attacked the Air Force findings, insisted that the radar echoes had
been caused by strange machines and, in effect, accused the official
investigators of releasing an explanation they knew to be at variance
with the facts shown by radar[VIII-8].
Dr. Vernon G. Plank, now at the Aerophysics Laboratory of the Air Force
Cambridge Research Center, was at that time Radar Meteorologist at
Walpole, Massachusetts. A specialist in the science of radar, Dr. Plank
had made a detailed study of the refractive conditions prevailing
over Washington for July 20 and 21, 1952. In a letter (which was never
published) to the editor of _True_, he pointed out that the saucer
theory of the Washington radar returns had no basis in fact. The
material given in the letter merits quotation:
“The regular Washington radiosonde observations, when converted into
refractive index terms, reveal that a very marked superrefractive
condition (a condition favorable to earthward bending of radar rays)
prevailed in the lower atmosphere during this period. The cause of this
superrefractive condition was primarily the rapid decrease of water
vapor with altitude.
“Although this superrefractive layer was not quite intense enough to
cause the radar rays to be bent completely back to earth, the rays
would be very markedly bent downward from their normal position.
From past experience with other situations of this type it is to be
expected that certain regions in this layer might be considerably more
superrefractive than others, or that particular terrain features, such
as rivers or small bodies of water, might create local, transitory
conditions favorable to extreme superrefraction or even reflection.
Another factor to consider is that whereas such local anomalies are
usually due to moisture, localized temperature effects may also create
or help create such intense superrefractive regions. Therefore,
it would not be at all surprising that such local anomalies, when
superimposed on the generally superrefractive layer already existing
over Washington, could create a situation conducive to radar echoes of
the type observed.
“Under such conditions the general ground clutter referred to in the
Keyhoe article would not be present and the radarscope would only
show echoes whenever and ‘wherever’ (qualified below) a favorable
superrefractive region occurred. As the radar ray has to travel from
the radar set to the particular region of refraction and thence onward
to the ground, the scope echoes created by such disturbances would
occur at an indicated range of roughly twice the disturbance range.
“Even slow air movements within a localized disturbance (one
sufficiently intense to bend the ray into the ground) would be
translated into enormous movements of the echo over the scope face.
Both lateral and radial movements could be expected and disappearance
of echo between sweeps would not be surprising.
“Of course, the optical effects noted in conjunction with the radar
echoes would depend upon temperature effects. However, the lack of a
temperature inversion in the type of data referred to by Mr. Keyhoe
does not preclude the possibility that extremely sharp and localized
inversions existed over the area, perhaps in close association or in
conjunction with the regions causing the radar echo. The Weather Bureau
data cited are not sufficiently accurate nor do the instruments used
in obtaining the data have a sufficiently rapid response to measure
such small inversions. Also, such data are usually obtained at only two
definite periods during each day.
“As the distance between Andrews AFB and the Washington National
Airport is only some few miles, the refractive effects of a given
disturbance might appear to be quite similar, and the position of the
resulting ground echo on the two sets might coincide to a fair degree
of approximation. However, as information about the degree of accuracy
maintained in plotting echo position is not available to me, I cannot
comment with any degree of intelligence. It does seem though, that
with the observed echo speeds and radical direction changes, as well
as the echo appearance and disappearance phenomena, that accurate
scope coordination between the separate fields would be extremely
difficult.”[VIII-9]
_“Simultaneous” Radar-Visual Reports_
On the night of July 29, three days after the second Washington crisis,
the radar installation of the Air Defense Command post near Port
Huron, Michigan, had been tracking three F-94s as they made practice
runs on a B-25 bomber. At 9:40 P.M. C.S.T., ground control picked
up an unidentified target moving from north to south at a speed of
about 625 miles an hour. The operators notified the pilot of one of
the F-94s and vectored him in for an attempted intercept. The plane’s
radar did not show the reported target, but when the plane had climbed
to a height of 21,000 feet, both the pilot and his radar man saw a
brilliant multicolored light, many times larger than a star, close to
the northern horizon. At the same time the plane’s radar picked up an
echo in the north; it disappeared after thirty seconds, although the
light was still visible dead ahead. As the pilot began the chase, the
light changed color from bluish white to reddish and slowly diminished
in size as though it were moving away. The pilot pursued the light for
about half an hour without gaining on it, and eventually had to return
to base. The ground radar, meanwhile, had been trying to keep track
of events in the sky. When the chase began, the target appearing on
ground radar had first made a 180-degree turn and reversed direction
from south to north; it had then moved erratically, doubling its speed
instantaneously, and then slowing down. It once seemed to reach a
speed of about 1400 miles an hour, then slowed to about 300 mph, and
disappeared from the scope shortly after the plane had returned to
base[VIII-2].
