Wilmington, MassachusettsJune 1960

On June 29, 1960, a self-employed plumbing and heating contractor in Wilmington, Massachusetts reported seeing an unusual object in the sky. The sighting lasted about five minutes. The man was sitting in his backyard around 4:25 p.m. looking upward when he spotted what he described as a dark, ball-shaped object flying at extremely high altitude. The object appeared to be white at first, then metallic in color as it turned. The witness estimated it was the size of a matchhead held at arm's length and appeared above 50,000 feet. He said it moved at approximately 1,000 miles per hour, moving roughly northeast before disappearing straight upward.

The investigating officer, Captain Albert J. Mariconda, determined that the object was egg-shaped rather than round, with fuzzy edges on opposite sides. The witness noted the object made no sound or vapor trail and gave off no visible reflection, unlike aircraft he had observed in the past near the nearby Air Force base. After the object vanished, two swept-wing jets with red and blue tails passed overhead at lower altitude.

The investigation examined several possibilities. A weather balloon had been released from the base that same afternoon and burst around 2:16 p.m. at 110,000 feet. Based on wind patterns, the balloon would have passed over Wilmington around 3:57 p.m., well before the sighting time. The Boston Air Defense Sector reported no unusual radar tracks at the time and location. Air traffic control had no pilot reports of unusual objects. The National Space Surveillance Control Center confirmed no satellites were in a position to be observed. No astronomical activity could explain the sighting. Weather conditions were clear with scattered clouds.

Captain Mariconda concluded that he could not classify the object. He noted the witness seemed credible and had knowledge of military aircraft, but the lack of concrete evidence left the sighting unexplained. The Air Force's official evaluation listed the case as "unknown."

The full case file, comprising 10 pages as held by the National Archives, is reproduced below.