DISCLOSURE / FILE
Final report of Project Sign, the Air Force's first formal UFO program, summarizing 243 domestic and 30 foreign incidents and concluding no proof yet exists for unidentified flying objects as real unconventional aircraft.
Project Sign Final Report (Technical Intelligence Report No. F-TR-2274-IA), Project SIGN - Feb. 1949.pdf
Final report of Project Sign, the Air Force's first formal UFO program, summarizing 243 domestic and 30 foreign incidents and concluding no proof yet exists for unidentified flying objects as real unconventional aircraft.
Technical Report No. F-TR-2274-IA, released February 1949 by the Technical Intelligence Division at Air Materiel Command, Wright-Patterson AFB, is the final report of Project Sign (Project No. XS-304), the Air Force's first formal UFO investigation. Authors L. H. Truettner and A. B. Deyarmond reviewed 243 domestic and 30 foreign incidents, grouped reports into four configurations (flying disks, torpedo or cigar shapes, spherical or balloon objects, and balls of light), and drew on consultants including Ohio State astrophysicist J. Allen Hynek, MIT's Dr. G. E. Valley, and General Electric's Dr. Irving Langmuir, plus a Rand Project study by Dr. Lipp on the space-ship question. The report concludes no definite evidence yet proves or disproves the existence of these objects as real aircraft, judges atomic propulsion 'highly improbable,' and recommends the project be downgraded to routine intelligence work once enough incidents are solved to rule out a national-security threat.
No definite evidence is yet available to confirm or disprove the actual existence of unidentified flying objects as new and unknown types of aircraft.p.4
The objects sighted have been grouped into four classifications according to configuration: 1. Flying disks, i.e, very low aspect ratio aircraft. 2. Torpedo or cigar shaped bodies with no wings or fins visible in flight. 3. Spherical or balloon-shaped objects. 4. Balls of lightp.7
Based on experience with nuclear power plant research in this country, the existence on Earth of such engines of small enough size and weight to have powered the objects described is highly improbable.p.8
No definite and conclusive evidence is yet available that would prove or disprove the existence of these unidentified objects as real aircraft of unknown and unconventional configuration. It is unlikely that positive proof of their existence will be obtained without examination of the remains of crashed objects.p.10
The Air Weather Service has reviewed the list of incidents and has provided the information that twenty-four of them coincide, both with respect to location and time, with the release of weather balloons.p.12
Inasmuch as multiple surmises have been advanced that some of the reported observations may have represented "space ships" or satellite vehicles, a special study has been initiated with the Rand Corporation, under the Rand Project, to provide an analysis from this standpoint and also to provide fundamental information, pertaining to the basic design and performance characteristics that might distinguish a possible "space ship."p.13
Future activity on this project should be carried on at the minimum level necessary to record, summarize, and evaluate the data received on future reports and to complete the specialized investigations now in progress.p.9
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UNCLASSIFIED Technical Report No. F-TR-2[REDACTED] [REDACTED] RETURN TO [REDACTED] AFB AL 36112 K2443 6012 49/02/00 UNIDENTIFIED AERIAL OBJECTS PROJECT "SIGN" SMC AMC Release Date: February 1949 HEADQUARTERS AIR MATERIEL COMMAND WRIGHT-PATTERSON AIR FORCE BASE DAYTON, OHIO UNCLASSIFIED [REDACTED] DOWNGRADED AT 3 YEAR INTERVALS; DECLASSIFIED AFTER 12 YEARS. DOD DIR 5200.10 WP-(B)-0-9 JUL 48 10M S-11750-18 7-3745 - 1003281 - 1/4/1/ 3-10
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NOTE When drawings, specifications, and other data prepared by the War Department are furnished to manufacturers and others for use in the manufacture or purchase of supplies, or for any other pur- pose, the Government assumes no responsibility nor obligation whatever; and the furnishing of said data by the War Department is not to be regarded by implication or otherwise, or in any manner licensing the holder, or conveying any rights or permission to manufacture, use, or sell any patented inventions that may in any way be related thereto. The information furnished herewith is made available for study upon the understanding that the Government's proprietary interests in and relating thereto shall not be impaired. It is desired that the Patent & Royalties Section, Office of the Judge Advocate, Air Materiel Command, Wright Field, Dayton, Ohio, be promptly noti- fied of any apparent conflict between the Government's proprietary interests and those of others. Espionage Act Notice: This document contains information affecting the national defense of the United States within the meaning the Espionage Act (U. S. C. 50:31, 32). The transmission of this docu- ment or the revelation of its contents in any manner to an un- authorized person is prohibited by law. (AR 380-5, paragraph 17 b.) "The above Espionage Notice can be disregarded unless this document is plainly marked with a security classification as "Restricted," "Confidential," "Secret," or "Top Secret." The U. S. Government is absolved from any litigation which may ensue from the contractor's infringing on the foreign patent rights which may be involved.
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Dr. HYNEK'S EVALUATIONS EXTRACTED FROM PROJECT GRUDGE REPORT.
INCIDENT INDEX
1. Astronomical
a. High probability:
#26, 27, 30, 31, 32, 33, 34, 48, 49, 59, 60, 66, 69, 70, 94,
95, 96, 97, 98, 101, 102, 103, 104, 116, 119, 132, 136, 140,
147, 148, 158, 174, 184, 185, 187, 197, 203, 204, 208, 216,
219, 238.
b. Fair or low probability:
#15, 20, 23, 24, 28, 35, 36, 46, 50, 63, 67, 80, 82, 93, 100,
112, 120, 121, 129, 130, 144, 153, 165, 166, 167, 175, 192,
199, 202, 205, 220, 230, 240.
2. Non-astronomical but suggestive of other explanations
a. Balloons or ordinary aircraft:
#3, 11, 22, 41, 42, 53, 54, 73, 81, 83, 91, 92, 113, 114, 115,
126, 131, 138, 141, 145, 155, 156, 157, 159, 160, 161, 163,
169, 171, 173, 178, 180, 182, 188, 190, 194, 195, 196, 198,
200, 201, 209, 210, 217, 222, 235, 237, 239.
b. Rockets, flares or falling bodies:
#4, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16, 25, 56, 65, 78, 106, 107,
108, 109, 133, 170, 211, 218.
c. Miscellaneous (reflections, auroral streamers, birds, etc.):
#39, 69, 123, 124, 128, 146, 164, 181, 189, 214, 221, 231, 234.
3. Non-astronomical, with no explanation evident
a. Lack of evidence precludes explanation:
#38, 44, 45, 47, 56, 57, 72, 86, 87, 88, 90, 99, 110, 117, 118,
125, 127, 137, 139, 149, 150, 177, 179, 191, 206, 212, 213,
229, 232, 233.
b. Evidence offered suggests no explanation:
#1, 2, 10, 17, 21, 29, 37, 40, 51, 52, 58, 61, 62, 64, 68, 71,
75, 76, 77, 79, 84, 105, 111, 122, 135, 151, 152, 154, 162,
168, 172, 176, 183, 186, 193, 207, 215, 223, 224, 225, 226,
227, 236, 241, 242, 243, 244, 134.Concatenated page-by-page transcript. Born-digital pages came through pdf.js; scanned pages were transcribed by Claude vision OCR. Pages marked unreadable failed multiple OCR retries (heavy redaction, microfilm artifacts, or blank separators) and are kept in place for audit.
