Lombard, IllinoisMay 1952

On the morning of May 21, 1952, a spherical glass object struck a mailbox at a home in Lombard, Illinois. The impact happened around 5:30 a.m. and dented the rounded corner of the steel mailbox by about three-sixteenths of an inch. The object then bounced onto the porch, leaving a black line behind as it rolled.

The homeowner, Ed F. Marquardt, found the object about four minutes after the impact. He tried to pick it up but had to drop it immediately because it was too hot to hold. The object was roughly one inch in diameter and appeared to be made of glass covered with a tar or asphalt-like coating, partly black and reddish in color. When it cooled, Mr. Marquardt picked it up again and brought it to the Lombard Police Station.

The Air Force investigators studied where the mailbox was positioned on the partially closed porch and determined the object had come from the south-southeast at a 45-degree angle downward. A few seconds before the impact, an aircraft had been heard passing overhead. At the time, six F-86 fighter jets were airborne from O'Hare International Airport, about ten miles away. The investigators checked two of these aircraft that had been on display for Armed Forces Day but found no tar residue in their rear sections.

The Air Force concluded the object was a large glass marble covered with tar-like material. The Technical Analysis Division noted that the marble could not have traveled far at high speed, since the coating would have melted away. They considered it most likely that the object had been thrown or shot from a slingshot or similar device. Because of these findings, the Air Force decided no further investigation was necessary. The complete case file, consisting of 9 pages, is reproduced below as held by the National Archives.