Confronting Maritime Terrorism
most of the Cold War it was a deep, dark secret. Although completely
declassified in 1991, even today, few really understand what SOSUS was (and is)
and what it could (and can) really do.
is an acronym for SOund SUrveillance System. In 1949 Congress first authorized
money for what eventually became a world-spanning ocean surveillance system.
That system, mothballed after the end of the Cold War, is coming back to life as
a major weapon to fight the terrorist threat on the high seas.
is how the system works:
generated by an object in waters deeper than 100 fathoms radiates in all
directions. Sound near the surface is absorbed and scattered quickly by surface
wave action. Sound that radiates downward, however, eventually is bent back
toward the surface by the increasing pressure of the water column. Typically,
this sound reaches the surface about 30 nautical miles from the source, forming
a ring of sound about 3 nautical miles wide centered on the source. This sound
reflects again, and eventually arrives back at the surface 30 nautical miles
further out in a 6-mile-wide ring, and again at 90 nautical miles in a
12-mile-wide ring, and at 120 nautical miles in a 24-mile-wide ring. After that,
the entire surface of the ocean contains sound from this original source.
the level of this sound is a tiny fraction of the ambient noise level, way below
the background noise generated by the ocean and everything it contains.
Nevertheless, in principle any sound-producing object, whether ship, submarine
or marine animal, projects its sound over the entire world ocean.
SOSUS did was nothing less than enable the U.S. Navy to identify and track all
of these sounds. From a practical engineering point of view, two problems must
be solved in order to do this. First, you must find a way to filter out and
identify the sounds produced by one ship, sounds that are orders of magnitude
below the ambient sound level. Remember, this task was accomplished way before
the advent of digital technology. It was done so well that, when I was a young
Navy Sonar Technician in the early 1960s, I could take a chart produced by a
SOSUS array and identify a specific vessel by name and hull number, often
thousands of miles distant from the receiving array.
second task is to locate the source of that sound, to pinpoint it in the
vastness of the world’s oceans. This is why we placed arrays consisting of
over 1,000 hydrophones and more than 30,000 miles of interconnecting cable in
different locations around the world. Incoming sound was not only analyzed for
its acoustic content in order to identify the source, but it was also analyzed
over short time intervals, using the huge arrays as vectoring antennae that
could generate circles of position. Crossing three of these circles resolved the
location of the sound source.
bottom line is that we actually knew the precise location of every single vessel
of interest above and below the surface, essentially all the time, throughout
most of the Cold War. Furthermore, the other guys knew that we knew. They did
everything possible to thwart our ability. They mapped shadow zones unseen by
SOSUS, where they hid their submarines. They dragged the bottom with special
anchors designed to pull up and destroy specific hydrophone arrays when they
could find them. (This resulted in some interesting surreptitious placements of
arrays in a poker game of subterfuge and bluff that proved unequivocally that
while the Soviets may have been master Chess players, Stud Poker was our game.)
the fall of the Soviet Union, we no longer needed to know the exact locations of
the world’s shipping, since most commercial vessels were tracked by one or
more international tracking systems similar to air traffic control, and there no
longer were submarines out there capable of threatening our existence. SOSUS was
expensive to operate, so eventually we shut it down, keeping it in a standby
mode in the event we would ever need it in the future.
some point scientists within the National Oceanic and Atmospheric Administration
(NOAA) determined that the old SOSUS network could help them identify and locate
deep ocean vents and volcanoes. And so the old Cold War sword and chariot was
beaten into plowshares for science where even today it serves the scientific
community in ways never envisioned by its creators a half-century ago.
9/11, we found ourselves at war once again – this time with an unseen enemy
who kills women and children and innocent civilians with a glee normally
reserved for great victories on the battlefield. We have dramatically changed
our society to accommodate this enemy. In fact, we have made it so tough for him
in our own country that he has turned to blowing up innocents in places where
the watchers are less observant and the system is less secure.
still have a major gap in our homeland protection, however. Our great shipping
ports still bring in huge amounts of goods and materials, some in bulk like oil
and minerals, but much of it in 20-foot containers called TEUs (for twenty-foot
equivalent) units. The west coast ports of
are some 90,000 ships plying the oceans of this planet. The
vast majority of these vessels sail under flags of convenience, registered in
In other words, we need to know where these guys are all of the time.
This is where the old Cold War SOSUS network comes into play. Newly updated, and outfitted to pinpoint the locations of ships that are not controlled by any international or national authority, SOSUS once again is available to protect our shores and those of other peace-loving nations from international maritime threats.
Knowing where the ships are located is ninety percent of the battle. It matters little that terrorists know we can do this, because there is absolutely no way for them to avoid being detected – except to stay within the 100-fathom curve, which puts them squarely under Coast Guard surveillance or that of the Guard’s foreign equivalent.
Constantly knowing the location of all the world’s rogue ships leaves little opportunity for them to meet with or be controlled by terrorists. Knowing where they are, and what they are doing, whom they are meeting, and where they are headed leaves little to chance, and goes a long way towards securing our shores from the horror of a ship borne nuclear, biological, or chemical attack.
In the words of the Commander-in-Chief: “Bring ‘em on!”