SIGNALING SUBS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP92B00181R000300270027-0
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 5
• Document Creation Date: December 27, 2016
• Document Release Date: April 22, 2013
• Sequence Number: 27
• Publication Date: April 1, 1987
• Content Type: OPEN SOURCE

: CIA-RDP92BOO181 R000300270027-0 `
Navy submarines must-rise to the ocean's surface at preset times to receive radio commu-
nicns, but such rendezvous can give away their;strategic positions. Now subs can stay'
radio waves from `giant transmitters
den longer,. receiving extremely' low frequency
hidet all their signals from Orbiting
that issue abbreviated commands. Eventually, subs may g
di
By T. A. HEPPENHEIMER noon the sun's glare hides it. The laser ain lanes
the older TACAMO (Take
Painting by Jeff Mangiat, - beam scans back and forth, plunging rP
through the churning waves deep into Charge and Move Out) system. Now, ing he North Atlantic is fearsome in' the sea; where it sweeps over the sub- stwo.new ubs to receive instrutc ons will
witho t
.
asses onward.
nd
r marine-a
p
interrupting
winter. Sleet slants down from
mmunications T thick cloud banks scudding loin Aboard
watches as her computer fermi- already in operation, is a mi
lights up. Quickly she sends -the plus extremely low frequency (ELF)
slash through hty windblown sp sprra y as the as t she ? offinal cer
ma own sages tto subs th oughout the orld
storm raises enormous swells. ubcoent, the sh p's executive officer. tHis
dreds feet below the surface,
;
marine e slowly, , quietly heads ds north. 1- cma U SOODALi aws,tPRO EC ED TO sE c ded three-letter commands tell subs
From its polar orbit in space,
life shoots adeep-blue laser beam'; TOR c. He issues?a rudder order; the when and where it's safe to come up d downward. It quickly spreads to form, sub slowly turns. Now it will patrol' afor nd more-detaileusing blue messaglaseres. Sec-
a broad spot. If this were nighttime, closer to the Soviet Union.' ? ~ ;
the 'ipot would show dimly at the tops ':`Until recently, subs had to rise to' relay more-complex signals, ma ing'
of_the-clouds,.but_in the.early after- .the surface at appointed times to lis-ontinue
44 POPULAR SCIENCE
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feet into. seawater. But. ELF radio signals (left)
can penetrate hundreds of feetwithoufibeing
absorbed. They have even been picked up 30
feet under the Arctic ice pack. The waves
bounce off the ionosphere and strike anten-
nas towed by subs. The signals that emerge
from ELF have wavelengths of 2,500 miles-
10,000 times longer than the radio waves
you pick up with your car antenna.
The blue laser (right) must scan across a
large area because the sub's location is a mys-
tery. But the laser flashes 100 or more times
a second, so a brief encounter with the sub
will suffice. Here's how the laser works: A
ground station, airplane, or ship sends a radio
signal to the laser satellite. Inside a chamber
containing xenon and chlorine, an electric dis-
charge momentarily causes atoms of the two
gases to form excited molecules of xenon chlo-
ride, called excimers. The excimers quickly
break apart, releasing photons that form an
intense beam of ultraviolet light. The beam
passes through a chamber filled with lead
vapor; the vapor absorbs the ultraviolet light
and shifts its wavelength to 459 nanometers.
This corresponds to a deep-blue color.
The blue beam cuts through the water, strik-
ing a receiver aboard the sub. Inside a filter,
cesium vapor absorbs photons at the specific
wavelength of the laser, then re-emits this
energy as photons with near-infrared wave-
lengths. A photodetector watches for these
photons, which could not have penetrated
from the surface. Radio signals sent up to
the satellite convey information by modulat-
ing the laser photon stream.
APRIL 1987 145
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it possible for subs to stay hidden from
enemy detection even longer. In addi-
tion, a torpedo-like receiver dubbed
RAGU, deployed by sub, has been
proposed to relay messages from
satellites, eliminating the problems
associated with receiving radio signals
from aircraft. More about that. later.
Submarines spend most of their
time at great depths, moving slowly.
That way, they emit very little noise
while they listen-with sensitive
sonar-for other subs (PS, July '83,
July '85].
A sub never transmits while it is
underway because that would reveal
its position. But it must be able to re-
ceive incoming radio traffic. Much of
this is purely routine: WHEN YOU GET
TO POINT B, LOAD 500 POUNDS OF POTA-
TOES AND 50 QUARTS OF OIL. From time to
time, subs get more important signals
rders to move to designated loca-
-o
tions, or to patrol in a different part
of the sea. The new communications
techniques are essential for these
transmissions.