To many persons this incident seemed a simultaneous visual and radar
sighting of a single unknown object but the Air Force soon demolished
this theory. A study of the facts revealed that the movement of the
radar target and that of the mysterious light had not coincided. The
radar target had traveled from north to south, had then reversed
direction, had slowed down, speeded up, and moved erratically. The
light, however, had remained steadily in the north, diminishing in size
and brilliance but not vanishing. It behaved, in fact, like the image
of a star or a planet seen through turbulent atmosphere (see _Chapter_
IV).
For several nights before the sighting, many residents in this part
of Michigan had noticed a similar light that appeared in the northern
sky each evening at about the same time and place, displaying various
changing colors. The investigators were able to identify the shining
unknown as the star Capella. The position of the lights coincided with
that of the star for that time, date, and latitude. Capella was at
lower culmination--that is, at the lowest point of its swing around
the pole star, just skirting the horizon where its spectacular blue,
yellow, and red twinkling is familiar to astronomers of the region.
The pilot’s description, and the fact that he could get no closer to
it even after a thirty-minute chase, confirmed this identification.
Neither the brief blip that appeared on the plane’s radar nor the
erratic returns picked up by ground radar had any relation to the star;
they were merely phantom returns caused by weather conditions[VIII-2].
Like this Michigan sighting, many UFO problems are difficult to solve
because they result from more than one cause. The observations seem at
first glance to refer to a single phenomenon, although actually two
or more unrelated phenomena are involved. On August 1, 1952, two days
after the Michigan incident, such a puzzle arose with an impressive
radar-visual-photographic sighting near Bellefontaine, Ohio[VIII-2].
At 10:45 A.M. C.D.S.T., the radar operator at the Air Defense Command
post picked up an unidentified target north of Dayton, moving southwest
at a speed of about 525 miles an hour. Two jets from Wright-Patterson
Air Force Base were scrambled for an intercept and were vectored
in by ground control. Since the ground radar was not equipped with
height-finding devices, however, the operator could not direct the
pilots to a specific altitude; he could only tell them whether they
were nearer to or farther from the target.
When the jets had reached 30,000 feet, ground radar informed them
that they were almost on target, which was still moving southwest
at the same speed. A few seconds later, the returns from the jets
and the UFO blended on the radarscope and the operator advised the
pilots that they would have to continue the search visually. At this
moment, unfortunately, the ground radar suddenly failed. Soon after
communication between ground and air had ended, the lead pilot observed
a silver-colored sphere several thousand feet above him. Both jets went
after it but although they climbed to their maximum altitude, 40,000
feet, neither could get close enough to identify the object, which
was still some 30,000 feet above them. One pilot, however, managed to
expose several feet of film with his gun camera. At the same moment the
warning light on his gunsight radar blinked on to indicate it detected
a solid object. At this point the jets broke off the intercept and
started back to Wright-Patterson Field.
Both pilots then realized that, although they had been chasing an
unknown for some ten minutes, they were still northwest of the base
in almost the same area where they had started the intercept. This
surprising fact seemed to indicate that the unknown had slowed down
from its original speed of 525 miles an hour, to hover in the sky
nearly motionless.
