Operation Igloo White

To counter the infiltration of South Vietnam through the demilitarized zone and borderlands, the U.S. developed an electronic barrier.

It was called Operation Igloo White.

This barrier stretched some 100 kilometers and used an array of technologies, including acoustic and seismic sensors, orbital planes, early machine learning, and IBM mainframes.

Air and hand-dropped sensors hidden by the jungle topography maintained this border barrier.

So this is basically, this is the, the killing zone, the target for the air war.

[clears throat] At a peak of about a billion dollars a year, peak cost a billion dollars a year, the United States Air Force, so-called Operation Igloo White, dropped 20,000 acoustic, seismic, heat-sensitive, and ammonia sensors across the mountains to detect truck convoys that were bombed by US fighters based across the Mekong River in Thailand.

Why ammonia sensors? Well, because mammal urine smells of ammonia.

It's a way to detect movement.

[clears throat] And this is a schema of how Operation Igloo White...

Okay.

So here you have a sensor, okay, uh, sending those signals.