High Quality Content by WIKIPEDIA articles! Project Mogul (sometimes referred to as Operation Mogul) was a top secret project by the US Army Air Forces involving microphones flown on high altitude balloons, whose primary purpose was long-distance detection of sound waves generated by Soviet atomic bomb tests. The project was carried out from 1947 until early 1949. The project was moderately successful, but was very expensive and was superseded by a network of seismic detectors and air sampling for fallout which were cheaper, more reliable, and easier to deploy and operate.