For most of its 59-year history, the Air Force has focused on building bigger bombs and faster planes that could reach beyond the front lines and destroy an enemy's critical infrastructure. The pinnacle was the powerful "shock and awe" campaign that opened the Iraq war three years ago.
But as the swift toppling of Saddam Hussein has gotten bogged down in the long slog of battling an insurgency, the Air Force is shifting its emphasis. One hot new project in the service these days: a bomb designed to limit damage, not expand it.
If it works right, the "focused-lethality munitions" will kill insurgents hiding in an urban building without injuring people next door. The story of this unusual bomb is just one example of how the Iraq war is triggering changes throughout a U.S. military coming to grips with the shadowy 21st century wars against terrorists and guerrillas. The Army and Marine Corps are rewriting the doctrine that guides the way they fight such wars, emphasizing restraint instead of overwhelming firepower. The Navy is pouring $200 million into developing a force that can police rivers -- its first since Vietnam. Billions are being spent Pentagon-wide to spot and destroy low-tech killers like remote-detonated roadside bombs.
For the Air Force, the new bomb is part of an effort to carve out a role for itself in today's messy, low-tech wars, which are being fought largely on the ground. The development of the focused-lethality munition is also an example of how the massive Pentagon bureaucracy often isn't as nimble as the enemy it is fighting. The project languished for several years until Air Force Secretary Michael Wynne remembered a briefing he had received on it in 2003 when he was a Pentagon acquisition official. He soon asked Air Force pilots and planners waging the war in Iraq if they could use such a weapon.
Their response: "You have no idea," says Maj. Casey Eaton, Mr. Wynne's military aide.
When the Iraq war started in 2003, Air Force strategy was heavily influenced by a theory known as "effects-based operations." It argued that rapid, highly precise air strikes aimed at the enemy's essential infrastructure could temporarily shatter its ability to fight as a coherent force and bring a rapid end to the conflict. This theory was the main driver behind the "shock and awe" air assault that kicked off the war.
But "shock and awe" is largely irrelevant to fighting insurgents in Iraq or al Qaeda terrorists hiding out in the mountains of Pakistan and Afghanistan. The sudden shift has left the Air Force struggling to figure out its place. "The Air Force and the Navy are almost invisible in Iraq. After a while you wonder what they do," says Loren Thompson, chief operating officer of the Lexington Institute, a Washington-based defense think tank.
Now the Air Force is feverishly refashioning its weapons systems to fight this new enemy. Nowhere is that more evident than in the service's push to make smaller and smaller bombs with increasingly precise laser- and satellite-guidance systems. As recently as 2002, the smallest satellite-guided bomb in the Air Force arsenal weighed a whopping 2,000 pounds -- enough to destroy a four-story building.
In the past two years, the Air Force has retrofitted all its warplanes to carry new 500-pound satellite-guided bombs, which have become the "weapon of choice in urban environments," says Maj. Gen. Allen Peck, deputy commander of the headquarters overseeing the air wars in Iraq and Afghanistan. It's also spending $1.6 billion to mass produce a new 250-pound satellite-guided bomb. All three of those bombs are made by Boeing Co. The Air Force has even experimented with dropping satellite-guided inert bombs, filled with cement instead of traditional explosives.
The smaller bombs -- especially the 250-pound bombs -- are more useful in cities because they don't cause the same destruction that the larger bombs do. But they still can cause considerable unintended casualties by spraying deadly shrapnel for hundreds of yards.
The focused-lethality munition, which has the potential to produce even less collateral damage, is different from typical bombs in two big ways: the makeup of the casing and what's inside it.
A traditional bomb's casing is made of metal, which shatters when the bomb explodes and provides most of the blast's killing power. The new Air Force munition is encased in a carbon-fiber composite. When the bomb goes off, the special case breaks into thousands of harmless fibers -- limiting the bomb's killing range. On the other hand, the new case fractures more easily than a metal one -- meaning the explosion is stronger close to the target. "More of the blast energy is available as blast as opposed to being absorbed in the steel case," says Dennis Baum, a special technical adviser on munitions in the Pentagon.
The inside of the bomb, which will weigh 250 pounds, is also different. Along with the traditional explosive found in most bombs, the new bomb mixes in a special dense metal powder. The initial blast propels the powder out at such speed that it is highly deadly. Then after traveling a short distance, drag and gravity cause the heavy powder to fall quickly to the ground.
The result is an explosion that is powerful and lethal, but relatively well-contained.
In tests using dummies made out of a special gel that replicates human flesh the blast obliterated everything in the bomb's immediate area, including the gauges the Air Force uses to measure the power of the blast. Scientists at Eglin Air Force base in Fort Walton Beach, Fla., where the tests were conducted, eventually had to design new, hardier pressure gauges.
"Everyone was surprised by the ferocity of the blast," says Mr. Wynne, the Air Force's top civilian official. Even more shocking was that "soft targets relatively close to the blast were not damaged," he says.
Government scientists stumbled onto the new munitions almost by accident. In 2000, scientists at Lawrence Livermore National Laboratory outside San Francisco were trying to build a bomb that could penetrate cement or stone to take out bunkers. The Pentagon was increasingly worried that nations like North Korea or Iran would try to protect stockpiles of nuclear or chemical weapons by burying them deep underground.
