Incident #163 Sighting Report — Van Nuys, California, 21 July 1948

This document details the investigation of Incident #163, a sighting of an unidentified aerial phenomenon over Van Nuys, California, on 21 July 1948. The object was initially reported by an Ordnance Reserve Officer and his wife, who described a round, spherical object that appeared to be a weather balloon but exhibited unusual characteristics, such as a bluish luminescence that changed to orange at dusk. The object was observed for approximately one hour, traveling in a vertical arc from East to West. Following the initial report, the Air Materiel Command requested a formal investigation under Project SIGN. Investigators interviewed several witnesses, including professional astronomers at the Mount Wilson Observatory and the Griffith Observatory. These experts, who viewed the object through telescopes, provided a more detailed description, characterizing it as a ribbed, pear-shaped balloon made of translucent material with a square yellow disk suspended from its lower portion. The astronomers estimated the object's altitude at approximately 20,000 feet and its diameter at roughly 25 feet. The investigation concluded that the object was a meteorological balloon. The report includes correspondence between various military and civilian agencies, including the Air Weather Service, to determine if the object could be linked to any known domestic balloon launches. Despite the initial confusion and the sensationalized reporting in local newspapers, such as the 'Los Angeles Times' and 'Daily News,' the consensus among the experts was that the object was a balloon. The document also contains copies of the newspaper articles and the formal statements provided by the witnesses, including the astronomers who were able to observe the object with scientific equipment. The investigation was eventually closed, with the determination that the object was a balloon, and the file was used as a reference for other Project SIGN and Project Grudge reports.