A military convoy is making its way through a crowded Baghdad street. Without warning, a blast rings out and the Bradley fighting vehicle leading the convoy is destroyed, along with the men and women it carried.
A crowd of what appears to be civilians rushes the decimated vehicle, surrounding it, and units are called in to calm the situation and secure the Bradley. The crowd grows unruly. Units on the scene fear that insurgents or sympathizers may have blended into the crowd and are attempting to loot the vehicle of ammunition and parts.
Today, those units have two choices -- and both of them are bad. They can attempt to disperse the crowd by ordering them to get away from the vehicle -- which would likely have little effect -- or they can fire into the crowd, possibly injuring or even killing innocent civilians in the process.
"If you're a soldier dealing with an unruly mob, you don't have a lot of options," says Noah Shachtman, editor-in-chief of Defensetech.org. "You have the M-16 option, the bullhorn option, and there's not that much in between."
That is, until now. A new non-lethal weapon developed by the Department of Defense intends to give soldiers a third option in these situations.
The ADS, or Active Denial System, fires an invisible beam that penetrates the top 1/64th of an inch on a target's skin, hitting sensitive pain receptors and causing a burning sensation some have likened to being dipped in molten lava.
When the target steps out of the beam's path, the pain goes away instantly, causing no permanent damage and leaving no marks, bruises or burns.
Some military experts are calling it the Holy Grail of crowd control. But critics fear that after incidents like the Abu Ghraib prison torture scandal, the potential for the technology to be used for more sinister means is simply too great.
"The big concern is exactly what it's going to be used for and do we want a weapon that simply causes pain because there are all sorts of ways that this could be misused," said David Hambling, who has monitored the ADS and other non-lethal technologies and written the book "Weapons Grade: How Modern Warfare Gave Birth to Our High-Tech World."
A Non-Lethal Alternative to Deadly Force?
The ADS looks like a flat radar dish mounted on a military Hummer. Engineers are also developing an airborne, shipboard and hand-held version as well. Operators use a focused camera that shows exactly where the beam will hit and fire on targets from afar, keeping the device and the soldiers around it out of range of small arms fire.
"If you've ever used a blow dryer on your hair, and if you leave the blow dryer in one place for too long, you have to move it away -- it's very similar to that effect," said Susan LeVine, principle deputy for policy and strategy at Defense Department's Joint Non-Lethal Weapons Program.
The device uses millimeter waves that are much easier to control than microwaves but have a similar effect -- they heat things up.
LeVine insisted that millimeter waves are not nearly as harmful as microwaves -- though both can cause cancer. She said extensive testing has proven that the device isn't dangerous beyond the pain it generates.
"It does not penetrate or reach deep into the body, so it's not going to affect your internal organs or pacemaker -- it's only going to touch the outermost surface of the skin," she said. "This is by far the most researched non-lethal weapon in the history of the Department of Defense."
According to LeVine, there are no know long-term side effects and the weapon doesn't cause cancer. She also said that due to the instinctive reaction to close one's eyes and turn away from the heat the beam generates, it has shown no negative effect on a target's eyesight.
Enter the 'Hall of Justice'
According to experts, the device is the darling of the non-lethal weapons program, which is working on weapons that sound more like they come out of the world of science fiction than military science.
"The world of less lethal weapons sometimes feels like you're stepping into the 'Hall of Justice,'" said Shachtman. "There are slippery foams, hardening foams, there's wireless Tasers where the electrical energy just leaps out at you, there are vortex rings of compressed air."
Though Shachtman said the military's non-lethal weapons research only accounts for a tiny portion of the military research budget as a whole, he said the Pentagon's Quadrennial Defense Review called for doubling the budget for non-lethal research. He said he believes this is a sign of increased confidence in -- and the necessity for -- the technologies being developed.
LeVine said that testing the ADS on more than 600 volunteers over the last 12 years showed that it makes people run away, leading to David Hambling nicknaming it the "Goodbye Gun."
"When you feel that millimeter wave energy, you get a heating sensation, a clear distinct sensation that you know somebody's telling you to stop your actions and get out of the area," said LeVine.
But what if you're stuck in a crowd? Trapped on the ground or simply unable to get out of the weapon's path?
LeVine said that's not possible due to the operator's training and the camera used to target the device. She said the operator will see what is happening.
But LeVine also said that the ADS is not meant to replace all of the other lethal and non-lethal weaponry and options at soldiers' disposal.
"They're going to make a choice on how to deal with the situation. And if they were to engage and employ the Active Denial System, and they're not getting the desired response, then they may use other force options," LeVine said. "We're not saying this is the end-all weapon and will solve all problems. It's just another tool for our troops."
Those troops will have to wait until at least next year for the ADS. It wraps up the final phase of testing -- the Advanced Concept Technology Demonstration -- with the 820th Security Forces Group at Moody Air Force Base in Georgia in 2007.