UNCLASSIFIED Technical Report No. F-TR-2[REDACTED] [REDACTED] RETURN TO [REDACTED] AFB AL 36112 K2443 6012 49/02/00 UNIDENTIFIED AERIAL OBJECTS PROJECT "SIGN" SMC AMC Release Date: February 1949 HEADQUARTERS AIR MATERIEL COMMAND WRIGHT-PATTERSON AIR FORCE BASE DAYTON, OHIO UNCLASSIFIED [REDACTED] DOWNGRADED AT 3 YEAR INTERVALS; DECLASSIFIED AFTER 12 YEARS. DOD DIR 5200.10 WP-(B)-0-9 JUL 48 10M S-11750-18 7-3745 - 1003281 - 1/4/1/ 3-10
NOTE When drawings, specifications, and other data prepared by the War Department are furnished to manufacturers and others for use in the manufacture or purchase of supplies, or for any other pur- pose, the Government assumes no responsibility nor obligation whatever; and the furnishing of said data by the War Department is not to be regarded by implication or otherwise, or in any manner licensing the holder, or conveying any rights or permission to manufacture, use, or sell any patented inventions that may in any way be related thereto. The information furnished herewith is made available for study upon the understanding that the Government's proprietary interests in and relating thereto shall not be impaired. It is desired that the Patent & Royalties Section, Office of the Judge Advocate, Air Materiel Command, Wright Field, Dayton, Ohio, be promptly noti- fied of any apparent conflict between the Government's proprietary interests and those of others. Espionage Act Notice: This document contains information affecting the national defense of the United States within the meaning the Espionage Act (U. S. C. 50:31, 32). The transmission of this docu- ment or the revelation of its contents in any manner to an un- authorized person is prohibited by law. (AR 380-5, paragraph 17 b.) "The above Espionage Notice can be disregarded unless this document is plainly marked with a security classification as "Restricted," "Confidential," "Secret," or "Top Secret." The U. S. Government is absolved from any litigation which may ensue from the contractor's infringing on the foreign patent rights which may be involved.
UNCLASSIFIED Technical Report No. F-TR-2274-IA UNIDENTIFIED AERIAL OBJECTS PROJECT "SIGN" L. H. Truettner A. B. Deyarmond (Project No. XS-304) Approved by: [signature] W. R. Clingerman, Colonel, USAF Chief, Technical Intelligence Division Intelligence Department For the Commanding General: [signature] Col USAF H. M. McCoy, Colonel, USAF Chief, Intelligence Department Published by Technical Intelligence Division Intelligence Department, Air Materiel Command Wright-Patterson Air Force Base, Dayton, Ohio UNCLASSIFIED [REDACTED] Release Date: February 1949 S-11750 DOWNGRADED AT 3 YEAR INTERVALS; DECLASSIFIED AFTER 12 YEARS. DOD DIR 5200.10
ABSTRACT UNCLASSIFIED A descriptive and analytical study of the unidentified aerial objects, that have been reported both in the United States and from foreign countries, is presented. Individual cases are described in brief form, as an appendix. The analytical treatment of the subject is largely of a qualitative and generalized nature. However, detailed analyses and detailed results are presented, where this procedure is possi- ble and will assist in establishing the validity or tenability of an overall hypothesis. Project "Sign" is still largely characterized by the collec- tion of data, without sufficient information to permit definite, specific conclusions to be made. No definite evidence is yet available to confirm or disprove the actual existence of uniden- tified flying objects as new and unknown types of aircraft. A limited number of the incidents have been identified as known ob- jects. UNCLASSIFIED S-11750
UNCLASSIFIED FOREWORD Project "Sign" was initiated by the Technical Intelligence Division, Air Materiel Command, and assigned Project Number XS-304, 22 January 1948, under authority of a letter from the Deputy Chief of Staff, Materiel, USAF. This letter is referenced C/S, USAF, 30 December 1947, subject "Flying Disks." Assistance in analyzing the reported observations has been provided by other Divisions of Air Materiel Command in accordance with Technical Instructions TI-2185, Addendum No. 3, dtd 11 Febru- ary 1948, subject: "Project Sign" - Evaluation of Unidentified Flying Objects". Analysis of the reported incidents, as an effort to identify astro-physical phenomena, is being accomplished by Ohio State University under contract with Air Materiel Command. A special study has been initiated with the Rand Project in accordance with Air Corps Letter No. 80-10 dtd 21 July 1948 to present information that would serve to evaluate the remote possi- bility that some of the observed objects may be space ships or satellite vehicles. Members of the Scientific Advisory Board to the Chief of Staff, USAF, have also supplied their services in a consulting capacity. 11 UNCLASSIFIED [REDACTED] S-11750
UNCLASSIFIED INTRODUCTION This report is written to present the status of work being accomplished on Project "Sign", to summarize the data collected on sightings of unidentified aerial objects, to review the methods and reasoning applied in the evaluation of the data, and to pre- sent the results so far obtained from the study of data available. It is not expected that this report can present a final es- timate of the situation regarding all the incidents reported. The data is still being studied by specialists in the fields of astrophysics and psychology, and further information is being col- lected to enable personnel evaluating project "Sign" incidents to determine possible explanations of some of the sightings. How- ever, the report will furnish information on the present state of the investigation to staff personnel in this headquarters and in higher echelons, and to others who are required to assess the possibility of a threat to national security presented by the sighting of such large numbers of unidentified flying objects. 111 UNCLASSIFIED [REDACTED] S-11750
UNCLASSIFIED SUMMARY The results of the study reviewed in this report are based on data derived from reports of 243 domestic and thirty (30) foreign incidents. Data from these incidents is being summarized, repro- duced and distributed to agencies and individuals cooperating in the analysis and evaluation. Distribution has so far been accom- plished on the summaries of [illegible] incidents and more are in process of reproduction at this time. A check list of items to be noted in reporting incidents has been prepared and distributed to government investigative agencies. The data obtained in reports received are studied in relation to many factors such as guided missile research activity, weather and other atmospheric sounding balloon launchings, commercial and mili- tary aircraft flights, flights of migratory birds, and other con- siderations, to determine possible explanations for sightings. Based on the possibility that the objects are really uniden- tified and unconventional types of aircraft a technical analysis is made of some of the reports to determine the aerodynamic, pro- pulsion, and control features that would be required for the object to perform as described in the reports. The objects sighted have been grouped into four classifications according to configuration: 1. Flying disks, i.e., very low aspect ratio aircraft. 2. Torpedo or cigar shaped bodies with no wings or fins visible in flight. 3. Spherical or balloon-shaped objects. 4. Balls of light The first three groups are capable of flight by aerodynamic or aerostatic means and can be propelled and controlled by methods known to aeronautical designers. The fourth appears to have no physical form attached, but the means of support may not have been seen by the observer. Approximately Twenty ten percent of the incidents have been identi- fied as conventional aerial objects to the satisfaction of person- nel assigned to Project "Sign" in this Command. It is expected that a study of the incidents in relation to weather and other at- mospheric sounding balloons will provide solutions for an equiva- lent number. Verbal statements by an astro-physicist at Ohio State University and by psychologists of the Aero-Medical Laboratory of this Command, indicate the possibility of solving an appreciable number of the sightings as a result of their investigations. Elim- ination of incidents with reasonably satisfactory explanations will clarify the problem presented by a project of this nature. UNCLASSIFIED
UNCLASSIFIED The possibility that some of the incidents may represent technical developments far in advance of knowledge available to engineers and scientists of this country has been considered. No facts are available to personnel at this Command that will permit an objective assessment of this possibility. All infor- mation so far presented on the possible existence of space ships from another planet or of aircraft propelled by an advanced type of atomic power plant have been largely conjecture. Based on experience with nuclear power plant research in this country, the existence on Earth of such engines of small enough size and weight to have powered the objects described is highly improbable. Reports of unidentified flying objects are not peculiar to the present time. In, "The Books of Charles Fort" by Tiffany Tay- lor, published in 1941 by Henry Holts & Co., New York, similar phenomena are described as having been sighted during past cen- turies. In the last war, numerous sightings of "balls of fire" in the air were reported by bomber crews. UNCLASSIFIED
UNCLASSIFIED RECOMMENDATIONS Future activity on this project should be carried on at the minimum level necessary to record, summarize, and evaluate the data received on future reports and to complete the specialized investigations now in progress. When and if a sufficient number of incidents are solved to indicate that these sightings do not represent a threat to the security of the nation, the assignment of special project status to the activity could be terminated. Future investigations of reports would then be handled on a routine basis like any other intelligence work. Reporting agencies should be impressed with the necessity for getting more factual evidence on sightings, such as photographs, physical evidence, radar sightings, and data on size and shape. Personnel sighting such objects should engage the assistance of others, when possible, to get more definite data. For example, military pilots should notify neighboring bases by radio of the presence and direction of flight of an unidentified object so that other observers, in flight or on the ground, could assist in its identification. vii UNCLASSIFIED [REDACTED] [REDACTED]
UNCLASSIFIED CONCLUSIONS No definite and conclusive evidence is yet available that would prove or disprove the existence of these unidentified objects as real aircraft of unknown and unconventional configuration. It is unlikely that positive proof of their existence will be ob- tained without examination of the remains of crashed objects. Proof of non-existence is equally impossible to obtain unless a reasonable and convincing explanation is determined for each incident. Many sightings by qualified and apparently reliable witnesses have been reported. However, each incident has unsatisfactory features, such as shortness of time under observation, distance from observer, vagueness of description or photographs, inconsis- tencies between individual observers, and lack of descriptive data, that prevents definite conclusions being drawn. Explanations, of some of the incidents revealed the existence of simple and easily understandable causes, so that there is the possibility that enough incidents can be solved to eliminate or greatly reduce the mystery associated with these occurrences. Evaluation of reports of unidentified objects is a necessary activity of military intelligence agencies. Such sightings are inevitable, and under wartime conditions rapid and convincing solu- tions of such occurrences are necessary to maintain morale of military and civilian personnel. In this respect, it is considered that the establishment of procedures and training of personnel is in itself worth the effort expended on this project. vi UNCL[ILLEGIBLE] [REDACTED]
UNCLASSIFIED
DISCUSSION
Organization of Data on Incidents
Approximately 243 domestic incidents have been reviewed,
at the present time. In each incident, the observers have been
interrogated by investigators and the results have been analyzed
by technical personnel.
