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Transcript of a Presentation by Captain Edward J. Ruppelt, 1952

U.S. Department of War · 1952-03-26 · 19 pages · text from the file's own layer

This declassified transcript, released by the Office of the Under Secretary of War, records a March 1952 presentation by Captain Edward J. Ruppelt on the Air Force's reorganized UFO investigation. Ruppelt reports that about 20% of roughly 800 cases remain unexplained and notes clusters of reports near Los Alamos, Albuquerque and Oak Ridge. He discusses the Lubbock lights photographs, the Phoenix 1947 photograph and the Mantell case. He concludes that the Air Force has no firm evidence about what the objects are.

From the source: Release of 2026-09-18 Incident: 3/26/52, Boston, Massachusetts. This document is a transcript of a March 1952 presentation by Captain Edward J. Ruppelt outlining the U.S. Air Force’s reorganized investigation into unidentified flying objects (UFOs). The presentation previews prospective technical methodologies, such as diffraction-grating photography and radar-scope synchronization, that were subsequently incorporated into Project Blue Book, a U.S. Air Force program active from 1952 to 1969 that investigated the nature and origin of UFOs. Ruppelt explains that out of approximately 800 historical cases reviewed by the Air Force, approximately 20% remained unexplained after technical analysis. These unresolved reports were sourced from credible military personnel, commercial pilots, and other qualified technical observers. He highlights geographic report concentrations around sensitive national security and nuclear weapons installations (including Los Alamos, Albuquerque, and Oak Ridge National Laboratories) and notes recurring anomalous characteristics, including silent high-speed flight and radar detections indicating unconfirmed air speeds between 1,000 and 3,500 miles per hour. Emphasizing that the Air Force found no conclusive evidence regarding the nature or origin of the phenomena, Ruppelt underscores the national security need for a systematic physical data collection effort to better evaluate these sightings.

DOW-UAP-PR160 · recording · 1952-03-26 Presentation by Captain Edward J. Ruppelt, 1952 This audio file records a March 1952 presentation by Captain Edward J. Ruppelt, outlining the U.S. Air Force’s reorganized investigation into unidentified flying objects (UFOs). The presentation previews prospective technical methodologies, such as diffraction-grating photography and radar-scope synchronization, that were subsequently incorporated into Project Blue Book, a U.S. Air Force program active from 1952 to 1969 that investigated the nature and origin of UFOs. Ruppelt explains that out of approximately 800 historical cases reviewed by the Air Force, approximately 20% remained unexplained after technical analysis. These unresolved reports were sourced from credible military personnel, commercial pilots, and other qualified technical observers. He highlights geographic report concentrations around sensitive national security and nuclear weapons installations (including Los Alamos, Albuquerque, and Oak Ridge National Laboratories) and notes recurring anomalous characteristics, including silent high-speed flight and radar detections indicating unconfirmed air speeds between 1,000 and 3,500 miles per hour. Emphasizing that the Air Force found no conclusive evidence regarding the nature or origin of the phenomena, Ruppelt underscores the national security need for a systematic physical data collection effort to better evaluate these sightings. Download (765 MB)
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diameter, and judging the rate of closure, he assumes it's going at a very terrific speed. But we've
been able in some cases to actually show how that pilot was misled and that it was actually a
balloon. However, we don't, we don't try to say that everything was a balloon. In other words, if
a balloon was launched in the area, we try to definitely pin that down. We can get the time of
launch of the balloon, the rate of ascent, the winds aloft, we can plot out the path of that balloon
and plot out the pilot's path and show by various lines of sight how he actually did see the
balloon. In the past, it's been a practice to say, "Well, there was a balloon launched within 100
miles, consequently the pilot must have seen the balloon." We don't want to try that because it's,
well, we just want to have more proof before we say that it's a balloon. And the Air Force has
gotten into a lot of trouble in the past by very loosely tying up these balloons with the sightings.
We have some photographs of these objects that, we have quite a few photographs, I should say.
A lot of them are definitely either hoaxes or else they're flaws in the negative and the people that
have found this print have looked at it and said, "Ah, I took a picture of the sky and I didn't see
this flying saucer, although here's a picture of it," and they'll send it into us. It's not too difficult
to examine those under a microscope and find out that the image is due to an imperfection in the
negative. However, we have a few photographs that are very difficult to evaluate. This is one of
them right here. It was taken in Phoenix, Arizona, on the 7th of July, 1947. This has been hashed
around quite a bit, and there's a little bit of doubt as to the, whether or not this was purposely
faked, but we've never been able to prove it.
This picture is probably the most interesting one that we've ever received, mainly because we
went into the background of this thing a lot more. This was taken in Lubbock, Texas last
September. Now, this Lubbock case is probably the most interesting one, the whole case is the
most interesting one we've ever had. These five college professors from Texas Tech were sitting
out in the backyard one evening, in what was it, August, yes, August 25th, and they happened to
be discussing meteors and so they were sitting there looking up in the sky, and all of a sudden
this bunch of lights went over. And so one of them, they looked at each other and said, "What
was that?" Nobody seemed to know. And so, about a half an hour later, why they were still
discussing the lights and they said they wished that something like that would go over again, and
it did. So, for, well, altogether in a period of, I believe it was five or six nights, they observed 12
of these things that went over. Well, they assumed that it was some kind of a missile that the Air
Force had been developing, and being nosy, they thought they'd find out what this, well, they
reached this conclusion after they saw the first two, that they'd find out what these missiles were.
So they set up their own measuring, crude measuring systems. They were able to set up a, or
measure the angles on the houses and things in their backyards so they could tell the angle this
thing went through, and they timed it with a stopwatch. They also set up a baseline 90 degrees to
the path—and incidentally, these things always came over the same path and at roughly the same
time every night, so they knew about what was going on. They set up this baseline and got at
each end with two-way radios and some homemade, well, you might call them theodolites or
measuring, angle measuring devices, and tried to get an altitude. Well, they were unsuccessful on

Cases discussed

About this file

Hearing transcript, from the pursue collection. The PDF is mirrored here; the original link is above. 19 pages are in the text index: search them above, or from the library's search.