In flying saucer circles, this series of events was regarded as an
iron-clad case of a physically material UFO observed simultaneously by
radar, the human eye, and the camera.
After sifting the evidence, ATIC investigators eventually found the
more prosaic though complicated solution to the puzzle:
1) The object picked up on ground radar had actually been a jet plane,
flying out of Cleveland. It had not been identified immediately because
the Bellefontaine station had not received its flight plan. At 10:45
that morning the jet had been north of Dayton, flying at low altitude
on a southwest heading, at a speed of around 525 miles an hour--the
exact time, position, and speed of the radar unknown.
2) The pilots of the interceptors never saw this jet. What they saw,
what their gun radar detected, and what their gun camera photographed
was a twenty-foot radiosonde balloon that had been released from
Wright-Patterson Air Force Base that morning shortly before the
sighting. Ground radar, on the other hand, never picked up the balloon.
3) The chief reason for the confusion was that ground radar did not
have a height-finding device. When the operator notified the pilots
that his scope showed a blending of the returns produced by the pursuit
jets and by the unknown, neither he nor the pilots had any way to tell
whether the unknown was directly above or directly below the pursuing
jets. At 30,000 feet the pilots were too high to see the Cleveland jet
far below them. But they did see the balloon above them and naturally
assumed that it was the object they were supposed to be chasing.
4) Since the ground radar stopped functioning at this point, the
operator could no longer track the course of the unknown or of the
interceptors. If the radar had been working, he would have seen that
the target continued on to the southwest while the interceptors were
searching in a different area to the north.
5) The photographs confirmed this reconstruction of a complicated
series of events. The pictures obtained by the gun camera displayed a
round, indistinct blur. Analysis showed that the size of the object was
that of a twenty-foot sphere--a balloon--photographed from a distance
of 30,000 feet.
_“Ghosts” and “Angels” on Radar_
Every experienced radar man has observed blips on his scope that he
cannot account for[VIII-4], but he recognizes many characteristics of
these “ghosts” or “angels.” They often come from an apparently clear
and normal sky. They are usually concentrated in the lower atmosphere,
are weak in character, and last only a short time. Although they may
occur at any time of the year, they appear most often on summer nights
in calm weather[VIII-10]. Summer atmospheric conditions, in which the
air is relatively quiet but varies in temperature and moisture content,
have an adverse effect on radio and radar transmission and produce many
of these ghost returns.
The uneven distribution of temperature and humidity in the atmosphere
is only one of the many possible causes of the radar angels often
labeled as saucers[VIII-11, VIII-12]. These ghosts may be produced by
peculiar atmospheric conditions, back and forward scatter of radio
waves[VIII-13], smoke, wind-carried debris, moisture-laden clouds, ice
crystals in clouds or air, lightning, meteors, the Aurora Borealis,
birds, insects, bats, electronic reflections from the moon, flares on
the sun, or by “chaff” or “window” (foil dropped from airplanes). A
radar operator once picked up a group of phantom echoes that seemed
to form the letters “GI” which, according to the scope, apparently
stretched over a distance of about eighty miles. He tracked them for
two hours, but gave up trying to interpret the message when he learned
that it was produced by chaff dropped from an Air Force plane during an
experiment.
An extremely unusual pattern of “angels” (see Plate IVc) appeared
on the radarscope at Schilling Air Force Base at Salina, Kansas,
on September 10, 1956, and was attributed to forward scatter from
atmospheric eddies to ground targets and back[VIII-13].
Many radar angels are caused by insects and birds. Their detection on
sensitive, high-resolution, Q-, K-, and X-band radars has been verified
both observationally and theoretically. Since a radar set surveys
a very large volume of the atmosphere and maps it on a relatively
small dial, a surprisingly small concentration of insects can cause
appreciable clutter on the scope. On sets such as the 0.86-cm TPQ-6
(Cloud Base and Top Indicator), a single insect of detectable size
in a volume of 100,000 cubic feet of air is enough to fill the scope
with return[VIII-4]. Since the guilty insect would be invisible both
to ground observers and to the crew of pursuing jets, a flying-saucer
report inspired by the radar echoes would remain forever an “Unknown.”
