|The sighting described below took place during the theodolite tracking
of a 79-ft. balloon floating at approximately 80,000 feet, on Project
85021-Grab Bag. No sound was detected at any time during the observation.
The object was first observed as it passed below the sun at an elevation
(solar elevation) of approximately 25 degs, heading southward in horizontal
flight. It was detected by a smoke or vapor trail which extended some
distance behind it, but which did not persist or form a cloud. The object
itself was not visible even through the theodolite during the first part
of the sighting. During the horizontal part of its trajectory, the object
moved across the sky at a rate of 10 degrees in 9 seconds. With an estimated
altitude of 40,000 ft. this represents 15 miles per minute or 900 miles
per hour. (All three men agreed that object could have been as high
as 60,000 feet, which would give a speed of 1,200 miles per hour.)
After about 10 seconds of horizontal flight, the object appeared to
go into a vertical dive. The possibility that the appearance of a dive
was produced by the object merely receding into the distance seems unlikely
since the speed normal to the line of sight was undiminished in the dive.
The dive lasted for from 10 to 15 seconds, at the end of which time the
object was visible two or three times as it appeared to glow or reflect
the light of the sun for perhaps a second at a time. Just at this time
the vapor trail ceased, and for a second or two thereafter the object,
its outlines still unrecognizable, was seen through the theodolite not
as a glare (reflected?) light, but as a gray mass in the act of leveling
off. Its size in the theodolite field was of the same magnitude as the
79-foot balloon, which means that, since it was nearer,, it would not
be as large [linearly).
The observers believe that the object was most likely a jet aircraft,
but several features were unusual:
1. The speed was higher than normally observed;
2. The vertical dive was a highly dangerous if not suicidal maneuver;
3. A jet aircraft in such a dive would be heard for miles and would
certainly cause a noticeable shock wave detectable in the area beneath
4. Vapor trails do not ordinarily occur during vertical motion though
smoke trails could, of course.
It was thought that the Air Defense Command would be interested in
what was seen if.
a. They had no aircraft in the vicinity which could account for it;
b. They had no aircraft accident which might be partly explained by