PRO reference DEFE 44/119, DSI/JTIC Report No 7 (Report by "Flying Saucer" Working Party, June 1951).
This document is the property of
His Britannic Majestys Government
DISCREET/SECRET COPY NO. 17
BUT CLEARED FOR CANADA
(Redacted Copy)
MINISTRY OF DEFENCE
DIRECTORATE OF
SCIENTIFIC INTELLIGENCE
AND
JOINT TECHNICAL INTELLIGENCE COMMITTEE
UNIDENTIFIED FLYING OBJECTS
June 1951 D.S.I./J.T.I.C. REPORT No. 7
SECRET/DISCREET
SECRET
UNIDENTIFIED FLYING OBJECTS
Report by the Flying Saucer Working Party
Introduction: Historical
Unidentified flying objects were first reported after the war
from Sweden in the summer of 1946, and for some months there was
a considerable number of alleged sightings, mostly in Sweden, but
a few also in Norway, Finland and Germany. The descriptions given
were usually of some sort of wingless missile travelling at very
high speed, cigar-shaped and circular, sometimes emitting bright
lights, and occasionally sound. The reports attracted
considerable attention in the press, where the objects became
known as ghost rockets or spook bombs.
The reports died away after the summer of 1946, and very few have
appeared since the end of that year.
The first report of a flying saucer came from the
United States in June 1947; the name arose because the observer (Mr
K. Arnold, of Boise, Idaho) described what he had seen as a
saucer-like disc. The report received much publicity,
and was quickly followed by a great many more. Since then reports
of sightings have been made at intervals in large numbers, mostly
from the United States, but some from other parts of the world,
including Great Britain, where there was a notable outbreak
during the summer and autumn of 1950. The objects reported have
become popularly known by the generic title flying saucers,
but the descriptions given have included not only flying disc-like
objects of the original saucer type, but also
wingless torpedo or cigar-shaped bodies, spherical or balloon-shaped
objects, and luminous phenomena of various types.
The reported observations have been almost exclusively visual;
reports of any associated sound have been rare. In no case has
any tangible, material, or objective evidence, been submitted. It
is therefore extremely difficult, if not impossible, to arrive at
anything like scientific proof of the nature of the phenomena.
Review of previous evidence
A systematic and extensive investigation of all the reported
incidents in the United States was carried out between 1948 and
1950 by the U.S.A.F., in conjunction with the Rand Corporation,
Dr. Hynek, a well-known astronomer from Ohio State University,
and other specialist consultants. [Deletion retained
under Section 3(4)] .....we have been enabled to study
two reports (Project Sign and Project Grudge)
covering the investigation of incidents up to the beginning of
1949.
[Deletion - Retained under Section 3(4)]
On the Scandinavian sightings in 1946, Project Grudge
reports as follows:--The Swedish Defence Staff conducted a
comprehensive study of the early incidents. Several thousand
reports were thoroughly investigated and plotted, with resultant
conclusions that all evidence obtained of sightings was
explicable in terms of astronomical phenomena.
Dealing with reports from the United States, Project Grudge
quotes the opinion of the Rand Corporation after an examination
of 172 incidents: to date, we have found nothing which
would seriously controvert simple rational explanations of the
various phenomena in terms of balloons, conventional aircraft,
planets, meteors, bits of paper, optical illusions, practical
jokers, psychopathological reports, and the like.
Dr Hynek investigated 228 incidents and concluded that
approximately 33 per cent were astronomical with varying degrees
of probability; 37 per cent. were not astronomical but suggestive
of other explanations, such as birds, rockets, balloons, ordinary
aircraft, &c.; the remaining 30 per cent. either lacked
sufficient evidence or the evidence offered suggested no
explanation, though some of these might conceivably be
astronomical.
Summing up their own conclusions and those of their consultants,
the authors of the Grudge report finally concluded
that, of the 228 incidents considered, thirty must be disregarded
for lack of workable evidence, while 164 can be satisfactorily
explained. For the balance of thirty-four, containing some
evidence, there is no apparent ready explanation, if the evidence
is accepted as accurate and reliable. When psychological and
physiological factors are taken into consideration, the opinion
is expressed that all these incidents can also be rationally
explained.
All the more spectacular incidents, of which much has been made
recently in the British press and publications, have been fully
explained. Two examples may be quoted.
The incident at Fort Knox, Kentucky, in January 1948, which
caused the death of Lieutenant Mantell, U.S.A.F., is fully
analysed, and all the evidence collated in the Grudge
report. The conclusion is reached that without any doubt whatever
Lieutenant Mantell met his death while pursuing the planet Venus,
which was of unusual brightness on the night in question.
We have been informed, in conversation with a member of the
United States investigating team, that the even more sensational
report of the discovery of a crashed flying saucer,
full of the remains of very small beings, was ultimately admitted
by its author to have been a complete fabrication.
