mission had been expanded to include sensors for a "wide range of tactical applications," as well as, a "Ground Tactical System" in 1968. The Ground Tactical System was envisioned as a tool for ground commanders in defending fire bases and other secured areas against attack, and was eventually employed around Khe Sanh. It was also noted that the US border patrol was testing the sensor equipment as a method of protecting US continental borders. Sensor equipment was deployed by July 1969 in South Vietnam for the purposes of countering boobytrapping and mining teams. A total of 56 sensors were diverted to the problem as a test, with testimony that vehicle losses were reduced by 50 percent in the first month. 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 Vietnam tenable. 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.<ref>Nalty, War Against Trucks, p. 298.</ref> The price in casualties for the PAVN/NLF was high, but it was a price that Hanoi was able and 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 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. The interdiction campaigns were also expensive. Igloo White cost around one billion dollars per year to operate. The cost of the bombing operations that the sensors supported amounted to approximately 18.2 million dollars per week. Those costs did not