The Active Denial System (ADS) is a form of non-lethal weapon developed by Raytheon Corp. It takes advantage of existing knowledge about electromagnetic energy to create a weapon which can be used for crowd control without causing lasting pain or damage. The weapon is one among many non-lethal weapons under development by defense contractors in response to the changing face of warfare and a growing need for weapons which can disperse a crowd without injuring people. The device entered the human testing phase in early 2007.
Several different prototypes of the Active Denial System have been tested, including portable versions and versions which were designed for mounting on military vehicles. Both versions work in the same way; they use a specific frequency of electromagnetic radiation to excite water molecules in the upper layers of the skin, causing a burning sensation. The radiation is directed to a specific area, encouraging people to move out of that area to avoid the painful sensation.
According to Raytheon, the radiation from the Active Denial System does not penetrate deeply enough to cause damage, and there should be no after-effects after someone has moved out of range of the “pain ray,” as the Active Denial System is colloquially called. People who have experienced the energy of the pain ray have said that it is akin to being blasted with air from a hot oven; while not exactly painful, the device certainly encourages someone to move out of range.
The goal behind the pain ray and similar devices is the ability to control groups and crowds in a more humanitarian way. The United States military has clamored for such weapons since the early 21st century, in response to concerns about injuring or killing civilians while attempting to control a rioting crowd. The use of the Active Denial System could be effective in war zones for working with amorphous groups which may contain soldiers mixed with civilians. Pain rays are also potentially useful in non-military situations, like riots and out of control crowd situations at home.
Some concerns have been raised about the Active Denial System. Some activists are worried, for example, that the device could be used for torture; it could be directed into the cell of a prisoner who could not move, for example. The pain ray may also cause actual damage in uncontrolled situations, due to a variety of factors like metal objects carried near the skin, or a crowd which is hemmed in on several sides, making it difficult for people to leave.