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Reports categorized as INSUFFICIENT DATA are those for which one or more elements of in- formation, essential for evaluation, are missing. Some examples are the omission of the duration of the sighting, date, time, location, position in the sky, weather conditions, and the manner of appear- ance or disappearance. If an element is missing and there is an indication that the sighting may be of a security, scientific, technical, or public interest value, the Project Blue Book Office conducts an additional investigation and every attempt is made to obtain the information necessary for identi- fication. However, in some instances, essential information is requested from the observer and is never received; therefore, no further action can be taken. ; The third and by far the smallest group of evaluations is categorized as UNIDENTIFIED. A sighting is considered unidentified when a report apparently contains all pertinent data necessary to suggest a valid hypothesis concerning the cause or explanation of the report, but the description of the object or its motion cannot be correlated with any known object or phenomena. TYPES OF UFO IDENTIFICATIONS AND EVALUATIONS There are various types of UFO sightings. Most common are reports of astronomical sightings, which include bright stars, planets, comets, fireballs, meteors, auroral streamers, and other celestial bodies. When observed through haze, light fog, moving clouds, or other obscurations or unusual con- ditions, the planets, including Venus, Jupiter, and Mars, have been reported as unidentified flying objects. Stellar mirages are also a source of reports. . Satellites are another major source of UFO reports. An increase in satellites reported as UFOs has come about because of two factors. The first is the increase of interest on the part of the public; the second is the increasing number of satellites in the skies. Positive knowledge of the location of all satellites at all times enables rapid identification of satellite sightings. Keeping track of man- made objects in orbit about the earth is the responsibility of the North American Air Defense Com- mand Space Detection and Tracking System at Ent AFB, Colorado. This sophisticated electronics system gathers complex-space traffic data instantly from tracking stations all over the world, Other space surveillance activities include the use of ballistic tracking and large telescopic cameras. ECHO schedules of the South/North equator crossings are prepared by the Smithsonian Institution at Cambridge, Massachusetts. From the data produced by these agencies, satellites mis- takenly reported as UFOs can be identified quickly. Some of these are visible to the naked eye. 4 Aircraft account for another major source of UFO reports, particularly during adverse weather conditions. When observed at high altitudes and at some distance, aircraft can have appearances ranging from disc to rocket shapes due to the reflection of the sun on their bright surfaces. Vapor or condensation trails from jet aircraft will sometimes appear to glow fiery red or orange when re- flecting sunlight. Afterburners from jet aircraft are often reported as UFOs since they can be seen . from great distances when the aircraft cannot be seen. The Project Blue Book Office has direct contact with all elements of the Air Force and the Federal Aviation Agency civil air control centers. Allaerial refueling operations and special training flights can be checked immediately. Air traffic of commercial airlines and flights of military air- craft are checked with the nearest control center, enabling an immediate evaluation of aircraft mistakenly reported as UFOs. However, since many local flights are not carried, these flights are probable causes of some reports. Balloons continue to be reported as UFOs. Several thousand balloons are released each day from military and civilian airports, weather stations, and research activities. There are several types of balloons - weather balloons, rawinsondes, radiosondes, and the large research balloons which have 2 > ’ . ~ r) G39NGOwd3y ied tes t S3AIHOMY TWNOILVN 3HL 4O SONIGTOH WOU