed at any one time without signal duplication in a single operational zone.^[21]

PAVN personnel moving on foot through the trail system would be detected by the detonation of air-sown, asprin-sized, wide-area Gravel mines, which would activate the sensors. 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, Viêt Nam Studies and Observations Group (SOG).^[22]

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.^[23]

The second phase of sensor development improved the older models by providing for non-contimuous 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).^[24]

During late 1969, Phase IV sensors began to be deployed in-theater. These had a greater number of available communications channels, which allowed the seeding of a larger sensor field without fear of signal influence. By 1971–1972 a new sensor with a commandable microphone and another with a vehicle ignition detector (which could detect the unshilded ignition systems of gasoline engines) were introduced.^[25] The sensors were not cheap. In 1972 U.S. dollars the ADSID cost $619.00, the ACOUSID $1,452.00, and the engine detector $2,997.00. During the life of the operation approximately 20,000 sensors were deployed in Laos.^[26]

Pinball wizards

The sensor transmitters would relay their data to the second element of the system, an orbiting EC-121R aircraft of the Air Force's 553rd Reconnaissance Wing, based at Korat Royal Thai Air Force Base. The EC-121s would then relay the collected information to Nakhon Phanom. At Task Force Alpha, the last of the three components in the system, the intelligence data (from a variety of sources, not just the sensors) would be entered, collated, retrieved, and stored by two IBM 360/40 (later two 360/65) computers.^[27] Technicians at the center controlled the system from a variety of video displays that were also linked to the computers.

Analysts at the 200,000 square-foot center concentrated on such arcane topics as pathway predictions, delay intervals, route segments, and choke points. The computers analyzed sensor data and compiled intelligence information and then made predictions as to where and when a particular PAVN truck convoy would be geographically located.^[28] According to author John Prados, the system functioned "exactly like a pinball machine… in truth, the mavens of the electronic battlefield became pinball wizards".^[29]

The effectiveness of the system was determined not by how long a sensor would last in the field, but by the adequacy of coverage by a particular string of sensors.^[30] For instance, a well placed string with several failed sensors was more effective than a fully functional string placed in the wrong location. The electronic data was, however, only as good as the human analysts and operators at the ISC. The knack of timely sensor activation depended on careful study of device locations and the patterns of PAVN logistical behavior.^[24]

The sensors were delivered to the target areas by U.S Navy OP-2 Neptunes of VO-67 or by U.S. Air Force helicopters, both based at Nakhon Phanom. Due to increasing PAVN anti-aircraft artillery defenses encountered in southeastern Laos, delivery in high-risk areas of the trail system was handed over from the Neptunes to Air Force F-4 Phantom fighter-bombers that had been specially equipped for the missions.

U.S. strike aircraft were directed to predicted target areas by a variety of means. The first was for the ISC to relay target information to an airborne battlefield command and control center (ABCCC), which then routed bombers to a forward air control aircraft (FAC).^[28] The FAC then led the strike to the target. During inclement weather or complete darkness, aircraft could still attack the trail by utilizing either MSQ-77 Combat Skyspot (a radar-directed system) or LORAN (a radio-directed navigational system).^[31]

As the program (and PAVN air defenses) evolved, so did the relay aircraft. The EC-121Rs and their crews proved too vulnerable and were partly replaced in 1969 and 1970 by QU-22Bs (modified Beech A-36 Bonanzas) which were to be remotely piloted.^[32] The aircraft suffered from mechanical difficulties, however, and were never flown during an operational mission without a pilot. They were replaced by C-130B models in december 1971.^[33]

Operations

On 25 novembre 1967, Muscle Shoals began to undergo field testing and evaluation in southeastern Laos.^[34] This process was interrupted by the battle of Khe Sanh, when an estimated three PAVN divisions approached, and then surrounded a Marine outpost in western Quang Tri Province adjacent to Laos. The U.S. commander in Vietnam, General William C. Westmoreland, ordered Task Force Alpha to support the aerial effort to defend the base (Operation Niagara). On 22 janvier, the first of 316 sensors were implanted near Khe Sanh in 44 strings.^[35]

Although the Marine Direct Air Support Center was at first reluctant to trust the sensors (which in fact replaced ground patrolling), they were soon convinced of their utility.^[36] The Marines credited 40 percent of intelligence available to the Khe Sahn fire support coordination center to the sensors.^[37] General Westmoreland was ecstatic about Task Force Alpha's contribution to the victory at Khe Sanh. He had been one of the few high-ranking military officers that had supported the barrier concept since its planning stages.^[38]

With the conclusion of aerial operations around Khe Sanh and the close out of the Marine base, the focus of Igloo White (as the operation was redesignated in June) turned once again to Laos. On 15 novembre 1968 the Seventh/Thirteenth Air Force had inaugurated Operation Commando Hunt, a series of continuous interdiction operations against the Ho Chi Minh Trail that would continue until the end of American participation in the conflict. For the next four years Igloo White and Commando Hunt would be interlinked in the anti-infiltration effort.