Birds can cause substantial echoes on many radars. Large birds at a
distance of ten miles can give signals equivalent to those from a
medium-sized aircraft at a distance of fifty miles; in fact, even the
fading and fluctuation resemble those of aircraft echoes. On radar,
a sea gull may cause a return equivalent to that of a quart of water
flying around. The radar cross section of the blip may be several
times larger than the geometric cross section of the bird, so that a
single adult sea gull at a distance of twenty nautical miles gives
a very large radar return. As few as eight birds per square mile
can completely fill a PPI (Planned Position Indicator) scope with
return[VIII-14]. If conditions were exactly right, the birds might
be visible to an observer and the source of the angel would thus be
explained. But if no one happened to see the birds, the “mysterious”
returns could serve as a basis for still another report of invisible
flying saucers.
Birds have also been responsible for some of the “ring” angels that
have been interpreted as fleets of invisible spaceships. In September
1953 several radar sites in England picked up unidentified objects
apparently encircling the city of London. They performed peculiar
maneuvers including, according to one saucer publication, the formation
of the letters Z and U of the English alphabet. How the correct
orientation of this invisible sky writing was determined has never been
explained. If the letters are turned top to bottom, back to front, or
rotated 90 or 180 degrees, they take on new meanings. Scholars might
well argue about whether the first giant symbol should be interpreted
as a Roman Z, a Roman N, a Greek Ζ, or a Russian И; and whether the
second symbol should be read as a Roman U, a Greek Ω, the mathematical
symbol ⊂ standing for “is contained in,” or a Roman C lying on its side.
On the scope, ring angels produce outwardly expanding rings and arcs
that sometimes move on and off the screen at incredible speeds. Such
echoes have been a fairly common phenomenon in England since 1940 and
1941[VIII-15], and experimental research has shown that many of those
occurring at dawn or at dusk are caused by flocks of starlings. At dawn
thousands of starlings leave the roost in waves at intervals of about
half a minute. The birds in each wave are often closely packed in a
tight circle or semicircle as the wave ascends. All are flying outward,
dispersing in all directions, so that the ring diffuses rapidly on the
radar screen and disappears, but is followed almost at once by a new
ring. At dusk the birds may return separately to the roost during the
course of an hour. Sometimes, however, they assemble first in a field
some distance from the roost; they finally take off at the same time
as a group and head for the roost in a single giant wave, causing a
tremendously impressive but quickly vanishing angel on the radarscope.
Ring echoes observed at Texarkana, Arkansas, have been traced to the
movements of red-winged blackbirds. Thousands of birds flying out from
a common roosting ground a few minutes before sunrise show up on the
PPI scope as an expanding ring that grows broader and more diffuse with
time until the composite echo breaks into individual ones and fades at
a distance of twelve to thirty-five miles[VIII-16].
Other types of ring angels have been observed on radarscopes, but the
causes are not yet fully understood[VIII-17, VIII-18].
Recognizing the true character of these radar angels and spurious
reflections has tremendous importance for the security of the United
States. Our Early Warning System, designed to notify Air Defense of
imminent attacks by intercontinental ballistic missiles, has already
had troubles with such radar ghosts. On October 5, 1960, a signal from
Thule, Greenland, to the North American Air Defense Command flashed
the warning, “Massive ICBM attack is underway.” The Canadian officer
in charge had only seventeen minutes in which to decide whether to
order several hundred bombers of the Strategic Air Command to retaliate
against the USSR or to push the button that would cause our long-range
missiles with atomic warheads to come roaring out of their underground
sites. He immediately asked Washington: Where was Khrushchev?
Khrushchev was in New York at the United Nations: the officer did not
push the button that would have set the world at war.
