WASHINGTON - For the first time in combat, America has lobbed a still-experimental bomb so fierce it can crush an enemy's internal organs as he hides far beneath the surface of the earth.
U.S. military officials said American bombers dropped two of the little-tested munitions Saturday in the rough mountains of eastern Afghanistan, where U.S. and allied fighters are locked in a new ground offensive against Taliban and al Qaeda forces.
Pentagon officials gave no indication Sunday of the effectiveness of the bombs, which struck near Gardez, about 95 miles south of the capital Kabul.
As heavy as a Volkswagen, these "thermobaric" bombs are designed to suck the oxygen out of a cave or tunnel, killing even earthworms deep underground. Though the blasts are believed capable as well of wrecking sensitive equipment and destroying chemical weapons beyond the reach of conventional bombs, they are designed to leave the subterranean structure intact so it can later be searched.
Named from the Greek words for "heat" and "pressure," thermobaric bombs are meant to address a glaring weakness in America's military might - the ability to penetrate well-fortified or deeply buried targets.
"The United States and its allies face a growing threat related to critical military targets hidden within and shielded by hardened, deeply buried tunnel complexes," John Pike, director of globalsecurity.org, a defense research Web organization, recently wrote.
Such netherworld hideouts could become the place of choice for America's enemies to hide nuclear, chemical or biological weapons, or install impervious command centers, Pike wrote. One advantage of thermobaric bombs would be their theoretical ability to incinerate deadly weapons without spreading the poison into the atmosphere.
Before this weekend, only 10 of these GBU-118B bombs existed. The Pentagon had planned to begin final testing of the munitions later this year, but rushed them into production after the war on terrorism began last October, Pentagon officials said. They had been under development for two years.
After a hastily called test firing Dec. 14 in Nevada, an undisclosed number of the bombs - whose cost the Pentagon has yet to reveal - were whisked to Afghanistan, where Taliban and al Qaeda fighters have shown an affinity for using caves to hide weapons, ammunition and troops.
"It's something that we clearly have a need for in Afghanistan," Pete Aldridge, undersecretary of defense for acquisition said in announcing the first-ever deployment of the bombs, which were developed by the Naval Surface Weapons Center and adapted by the Air Force.
Attached to a laser-guided smart weapon and dropped from an F-15 fighter jet, the one-ton thermobaric warheads pack an extraordinary one-two punch.
Aimed at the entrance of a cave or tunnel, a first explosion from the 8-foot-long warhead spreads a fine dust of solid explosive, which penetrates the opening and beyond. After a 120-millisecond delay, a more ferocious blast ignites the cloud of explosive.
That creates an enormous wave of pressure and heat that essentially sucks the air out of the cave like a vacuum cleaner, collapsing the lungs of, and causing internal hemorrhages to, those unfortunate enough to be inside.
On the Web:
http://www.dtra.mil - The Pentagon's Defense Threat Reduction Agency