And that was enough. The results are classified, but the official assessment from Ward's office says the BLU-118/B offers "improved lethality."
Duong would characterize it only as "quite effective."
Carpenter said simply: "We're very proud."
A week later, the world found out what the scientists at Indian Head had been up to. A videotape of the test was released by the Pentagon and quickly aired on most national networks. The scientists were hailed as the nation's high-tech warriors - the deadly might of American science.
"I couldn't believe it," Carpenter said about seeing the report on television. "That just doesn't happen much in this business.
But there was an unexpected consequence: Outrage. Almost immediately, critics in Europe and Asia began ascribing characteristics to the bomb that seemed straight out of a horror story - a fictional one at that.
It was a weapon of mass destruction. A nuclear blast without radiation. A "vacuum bomb" that sucked oxygen out of caves. It would, alternatively, asphyxiate people, suck out their eyes or burn them alive.
A Greenpeace official likened the bombs to nuclear weapons and called for their ban. A Russian geologist blamed them for earthquakes that killed hundreds of villagers in the Hindu Kush mountains, a claim American geologists called preposterous.
The bomb's name - BLU-118 - caused some of the confusion. It is a standard military designation, short for "bomb live unit" with a number to distinguish it from others. But the same designation was used during the Vietnam War for a very different weapon: napalm.
The term thermobaric compounded the problem. The Russian military uses it to refer to "fuel-air bombs," a much-derided killer that disperses a cloud of liquid fuel with one explosion and ignites it with a second.
PBXIH-135 is neither napalm nor a fuel-air bomb, but a traditional "single event" explosive, with common ingredients. Even its aluminum fuel is nothing unusual - many standard munitions contain aluminum, albeit not the precise mixture needed to send a blast creeping through tunnels and around corners.
Scientists often joke that no one cared about PBXIH-135 when it was simply called an "internal blast" explosive. But since last fall, when the Pentagon started calling it "thermobaric" and packing it inside something called a BLU-118, it seems the devil himself isn't nearly as frightening.
Doug Elstrodt, a 44-year-old Indian Head engineer responsible for assembling the BLU-118/B, took the phone calls from military lawyers two days before Christmas. They wanted to know just how deadly their new secret weapon was - the ingredients, the physics behind it, how long and hot it exploded.
"It's not a weapon of mass destruction or a vacuum bomb or anything like that, it's just a bomb - a big one that has been engineered to enhance the internal blast effects," Elstrodt said.
The criticism caught the Pentagon off guard. Ward and the Defense Threat Reduction Agency would issue a news release declaring that the BLU-118/B was not nearly as deadly as everyone seemed to think, and assuring that it did not violate international treaties.
Duong and the others were mostly amused. "If they believe the worst, why not let them?" Duong said.
But the role of the scientists and engineers was over by then, the bleary-eyed dash long finished. Ward was back in Virginia, trying to make an even better thermobaric bomb, and the Indian Head scientists were working on new projects - a shoulder-launched thermobaric, for instance.
The rush took months to fade - the urgency of war that these scientists had never known before.
"This was one of the highlights of my career, to be there and know why we were doing this, and then to be able to deliver what the country needed," said Carpenter. "I'll never forget it."
And for Duong, home in Laurel with her husband and four children, the family members who fled Vietnam with her all settled nearby, the satisfaction was even sweeter. She had made a hefty installment on a private debt that she never truly expects to repay.
"The BLU-118/B, to me, is another example of what is wonderful about this country," she said. "At a time that was supposed to be a moment of weakness, the American people worked together - people of all religions and colors and backgrounds.
"We didn't panic, we stayed focused, and in a very disciplined manner, with a specific goal, we built a weapon targeted at a very specific military threat.
"I think it's a prime example of united we stand, united we fall, united we win," she said. "It makes me very proud."
As for the bombs, no one at Indian Head knows where they are. They left on a flatbed truck headed for Texas.
"Our role was finished at that point," said Elstrodt. "They just sort of dropped out of sight."
`We did our job'
On March 2, somewhere in or near Afghanistan, an American F-15E Strike Eagle took off toward the Shah-i-Kot mountains on the country's eastern border, with the United States' newest anti-terrorist bomb hanging from its racks.