Warfare is changing as weapons that destroy electronics, not people, are deployed on the field of battle
Oct 15th 2011 | from the print edition
BULLETS and bombs are so 20th-century. The wars of the 21st will be
dominated by ray guns. That, at least, is the vision of a band of
military technologists who are building weapons that work by zapping the
enemy’s electronics, rather than blowing him to bits. The result could
be conflict that is less bloody, yet more effective, than what is now
seen as conventional battle.
Electromagnetic weapons, to give these ray guns their proper name,
are inspired by the cold-war idea of using the radio-frequency energy
released by an atom bomb exploded high in the atmosphere to burn out an
enemy’s electrical grid, telephone network and possibly even the wiring
of his motor vehicles, by inducing a sudden surge of electricity in the
cables that run these things.
That idea, fortunately, was never tried in earnest (though some
tests were carried out). But, by thinking smaller, military planners
have developed weapons that use a similar principle, without the need
for a nuclear explosion. Instead, they create their electromagnetic
pulses with magnetrons, the microwave generators at the hearts of radar
sets (and also of microwave ovens). The result is kit that can take down
enemy missiles and aircraft, stop tanks in their tracks and bring
speedboats to a halt. It can also scare away soldiers without actually
killing them.
Many electromagnetic weapons do, indeed, look like radars, at least
to non-expert eyes. America’s air force is developing a range of them
based on a type of radar called an active electronically scanned array
(AESA). When acting as a normal radar, an AESA broadcasts its microwaves
over a wide area. At the touch of a button, however, all of its energy
can be focused onto a single point. If that point coincides with an
incoming missile or aircraft, the target’s electronics will be zapped.
Small AESAs—those light enough to fit on a plane such as a joint
strike fighter (F-35)—are probably restricted to zapping air-to-air and
surface-to-air missiles (the air force is understandably reticent about
supplying details of their capabilities). Ground- or ship-based kit can
draw more power. This will be able to attack both ballistic missiles and
aircraft, whose electronics tend to be better shielded.
In the case of the F-35, then, this sort of electromagnetic artillery
is mainly defensive. But another plane, the Boeing Growler, uses
electromagnetics as offensive weapons. The Growler, which first saw
action in Iraq in 2010 and has been extensively (though discreetly)
deployed during the NATO air war against Colonel Qaddafi’s forces in
Libya, is a souped-up version of the Super Hornet. It is fitted with
five pods: two under each wing and one under the fuselage. Some pods
contain AESAs or similar electromagnetic weapons. Others have
eavesdropping equipment inside them. In combination, the pods can be
used either to spy on enemy communications or to destroy them; to
suppress anti-aircraft fire; to disable the electronics of ground
vehicles; and to make life so hazardous for enemy aircraft that they
dare not fly (and probably to shoot them down electronically, too,
though no one will confirm this). The Growler is able to keep its
weapons charged up and humming by lowering special turbines into the
airstream that rushes past the plane when it is flying. America has
ordered 114 of the planes, and has taken delivery of 53.
By land, sea and air
Nor are aircraft the only vehicles from which destructive
electromagnetic pulses can be launched. BAE Systems, a British defence
firm, is building a ship-mounted electromagnetic gun. The High-Powered
Microwave, as it is called, is reported by Aviation Week
to be powerful enough to disable all of the motors in a swarm of up to
30 speedboats. Ships fitted with such devices would never be subject to
the sort of attack that damaged USS Cole in
2000, when an al-Qaeda boat loaded with explosives rammed it. A gun like
this would also be useful for stopping pirate attacks against
commercial shipping.
Land vehicles, too, will soon be fitted with electromagnetic cannon.
In 2013 America hopes to deploy the Radio-Frequency Vehicle Stopper.
This device, developed at the Joint Non-Lethal Weapons Directorate in
Quantico, Virginia, is a microwave transmitter the size and shape of a
small satellite dish that pivots on top of an armoured car. When aimed
at another vehicle, it causes that vehicle’s engine to stall.