Condensed summaries have been prepared for the list of in-
cidents in sufficient quantity to make the basic information
easily available to individuals or agencies having an authority
or an interest in the project. (See Appendix A).
A detailed check list, compiled by technical personnel, in-
dicating the basic elements of information, necessary for analysis
of the individual incident, has been prepared and distributed
to appropriate government agencies.
In order to identify ordinary and conventional objects, that
have probably been included in the list of reported incidents,
graphical methods have been applied, so as to present the basic
data in such form that overall facts, implicit in the grouped data,
will be made apparent. (See Appendix B).
The prepared graphical data includes:
(a) Charts concerning unidentified aerial objects, to indi-
cate:
1. Type of object observed
2. Vicinity in which particular type of object was ob-
served
3. Direction of flight
(b) Locations of guided missiles, research and related
centers
(c) Locations of airlines, airfields, both military and
commercial.
(d) Locations of radio beacon stations
(e) Known or projected radar stations from which reports
and assistance may be derived
(f) Meteorological stations from which balloon release data,
radiosonde or theodolite readings may be obtained
(g) Past, current, and projected celestial phenomena
(h) Flight paths of migratory birds
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S-11750UNCLASSIFIED Psychological Analysis A psychological analysis of the reported data is being pre- pared by Aero-Medical Laboratory, A.M.C., for the purpose of de- termining those incidents that are probably based upon errors of the human mind and senses. A preliminary verbal report from the professional psychologists indicates that a considerable number of incidents can be explained as ordinary occurrences that have been misrepresented, as the result of human errors. The condition of "vertigo", well known to airplane pilots, as well as others, is considered to be an important factor in some of the reported incidents. "Vertigo" is defined from a medical viewpoint by Webster's Dictionary as "Dizziness or swim- ming of the head; a disturbance in which objects, though stationary, appear to move in various directions, and the person affected finds it difficult to maintain an erect posture. It may result from changes in the blood supply of the brain or from disease of the blood, eyes, ears, stomach, or other organs." Accelerations, resulting from airplane maneuvers, together with space-orientation difficulties at night in an airplane, due to the lack of or strangeness of visual references, makes a condition of "vertigo" more likely to appear in personnel in night-flying aircraft than under more normal conditions. The fact that both pilot and co-pilot may report the same impressions is not complete proof of accuracy, since both individuals have experienced the same maneuvers and accelerations and have viewed the same lights and surroundings under the same optical conditions (including the same windshield and canopy glass). A more complete discussion of psychological factors is expected to be provided in a future status report. Quite probably, some of the incidents of fast, highly maneuvering "lights", reported by both air and ground observers, are the result of "vertigo" or optical illusions. Strictly speaking, no engineering analysis of an incident should be initiated until the psychological analysis has been made and has shown that psychological factors cannot explain the observation. Agencies, Outside Air Materiel Command, Supplying Information and Analysis Specialist services, supplementary to those of Air Materiel Command technical offices, are being provided by a number of agen- cies. The Air Weather Service has reviewed the list of incidents and has provided the information that twenty-four of them coincide, both with respect to location and time, with the release of weather balloons. - 2 - UNCLASSIFIED S-11750
UNCLASSIFIED The Ohio State University has contracted with Air Materiel Command to supply astronomical services in an effort to identify meteors, planetoids and associated phenomena. Professor Hynek, Ohio State University Astro-Physicist and head of the University Observatory has undertaken to review the incident summary sheets. While this work has not yet been completed, Professor Hynek has reported verbally that he is satisfied that a number of the re- ported observations represent astro-physical phenomena. Members of the Scientific Advisory Board to the Chief of Staff, USAF, who have provided consultant services to Project "Sign", include Dr. Irving Langmuir, Chief, General Electric Research and Dr. G. E. Valley of MIT. A preliminary type of interview has been held between Dr. Langmuir and personnel of Project "Sign" during early stages of the project. It is intended to consult further with Dr. Langmuir in an effort to supplement present technical efforts toward iden- tifying the reported objects. Dr. G. E. Valley has displayed an active interest in Project "Sign", to the extent of reviewing the reported incidents and writing an overall type of analysis in which he groups the various objects and then analyzes each group from the standpoint of scien- tific feasibility. This analysis is provided as Appendix (C) to this report. Inasmuch as various surmises have been advanced that some of the reported observations may have represented "space ships" or satellite vehicles, a special study has been initiated with the Rand Corporation, under the Rand Project, to provide an analysis from this standpoint and also to provide fundamental information, pertaining to the basic design and performance characteristics that might distinguish a possible "space ship." As a preliminary undertaking, the Rand Project has submitted a study by Dr. Lipp in which the possibility is explored of any planet in the known universe being in a physical and cultural position to allow the development and use of the "space ship". This study has been prepared in the form of a report that is pre- sented as Appendix (D). The Weather Bureau Library of the Department of Commerce has supplied information on "ball lightning". This was requested be- cause of the belief by some persons that some of the observations may have represented "ball lightning". It appears that the sub- ject of "ball lightning" occupies an undetermined status and authorities are not at all convinced that such a phenomena actually exists. The Federal Bureau of Investigation has assisted Project "Sign" in a number of instances, both by investigations of the character and reliability of witnesses of incidents and by providing other investigative services. - 3 - UNCLASSIFIED S-11750
UNCLASSIFIED
Considerations Affecting Analysis and Evaluation
OPERATIONAL
Inasmuch as there is a distinct possibility that a number
of the reported incidents represent domestic projects of a secur-
ity-classified nature, the list of incidents has been submitted
to higher echelons for review.
Since weather balloons, blimps, airplanes of unusual size
or configuration, and guided missiles test vehicles may represent
some of the observations, action has been taken to obtain informa-
tion, concerning schedules and flights of such craft from the
appropriate agencies.
In connection with the psychological studies being performed,
extensive investigations, concerning the character and reliability
of the reporting witnesses have been made.
TECHNICAL
A certain proportion of incidents appear to be real aircraft,
though of unconventional configuration. In order to investigate
the credibility of their existence the following factors must be
considered in any technical analysis.
Aircraft
Method of Support (lift)
Wings
Fuselage Lift (Wingless)
Rotor
Vertical Jet
Magnus Effect (rotating cylinder, cone or sphere, sub-
jected to relative translational air velocity)
Aerostatic (lighter-than-air craft)
Method of Propulsion (Thrust)
Propeller-reciprocating engine combination
Jet, rocket, ramjet (utilizing conventional fuels and
oxidants or possibly atomic energy)
Marodynamic (Katzmayer Effect - oscillating airfoils
developing negative drag (thrust)
If an atomic energy powered engine were available, a small
mass flow at a large velocity would accomplish the required lift
and propulsive forces and the large energy expenditure would
be of small importance.
