that is normally seen in the air. Balloons, airplanes, and astronomical bodies are the commoner stimuli. Birds and insects are common also, but usually are seen at such close range that they are nearly always recognized. Infrequently observed things, such as sundogs, mirages, huge fireballs, and a host of other unusual flying objects, are also known stimuli.
On Project Blue Book the problem was to identify these stimuli. We had methods for checking the location, at anytime, of every balloon launched anywhere in the United States. To a certain degree the same was true for airplanes. The UFO observer’s estimate of where the object was located in the sky helped to identify astronomical bodies. Huge files of UFO characteristics, along with up-to-the minute weather data, and advice from specialists, permitted us to identify such things as sundogs, paper caught in updrafts, huge meteors, etc.
This determination of the stimuli that triggered UFO sightings, while not an insurmountable task, was a long, tedious process. The identification of known objects was routine, and caused no excitement. The excitement and serious interest occurred when we received UFO reports in which the observer was reliable and the stimuli could not be identified. These were the reports that challenged the project and caused me to spend hours briefing top U. S. officials. These were the reports that we called “Unknowns.”
Of the several thousand UFO reports that the Air Force has received since 1947, some 15 to 20 per cent fall into this category called unknown. This means that the observer was not affected by any determinable psychological quirks and that after exhaustive investigation the object that was reported could not be identified. To be classed as an unknown, a UFO report also had to be “good,” meaning that it had to come from a competent observer and had to contain a reasonable amount of data.
Reports are often seen in the newspapers that say: “Mrs. Henry Jones, of 5464 South Elm, said that 10:00 a.m. she was shaking her dust mop out-of the bedroom window when she saw a flying saucer”; or, “Henry Armstrong was driving between Grundy Center and Rienbeck last night when he saw a light. Henry thinks it was a flying saucer.” This is not a good UFO report.
This type of UFO report, if it was received by Project Blue
