<text id=00he2004><title>Technology on Test</title>
<history>US Air Force: Events History</history>
<article><hdr>Technology on Test</hdr><body>
<p>The building blocks were air-dropped sensors, reacting either acoustically or seismically to the sounds and movements of troops and trucks. Each sensor would transmit its data via an orbiting relay aircraft to a ground station, where computers would analyze the data and present it in displays on CRT (cathode-ray tube) screens. The computers would be able to show the area of activity in terms of coordinates on the trail, and the strike force could be tailored for the mission, which was to cut the enemy lines of communications, and to keep them cut for extended periods of time. That would make it costly and difficult for the enemy to move materiel and men.
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<p>The development of ordnance for Igloo White was guided by several intended uses. Bombs would be used to cut the roads. Anti-truck or anti-tank mines would be needed to destroy the moving vehicles on the Trail. Anti-personnel mines would certainly deter, if not prevent, mine-clearing operations. Still another type of bomb would be needed to hit trucks that were concentrated by a chokepoint, or parked in a camouflaged area during the day.
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<p>Each air-dropped sensor was a self-contained sensing and transmitting system. The acoustic types were modifications of the Navy's basic sonobuoy. Called Spikebuoy and Acoubuoy, both types detected and transmitted acoustic signals only. Spikebuoy, as the name implies, had a long nose spike that emplaced the unit in the ground. Acoubuoy was dropped by parachute and was designed to hang in the trees. The mainstay of the program was the air-delivered seismic intrusion detector (ADSID). It detected a very low level of seismic disturbance and translated it into the presence of a tank, truck, or body of troops. That unit led finally to the development of Acousid, a combined acoustic and seismic detector.
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<p>Air delivery of the sensors had to be done with accuracy in order for the system to work at all. The only available aircraft with precision navigational gear were Navy Lockheed OP-2Es, and special squadron VO-67 was formed to do the job under operational control of Seventh AF. Some sensors also were dropped by A-1Es and CH-3 helicopters, both able to make relatively slow runs and accurate drops on the trail. The drops still had to be referred to map coordinates, and to be coordinated with local FACs.