The Grudge report includes a frequency
distribution curve of the reports of incidents received
between May 1947 and December 1948. This shows a marked tendency
towards peaks in the few weeks immediately following an incident
which received wide publicity, and is of interest in indicating
the extent to which sightings may be psychological in origin.
The final conclusion reached by the Americans is that all reports
of unidentified flying objects may be categorical as either---
misinterpretation of various conventional objects (e.g.,
aircraft, balloons, meteors and meteorites, stars, fireballs);
a form of mass hysteria; or
deliberate hoaxes.
Investigation of incidents in the United Kingdom
During the summer and autumn of 1950 the British press gave
considerable publicity to reports of alleged sightings of
luminous bodies travelling at high speed, usually after dark, but
occasionally in daylight. The Air Ministry also received a number
of letters from members of the public with similar reports. One
of these, from a locomotive fireman at Derby, who was clearly a
careful and accurate observer, gave an excellent description of
what was undoubtedly a meteorite. We have not attempted any
systematic investigation of all the evidence presented, but can
find no reason for supposing that any of the phenomena reported
cannot be similarly explained; in certain cases, when
observations were reported at approximately the same time from
widely separated localities, this was undoubtedly the explanation.
Three incidents were reported officially by experienced officers
from R.A.F. stations. These have been investigated in as much
detail as is possible with reports of visual observations.
On 1st June, 1950, the pilot of a Meteor reported on landing at
Tangmere that at 1430, while flying at 20,000 feet on an easterly
course over the Portsmouth area, he had sighted an object
travelling at very high speed on a reciprocal course, 1,000-2,000
feet above him and roughly 1,200 yards to starboard. He described
the object as circular, and of bright metallic appearance. He
could not give any real estimate of its speed, but thought it
might be about 800 knots. He had observed it for about 15
seconds, during which period he had looked away to port and back,
having no difficulty in picking up the object again.
Tangmere made inquiries of the radar station at Wartling, and
were informed that, at about the same time as the pilots
report, the Duty Controller and three radar operators had
observed an unusual response on the P.P.I., which appeared to be
due to a target moving at 1,300-1,650 knots, first approaching
and then receding from the station. The Controller stated that
the response looked to be very thick, leaving more
afterglow than a usual response behind. The operator,
observing on a separate display, said that it was slim,
short and weaker than aircraft, and that a series of shadows
appeared in the space between successive points.
As the receding course of the radar target could have tallied
with the course of the object reported by the Meteor pilot, all
the people concerned were interviewed by a member of the Research
Branch, Fighter Command, from whose report the above data have
been taken. It was established that there was in fact a
discrepancy of ten minutes between the times of the two reports,
which were estimated as individually accurate to ± 1 minute. It
must therefore be concluded that there was no connection between
the unusual P.P.I. response and the pilots visual
observation.
We believe that the radar response can be very simply explained
as due to interference from another transmitter, a phenomenon
which has been frequently observed, and which is described in
detail in Appendix A. It is impossible to be entirely definite
about the pilots report. Assuming that he was not merely
the victim of an optical illusion, the most probable explanation,
which is borne out by his description of the object as circular,
implying a spherical body, is that he saw a meteorological
balloon and greatly over-estimated its speed. We can find no
reason whatever for adopting any less simple hypothesis.
The remaining two incidents were reported from the Royal Aircraft
Establishment, Farnborough, and the officers concerned were
interviewed by members of this Working Party.
F/Lt. Hubbard, an experienced pilot, said that at 1127 on 14th
August, 1950, he and two other officers on the airfield heard a
subdued humming noise, like a model Diesel motor, which caused
them to search the sky overhead. The weather was fine and
visibility good. The other two officers saw nothing, but F/Lt.
Hubbard, who alone was wearing sun-glasses, states that he saw,
almost directly overhead at first sighting, an object which he
describes as a flat disc, light pearl grey in colour, about 50
feet in diameter at an estimated height of 5,000 feet. He stated
that he kept it under observation for 30 seconds, during which
period it travelled, at a speed estimated at 800-1,000 m.p.h., on
a heading of 100 degrees, executing a series of S-turns,
oscillating so that light reflection came from different segments
as it moved.
We have no reason to doubt that F/Lt. Hubbard honestly described
his own impression of what he saw, but we find it impossible to
believe that a most unconventional aircraft, of exceptional
speed, could have travelled at no great altitude, in the middle
of a fine summer morning, over a populous and air-minded district
like Farnborough, without attracting the attention of more than
one observer. We conclude, either that F/Lt. Hubbard was the
victim of an optical illusion, or that he observed some quite
normal type of aircraft and deceived himself about its shape and
speed.
F/Lt. Hubbard was also concerned in the other incident, when, at
1609 on 5th September, 1950, he was standing on the watch-tower
with five other officers, looking south in anticipation of the
display by the Hawker 1081. The sky was about 3/8 obscured, with
a strato-cumulus cloud base at 4,000 feet. At about the same
moment they all saw, at an estimated range of 10-15 miles, an
object which they described as being a flat disc, light pearl
grey in colour, and about the size of a shirt button.
