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 553d 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. Since then, the defensive barrier system project has 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 project was renamed to Muscle Shoals, it indicates the air-supported subsystem in eastern and central Laos. In June 1968, when the program was renamed to 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