The first 3 weeks of July show an average of 8 reports per day, many of them coming from Air Force jet interceptor pilots scrambled in response to radar or visual sightings from the ground. Starting on the 22nd and lasting through the 29th, reports jumped to an average of 27 per day. At the end of that very busy month, almost 400 reports had been recorded, which was more than in any previous full year.
The Project Blue Book office at Wright Field, Dayton, Ohio, was conducted by Captain Edward J. Ruppelt, whose tiny staff of two persons was totally overwhelmed by the volume of work. Reports poured in by mail, teletype, telephone and messenger faster than they could be processed, let alone investigated. They were stacked up with vague plans to investigate when things finally calmed down, but mostly they never were.
The Blue Book list of unexplained observations for 1952 reflects this dramatic increase.
There were 3 nights of intense activity over Washington, D.C. On July 19/20, July 26/27 and August 2/3, the skies above the nation's capital were crowded with UFOs darting here and there, over the White House, over the Capitol Building, over the Pentagon.
They were seen from the ground, seen and also detected on radar from control towers at Washington National Airport, Bolling Air Force Base across the Potomac River, and from nearby Andrews Air Force Base. The radar operators conferred by telephone to ensure they were tracking the same targets. In many cases, airline pilots flying in the area were able to provide visual confirmation of radar tracking.
The appearance of unidentified objects flying with impunity over the heart of the American government and its military establishment was embarrassing to the Department of Defense, whose responsibility it was to protect the country from airborne intrusion. A flood of questions from reporters led the U.S. Air Force to call its biggest but also most embarrassed and confused press conference since World War II.
The conference was held in Room 3E-369 of the Pentagon, and was presided by Air Force Intelligence Chief, Major General John Samford. The main explanation given for the rash of sightings over Washington was something called a "temperature inversion," which is the immediate cause of a mirage, but usually on the ground. General Samford suggested that lights on the ground may have looked like they were in the air because an inversion can act like an "air lens" and bend light rays. He added that something similar could have "tricked" radar into thinking it was tracking aerial targets, which were actually ground objects. This was the first time that this ad hoc explanation was used, it became very useful as an explanation for numerous later cases, though no one in the larger scientific community had a clue about this phenomenon. It wasn't until 1969 that an Air Force scientific report made it clear that inversions strong enough to create the effects with which General Samford credited them, could not exist in the earth's atmosphere! Moreover, probably no radar/visual UFO report had ever been caused by a temperature inversion or mirage.
For the larger audience, there were two surprises. First, the pres was surprised to learn that UFOs were picked up on radar. Until then, this was never mentionned by the Air Force. Second, they were told it is all a natural phenomena, temperature inversion. From then on, the press, the larger scientifi community, the public, all accepted that radar UFOs are "temperature inversions." 50 years later, it is mostly still so.
(Of course, it happens that hot air layer are under cold air layers, but the thermal gradient necessary to creates anomaous propagation echoes that can be interpreted as solid flying object with anomalous performances is quite high. If one also expects that temperature inversion produce simultaneoulsy a visual mirage, the required gradient becomes impossible to reach except at ground level, as in mirages on a heated road. If the visual mirage is supposed to be luminous, then it requires a ship with lights at sea under a very important temperaure inversion layer. If all that flies in the air, tracked at the same location by several different radar systems located at different places, then ... it is not possible to get the required conditions. Even if it arrives very exceptionally that such inversions returns echoes vaguely definite of vehicles on the ground, one visually does not see them in the sky with naked eyes, obviously. In the cases of Washington 1952, the weather conditions did not at all allow such an explanation.)
The same day that General Samford held his press conference, the wheels began to turn at the Central Intelligence Agency. A memo from Ralph Clark, Acting Assistant Director for Scientific Intelligence to the Deputy Director for Intelligence, stated:
"In the past several weeks, a number of radar and visual sightings of unidentified aerial objects have been reported. Although this office has maintained a continuing review of such reputed sightings during the past three years, a special study group has been formed to review this subject to date."
In 1952, few people other than radarmen knew what a temperature inversion layer could produce and what it could not produce. Among these few people was Major Donald E. Keyhoe, USMC ret., who explained it properly. But of course, only those willing to hear this, heard it.
See the official CIA report to get details on the CIA deep concerns about UFOs at that time: "...so long as a series of reports remains 'unexplainable' (interplanetary aspects and alien origin not being thoroughly excluded from consideration), caution requires that intelligence continue coverage of the subject."
Captain Edward J. Ruppelt (standing), director of Project Blue Book, and Major General Samford, Chief of Air Intelligence. Photograph source United Press International.
Diagram of the UFOs tracked by Washington's National Airport radar scope on July 20, 1952. At A, 7 objects approach the Nation's capital from the south. At B, some are seen over the White House and Capitol. At C, they appear over Andrews Air Force Base. At D, one UFO tracks an airliner. At E, one is seen to make a sharp right-angular turn. Source: UFOs - A Pictorial History From Antiquity to the Present, by David C. Knight. (McGraw Hill Book Co., 1979.)
|The New York Times||USA, July 22, 1952||"Strange objects in US sky - observed by radar".|
|The Washington Post||USA, July 28, 1952||"'Saucer' outran jet, pilot reveals Investigation on in secret after chase over capital - Radar spot blips like aircraft for nearly six hours - only 1.700 feet up."|
|The Bridgeport Post||USA, July 28, 1952||"Jet interceptors fail to contact ghostly 'saucers' over capital".|
|The Alexandria Gazette||USA, July 28, 1952||"Jet fighters outdistanced by "Flying Saucers" over Mt. Vernon and Potomac" observations in North America around the famous 1952 Washington flap.|
|Grand Haven Tribune||USA, July 28, 1952||"See odd objects in Michigan skies".|
|Observer-Dispatch||USA, July 28, 1952||"New reports of saucers above state and Washington".|
|Wilkes Barre Record||USA, July 28, 1952||"Air Force jet fighters fail to catch objects flying over Washington".|
|Ypsilanti Press||USA, July 28, 1952||"'Things' in sky here sunday appear like flying saucers".|
|The Alexandria Gazette||USA, July 29, 1952||"Flying saucers circled the Northern Virginia area again this morning:" observations in North America around the famous 1952 Washington flap.|
|Le Méridional||France, July 29, 1952||"Jet fighters have hunted strange "objects" reported for one week in the sky of Washington DC".|
|The Sheboygan Press||USA, August 4, 1952||"This time it's hard to brush off those mystery 'saucers'."|
|The Washington Post||USA, July 21, 2002||"50 Years Ago, Unidentified Flying Objects From Way Beyond the Beltway Seized the Capital's Imagination:" 50 years later, the Washington Posts remembers the events.|
|Athens News||USA, October 17, 2002||"Strange happenings: Similar UFO sightings occur exactly 50 years apart".|