They all observed it to follow a rectangular flight path,
consisting in succession of a falling leaf,
horizontal flight very fast, an upward falling
leaf, another horizontal stretch, and so on; finally it
dived to the horizon at great speed. The pattern was estimated to
be executed somewhere over the Guildford-Farnham area.
F/Lt. Hubbard was satisfied that the objects he saw on the two
occasions were identical; the other observers agreed that the
second object fitted the description they had been given of the
first.
We have no doubt that all these officers did in fact see a flying
object of some sort. We cannot, however regard the evidence of
identification of this object, which was only seen at very long
range with the earlier one as of any value whatever. Further, we
again find it impossible to believe than an unconventional
aircraft, manoeuvring for some time over a populous area, could
have failed to attract the attention of other observers. We
conclude that the officers in fact saw some quite normal
aircraft, manoeuvring at extreme visual range, and were led by
the previous report to believe it to be something abnormal - an
interesting example of one report inducing another. We are
reinforced in this belief by an experience of one of our number (Wing
Commander Formby, R.A.F.) which is recounted in Appendix B and
illustrates the ease with which mistaken identification may be
made, even by experienced observers.
Conclusions and Recommendations
When the only material available is a mass of purely subjective
evidence, it is impossible to give anything like scientific proof
that the phenomena observed are, or are not, caused by something
entirely novel, such as an aircraft of extraterrestrial origin,
developed by beings unknown to us on lines more advanced than
anything we have thought of. We are, however, satisfied that the
bulk of the observations reported do not need such an
explanation, and can be accounted for much more simply. There is
a very old scientific principle, usually attributed to William of
Occam, which states that the most probable hypothesis is the
simplest necessary to explain the observations.
We believe that this principle should be applied to the present
case, and accordingly conclude that all the observations reported
were due to one or other of the following causes:---
Astronomical or meteorological phenomena of known
types.
Mistaken identification of conventional aircraft, balloons,
birds, or other normal or natural objects.
Optical illusions and psychological delusions.
Deliberate hoaxes.
We consider that no progress will be made by attempting further investigation of uncoordinated and subjective evidence, and that positive results could only be obtained by organising throughout the country, or the world, continuous observation of the skies by a co-ordinated network of visual observers, equipped with photographic apparatus, and supplemented by a network of radar stations and sound locators. We should regard this, on the evidence so far available, as a singularly profitless enterprise. We according recommend very strongly that no further investigation of reported mysterious aerial phenomena be undertaken, unless and until some material evidence becomes available.
Metropole Buildings, W.C.2.
APPENDIX A
A NOTE ON AN UNUSUAL RADAR RESPONSE BY Mr. G.E.G. GRAHAM, D.S.I. 1
With reference to the unusual response observed
at Wartling on 1st June, 1950, it is suggested that the signal
observed was received directly from another radar transmitter,
possibly ship-borne, in the Portsmouth-Isle of Wight area. This
will be termed the Western transmitter.
Assuming the modulation pulses of the Western
transmitter to be isochronous with those of the Wartling set, and
that the pulse of the former was occurring anything up to, say, 1.2
milliseconds minus the transmission time later than that of the
latter, the received signal would be visible on the P.P.I.
display. Moreover, unless the Western transmitter
were very far away it is probable that the received signal would
be of large amplitude and would therefore, as stated in the
report, appear very thick leaving more afterglow than a
usual response behind.
It is reasonable to suppose that the repetition rates mentioned
above would not remain identical for more than a few seconds. A
relatively small drift in the repetition rates will produce a
considerable change in the time interval between the transmitter
pulse and the firing instant of the receiver time base. This
would result in a large displacement of the received signal along
the scan, which would be interpreted as a high speed movement of
the target in the radial direction. It will be
appreciated that if at the instant of first sighting the
repetition rate of the Western transmitter were above
but slowly approaching that of the Wartling set, the target
would appear to close range rapidly; as the repetition rates
became equal the target would appear stationary, and
as the Western repetition rate fell below that of the
Wartling set, the target would appear to open range
rapidly. It may further be noted that one would expect
reflections from objects (hills, &c.) relatively close to the
Western transmitter to be of sufficient amplitude to
be displayed also on the P.P.I., which would give the impression
of shadows between successive points as described in
the report.
APPENDIX B
AN OBSERVATION OF A FLYING SAUCER BY WING COMMANDER FORMBY, R.A.F.
While on the rifle range at Tipner, Portsmouth, an object having the appearance of a Flying Saucer was observed in the distance. Visibility was good, there being a cloudless sky and bright sunshine. The object was located and held by telescope (x 20 magnification), and gave appearance of being a circular shining disc moving on a regular flight path. It was only after observation had been kept for several minutes, and the altitude of the object changed so that it did not reflect the sunlight to the observers eye, that it was identified as being a perfectly normal aircraft.