This gentle way of handling the enemy—stopping his speedboats,
stalling his tanks—has surprising advantages. For example, it expands
the range of targets that can be attacked. Some favourite tricks of
modern warfare, such as building communications centres in hospitals, or
protecting sites with civilian “human shields”, cease to be effective
if it is simply the electronics of the equipment being attacked that are
destroyed. Though disabling an aircraft’s avionics will obviously cause
it to crash, in many other cases, no direct harm is done to people at
all.
The logical conclusion of all this is a so-called “human-safe”
missile, which carries an electromagnetic gun instead of an explosive
warhead. Such a missile is being developed at Kirtland Air Force Base in
New Mexico, and will soon be tested at the White Sands Missile Range.
There is, however, at least one electromagnetic weapon that is
designed to attack enemy soldiers directly—though with the intention of
driving them off, rather than killing them. This weapon, which is called
the Active Denial System, has been developed by the Joint Non-Lethal
Weapons Directorate, in collaboration with Raytheon. It works by heating
the moisture in a person’s skin to the point where it feels, according
to Kelley Hughes, an official at the directorate who volunteered to act
as a guinea pig, like opening a hot oven. People’s reaction, when hit by
the beam, is usually to flee. The beam’s range is several hundred
metres.
Such anti-personnel weapons are controversial. Tests on monkeys,
including ones in which the animals’ eyes were held open to check that
the beam does not blind, suggest it causes no permanent damage. But when
a vehicle-mounted Active Denial System was sent to Afghanistan in May
2010, it was eventually shipped back home without being used. The
defence department will not say exactly why. The suspicion, though, is
that weapons like the Active Denial System really are reminiscent in
many minds of the ray guns of science fiction, and that using them in
combat would be a PR mistake. Disabling communications and destroying
missiles is one thing. Using heat-rays on the enemy might look bad in
the newspapers, and put civilians off their breakfast.
Cold showers are good for you
To every action there is, of course, an equal and opposite reaction,
and researchers are just as busy designing ways of foiling
electromagnetic weapons as they are developing them. Most such foils are
types of Faraday cage—named after the 19th-century investigator who did
much of the fundamental research on electromagnetism.
A Faraday cage is a shield of conductive material that stops
electromagnetic radiation penetrating. Such shields need not be heavy.
Nickel- and copper-coated polyester mesh is a good starting point.
Metallised textiles—chemically treated for greater conductivity—are also
used. But Faraday cages can be costly. EMP-tronic, a firm based in
Morarp, Sweden, has developed such shielding, initially for the Gripen, a
Swedish fighter jet. It will shield buildings too, though, for a
suitable consideration. To cover one a mere 20 metres square with a
copper-mesh Faraday cage the firm charges €300,000 ($400,000).
Shielding buildings may soon become less expensive than that. At
least two groups of scientists—one at the National Research Council
Canada and the other at Global Contour, a firm in Texas—are developing
electrically conductive cement that will block electromagnetic pulses.
Global Contour’s mixture, which includes fibres of steel and carbon, as
well as a special ingredient that the firm will not disclose, would add
only $20 to the $150 per cubic metre, or thereabouts, which ordinary
concrete costs.
The arms race to protect small vehicles and buildings against
electromagnetic warfare, then, has already begun. Protecting ships,
however, requires lateral thinking. For obvious reasons, they cannot be
encased in concrete. And building a conventional Faraday cage round a
naval vessel would be horribly expensive.
Daniel Tam, of the Space and Naval Warfare Systems Command in San
Diego, thinks he has a way to get round that. He proposes to use the
electrical conductivity of the sodium and chloride ions in seawater to
create a novel type of Faraday cage. A shroud of seawater around a ship,
thrown up by special pumps and hoses if the vessel came under
electromagnetic attack, would do the trick, he reckons.
It is an ambitious idea. Whether it works or not, it shows how much
the nature of modern belligerency is changing. Bombs and bullets will
always have their place, of course. But the thought that a cold shower
could protect a ship from attack is almost surreal.