However, the heat exchange requirements for the atomic-
powered engine appear to demand physical dimensions of inordinate
size that presently would [ILLEGIBLE] the use of this powerplant
for aircraft.
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S-11750UNCLASSIFIED
In addition, manned aircraft would require an excessive
percent weight of shielding for human protection, unless configura-
tions of extremely large size were used. If unshielded craft
were in operation, existing detection means would probably have
indicated their presence.
Metallurgical limitations to date, limit the rate of con-
verting the heat energy of the atomic source to useful propulsive
work to such an ineffective order of magnitude that such a power
system is quite unlikely from the standpoint of size and weight.
Stability
Aerodynamic (both static and dynamic through the use of
aerodynamic surfaces and weight distribution).
Servo-mechanism (gyro or accelerometer - servomotor system)
Control
Movable surfaces in airflow or jet
Jet (flow control or swiveling types).
Possible Spaceships
World knowledge, techniques, and resources are considered
to be presently adequate for the development of spaceships.
Distinguishing design and performance parameters are ex-
pected to be supplied as a special study by the Rand Project.
Probable Natural Phenomena
Astrophysical (meteors, comets, planetoids, etc.)
Astrophysical analysis is expected to be performed by
personnel of Ohio State University Research Foundation.
Electromagnetic (ball lightning, St. Elmo's Fire, Phos-
phorescence, corona, etc.).
Ordnance Items
While this analysis considers the reported objects largely
from the standpoint of aircraft with requirements for speed and
substantial duration of flight and range, it is entirely possible
that the configurations reported in small sizes could serve as
very useful ordnance items to take the place of (or supplement)
such short-range weapons of ground (infantry) warfare as the trench
mortar, hand grenade, etc. The small saucer-like, spinning,
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UNCLASSIFIEDUNCLASSIFIED
disks, reportedly under development by the USSR with the aid of
German Scientists, having explosive edges and launched by a com-
pressed air catapult, (perhaps in the manner of clay pigeons pro-
jected by a trap mechanism) could possibly be ordnance articles.
Also, such devices could be used by aircraft in attacking enemy
airplane formations. In such cases, only a modest speed, short
range, and limited flight duration would be required, hence the
aerodynamic efficiency of the design would not be of very much
importance.
Insufficient Information for Even 'Possible or Hypothetical
Type Determination'.
Discredited Reports
Erroneous (See Discussion, Psychological Errors)
False
Technical Analysis of Various Configurations
The extreme lack of data for each of the incidents that have
been reported makes it presently impossible to accurately identify
any of the reported craft with respect to design and performance.
Technical analysis must be made by considering possibilities and
probabilities, which are expected to be proved or disproved only
when complete data or physical specimens of aircraft (crash) are
available. Unidentified aerial objects appear to be grouped as
follows:
(1) Flying disks (saucers)
(2) Torpedo or Cigar Shaped Bodies (no wings or fins visible
in flight)
(3) Spherical or Balloon-Shape Objects (capable of hov[ILLEGIBLE],
descending, ascending or travelling at high speed).
(4) Balls of light (no apparent physical form attached).
Capable of maneuvering, climbing, and travelling at high
speed.
The first three groups of objects are capable of flight
through the atmosphere by means of aerodynamic and propulsion de-
signs (to produce the required lift and thrust) that are readily
conceivable by aeronautical designers. The stabilizing and con-
trol features that would be required, while more obscure, could
conceivably be provided. The question arises, however, as to
whether these configurations would develop much speed and allow
a sufficient duration of flight and adequate range to be of prac-
tical use as aircraft.
Flying Disks
The disk or circular planform has not been used in represen-
tative aircraft, either military or civilian, for the reason that
the induced drag, as determined by the Prandtl theory of l[ILLEGIBLE]t, would
- 6 - UNCLASSIFIED
S-11750UNCLASSIFIED apparently be excessively high, since the aspect ratio of a cir- cular planform is only 1.27. Extension of the Prandtl theory, has also shown that the maximum possible lift coefficient to be expected from such low aspect ratio planforms should also be poor. In addition, the relatively large mean aerodynamic chord would present difficult design problems, to achieve static longi- tudinal stability for airfoil sections having a significant center- of-pressure travel, or for airfoil sections of so-called "stable" type, when equipped with ailerons at the trailing edge. In the very low aspect ratio range, the Prandtl theory is probably very inaccurate. Wind-tunnel tests of very low aspect ratio airfoils indicate much less induced drag increase than ex- pected from theory and can also demonstrate very high maximum lift coefficient accompanied by extremely high stalling angles. How- ever, in general the induced drag of very low aspect ratio wings is much larger than the induced drag of conventional aircraft wings, a condition which would adversely affect all performance values in flight conditions which require medium and high lift coefficients. Thus, performance in climb, at altitude, and for long-range conditions would be relatively poor, although high speed would be little affected. Notwithstanding the predicted aerodynamic disadvantages of circular planform wings, quite a number of experimental efforts have been made to use this configuration - and not all of them by persons ignorant of aerodynamic fundamentals. Experimental wind-tunnel work at the NACA (1933) showed both maximum lift co- efficients and stall characteristics much more favorable than could be anticipated. The problem of static longitudinal stability could possibly, be solved by the use of a stable airfoil section of the reflexed trailing edge type with wing tip ailerons (perhaps floating) aero- dynamically independent of the wing. At supersonic speeds, where the induced drag is small, the circular planform offers the probability of reduced drag, characteristic of low aspect ratio airfoils in the supersonic range. Also the circular planform presents a swept-back leading edge (of variable sweep along the span), which should result in a reduced effective Mach Number, with attendant reduced drag for a certain supersonic speed range. No definite information has been received on the method of propulsion used on flying disks which have been sighted. However, because of distance factors involved in the sightings it is quite possible that either propellers or jet propulsion could have been employed without being noted by the observer. Flying Fuselages (Torpedo or Cigar-Shaped Body) While the cigar or torpedo-shaped body represents an efficient form for the fuselage of an airplane or the body of a guided missile, - 7 - UNCLASSIFIED S-11750
UNCLASSIFIED in neither case has it been used as a primary lift-producing sur- face. However, an extension of the Prandtl theory of lift indi- cates that a fuselage of the dimensions reported by the Eastern Airlines pilots Whited and Chiles in the Montgomery, Alabama, in- cident could support a load comparable to the weight of an aircraft of this size at flying speeds in the subsonic range. The Prandtl theory probably gives very conservative values of maximum lift for bodies of this shape. German experience indicates that the maximum lift may be twice as high as that given by the theory. Although the craft sighted by Whited and Chiles was reported to be without wings and fins, it is possible that it could have been equipped with extensible wings for take-off and landing, contained within the fuselage in cruising flight. This type of aircraft could also be partially supported in the take-off and landing condition by the vertical component of the jet thrust, if the landing and take-off took place with the fuselage axis, or the jet stream direction in a vertical or nearly vertical altitude. The further possibility that an extensible rotor, concealed within the fuselage, could have been used, would provide another method for landing and take-off that would allow wingless flight at very high speed. Such a design could result in a relatively large duration of flight and corresponding range. While no stabilizing fins were apparent on the "flying fuse- lage" reported by Whited and Chiles, it is possible that vanes within the jet, operated by a gyro-servo system could have pro- vided static stability, longitudinally, directionally and laterally. The same vanes could also have been used for accomplishing static balance or trim, as well as control for maneuvering. The above discussion regarding weight, controllability, sta- bility, etc. is not intended to represent deductions regarding the exact nature of the torpedo or cigar-shaped aircraft which were sighted by the airline pilots, Whited and Chiles, and others. They are merely statements of possibilities, which are intended to show that such an aircraft could support and control itself by aerodynamic means. The propulsive system of this type of vehicle would appear to be a jet or rocket engine. The specific fuel consumption of engines to this type would be rather high. This, coupled with the fact that aerodynamic lift on such a body would be accompanied by high drag, places a serious limitation on the range of this air- craft for any particular gross weight. If this type of unidenti- fied aerial object has extremely long range, it is probable that the method of propulsion is one which is far in advance of presently known engines. Round Objects (Spherical- and Balloon-Shaped Objects) Spherical or balloon-shaped objects, are not usually considered as efficient aircraft. Not only would the drag of such bodies be high, but the energy expenditure that would be required to develop lift by aerodynamic means would be excessive. The only conceivable - 8 - UNCLASSIFIED S-11750