Supersensitive receiver
The blue laser being developed at
Northrop Corp.'s Electronics Division
in Hawthorne, Calif., is highly secret.
The same is true of the blue-laser sat-
AT (Submarine
S
ellite, called SLC
s nearing
Laser Communications Satellite), ver which is under development at Lock- radio a sages land fi essan on board completion amid the forests of upper
heed Missiles Calif. Space Gears thSunny- at if up
vae, ela. The Navy Mears that if ace.The supersensitive light detec- though the blue laser sVcloaked in se-
the blue laser system is le cthe closely P
the guarded, SoThe may learn
be lasers with relatively vely modest outputs To visit its sites,gI flew to in
. Then they might
SLCSAT codes
able send false. messages to U.S. to do the job. beBsubmarines. show, would impressive. Donald Sh eld rock
Still, several Pentagon officials have Latham, the Pentagon's chief of com-
laser munications
"a several-hundredf oot like those of a power 1 ne, runnig for
statementhe new laser in "sanitized"
given at statements distilled from testimony provides the naval lieuten-in the depth
lieuten-
miles on iven at secret. hares. before Con- increase
Here's how a recent field test lof'the plains Wiley Cress,e the es, en-
trans-
Robert director According to
Advanced s director of Projects Agency, Defense bl It's a clear, bright day off San Cle- mitter's 56 miles of stiff braided-wire
a new oesearch r has greatly has letter F on
based on land
vented a new optical pt the laesce?seusefullness. The Dolphin lies beneath the Pacific. sver- a map. (The shape ragged
availability and has no special signifi-
University detector, invented at the head, scarcely visible from the ground, granite shat is ts con
can University of Arizona, is far more sen- a Sabreliner business sky, 2j 0 traces i 0 000 arece.) The circuit is completed by the
aviation g. It's like trail through the X
s
"a development than its
feet up . ownward, A blue laser beam slants shot from an 80-watt sys- ent an of a Shield. The n Navy
"a in n aviation goin ng from jet d
a a Piper chose this
plane to tom aboard the aircraft. The beam site because the rock, which has very
currlend
Cooper er declares. propeller
airliner," ner," Cub
ng messagess the low deep underground the current
loop ivity, The blue-laser system has ones Dolphin, the sea and
from an older proposal based longer-wavelength blue-green laser: A "The depths we reached are aston- (see drawings)? where the ELF
large' ground-based laser would pro- ishing-and classified," says a Penta- F Cress ana d oI de by to K.I. Sawyer Air
duce a powerful sea-colored beam, and gon official. Bigger lasers are coming. contr
is located.
R an orbiting mirror would reflect the Already,
laser called EXCELtwhi h will ClassoMl Marshman, dressed in na-
beam into nto the ocean. The original blue us. "SUBLANT,
blue-green laser idea was problematic. be able to penetrate hundreds of feet. val uniform, greets
nter in The beam spread out as it rose Still,
according ont be ready until the folk, s Va., co trols the signal traffic,"
,ors through the would be huge. atmosphere, phere, and the e mir- plete he states. "They will never let you in-
In In the new blue-laser system, a. In the meantime, the Navy will rely side the message center at Norfolk,
46 I POPULAR SCIENCE
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 Declassified and Approved For Release 2013/04/23: CIA-RDP92B00181 R000300270027-0
RADIATED
ELECTRIC FIELD
GROUND ' ?`
CONNECTION.
Gp0 TRANSMITTER
Ile loo, /CURRENT FLOW
j j / THROUGH EARTH
but what we have is nearly the same."
Marshman demonstrates the signal-
ing procedure: "We receive teletype
messages from SUBLANT, or orders
over an encrypted telephone: SEND
SUCH-AND-SUCH A MESSAGE FOR TWO
HOURS." As he types on a keyboard, the
console makes a mechanical clacking
sound. "I'm sending a message that
this is a training exercise. We don't
have the code book. There's no coded
message we could send that would
order, `Launch your missiles.' The or-
ders are more like,-'Come up to re-
ceive further messages.' "
ELF can also direct course changes.
For example, a carrier battle group
might be in the Norwegian Sea, close
to the Soviet Union. An attack sub
rides out ahead, listening for Soviet
subs armed with cruise missiles. A
storm comes up, and the carrier force
changes course. In the old days, the
U.S. sub would blithely continue on
its path. "I've been in exercises like
this, and it's very frustrating," Cress
recalls. "The sub could be three hun-
dred miles away by the time he gets
the word." But with ELF, the orders
can reach the sub in a timely fashion.
Because the Michigan site is not yet
operational, the next day Cress and I
visit the Wisconsin facility to see a
superpowerful transmitter working.
