Active Denial System

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Humvee with ADS mounted.
Humvee with ADS mounted.

The Active Denial System (ADS) is a non-lethal, directed-energy weapon system under development by the U.S. military. It is a strong millimeter-wave transmitter used for crowd control (the "goodbye effect"[1]). Raytheon is currently marketing a reduced range version of this technology."[2]

[edit] Operation

The ADS works by directing electromagnetic radiation at a frequency of 95 GHz[3] toward the subjects. The waves excite (see Excited state) water molecules in the epidermis (skin) to around 55 °C (130 degrees Fahrenheit), causing an intensely painful burning sensation. While not actually burning the skin, the burning sensation is similar to that of a light bulb being pressed against the skin.[3] The focused beam can be directed at targets at a range of just under half a kilometer, or 500 yards[4]. The device can penetrate thick clothing, although not walls[4]. There is no indication on the feasibility of electromagnetically shielding a person from its effects with a wire mesh, in a similar manner that a microwave oven prevents radiation escaping.

A higher radio frequency is chosen because, as a property of electromagnetic waves (known as "skin depth"), they are unable to penetrate the body as deeply as lower frequency waves, thereby affecting external organs only, such as skin. The United States Military states the effect "penetrates the skin to a depth of less than 1/64 of an inch."[1] A spokesman for the Air Force Research Laboratory described his experience as a test subject for the system: "For the first millisecond, it just felt like the skin was warming up. Then it got warmer and warmer and you felt like it was on fire.... As soon as you're away from that beam your skin returns to normal and there is no pain."

The ADS is currently only a vehicle mounted weapon, however, U.S. Marines and police are both working on portable versions.

A fully operational and mounted system was demonstrated Wednesday, January 24, 2007, at Moody Air Force Base, Georgia. A Reuters correspondent who volunteered to be shot with the beam during the demonstration described it as "similar to a blast from a very hot oven - too painful to bear without diving for cover."[5]

A BBC TV television program in 25 January 2006 expressed a concern that the Active Denial System might be less effective in the Middle East against people accustomed to hot desert sun and air on their skin all day.

[edit] Controversy

Closeup of the ADS projection mechanism.
Closeup of the ADS projection mechanism.

The effects of this radio frequency on humans have been studied by the military for years, and much, but not all, of the research has been published openly in peer reviewed journals. A listing of many of these articles can be found on the military Joint Non-Lethal Weapons Program website on the ADS page.

Controversy as to the methodology of testing, in which volunteers were asked to remove glasses, contact lenses and metallic objects that could cause hot spots, has raised concerns as to whether the device would remain true to its purpose of non-lethal temporary incapacitation if used in the field where safety precautions would not be taken. Proponents of the system claim that these tests were early in the program and part of a thorough and methodical process to demonstrate the safety and effectiveness of the technology, which has now involved more than 600 volunteer subjects and some 10,200 exposures. As safety was demonstrated in each step of the process, restrictions were removed and now, according to ADS proponents, there are no restrictions or precautions necessary for volunteers experiencing the effect.[6]

Critics cite that although the stated intent of the ADS is to be a non-lethal device designed to temporarily incapacitate, easy modifications or incorrect use by the operator could turn the ADS in to a torture device that would violate international conventions on warfare.

A prototype ADS being tested.
A prototype ADS being tested.

[edit] Silent Guardian

The defense contractor, Raytheon, has developed a smaller version of the ADS, named the Silent Guardian. This stripped down model is primarily marketed for use by law enforcement agencies, the military and other security providers. The system is operated and aimed with a joystick and aiming screen. The device can be used for targets up to 550 m away.[3]

[edit] Contracts

  • 22 September 2004 Raytheon was granted an FCC license to demonstrate the technology to "law enforcement, military and security organizations."[7]

Communications and Power Industries (CPI), Palto Alto [sic], Calif., is being awarded a $6,377,762 costs-reimbursement, cost-plus fixed-price contract. The contractor shall design, build, test, and delivery a two to 2.5 megawatt, high efficiency, continuous wave (CW) 95 gigahertz millimeter wave source system. The contractor shall perform extensive modeling, simulation, experiments, and testing to the maximum capabilities of their facilities (which shall no less than one megawatt peak RF output) that will ascertain the final CW capabilities of the source. The contractor also shall provide input for the requirements for the government’s test stand, which will serve as a full power facility in the future. At this time, $900,000 of the funds has been obliged. This work will be complete by January 2009. Negotiations were completed September 2004. The Air Force Research Laboratory, Kirtland Air Force Base, New Mexico, is the contracting activity (FA9451-04-C-0298).

[edit] See also

[edit] References

is how the active-denial technology would work in rainy, foggy or sea-spray conditions where the beam's energy could be absorbed by water in the atmosphere."

  • AP report August 16, 2004
  • Why-war September 22, 2004 "On Sept. 22, 2004, Thomas J. Fagan, an employee at Raytheon, was granted an FCC license"
  • Defense Tech November 16, 2004 "AFRL handed Palo Alto's Communications & Power Industries a four year, $7 million contract, according to the Hilltop Times — the in-house paper of Hill Air Force Base. "Dr. Diana Loree, the project officer for Active Denial, said four AFRL directorates are involved in developing this airborne capability: directed energy here; propulsion and vehicles at Wright Patterson Air Force Base, Ohio; and human effectiveness at Brooks City-Base, Texas. Experts from directed energy, as the lead directorate, focuses on the systems engineering and radiating system development, she said. Propulsion directorate experts focus on the airborne power generation and conditioning required for the radiating system. Vehicles directorate scientists and engineers put their efforts toward Active Denial's thermal management and aircraft integration issues while human effectiveness experts focus on biological effects research."
  • World Tribune February 3, 2005 "New non-lethal weapon lets troops dispel hostile crowds"
  • New Scientist July 23, 2005 "Details of US microwave-weapon tests revealed"
  • New Weapon, Human Tests Wired News December 5, 2006 - Contains links to test documents.
  1. ^ Wired News: Say Hello to the Goodbye Weapon (December 5, 2006).
  2. ^ Raytheon: Silent Guardian product brief (2006).
  3. ^ a b c Hambling, David (2006), "Techwatch-Forecasting Pain", Popular Mechanics 183(12): 32, ISSN 0032-4558
  4. ^ a b US unveils 'heat gun'. Daily Telegraph (January 25, 2007). Retrieved on 25 January, 2007.
  5. ^ US military unveils heat-ray gun. BBC ( January 25 2007). Retrieved on 25 January, {{{accessyear}}}.
  6. ^ Hearn, Kelly (August 19, 2005). Rumsfeld's Ray Gun. AlterNet. Retrieved on 15 August, 2006.
  7. ^ Active Denial System: A Nonlethal 'Counter-Personnel Energy Weapon'. Why War?.com (September 22, 2004). Retrieved on 15 August, 2006.
  8. ^ Contracts for October 4, 2004. U.S. Department of Defense (October 4, 2004). Retrieved on 15 August, 2006.
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