UNCLASSIFIED means of producing lift for such a body, other than by aerostatic (simple buoyancy) means, would be by rotation of the sphere with translational motion relative to the air; or by discharging a stream of air vertically downward. Aerodynamic flight could be accomplished with a rotating sphere, provided the detailed design problems, including stability and control were worked out. The methods, using a blower system or jets, would require relatively greater amounts of energy and while they could be used for flights of very short range and duration, would not ordinarily be con- sidered as practical by aeronautical designers. The obvious explanation for most of the spherical shaped objects is that they are meteorological or similar type balloons. This, however, does not explain reports that they travel at high speed or maneuver rapidly. It is possible that the movement of the objects was some kind of an optical illusion, or that movement for a brief period due to a gas leak in the balloon was exaggerated by observers. Balls of Light No reasonable hypothesis of the true nature of balls of light, such as that reported by Lt. German at Fargo, N. Dakota, has been developed that explains the behavior reported. The most reason- able explanation is that the lights were suspended from balloons, or other means of support, not visible at night, and the violent maneuvers reported are due to illusion. Possibility of Scientific Developments in Advance of Knowledge In this Country. Consideration has been given to the possibility that these unidentified aircraft represent scientific developments beyond the level of knowledge attained in this country. Since this is probably the most advanced of the industrial nations on the earth, and our interest in scientific developments throughout the world is very active, it would be necessary for any other country to conduct research and development work in extreme secrecy for any such project to have reached such an advanced state of development without a hint of its existence becoming known here. The only nation on earth with extensive technical resources which has such rigid security, is the U.S.S.R. An objective evaluation of the ability of the Soviets to produce technical developments so far in advance of the rest of the world results in the conclusion that the possibility is extremely remote. Most of the successful Soviet aeronautical developments have been produced by utilizing experience of other nations, some of them being very close copies, so it is very unlikely that they have developed the propulsion and control devices necessary to make these objects perform as described. Another possibility is that these aerial objects are visitors from another planet. Little is known of the probabilities of life on other planets, so there is no basis on which to judge the possibility that civilizations far in advance of ours exist outside the earth. The commentary on this possibility by Dr. James Lipp of the Rand Project in Appendix D, indicates that this solution of the mystery connected with the sighting of unidentified flying - 9 - UNCLASSIFIED S-11750
UNCLASSIFIED objects is extremely improbable. Pending elimination of all other solutions or definite proof of the nature of these objects, this possibility will not be further explored. - 10 - S-11750 UNCLASSIFIED
UNCLASSIFIED to produce any physical effects, other than the one case in which a cloud was evaporated along the trajectory, it is not certain that the laws of mechanics, for instance, would be sufficient. But suppose that mechanical laws alone are sufficient, then the following example is sufficient proof that at least a length could, in principle, be determined: suppose a simple pendulum were observed suspended in the sky; then after ob- serving its frequency of oscillation, we could deduce from the laws of mechanics its precise length. This suggests that something could be deduced from the observed fluttering motion of some of the objects of Group 1. Assume that we know the angular frequency and angular ampli- tude of this fluttering motion (they can be measured in prin- ciple from a motion picture). Then for purposes of calculation, assume the object to be thirty feet in diameter, to be as rigid as a normal aircraft wing of 30-foot span, to be constructed of material of the optimum weight-strength ratio and to be a structure of most efficient design. It is now possible to cal- culate how heavy the object must be merely to remain rigid under the observed angular motion. Let the calculation be made for a plurality of assumed sizes 1, 2, 4, 8, 16, 32, 64 ---- up to say 200 feet, and let calculated mass be plotted versus assumed size. The non-linear character of the curve should indicate an approximate upper limit to the size of the object. If, in addition, it is assumed that the flutter is due to aerodynamic forces, it is possible that more precise informa- tion could be obtained. The required angular data can probably be extracted from witnesses most reliably by the use of a demonstration model which can be made to oscillate or flutter in a known way. Summary -- PART II, Section A Geometrical calculations alone cannot yield the size of objects observed from a single station; such observation to- gether with the assumption that the objects are essentially aircraft, can be used to set reasonable limits of size. Section B -- The possibility of supporting and propel- ling a solid object by unusual means. Since some observers have obviously colored their reports with talk of rays, jets, beams, space-ships, and the like, it is well to examine what possibilities exist along these lines. This is also important in view of the conclusions of PART II, Section A, of this report. UNCLASSIFIED S-11750 21
UNCLASSIFIED Method I -- Propulsion and support by means of "rays" or "beams". By "rays" or "beams" are meant either purely electro- magnetic radiation or else radiation which is largely corpuscular like cathode-rays or cosmic-rays or cyclotron- beams. Now, it is obvious that any device propelled or supported by such means is fundamentally a reaction device. It is fund- amental in the theory of such devices that a given amount of energy is most efficiently spent if the momentum thrown back or down is large. This means that a large mass should be given a small acceleration -- a theorem well understood by helicopter designers. The beams or rays mentioned do the contrary, a small mass is given a very high velocity, consequently enormous powers, greater than the total world's power capacity, would be needed to support even the smallest object by such means. Method II -- Direct use of Earth's Magnetic Field One observer (incident 68) noticed a violent motion of a hand-held compass. If we assume from this that the objects produced a magnetic field, comparable with the Earth's field; namely, 0.1 gauss, and that the observer found that the object subtended an angle 9 at his position, then the ampere-turns of the required electromagnet is given by: ni = 30R/θ² where R is the range of the object. For instance, if R is one kilometer and the object is 10 meters in diameter, then ni ≠ 1 billion ampere-turns. Now, if the object were actually only 10 meters away and were correspondingly smaller; namely, 10 cm in diameter, it would still require 10 million ampere-turns. These figures are a little in excess of what can be con- veniently done on the ground. They make it seem unlikely that the effect was actually observed. Now, the Earth's magnetic field would react on such a magnet to produce not only a torque but also a force. This force depends not directly on the Earth's field intensity but on its irregularity or gradient. This force is obviously minute since the change in field over a distance of 10 meters (assumed diameter of the object) is scarcely measureable, moreover the gradient is not predictable but changes due to local ore deposits. Thus, even if the effect were large enough to use, it would still be unreliable and unpredictable. S-11750 UNCLASSIFIED 22
UNCLASSIFIED · Method III -- Support of an electrically charged object by causing it to move transverse to the Earth's magnetic field A positively charged body moving from west to east, or a negatively charged body moving from East to West will experience an upward force due to the Earth's magnetic field. A sphere 10 meters diameter moving at a speed of one kilo- meter/second would experience an upward force of one pound at the equator if charged to a potential of 5 x 10¹² volts. This is obviously ridiculous. Section D -- The anti gravity shield It has been proposed, by various writers, perhaps first by H. G. Wells, that it might be possible to construct a means of shielding a massive body from the influence of gravity. Such an object would then float. Recently, there appeared in the press a notice that a prominent economist has offered to support re- search on such an enterprise. Obviously, conservation of energy demands that considerable energy be given the supported object in order to place it on the shield. However, this amount of energy is in no way prohibitive, and furthermore it can be gotten back when the object lands. Aside from the fact that we have no suggestions as to how such a device is to be made, the various theories of general relativity all agree in assuming that gravitational force and force due to acceleration are indistinguishable, and from this assumption the theories predict certain effects which are in fact observed. The assumption, therefore, is probably correct, and a corollary of it is essentially that only by means of an acceler- ation can gravity be counteracted. This, we can successfully do for instance by making an artificial satellite, but this pre- sumably is not what has been observed. Summary -- PART II, Section B Several unorthodox means of supporting or propelling a solid object have been considered, all are impracticable. This finding lends credence to the tentative proposed assumption of Part II, that the objects are supported and propelled by some normal means, or else that they are not solids. No discussion of the type of Part II, Section B, can, in principle, of course, be complete. Section C -- Possible causes for the reports. Classification I -- Natural terrestrial phenomena 1. The observations may be due to some effect such as UNCLASSIFIED S-11750 23