Later, he learned that radar beams reflected from the moon had produced
the terrifying angels. This incident is only one of the reasons why the
Air Force continues to be interested in radar UFOs. Failure to identify
them correctly could threaten the effectiveness of our patrol system.
_The Rapid City Sighting_
One of the most complex incidents in saucer history occurred early
in August 1953 near Rapid City, South Dakota. Like the sightings the
previous year at Bellefontaine, Ohio, and Port Huron, Michigan, the
presence of a UFO seemed to be confirmed by several types of evidence.
Trained civilian and military personnel on the ground and in the air
observed an unknown visually and by radar. The blips on the ground
radarscope were photographed and a plane’s gun camera took a picture.
If a similar incident were to occur today, Air Force investigators
would probably find the answer without difficulty. In 1953, however,
they were less experienced and finally classified the case as “one of
the best” Unknowns.
It is clearly impossible to solve the mystery with absolute certainty
after nearly ten years, because vital information is lacking. The
original records are no longer on file. Few details are available
except those in Ruppelt’s sketchy summary[VIII-3, p. 303 ff.], and
some of these are inaccurate: the town of Black Hawk, for example, is
not west, but northwest, of Rapid City. Although many questions of fact
must therefore remain unanswered--exact times, directions, sequence of
events--we offer here a highly probable explanation.
The first report came at 8:05 P.M. M.S.T. when a spotter for the Ground
Observer Corps in the town of Black Hawk telephoned the Air Defense
Command post near Rapid City, approximately ten miles southeast of
Black Hawk, to report an extremely bright light hovering low on the
horizon to the northeast. The radar operators at Ellsworth Air Force
Base had been working with a jet patrol flying west of the base. After
receiving the phone call, they shifted the scope to scan the northeast
quadrant of the sky and picked up an unidentified target moving slowly
at about 16,000 feet. Although the controller wondered at first whether
the target might have been due to weather, he decided after a few
minutes that it was well defined, solid, and bright.
Since the ground spotter had a visual target and the traffic controller
had a radar target, he telephoned to compare notes on positions; as
they were talking, the spotter interrupted the conversation to say that
the light was beginning to move southwest toward Rapid City. Checking
the radarscope and finding a fast-moving target the controller sent two
of his men running outside to look at the sky. After a few seconds they
reported that they could see a large bluish-white light moving toward
them from the northeast. It made “a wide sweep” around Rapid City and
then returned to a stationary position in the northeast where it had
first appeared. (Unfortunately the account does not state clearly
whether the “wide sweep” was observed visually or on radar.)
By this time all the witnesses were greatly excited by the UFO. The
master sergeant couldn’t decide what to do next because he kept
thinking, “They’re bigger than all of us!” but the traffic controller
notified the F-84 patrolling in the west and asked for an intercept.
The pilot soon found the light, which was still stationary. He began
the chase, but when he had approached to within an estimated three
miles, the light rapidly began to retreat. He continued the chase
directly north for 120 miles (during which both the jet and the UFO
went off the ground scope) but he could not gain on the object. Running
short of fuel, he turned back toward the base. The ground scope soon
picked him up again and, a few seconds later, picked up an unknown
target apparently trailing the jet by ten or fifteen miles.
A second jet then took to the air, located the light, and began the
pursuit. Like the first pilot, he could not close the distance between
him and the receding UFO. After performing various tests to convince
himself that he wasn’t chasing a reflection, he finally turned on
his radar gun camera. After a few seconds the red light blinked on,
indicating a solid object ahead. The pilot thereupon asked permission
to break off the intercept and, having taken a photograph, returned
to base. As before, the ground scope picked up the returning jet but
this time the UFO did not reappear on the scope. The controller then
called officials at the filter center at Fargo, North Dakota. They
had not received any UFO reports; a few minutes later, however, they
called back to say that spotter posts between the two cities, on a
southwest-northeast line, had indeed seen a bluish-white light.
Investigators from ATIC arrived promptly but they were not able to
explain the sighting. Even the photographs showed nothing useful.
Conclusion: unknown.