The Active Denial System (ADS) is a non-lethal, directed-energy weapon developed by the U.S. military.[1] It is a strong millimeter-wave transmitter primarily used for crowd control (the "goodbye effect"[2]). Some ADS such as HPEM ADS are also used to disable vehicles.[3] Informally, the weapon is also called the heat ray.[4] Raytheon is currently marketing a reduced-range version of this technology.[5] The ADS was deployed in 2010 with the United States military in the Afghanistan War, but was withdrawn without seeing combat.[6] On August 20, 2010 the Los Angeles Sheriff's Department announced its intent to use this technology on prisoners in the Pitchess Detention Center in Los Angeles, stating its intent to use it in "operational evaluation" in situations such as breaking up prisoner fights.[7]
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The ADS works by firing a high-powered beam of electromagnetic radiation in the form of high-frequency millimeter waves at 95 GHz[8] (a wavelength of 3.2 mm). Similar to the same way that a microwave oven heats food, the millimeter waves excite the water and fat molecules in the body, instantly heating it and causing intense pain. (Note that while microwaves will penetrate human tissue and remove the water to "cook" the flesh, the millimeter waves used in ADS are blocked by cell density and only penetrate the top layers of skin, so it will not damage human flesh.) However DNA damage caused by these weapons is unknown and could lead to malignant cancers in operators and targets. Such is the nature of dielectric heating that the temperature of a target will continue to rise so long as the beam is applied, at a rate dictated by the target's material and distance, along with the beam's frequency and power level set by the operator. Like all focused energy, the beam will irradiate all matter in the targeted area, including everything beyond/behind it that is not shielded, with no possible discrimination between individuals, objects or materials, although highly conductive materials such as aluminium cooking foil should reflect this radiation and could be used to make clothing that would be protective against this radiation.[9] As demonstrated on Discovery Channel's "Future Weapons", all living things in the target area receive a similar dosage of radiation.
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."
Many aspects of the research are classified, but AFRL has taken care to include independent evaluation of the maker's claims in the formal test program. According to public releases, there have been over 10,700 "shots" by ADS,[10] and has been deemed safe for use. A Penn State Human Effects Advisory Panel (HEAP) has published findings of research showing
The HEAP has concluded that ADS is a non-lethal weapon that has a high probability of effectiveness with a low probability of injury.[11]
The ADS is currently only a vehicle-mounted weapon, though U.S. Marines and police are both working on portable versions.[12]
On September 22, 2004, Raytheon was granted an FCC license to demonstrate the technology to "law enforcement, military and security organizations."[13]
On October 4, 2004, the United States Department of Defense published the following contract information:
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 deliver 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).[14]
A fully operational and mounted version of the system was demonstrated on January 24, 2007, at Moody Air Force Base, Georgia, United States. 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."[15]
On June 21, 2010, Lt. Col. John Dorrian, a spokesman for then NATO forces commander Gen. Stanley McChrystal, confirmed in an e-mail to Wired Magazine reporter Noah Shachtman that the ADS was deployed in Afghanistan. The spokesman added however that the system has not yet been used operationally.[15]
The ADS has been removed from service in Afghanistan as of July 25, 2010. A spokesperson for the United States Department of Defense said "The decision to recall the weapons back to the US was made by commanders on the ground in Afghanistan."[16]
ADS has been designed as non-lethal, non-persistent method of crowd control and perimeter defense, "the gap between shouting and shooting." Other crowd control methods - including tear gas, water cannons, slippery foam and rubber bullets - carry implicit dangers of injury or accidental death, and often leave residue or residual materiel. ADS can be used to disperse a crowd or to move them from an area; a group of people can be dispersed or induced to leave the street without damage to personnel or the environment.
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.[17]
Some critics believe the development of such an expensive and complicated system for a single purpose does not seem plausible, as the water cannon has proven to be an effective (though occasionally unsafe) riot control tool. Another news article criticized the sheer amount of time it is taking to field this system, citing the potential it had to avert a great deal of pain and suffering in volatile areas around the world.[18]
Although the effects are described as simply 'unpleasant', the device has the ‘Potential for Death’.[19] The beam is claimed to only affect one individual for a short moment, but safety presets and features can be overridden by the operator.
While it is claimed not to cause burns under 'ordinary use',[20][21] it is also described as being similar to that of an incandescent light bulb being pressed against the skin,[8] which can cause severe burns in just a few seconds. The beam can be focused up to 700 meters away, and is said to penetrate thick clothing although not walls.[22] At 95 GHz, the frequency is much higher than the 2.45 GHz of a microwave oven. This frequency was chosen because it penetrates less than 1/64 of an inch (0.4 mm),[23] which - in most humans, except for eyelids and babies - avoids the second skin layer (the dermis) where critical structures are found such as nerve endings and blood vessels.
The early methodology of testing, in which volunteers were asked to remove glasses, contact lenses and metallic objects that could cause hot spots, 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. However, 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.[24] Long-term exposure to the beam may cause more serious damage, especially to sensitive tissues, such as those of the eyes. Two people have received second degree burns after exposure to the device.[21][25] (The actual number of injuries, according to Dr. Stephanie Miller of AFRL/RDHR, is a total of eight—the two previously mentioned, and six others, who healed without medical intervention.)
In addition, some claim that subjects who have body piercings, jewelry, or tattoos are likely to suffer serious skin damage. Tattooed people can become ill due to high amounts of toxins released from heated/melted tattoo pigment. Human effects testing on the large-scale version of ADT included more than 11,000 exposures on over 700 volunteers. Both laboratory research and full-scale test results demonstrated that there is only a 0.1% chance of injury from a System 1 or System 2 exposure.[26]
Critics cite that, although the stated intent of the ADS is to be a non-lethal device designed to temporarily incapacitate, modifications or incorrect use by the operator could turn the ADS into a more damaging weapon that could violate international conventions on warfare (although at this time, ADS has gone through numerous treaty compliance reviews and legal reviews by AF/JAO, and in all cases complies with every treaty and law).[27]
Some have focused on the lower threshold of use which may lead those who use them (especially civilian police) to become "trigger-happy", especially in dealing with peaceful protesters. Others have focused on concerns that weapons whose operative principle is that of inflicting pain (though "non-lethal") might be useful for such purposes as torture, as they leave no evidence of use, but undoubtedly have the capacity to inflict horrific pain on a restrained subject. According to Wired Magazine, the Active Denial System has been rejected for fielding in Iraq due to Pentagon fears that it would be regarded as an instrument of torture.[28]
Defense contractor Raytheon has developed a smaller version of the ADS, 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.[8]
LA County jail is now installing the smaller-sized unit on the ceiling of their jail.[29]
Michael Hanlon—who volunteered to experience its effects—described it as "a bit like touching a red-hot wire, but there is no heat, only the sensation of heat." Raytheon says that pain ceases instantly upon removal of the ray; still, Hanlon reported that the finger he subjected "was tingling hours later."[30]