Active Denial Technology (ADT)

Microwave beam weapon to disperse crowds

Jeff Hecht / New Scientist 24oct01

Also see Military Testing Future Additions to Nonlethal-Weapons Arsenal -  Stars and Stripes 22dec02

[ USAF Factsheet below ]

Images from USFA website listed below

Tests of a controversial weapon that is designed to heat people's skin with a microwave beam have shown that it can disperse crowds. But critics are not convinced the system is safe.

Last week, the Air Force Research Laboratory (AFRL) in New Mexico finished testing the system on human volunteers. The Air Force now wants to use this Active Denial Technology (ADT), which it says is non-lethal, for peacekeeping or riot control at "relatively long range" - possibly from low-flying aircraft.

ADT uses a 2-metre dish to create a narrow beam of microwaves that can be scanned across a crowd or even aimed at individuals. AFRL is using infrared photography to analyse the heating effect on the volunteers' bodies.

AFRL says that the 3-millimetre wavelength radiation penetrates only 0.3 millimetres into the skin, rapidly heating the surface above the 45 °C pain threshold. At 50 °C, they say the pain reflex makes people pull away automatically in less than a second - it's said to feel like fleetingly touching a hot light bulb. Someone would have to stay in the beam for 250 seconds before it burnt the skin, the lab says, giving "ample margin between intolerable pain and causing a burn".

Little data

But critics question the AFRL's claims that the weapon's undisclosed exposure levels are safe. John Pike of think tank Globalsecurity.org fears that the beam power needed to scare people may be too close to the level that would injure them. Air Force scientists helped set the present skin safety threshold of 10 milliwatts per square centimetre in the early 1990s, when little data was available, says Louis Slesin, editor of Microwave News.

That limit covers exposure to steady fields for several minutes to an hour - but heating a layer of skin 0.3 mm thick to 50 °C in just one second requires much higher power and may pose risks to the cornea, which is more sensitive than skin. A study published last year in the journal Health Physics showed that exposure to 2 watts per square centimetre for three seconds could damage the corneas of rhesus monkeys.

FACT SHEET
UNITED STATES AIR FORCE
Air Force Research Laboratory
Office of Public Affairs
3550 Aberdeen Avenue S.E., Kirtland AFB NM 87117-5776
(505) 846-1911; Fax (505) 846-0423
INTERNET: http://de.afrl.af.mil
ACTIVE DENIAL TECHNOLOGY

Directed Energy Non-Lethal Demonstration
Photograph of the demonstration hardware

Active Denial Technology is a breakthrough non-lethal technology that uses millimeter-wave electromagnetic energy to stop, deter and turn back an advancing adversary from relatively long range. It is expected to save countless lives by providing a way to stop individuals without causing injury, before a deadly confrontation develops. The technology was developed by the Air Force Research Laboratory and the Department of Defense's Joint Non-Lethal Weapons Directorate. Approximately $40 million has been spent on this technology over the past ten years.

This non-lethal technology was developed in response to Department of Defense needs for field commanders to have options short of the use of deadly force. Non-lethal technologies can be used for protection of Defense resources, peacekeeping, humanitarian missions and other situations in which the use of lethal force is undesirable.

How does it work?

Active Denial Technology uses a transmitter to send a narrow beam of energy towards an identified subject. Traveling at the speed of light, the energy reaches the subject and penetrates less than 1/64 of an inch into the skin, quickly heating up the skin's surface. Within seconds, an individual feels an intense heating sensation that stops when the transmitter is shut off or when the individual moves out of the beam.

Despite the sensation, the technology does not cause injury because of the low energy levels used. It exploits a natural defense mechanism that helps to protect the human body from damage. The heat-induced sensation caused by this technology, is nearly identical to the sensation experienced by briefly touching an ordinary light bulb that has been left on for a while. Unlike a light bulb, however, active denial technology will not cause rapid burning, because of the shallow penetration of the beam and the low levels of energy used. The transmitter needs only to be on for a few seconds to cause the sensation.

Testing

Humans and animals are being used in the test program. All testing is being conducted with strict observance of the procedures, laws and regulations governing animal and human experimentation. The tests have been reviewed and approved by a formal Institutional Review Board with oversight from the Air Force Surgeon General's Office. The testing is being conducted by the Air Force Research Laboratory's Human Effectiveness Directorate.

Military and civilian employees have volunteered for these tests. Prior to participating in the program, all volunteers are fully informed of the purpose and nature of the tests and of any reasonably foreseeable risks or discomforts expected from the research. Other than minor skin tenderness due to repeated exposure to the beam, there are no lasting effects. An institutional review board has determined that the risk level is minimal. No pay is received for participation, and volunteers may withdraw at any time with no negative personal or professional ramifications. Many of the project scientists are volunteers for the study. These tests, which are being conducted at Kirtland Air Force Base south of Albuquerque, New Mexico, employ more realistic military field conditions, following several years of successful and safe laboratory testing. These field tests are the first to expose an entire test subject to the energy beam.

These tests will demonstrate the technology, gather additional data on effects in realistic conditions, and allow the military benefits to be assessed.

Operational System

Although this testing is expected to continue into the summer, officials have begun examining appropriate platforms on which to deploy the technology. Currently, planning is underway for a vehicle-mounted version. Future versions might also be used onboard planes and ships. The vehicle-mounted version will be designed to be packaged on a vehicle such as a High Mobility Multi-purpose Wheeled Vehicle (HMMWV, more commonly referred to as a Humvee).

This technology and its proposed use in an operational system have been given a preliminary weapons legal review as required by Department of Defense Directive 3000.3 "Policy for Non-Lethal Weapons," and the United States' treaty - obligations. This preliminary review found that further research, development, and testing of this technology is permissible. As required by law, a final, comprehensive legal review will be completed prior to entering the acquisition cycle.

The Vehicle-Mounted Active Denial System concept
Organizations involved

Two primary organizations are executing this program: the Joint Non-Lethal Weapons Directorate at Quantico Marine Corps Base, Virginia, and the Air Force Research Laboratory, headquartered at Wright-Patterson Air Force Base, Ohio. The Air Force Research Laboratory is developing the technology with funding from both the Air Force and the Joint Non-Lethal Weapons Directorate.

From the Air Force Research Laboratory, two directorates are involved: the Directed Energy Directorate at Kirtland Air Force Base, New Mexico, and the Human Effectiveness Directorate at Brooks Air Force Base, Texas. The former works technology development and testing; the latter is in charge of biological effects research.

There are three primary contractors: Raytheon AET in Rancho Cucamonga, California, is the systems integrator, CPI (Communications and Power Industries) in Palo Alto, California, is the source developer, and Veridian Engineering in San Antonio, Texas, is performing biological effects research.

Other organizations and agencies that are involved in the this project include the Air Force Force Protection Battlelab at Lackland Air Force Base, Texas; the Marine Warfighting Laboratory at Quantico, Virginia; the Air Force Special Operations Command at Hurlburt Field, Florida; and the U.S. Special Operations Command at MacDill Air Force Base, Florida.

The Air Force's Electronic Systems Center at Hanscom Air Force Base, Massachusetts, will manage acquisition of the Vehicle-Mounted Active Denial System based on this technology.

Air Force Research Laboratory
Current as of March 2001

source: http://www.de.afrl.af.mil/factsheets/activedenial.html 24oct01