UNCLASSIFIED ball lightning. The writer has no suggestions on this essen- tially meteorological subject. 2. The objects may be some kind of animal. Even in the celebrated case of incident 172 where the light was chased by a P51 for half an hour and which was reported by the pilot to be intelligently directed, we can make this remark. For considering that an intelligence capable of making so remarkable a device would not be likely to play around in so idle a manner as described by the pilot. In this connection, it would be well to examine if some of the lights observed at night were not fire-flies. 3. The observed objects may be hallucinatory or psy- chological in origin. It is of prime importance to study this possibility because we can learn from it something of the character of the population: its response under attack; and also something about the reliability of visual observation. One would like to assume that the positions held by many of the reported observers guarantee their observations. Unfortunately, there were many reports of curious phenomena by pilots during the war -- the incident of the fire-ball fighters comes to mind. Further, mariners have been reporting sea- serpents for hundreds of years yet no one has yet produced a photograph. It would be interesting to tabulate the responses to see how reliable were the reports on the Japanese balloons during the war. There we had a phenomenon proven to be real. It is interesting that the reports swiftly reach a maximum frequency during the end of June 1947 and then slowly taper off. We can assume that this is actually an indication of how many objects were actually about, or, quite differently, we can take this frequency curve as indicating something about mass psychology. This point can be tested. Suppose the population is momentarily excited; how does the frequency of reports vary with time? A study of crank letters received after the recent publicity given to the satellite program should give the required frequency distribution. It is probably necessary but certainly not suffi- cient that the unidentified-object curve and the crank-letter curve should be similar in order for the flying disks to be classed as hallucinations. UNCLASS[ILLEGIBLE] S-11750 24
UNCLASSIFIED A large-scale experiment was made at the time of Orson Welles' "Martian" broadcast. Some records of this must persist in newspaper files. Classification II -- Man-made terrestrial phenomena 1. The objects may be Russian aircraft. If this were so, then the considerations of Sections A and B indicate that we would have plenty to worry about. It is the author's opin- ion that only an accidental discovery of a degree of novelty never before achieved could suffice to explain such devices. It is doubtful whether a potential enemy would arouse our curiosity in so idle a fashion. Classification III -- Extra terrestrial objects 1. Meteors: It is noteworthy that the British physicist Lovell writing in "Physics Today" mentions the radar discovery of a new daytime meteorite stream which reached its maximum during June 1947. The reported objects lose little of their interest, however, if they are of meteoritic origin. 2. Animals: Although the objects as described act more like animals than anything else, there are few reliable reports on extra-terrestrial animals. 3. Space Ships: The following considerations pertain: a. If there is an extra terrestrial civilization which can make such objects as are reported then it is most probable that its development is far in advance of ours. This argument can be supported on probability arguments alone without recourse to astronomical hypotheses. b. Such a civilization might observe that on Earth we now have atomic bombs and are fast developing rockets. In view of the past history of mankind, they should be alarmed. We should, therefore, expect at this time above all to behold such visitations. Since the acts of mankind most easily observed from a distance are A-bomb explosions we should expect some relation to obtain between the time of A-bomb explosions, the time at which the space-ships are seen, and the time required for such ships to arrive from and return to home-base. PART III -- RECOMMENDATIONS 1. The file should be continued. 2. A meteorologist should compute the approximate energy S-11750 25 UNCLASSIFIED
UNCLASSIFIED required to evaporate as much cloud as shown in the incident 26 photographs. Together with an aerodynamicist he should examine whether a meteorite of unusual shape could move as observed. 3. The calculations suggested in Part II, Section A, should be estimated by an aerodynamicist with such changes as his more detailed knowledge may suggest. 4. The mass-psychology studies outlined in Part II, Section C, Classification I 3 should be carried out by a com- petent staff of statisticians and mass-psychologists. 5. Interviewing agents should carry objects or moving pictures for comparison with reporter's memories. These devices should be properly designed by a psychologist exper- ienced in problems pertaining to aircraft and design of air- craft-control equipment so that he shall have some grasp of what it is that is to be found out. If the Air Force has reason to be seriously interested in these reports, it should take immediate steps to interrogate the reporters more pre- cisely. 6. A person skilled in the optics of the eye and of the atmosphere should investigate the particular point that several reports agree in describing the objects as being about ten times as wide as they are thick; the point being to see if there is a plurality of actual shapes which appear so, under conditions approaching limiting resolution or detectable con- trast. UNCLASSIFIED S-11750 26
UNCLASSIFIED APPENDIX "D" 13 December 1948 AI-1009 Brigadier General Putt United States Air Force Director of Research and Development Office, Deputy Chief of Staff, Materiel Washington 25, D. C. Dear General Putt: Please refer to your letter of 18 November 1948 relative to the "flying object" problem and to Mr. Collbohm's reply dated 24 November 1948. In paragraph (b) of the reply, Mr. Collbohm promised (among other things) to send a discussion of the "special design and performance characteristics that are believed to distinguish space ships." This present letter gives, in very general terms, a description of the likelihood of a visit from other worlds as an engineering problem and some points regarding the use of space vehicles as compared with descriptions of the flying objects. Mr. Collbohm will deliver copies to Colonel McCoy at Wright-Patterson Air Base during the RAND briefing there within the next few days. A good beginning is to discuss some possible places of origin of visiting space ships. Astronomers are largely in agreement that only one member of the Solar system (besides Earth) can support higher forms of life. It is the planet Mars. Even Mars appears quite desolate and inhospitable so that a race would be more occupied with survival than we are on Earth. Reference 1 gives adequate descriptions of conditions on the various planets and satellites. A quotation from Ref. 1 (p. 229) can well be included here. "Whether intelligent beings exist to appreciate these splendors of the Martian landscape is pure speculation. If we have correctly reconstructed the history of Mars, there is little reason to believe that the life processes may not have followed a course similar to terrestrial evolution. With this assumption, three general possi- bilities emerge. Intelligent beings may have protected themselves against the excessively slow loss of atmos- phere, oxygen and water, by constructing homes and cities* with the physical conditions scientifically con- *"Not too large or they might be visible. Perhaps underground, where the atmospheric pressure would be greater and where the temperature extremes would be reduced." S-11759 27 UNCLASSIFIED
