Dahlgren, VirginiaApril 1955

On April 28, 1955, personnel at Dahlgren, Virginia observed a round, metallic object in the sky using a theodolite (an optical surveying instrument used to measure angles and distances). The object appeared to be approximately 28 to 30 feet in diameter and was visible only through the theodolite's eyepiece, not to the naked eye.

The object was first spotted while observers were tracking a weather balloon (called a pibal, used to measure wind conditions in the upper atmosphere) with ground-based radar. The object remained visible for approximately one hour and fifty-six minutes, moving very slowly across the sky. As the observation continued, the object gradually dropped in elevation, shifting from an initial bearing of about 31 degrees to eventually 29 degrees, with its relative bearing changing to 245 degrees.

The Air Force received reports from the observation team at Dahlgren's flight service operations. Weather conditions at the time included scattered clouds with visibility of about 15 miles and southwesterly winds. Wind data at various altitudes was recorded during the sighting.

The Air Force investigation noted that the observer himself suggested the object resembled a balloon. Investigators determined that the object was likely a balloon released by the Norfolk Naval Base. However, the case file shows the official evaluation remained listed as "unidentified," suggesting some uncertainty remained about the precise identification despite the balloon hypothesis.

The full case file is reproduced below as held by the National Archives, comprising 13 scanned pages.