With the advent of Igloo White/Commando Hunt, the aerial interdiction effort entered a new phase. Armed reconnaissance - the patrolling of known segments of the trail system by aircraft searching for targets of opportunity - gave way to strikes directed by the sensor system.^[39] That is not to say the Task Force Alpha had operational control of the aircraft that carried out the missions. The Seventh Air Force was not about to surrender the single air manager control that it had just fought so hard to obtain.^[40] Task Force Alpha supported the Seventh by gathering, analyzing, and disseminating intelligence.^[41] This intelligence was delivered from Nakhon Phanom to the Seventh's headquarters at Ton Son Nhut Air Base, where it issued the strike orders. The ABCCCs were also under the control of the Seventh, not Task Force Alpha.

The only exception to this arrangement was Operation Commando Bolt, a real-time, LORAN-based technique which utilized sensor strike zones derived from predicted target locations.^[42] These missions were coordinated by Task Force Alpha's Sycamore control center against targets that passed through strike modules (four strings of three to six sensors each). Air controllers at Sycamore then directly delivered the correct course, altitude, and speed necessary for the strike aircraft to deliver their ordnance to the correct coordinates.^[43]

There were some initial problems with the system that were quickly resolved. During Operation Commando Hunt I, for example, there were so many aircraft piling up in the air space over southern Laos that the air controllers and FACs could not keep track of them. Pilots, many of whom were veterans of Rolling Thunder, tended to arrive over the area in large waves instead of spacing out their arrivals over time.^[44] One technical failure, however, would have hugh ramifications for the entire program. The anti-personnel system, which was based on the dispersal of wide-area Gravel mines (the explosions of which would activate acoustic sensors) failed completely. The mines deteriorated too rapidly in the heat and humidity of Laos, thereby negating the system.^[45]

The North Vietnamese response to the threat posed by the sensors was swift. If PAVN troops could detect the general location of a sensor, they immediately began to search out others and destroy them. Another response was to simply avoid them. The final evolution of anti-sensor measures was to attempt to deceive them.^[46] The chief protection of the sensors proved to be the dense foliage that covered the majority of the logistical system, turning the enemy's chief protection against him. Doubtless, PAVN troops negated the effects of many sensors, but so many of them were sown over such a long period of time that the majority survived.

Conclusion

The stated goal of the American aerial interdiction campaigns was to force Hanoi to pay too high a price in blood to make the continued support of its goals in South Viêt Nam tenable.^[47] In this effort, the U.S. failed. Not only were the PAVN/NLF able to continue their efforts, but they managed, under a deluge of ordnance, to launch two major offensives (the Tet Offensive in 1968 and the Nguyen Hue Offensive [known in the West as the Easter Offensive] in 1972 and a counteroffensive (against Operation Lam Son 719 in 1971). The key to the failure of the American strategy was that the anti-infiltration campaigns targeted supplies and transportation (both of which were imported), instead of manpower.^[48] The price in casualties for the PAVN/NLF was high, but it was a price that Hanoi was willing to pay.

Chief among the criticisms leveled against the system was its failure to detect the build-up to PAVN's 1972 Nguyen Hue Offensive. This cast doubt not only on the on the trustworthiness of the sensors, but on the adequacy of the entire system. The headquarters of the Pacific Air Force launched an investigation of the apparent failure and reported that "our estimates were in error." The report went on to state, however, that the lapse was not the result any failure of the sensors themselves, but the Air Force's false assumption that the trail net had adequate coverage.^[49]

The interdiction campaigns were also expensive. Igloo White cost around one billion dollars per year to operate.^[17] The cost of the bombing operations that the sensors supported amounted to approximately 18.2 million dollars per week.^[50] Those costs did not include the hundreds of aircraft lost during the interdiction campaigns or the priceless crews that manned them.

