Project 10073 Record Card — Altadena, California, 17 June 1955

On June 17, 1955, at 0900Z, a civilian Ground Observer Corps (GOC) observer in Altadena, California, reported a sighting of an unidentified aerial object. The witness described the object as round and reddish in color, appearing to be the size of a half-dollar held at arm's length. The object was observed for approximately ten minutes, during which it traveled from the north to the south, then rose vertically before fading from view. The observer noted that there was no sound associated with the object. Weather conditions at the time were reported as clear with five miles of visibility and some haze. The sighting was documented on a Project 10073 record card and reported via military message channels. The investigation, conducted by 1st Lt. Guy Renfroe, concluded that the sighting was likely a balloon. The report suggests that because the observer was in a brightly lit area, the object may have been illuminated by the reflection of city lights. Due to the description and the duration of the sighting, the official assessment was that the characteristics were consistent with a balloon, and no further investigation was authorized. The report also notes that an extreme time delay in reporting prevented a more thorough preliminary evaluation.