Engineering Division.
Memorandum Report No. MCREXD-694-18D
28 April 1949
UNCLASSIFIED
of daylight sightings should have been of dark objects... It is possible,
of course, that they may have thought the objects were bright because
they expected all aerial objects to be bright.
On the basis of the evidence thus far considered, the best guess
as to the nature of a visual stimulus that would elicit reports of
unidentified flying objects is that in the daytime it would be the
reflection of the sun from an aircraft, a wind-blown object, etc.,
and at night some direct light source, such as an engine exhaust, the
light on a weather balloon, a running light on an aircraft, a meteor,
etc., or lights from the ground or the moon reflected back by birds or
other objects in the air.
Discussion of Several Specific Reports
Discussion of a few specific reports will serve to illustrate some
of the points brought up earlier, particularly some of the factors that
make observations of aerial phenomena inaccurate.
Incidents No. 81 and 163.
In one case (Investigation No. 81) a civilian employee at Hickam
Field at 0900 observed what looked like a balloon with a bright object
suspended below it. It was estimated to be at about 6,000 ft. The
bright object appeared to reflect the sun's rays at times. After a
few minutes he looked away and then could not find the object again.
In another case (No. 163) a reserve officer at Van Nuys, California,
about an hour before dark saw an object that looked somewhat like a
weather balloon at about 2000 ft. He kept it in sight for about an
hour. He later concluded that it was at a great height. At first it
had the color of a fluorescent electric light but became orange as the
sun went down and then rather suddenly became invisible.
Both of these objects could well have been just what they appeared
to resemble most—balloons. The sun was low in the sky in both cases.
UNCLASSIFIED
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DOWNGRADED AT 12 YEAR
INTERVALS: NOT AUTOMATICALLY
DECLASSIFIED. DOD DIR 5200.10