The road leads through several small
mining towns. I recall that ELF was
the center of considerable controversy
for a time: Protesting demonstrators
sought to shut it down; environmen-
talists charged that it would create
dangerous radiation; and state gover-
nors took the Navy to court [PS,
Sept. '69].
Deep in the woods, we turn off on a
logging road. A cable strung. from
wooden poles soon appears overhead.
The Wisconsin transmitter features 28
miles of line, set in the shape of an
enormous letter X. .
Inside the transmitter station is a
control room somewhat like that at
Sawyer AFB. A row of seven security
monitors shows scenes outside the
fence. Digital counters flash bright-
orange data: CURRENT, 297 AMPS; VOLT-
AGE, 6,300 VOLTS; FREQUENCY, 76.5 HERTZ.
"We're sending'the idle message, BCJ,"
the operator says. BCJ means the sys-
tem is operating normally but says
nothing more.
We walk into a large room with a
concrete floor and a number of large
gray cabinets. Cress opens the door
to the transmitter cabinet, disclosing
green circuit boards and blinking
green and red lights. There is a loud
hum, shifting between higher and
lower pitches. "That's the coded sig-
nal," remarks Cress. "It takes five
minutes to send the message once."
Because the effective transmission
power is so low after the radio waves
dissipate in the earth, a sub must lis-
ten with care. '
Flying messengers
Still, within the Navy, ELF can only
convey prearranged messages that are
listed in the commander's code book.
Longer messages are delivered via the
TACAMO radio system. TACAMO uses
aircraft-modified C-130 transports-
that fly in random patterns. When it
is time to send a message to the subs,
a winch whirs to life, reeling out a
transmitting wire nearly five miles
long, with a 90-pound weight at the
end. The plane banks sharply and flies
in a tight circle-the aircraft and its
dangling cable' resembling an enor-
mous lasso. Because the radio signals
cannot reach the ocean depths, subs
must use towed cables or buoys to re-
ceive messages from TACAMO.
"In the old days, a sub would be car-
rying out exercises at depth," says
Cress. "To receive messages, it would
have to come up to one-hundred-thirty-
foot depth every twelve hours and
stream a cable. This takes time and
interferes with normal operations. The
sub has to clear its baffles, to start."
The baffles are the region behind a
sub where its on-board sonar cannot
Continued
APRIL 1987 147
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what can happen. Says Garwin: Skip-
pers at periscope depth have looked
out and seen birds perching on their
cables." And buoys, he adds, are hard
to handle.
Satellite link
with modified Boeing 707 jets. But to
receive the signals, subs will still have
to approach the surface and deploy a
cable that serves as an antenna, or
tow a buoy-hoping it stays beneath
the surface where it will not be seen
(see drawing). Sometimes this isn't
easy. IBM's Richard Garwin, a long-
time inventor of naval systems, knows
11
hear the souna of a siup. all four
have a carrier going with a
screws, and you'd never hear him, so
you turn to the left and right to hear
what's behind you. Then you come up
to periscope depth and look around.
Plus, your sub has no keel. In a storm,
it's like a hot. dog being tossed about
in a whirlpool bath."
At this moment, a TACAMO aircraft
is in flight somewhere over the Pa-
cific, and,another one is above the At-
lantic. This system is being upgraded.
The aging C-130s will be replaced
sages using a sonar-like acoustic sig-
nal, a high-frequency sound directed
at the sub.
These systems-the blue laser in
the 1990s, ELF today, TACAMO and
Us upgraded aircraft soon, and the fish
RAGU if it should be needed-will
make it easier for subs to hide from
enemies. Adm. James Watkins, the
chief of naval operations, describes the
payoff with the help of a story by Mark
Twain: "Two bulldogs met. They cir-
cled, snarling and growling. rred. were
bluffing, so nothing happe
they were about to walk off when one
of them opened his mouth. He had no
teeth. So the other dog tore him to
pieces." In Watkins's view, improved
communications are an important way
for submarine forces to sharpen their
teeth.
Garvin proposes what he
Instead
,
calls a "fish RAGU." (RAGU stands for
Radio Receiving and Generally Use-
ful.) It would be a small torpedo-like-
device, battery powered and able to
swim a few feet below the surface. It
would proceed at only a few knots, but
subs rarely go faster, because at
higher speeds they make more noise
and are more easily detected. As
Darwin describes it, "You could send
the fish a signal by radio: `Precisely
one minute from now a burst of satel-
lite communications will come.' The
fish would stop, put up a little antenna
that would point to the satellite's lo-
cation for a second .or so, and receive
a million bits of information." The
fish would then retransmit these mes-
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