Scholars today remain divided on the merits of the electronic barrier system and the efficacy of the bombing campaigns that it directed. The claims of destruction made by the U.S Air Force, both during and after the conflict, were originally taken as given. The only exception to this rule was at the CIA, which discounted Air Force claims at the time by as much as 75 percent.^[51] This was understandable due to the fact that the Vietnamese were basically silent during the 1970s and 1980s.

By the 1990s new historical research (especially by Air Force historians Earl Tilford, Bernard Nalty, and Jacob Van Staaveren) and the publications of the Military Institute of Viêt Nam finally opened new perspectives on aerial interdiction during the Viêt Nam Conflict. During Commando Hunt for example, the Air Force claimed that 46,000 PAVN trucks had been destroyed or damaged by air strikes in Laos.^[52] These figures were hard to reconcile with the 6,000 trucks imported annually into North Viêt Nam between 1965 and 1970 - for all of its operations.^[46] American claims that 80 percent of the materiel that started down the trail was destroyed while enroute to the southern battlefields had to be altered in the face of loss claims of only 15 percent by the Vietnamese.^[53]

Thomas C. Thayer, chief of the Advanced Research Projects Agency for four years during the conflict, believed that only about one-twentieth of the cargo imported into the north moved southward on the Ho Chi Minh Trail and that more than two-thirds eventually reached the battlefields in the south.^[54] More recently however, a new study by Air Force historian Eduard Mark has attempted to rehabilitate the Air Force's original claims by finding a rough correlation between trucks imported into North Viêt Nam during the conflict and those that were claimed by the American pilots as destroyed.^[55] Only the opening of the Vietnamese archives to scholarly research will reveal the true effectiveness (or lack thereof) of the American electronic and aerial effort.

Notes

References

Unpublished government documents

• Military Assistance Command, Viêt Nam, Command History, 1968, Annex F, Saigon, 1969.

Published government documents

• Correll, John T. Igloo White, Air Force Magazine. November 2004, Vol. 87, No. 11.
• Gilster, Herman L, The Air War in Southeast Asia: Case Studies of Selected Campaigns. Maxwell Air Force Base AL: Air University Press, 1993.
• Mark, Eduard M. Aerial Interdiction: Air Power and the Land Battle in Three American Wars. Washington DC: Center of Air Force History, 1994.
• Military History Institute of Viêt Nam, translated by Merle Probbenow, Victory in Viêt Nam: The Official History of the People's Army of Viêt Nam, 1954-1975. Lawrence KS: University of Kansas Press, 2002.
• Nalty, Bernard C, Air Power and the Fight for Khe Sanh. Washington DC: Office of Air Force History, 1986.
• Nalty, Bernard C. The War Against Trucks: Aerial Interdiction in Southern Laos, 1968-1972. Washington DC: Air Force Museums and History Program, 2005.
• Schlight, John, A War Too Long: The USAF in Southeast Asia, 1961-1975. Washington DC: Air Force History and Museums Program, 1996.
• Schlight, John, The War in South Viêt Nam: The Years of the Offensive, 1965-1968. Washington DC: Air Force History and Museums Program, 1999.
• Tilford, Earl H. Setup: What the Air Force Did in Viêt Nam and Why. Maxwell Air Force Base AL: Air University Press, 1991.
• Van Staaveren, Jacob, Gradual Failure: The Air War Over North Viêt Nam, 1965-1966. Washington DC: Air Force History and Museums Program, 2002.
• Van Staaveren, Jacob, Interdiction in Southern Laos, 1961-1968. Washington DC: Center of Air Force History, 1993.

Secondary sources

• Doleman, Edgar C., Jr., Tools of War. Boston: Boston Publishing Company, 1984.
• Morocco, John, Thunder from Above: Air War, 1941-1968. Boston: Boston Publishing Company, 1984.
• Morocco, John, Rain of Fire: Air War, 1968-1973. Boston: Boston Publishing Company, 1984.
• Prados, John, The Blood Road: The Ho Chi Minh Trail and the Viêt Nam War. New York: John Wiley and Sons, 1998.
• Prados, John and Ray Stubbe, Valley of Decision: The Siege of Khe Sanh. Annapolis MD: Naval Institute Press, 1991.
• Thompson, W. Scott and Donaldson W. Frizzell, The Lessons of Viêt Nam. New York: Crane, Russak, and Co, 1977.
• Jeppeson, Chris, Acoubuoy, Spikebuoy, Muscle Shoals and Igloo White, 1999.

• Portail de l’histoire militaire