Incident #81 Sighting Report — Hickam Field, 7 July 1947

This document contains a formal report regarding Incident #81, which occurred on 7 July 1947 at Hickam Field, Hawaii. An observer from the Air Communications Section reported seeing a spherical object, described as a large balloon with a silver disc suspended below it, moving slowly in a northwesterly direction at an altitude of approximately 6,000 feet. The observer noted that the object revolved and that the silver disc flashed, likely due to sunlight. The observation lasted for a few minutes before the object was lost in the clouds. The official conclusion reached by the evaluating authorities was that the object was an instrument-carrying balloon and that there was nothing astronomical about the incident. The document also includes correspondence between the Air Materiel Command and the Air Weather Service regarding Project SIGN, detailing the process for collecting and investigating reports of unidentified flying objects. It notes that the Air Weather Service was tasked with assisting in the identification of these objects by checking against synoptic balloon flight data. Additionally, the document contains an index of evaluations extracted from the Project GRUDGE report, categorizing various incidents based on the probability of them being astronomical, balloons, aircraft, or other phenomena.