UNCLASSIFIED trolled. As a second possibility, evolution may have developed a being who can withstand the rigors of the Martian climate. Or the race may have perished. "These possibilities have been sufficiently expanded in the pseudo-scientific literature to make further amplifi- cation superfluous. However, there may exist some interest- ing restrictions to the anatomy and physiology of a Martian. Rarity of the atmosphere, for example, may require a com- pletely altered respiratory system for warm-blooded creatures. If the atmospheric pressure is much below the vapor pressure of water at the body temperature of the individual, the process of breathing with our type of lungs becomes impossible. On Mars the critical pressure for a body temperature of 98.6F. occurs when a column of the atmosphere contains one sixth the mass of a similar column on the Earth. For a body temperature of 77°F. the critical mass ratio is reduced to about one twelfth, and at 60°F. to about one twenty-fourth. These critical values are of the same order as the values estimated for the Martian atmosphere. Accordingly the anatomy and phys- iology of a Martian may be radically different from ours - but this is all conjecture. "We do not know the origin of life, even on the Earth. We are unable to observe any signs of intelligent life on Mars. The reader may form his own opinion. If he believes that the life force is universal and that intelligent beings may have once developed on Mars, he has only to imagine that they persisted for countless generations in a rare atmosphere which is nearly devoid of oxygen and water, and on a planet where the nights are much colder than our arctic winters. The ex- istence of intelligent life on Mars is not impossible but it is completely unproven." It is not too unreasonable to go a step further and consider Venus as a possible home for intelligent life. The atmosphere, to be sure, apparently consists mostly of carbon dioxide with deep clouds of formaldehyde droplets, and there seems to be little or no water. Yet living organisms might develop in chemical environments that are strange to us: the vegetable kingdom, for example, operates on a fundamentally different energy cycle from Man. Bodies might be constructed and operated with different chemicals and other physical principles than any of the creatures we know. One thing is evident: fishes, insects, and mammals all manufacture within their own bodies complex chemical compounds that do not exist as minerals. To this extent, life is self-sufficient and might well adapt itself to any environment within certain limits of temperature (and size of creature). Venus has two handicaps relative to Mars. Her mass, and gravity, are nearly as large as for the Earth (Mars is smaller) and her S-11750 28 UNCLASSIFIED
UNCLASSIFIED cloudy atmosphere would discourage astronomy, hence space travel. The remaining Solar planets are such poor prospects that they can be ignored. In the next few paragraphs, we shall speak of Mars. It should be understood that most of the remarks apply equally well to Venus. Various people have suggested that an advanced race may have been visiting Earth from Mars or Venus at intervals from decades to eons. Reports of objects in the sky seem to have been handed down through the generations. If this were true, a race of such knowledge and power would have established some form of direct contact. They could see that Earth's inhabitants would be help- less to do interplanetary harm. If afraid of carrying diseases home, they would at least try to communicate. It is hard to believe that any technically accomplished race would come here, flaunt its ability in mysterious ways and then simply go away. To this writer, long-time practice of space travel implies advanced engineering and science, weapons and ways of thinking. It is not plausible (as many fiction writers do) to mix space ships with broadswords. Furthermore, a race which had enough initiative to explore among the planets would hardly be too timid to follow through when the job was accomplished. One other hypothesis needs to be discussed. It is that the Martians have kept a long-term routine watch on Earth and have been alarmed by the sight of our A-bomb shots as evidence that we are warlike and on the threshold of space travel. (Venus is eliminated here because her cloudy atmosphere would make such a survey impractical). The first flying objects were sighted in the Spring of 1947, after a total 5 atomic bomb ex- plosions, i.e., Alamogordo, Hiroshima, Nagasaki, Crossroads A and Crossroads B. Of these, the first two were in positions to be seen from Mars, the third was very doubtful (at the edge of Earth's disc in daylight) and the last two were on the wrong side of Earth. It is likely that Martian astronomers, with their thin atmosphere, could build telescopes big enough to see A-bomb explosions on Earth, even though we were 165 and 153 million miles away, respectively, on the Alamogordo and Hiro- shima dates. The weakest point in the hypothesis is that a continual, defensive watch of Earth for long periods of time (perhaps thousands of years) would be dull sport, and no race that even remotely resembled Man would undertake it. We haven't even considered the idea for Venus or Mars, for example. The sum and substance of this discussion is that if Martians are now visiting us without contact, it can be assumed that they have just recently succeeded in space travel and that their civilization would be practically abreast of ours. S-11750 29 UNCLASSIFIED
UNCLASSIFIED The chance that Martians, under such widely divergent condi- tions, would have a civilization resembling our own is ex- tremely remote. It is particularly unlikely that their civilization would be within a half century of our own state of advancement. Yet in the last 50 years we have just started to use aircraft and in the next 50 years we will almost certainly start exploring space. Thus it appears that space travel from another point within the Solar system is possible but very unlikely. Odds are at least a thousand-to-one against it. This leaves the totality of planets of other stars in the Galaxy as possible sources. Many modern astronomers believe that planets are fairly normal and logical affairs in the life history of a star (rather than cataclysmic oddities) so that many planets can be expected to exist in space. To narrow the field a little, some loose specifications can be written for the star about which the home base planet would revolve. Let us say that the star should bear a family re- semblance to the Sun, which is a member of the so-called "main- sequence" of stars, i.e., eliminate white dwarfs, red giants and supergiants. For a description of these types, see refer- ence 2, chapter 5. There is no specific reason for making this assumption except to simplify discussion: we are still consider- ing the majority of stars. Next, true variable stars can be eliminated, since conditions on a planet attached to a variable star would fluctuate too wildly to permit life. The number of stars deleted here is negligibly small. Reference 3, pages 76 and 85 indicate that the most common types are too bright to be in nearby space unnoticed. Lastly, we shall omit binary or multiple stars, since the condi- tions for stable planet orbits are obscure in such cases. About a third of the stars are eliminated by this restriction. As our best known sample of space we can take a volume with the Sun at the center and a radius of 16 light years. A compilation of the 47 known stars, including the Sun, within this volume is given in reference 4, pages 52 to 57. Eliminating according to the above discussion: Three are white dwarfs, eight binaries account for 13 stars and two trinaries account for 6 more. The remainder, 22 stars, can be considered as eligible for habitable planets. S-11750 30 UNCLASSIFIED
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[ILLEGIBLE] dtd [ILLEGIBLE] Sep 47, to CG, Hq AAF, [ILLEGIBLE], subj: "Flying Saucers"
g. Page 69, The Horten VIII.
h. Pages 71 and 72, Photographs of the Horten IX Versions.
i. Page 74, Drawing of the "Parabels".
This document should also be returned when it has served its intended
purpose.
X 452.1 [ILLEGIBLE] - [ILLEGIBLE]
4. A recent report from the U. S. Military Attaché [ILLEGIBLE],
dated 9 June 1947, indicates that 1800 aircraft, directly or indirectly
based on the Horten VIII design (six engine pusher, having a wing spread
of 131 feet and a gross weight of approximately thirty-three thousand
pounds) are being built for bomber squadron use. The Russian version,
however, is jet propelled, reference report whose identification No. is
V-32291-S.
5. The T-2 report "German Flying Wings Designed by Horten Brothers"
X 95
No. F-SU-1110-ND, also inclosed herewith, may be obtained by your office
if desired.
FOR THE COMMANDING GENERAL:
H. M. McCOY
Colonel, Air Corps
Deputy Commanding General
Intelligence (T-2)
3 Incls:
1. Drawing
2. RAE Tech Note, AERO 1703
3. T-2 Rpt, No. F-SU-1110-ND
SECRET
-2-Incl 3
SECRET
[ILLEGIBLE]UNCLASSIFIED
[ILLEGIBLE]
[ILLEGIBLE]
[ILLEGIBLE]
It is requested that this office be [ILLEGIBLE] information
concerning an alleged "Flying [ILLEGIBLE]" [ILLEGIBLE]
made by a radar station in Japan. This [ILLEGIBLE] [ILLEGIBLE]
Mr. Charles Carroll during a conference in [ILLEGIBLE] [ILLEGIBLE]
which was attended by Mr. A.H. Leadding, [ILLEGIBLE] [ILLEGIBLE]
September 1947.
FOR THE COMMANDING GENERAL:
/s/ H.M.Goll
H.M.McCOY
Colonel, Air Corps
Deputy Commanding General
Intelligence T-2
SECRETUNCLASSIFIED
[ILLEGIBLE]
[ILLEGIBLE photograph/image — aircraft silhouettes or diagrams]
[ILLEGIBLE]
[ILLEGIBLE]
acQ
CONFIDENTIAL
conf
OFFICE SYMBOL | AFTAI | 2. | 3. | 4. | 5.
GRADE AND
SURNAME OF
COORDINATING
OFFICERS | [ILLEGIBLE] | [ILLEGIBLE] | | |UNCLASSIFIED
(4)
[ILLEGIBLE paragraph — partially legible:]
vided [ILLEGIBLE] piloted aircraft [ILLEGIBLE] has the range [ILLEGIBLE]
paragraph (c) above which would be capable of [ILLEGIBLE]
7000 miles at subsonic speeds.
e. Any developments in this country [ILLEGIBLE]
would be extremely expensive, time consuming [ILLEGIBLE]
pense of current projects and therefore, if directed [ILLEGIBLE]
dependently of existing projects.
b. Due consideration must be given the following:-
(1) The possibility that these objects are of domestic
origin — the product of some high security project
not known to AC/AS-2 or this Command.
(2) The lack of physical evidence in the sense of crash
recovered exhibits which would undeniably prove the
existence of these objects.
(3) The possibility that some foreign nation has a form
of propulsion possibly nuclear, which is outside of
our domestic knowledge.
