Project 10073 Record Card and Associated Correspondence — Chanute AFB, Illinois, March 1961

This document contains a Project 10073 record card and subsequent official correspondence regarding a UFO sighting reported by five military personnel at Chanute Air Force Base, Illinois, on March 9, 1961. The witnesses described a round, bright white object, approximately the size of a basketball, which performed various maneuvers, including pulling up gradually and moving in a straight and level path before disappearing behind a building. The observation lasted between two and five minutes.

Following an investigation, the Base Training Division concluded that the sighting was not an unidentified aerial phenomenon but rather a misinterpretation of environmental and operational factors. The report highlights that the evening featured low, fast-moving scud clouds and bright stars shining through an overcast sky. Furthermore, there was extensive air traffic in the area, including a C-47 aircraft performing irregular holding patterns and a T-33 aircraft executing a GCA (Ground Controlled Approach) landing. The investigating officer noted that a warm, dry subsidence inversion layer between 3,500 and 12,000 feet may have caused light refraction, further distorting the appearance of the objects.

The investigating officer expressed skepticism regarding the witnesses' accounts, noting that the interviews with three of the four primary observers appeared 'somewhat rehearsed.' One observer, who was on K.P. (Kitchen Police) duty, was noted as not having had the opportunity to coordinate his story with the others. The report also mentions that the observers had discussed the event among themselves before officially reporting it, fearing ridicule. Ultimately, the official conclusion attributed the sighting to the combination of atmospheric conditions, the presence of Venus, and the complex flight patterns of military aircraft in the vicinity.