Defense department scientists began to experiment with carbon fiber, a lightweight but strong material used in everything from skis to automobiles. In early tests of bomb casings without explosives inside, the carbon-fiber-composite shells seemed to cut through cement and stone more efficiently than traditional steel. "If you look at the surface finish of a composite-cased penetrator after it has been recovered it looks very clean -- almost pristine," says Mr. Baum. "Steel-cased penetrators come out encased with rock and concrete sticking to them. They are ugly looking."
By 2002, interest in deep-penetrating bombs took a back seat to the war in Afghanistan. The Lawrence Livermore scientists working on the carbon-fiber-cased bombs began to wonder if these bombs might be suited to the new kinds of war the U.S. was engaged in following the Sept. 11, 2001, attacks. Such wars increasingly seemed to be focused on killing small groups of terrorists hiding among civilians. "There was a general sense that warfare had changed and targets had changed," says Mr. Baum, who oversaw some of the early work on the project.
U.S. forces in Afghanistan separately were coming to the same conclusion. Not long after the Taliban regime was toppled in November 2001, senior military officials using a Predator unmanned surveillance plane spotted what they believed was Taliban leader Mullah Omar's convoy pulling up to a warren of buildings outside Kabul. They asked for permission to level the building with a 2,000-pound precision-guided bomb, say two senior military officials involved in the decision-making process. But because of concerns that the bomb shrapnel might kill civilians in the surrounding buildings, the military officers directing the raid had to get special approval from lawyers at U.S. Central Command Headquarters in Tampa.
The approval was slow in coming. Instead of the 2,000-pound bomb, they ultimately fired a much smaller Hellfire missile, which is designed to penetrate armor and destroy tanks but doesn't create a large enough blast to be effective at killing people in buildings, say senior military officials. Ultimately Mullah Omar escaped unharmed and is still at large today. The incident was first described in the New Yorker magazine.
In 2003, Mr. Wynne, a former defense-industry executive who was then serving as the Pentagon's top acquisition official, got a briefing on the new type of bombs. He was intrigued, he says. But not much happened for the next couple of years. At the time, preparations for the impending war to drive Saddam Hussein from power held the full attention of most senior officials in the Defense Department.
"The project kind of stagnated," says Mr. Wynne's military aide.
Typically, new weapons programs are developed when the military officers charged with prosecuting wars or plotting strategy identify a gap in the existing arsenal. Acquisition officials in the Pentagon and defense contractors then try to fill that need.
As the Iraq war progressed, Air Force personnel prosecuting the war saw a need for a weapon that would allow them to kill insurgents in one building without spraying shrapnel. "In counterinsurgency warfare you are trying to preserve the support of the people," says Gen. Peck from his base in the Middle East. "You can't do that if you are destroying their houses and neighborhoods."
The needs of commanders in Iraq, however, didn't spur interest in the focused-lethality munition until the fall of 2005 when Mr. Wynne became Air Force secretary. One big reason for the two-year delay was that Air Force commanders in the field didn't know that Pentagon scientists were working on bombs that could kill without spraying shrapnel over a large area. "This is one of those cases where the art of the possible wasn't understood by the war fighter," says Maj. Gen. David Edgington, a senior Air Force acquisition official.
As Secretary Wynne talked to senior Air Force commanders in September 2005, it was obvious that collateral damage had become a huge concern for the military. He suspected the low-collateral-damage bomb might be of some help.
On a trip to the Middle East last fall he asked his military aide, Maj. Eaton, to talk to some of the Air Force's master attack planners, midranking officers involved in running the day-to-day air war, and see if they could use such a bomb. One military planner told Maj. Eaton that he had 15 to 20 targets in his computer that he couldn't hit because of concerns about collateral damage.
Mr. Wynne then asked Air Force acquisition officials in the Pentagon to work with commanders in the Middle East to produce a letter outlining the need for the new weapon.
In late February, the Air Force made a last-minute request to Congress to set aside $40 million for the project, dubbed the focused-lethality munition. "There is an urgent operational need" for this weapon, the Air Force wrote in its request to Congress.
The new bomb still needs more work before it will be ready for war -- in part because military officials aren't exactly sure what they need. "It is very easy for the war fighter to say I want the lowest collateral damage bomb that I can possibly get," Gen. Edgington says. "But what does that mean exactly? How does an engineer design that kind of specification? We have to give the contractor some clear parameters."
If Congress approves the Air Force's $40 million request, Air Force scientists and acquisition officials will begin more rigorous testing of the bomb. The goal is to produce about 50 of the bombs by 2008. If the bombs prove their worth in Iraq and Afghanistan, the Pentagon will contract with the defense industry to manufacture them on a larger scale.
Many new projects like the low-collateral-damage bomb don't pan out, but Air Force officials believe this program will be an exception. In the past few months, the Air Force has assigned four scientists to work full time on the weapon, up from one scientist working part time a few months ago. "We know that there is a real need out there for this kind of munition," Gen. Edgington says.