3. It is recommended that:-
a. Headquarters, Army Air Forces issue a directive assigning
a priority, security classification and Code Name for a detailed study of
this matter to include the preparation of complete sets of all available
and pertinent data which will then be made available to the Army, Navy,
Atomic Energy Commission, JRDB, the Air Force Scientific Advisory Group,
NACA, and the RAND and NEPA projects for comments and recommendations,
with a preliminary report to be forwarded within 15 days of receipt of
the data and a detailed report thereafter every 30 days as the investi-
SECRET
U-1995aUNCLASSIFIED
[ILLEGIBLE]
[ILLEGIBLE — page heavily damaged/dark, text not recoverable]
SECRET
[ILLEGIBLE]CONFIDENTIAL
HEADQUARTERS
AIR MATERIEL COMMAND
[ILLEGIBLE stamps left margin] TSEAD-E3/ACL/amb
WRIGHT FIELD, DAYTON, OHIO
TSEAD-E3
SUBJECT: Flying Discs 24 NOV 1947
TO: Chief of Staff
United States Air Force
Washington 25, D. C.
ATTENTION: Office, Director, of Intelligence
Lt Colonel George Garrett, Jr.
Reference letter, subject as above, dated 18 November 1947, it is
requested that immediate action be taken to appropriately mark or stamp
this correspondence with the classification "secret". This classifica-
tion number is as follows: U-48965
FOR THE COMMANDING GENERAL:
H. M. McCOY
Colonel, USAF
Chief of Intelligence
To OFI files
action completed CIR-CO
colonel garret 12-10-47
CONFIDENTIAL
CONFIDENTIALSpain evidently was printed in a number of leading newspapers throughout
the country. The significance of this article will be dependent upon cer-
tain essential elements for such alleged important developments, such as
funds, materials, experimental testing facilities, and technological
"know-how". The latter is supposed to be supplied by German scientists.
The German scientists at this Hq indicate that no important scientists
from Germany are working in Spain, and those mentioned in this article
are not known to them.
3. If possible, therefore, an effort should be made to obtain names,
qualifications, or any information that might help to identify the alleged
German scientists working in Spain.
4. A brief statement was made in a recent intelligence [ILLEGIBLE] from
Hq, USAF, AC/AS-2, regarding a flying disc incident in Alaska [ILLEGIBLE].
The close range sighting reported should render a more [ILLEGIBLE] information
than what was reported, which also suggests a follow-up.
5. It is further requested that this office be advised as to progress
being made on the plotting of all flying disc incidents to date, particu-
larly in North America. It was understood that Dr. Carroll was [ILLEGIBLE] to
plot these incidents, but no further word was received regarding this [ILLEGIBLE].
FOR THE COMMANDING GENERAL:
File
CD GARRETT Jr
CD CA[ILLEGIBLE]
LT CA[ILLEGIBLE]
1 Incl
newspaper clippings
H. M. McCOY
Colonel, Air Corps
[ILLEGIBLE] Intelligenceon 14 Nov 57 I called Miss Snoddy, who is Chief, Administrative Reference Branch, Mail and Records Management Division, Air Adj Gen Office, Hq USAF (extension 74835). AFCAG-22. Miss Snoddy is trying to locate letter from C/S, USAF, dated 30 Dec 44, subject: "Flying Discs".
HEADQUARTERS
AIR MATERIEL COMMAND
Wright-Patterson Air Force Base
Dayton, Ohio
MCIAXO-3/1903/rm
Jan 5 1949
) MCIAXO
SUBJECT: Project "SIGN"
TO: Chief, Air Weather Service,
Andrews Air Force Base,
Washington 25, D. C.
ATTN: DSS
1. Project "SIGN" is responsible for the collection, investi-
gation and interpretation of data relative to sighting of unidentified
flying objects. Attached Incident Summaries 1 thru 172 from the files
of Project "SIGN" are forwarded for study and recommendations as to
which of the incidents may be eliminated as balloons released on routine
synoptic ascents by the Air Weather Service, the Navy Aerological
Service or the United States Weather Bureau. The summaries attached
may be retained in your headquarters for working and reference purposes.
2. The Air Weather Service is the only agency of its type that
has been asked to assist in the accomplishment of Project "SIGN" except
that the United States Weather Bureau has provided information on ball
lightning. Research projects in which balloons are used and which are
conducted or sponsored by the Army, Navy or United States Air Force are
checked by the Intelligence Department of this Command. These checks
are usually made direct from the Project "SIGN" Office, MCIAXO-3. These
checks are distinct from the check of synoptic balloon flights made by
weather service stations of the Air Force, the Navy and the Department
of Commerce. (U. S. Weather Bureau) requested of Air Weather Service.
3. It is the opinion of this office that the below listed inci-
dents are those having the greatest possibility of being balloons. This
list does not eliminate the possibility that many of the remaining
incidents are balloons.
2 21 50 91 113 155
3 25 52 92 115 156
4 26 72 96 126 157
11 30 73 104 141 159
14 31 61 105 145 163
16 32 57 107,6,9 151 167
22 33 89 112(See122) 154 169
23 45
T-SU451-AHq AMC, Chief, Air Weather Service, Washington 25, D. C.
Subj: Project "SIGN"
4. The form used in interrogating witnesses to sightings is
inclosed as a matter of interest. Comment as to possible improvement
of the "Essential Elements of Information" in regard to routine
synoptic balloon flights is invited.
5. It is requested that correspondence be forwarded to the
Commanding General, Headquarters, Air Materiel Command, attention
MCIAXO-3.
FOR THE COMMANDING GENERAL:
/s/ W. R. Clingerman, Col, USAF
for H. M. McCOY
Colonel, USAF
Chief, Intelligence Dept
2 Incls:
Summaries 1-172 incl
"S21"
Copies furnished:
AFOIR, Hq. USAF
Capt Trakowski, Geophysics Lab
Major Kodis, MCREER
Colonel Neal, MCLANS
T-SU451-ADr. HYNEK'S EVALUATIONS EXTRACTED FROM PROJECT GRUDGE REPORT.
INCIDENT INDEX
1. Astronomical
a. High probability:
#26, 27, 30, 31, 32, 33, 34, 48, 49, 59, 60, 66, 69, 70, 94,
95, 96, 97, 98, 101, 102, 103, 104, 116, 119, 132, 136, 140,
147, 148, 158, 174, 184, 185, 187, 197, 203, 204, 208, 216,
219, 238.
b. Fair or low probability:
#15, 20, 23, 24, 28, 35, 36, 46, 50, 63, 67, 80, 82, 93, 100,
112, 120, 121, 129, 130, 144, 153, 165, 166, 167, 175, 192,
199, 202, 205, 220, 230, 240.
2. Non-astronomical but suggestive of other explanations
a. Balloons or ordinary aircraft:
#3, 11, 22, 41, 42, 53, 54, 73, 81, 83, 91, 92, 113, 114, 115,
126, 131, 138, 141, 145, 155, 156, 157, 159, 160, 161, 163,
169, 171, 173, 178, 180, 182, 188, 190, 194, 195, 196, 198,
200, 201, 209, 210, 217, 222, 235, 237, 239.
b. Rockets, flares or falling bodies:
#4, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16, 25, 56, 65, 78, 106, 107,
108, 109, 133, 170, 211, 218.
c. Miscellaneous (reflections, auroral streamers, birds, etc.):
#39, 69, 123, 124, 128, 146, 164, 181, 189, 214, 221, 231, 234.
3. Non-astronomical, with no explanation evident
a. Lack of evidence precludes explanation:
#38, 44, 45, 47, 56, 57, 72, 86, 87, 88, 90, 99, 110, 117, 118,
125, 127, 137, 139, 149, 150, 177, 179, 191, 206, 212, 213,
229, 232, 233.
b. Evidence offered suggests no explanation:
#1, 2, 10, 17, 21, 29, 37, 40, 51, 52, 58, 61, 62, 64, 68, 71,
75, 76, 77, 79, 84, 105, 111, 122, 135, 151, 152, 154, 162,
168, 172, 176, 183, 186, 193, 207, 215, 223, 224, 225, 226,
227, 236, 241, 242, 243, 244, 134.