IEEE Spectrum September, 2008 - 24

ing won't involve vast arrays of tanks,
fighter planes, and bombers, radar and
countermeasures, and troops firing ordnance at each other in accordance with
military doctrine as it has evolved over
the past 2500 years. Given their goals
and the means available to them, and
their need to counteract their opponents'
overwhelming advantages in technology
and resources, insurgents and militiamen will keep on using IEDs, including
car and suicide bombs.
To be specific: "The IED threat will
be long-term, because nobody will
want to fight the United States force-onforce," predicts Col. Dick A. Larry, head
of the IED division of the U.S. Army
Asymmetric Warfare Office.
"IEDs have the capability to inflict damage, political and psychological, out of all
proportion to their size and cost," noted
Maj. Gen. Anthony Stone, the former
director of special projects for the UK's
Ministry of Defense, at a recent conference
on counter-IED technology.
Some analysts warn that rogue fighters will inevitably use weapons of mass
destruction, probably in an improvised
way. And though the United States and
some European and Asian countries
have seen few IED attacks so far, not
many analysts think that state of affairs
will go on indefinitely.
"If we do not find solutions now in
Afghanistan and Iraq, we will continue
looking for solutions when this problem comes to the United States," says
Colonel Barry L. Shoop, who is director
of the electrical engineering program
at the U.S. Military Academy and was
JIEDDO's first chief scientist.
30

NA * iEEE SpEctrum * SEptEmbEr 2008

he difficulty of the counterIED challenge arises from
many factors. The physical,
electromagnetic, and chemical environments in which
IEDs are deployed are chaotic and cluttered. The social networks that let insurgents fund, build, and emplace IEDs are
incredibly complex. And IEDs themselves
are hugely diverse, their makers having
proved themselves tireless in adapting
and altering their creations.
All IEDs have a power source, a trigger, a detonator, and a main charge. The
power source is usually a battery. Its
function is to supply enough energy to
the detonator, usually a blasting cap,
to enable it to set off the main charge.
In 2004, as IEDs began proliferating
wildly in Iraq, the main charge was typically artillery rounds lashed together
to explode simultaneously, the casings
shattering to provide shrapnel. Bomb
makers also frequently pack ball bearings around the main charge to maximize casualties.
Over the past couple of years, Sunni
insurgents have favored homemade explosives for the main charge. They're more
easily used in the huge quantities needed
to fling through the air the 25-ton vehicles now commonly used by U.S. forces.
The typical homemade explosives in Iraq,
urea nitrate and ammonium nitrate, are
produced using nitrogen-based fertilizers.
To make urea nitrate, bomb makers separate the urea from the fertilizer and then
use nitric acid to attach a nitrate group
(NO3) to the urea molecule.
The fertilizers and other materials
are not easily controlled, because Iraq's

struggling economy has a large agricultural component. And even with hundreds of IED incidents a month in Iraq,
the relative amount of fertilizers diverted
to making IEDs is small.
Five-gallon cans or barrels are common containers for the main explosive.
For a barrel, the detonator might be a bag
filled with TNT and a blasting cap (ironically, the bag has often been the thick plastic bag that a military "meal, ready to eat"
comes in). To complete the IED, a trigger
of some sort is connected to the detonator. Such a bomb could easily destroy a
light vehicle like a Humvee or could seriously damage a heavier, more extensively
armored vehicle, such as an MRAP (mineresistant, ambush-protected) truck.
The two most lethal forms of IEDs are
deep-buried IEDs and explosively formed
penetrators (EFPs). They account for
only 5 to 15 percent of all IEDs in Iraq but
roughly 40 percent of the IED casualties,
according to the latest figures from the
U.S. Defense Department. Deep-buried
IEDs often contain hundreds of kilograms of explosive and have flung heavily armored vehicles like MRAPs tens of
meters, in one case killing all on board.

e went into an
intersection, and
the EFP went off
and went right
through our vehicle,"
says the deputy commander of the Gulf
Region Central District of the U.S. Army
Corps of Engineers in Iraq. At the time of
the attack, he was south of Baghdad, in a
heavily armored vehicle called a Wolf. "The
molten metal came up underneath us, and
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Table of Contents for the Digital Edition of IEEE Spectrum September, 2008