Heat Ray Warms Up for Operation

April 2009
By Henry S. Kenyon

The Active Denial System (ADS) uses a focused beam of directed energy to peacefully disperse crowds that could threaten U.S. forces. The system uses millimeter waves to heat the outermost layers of a person’s skin, causing a burning reaction. Targeted individuals automatically jump out of the beam’s path. The ADS technology provides U.S. forces with a viable option to lethal force in crowd control and riot situations.
After years of development, Active Denial System technology is close to acquisition, deployment.

U.S. troops soon may use a nonlethal directed energy weapon to disperse crowds and protect vital facilities. Operating at ranges beyond conventional small arms, the technology allows military units to protect themselves from demonstrations without resorting to lethal force. The technology has the potential to change how military and law enforcement agencies manage riots and other civil disturbances.

In both peacekeeping and combat situations, U.S. and coalition troops often find themselves confronted by crowds that potentially can become violent. Sometimes insurgents will mix in with civilians to shoot at troops, forcing units to choose between not returning fire or firing into the crowd and causing civilian casualties. For years, nonlethal or less-than-lethal options included relatively short-range weapons such as beanbag rounds fired from shotguns or grenade launchers, rubber bullets or tear gas. In addition to the range limitations, all of these systems had the potential to cause injury or death.

The Active Denial System (ADS) uses radio frequency radiation to cause the nerves in the outer layers of a target’s skin to feel sudden, burning heat. Targeted individuals immediately and uncontrollably jump away from the beam. Mounted on the back of a vehicle such as a high-mobility multipurpose wheeled vehicle (HMMWV) or a truck, the ADS is effective at ranges in excess of 500 meters (1,650 feet). This distance allows forces the time and safety to assess a situation, disperse a crowd and identify any insurgents.

Managed by the Joint Non-Lethal Weapons Program (JNLWP), part of the Joint Non-Lethal Weapons Directorate, Quantico, Virginia, the ADS is the result of more than 14 years of research and testing. The technology behind the system was developed by the U.S. Air Force Research Laboratory (AFRL) and the Raytheon Company and matured under the JNLWP’s sponsorship.

According to Susan LeVine, principal deputy director for policy and strategy at the JNLWP, the ADS began as a concept demonstration program. An ADS technology demonstrator was successfully tested in 2001. In 2002, the Defense Department designated the ADS as an advanced concept technology demonstration (ACTD) program to rapidly mature and move the technology to warfighters. Under the ACTD, the ADS System 1 was installed in a HMMWV.

A more ruggedized version designed to withstand the dust of Southwest Asia then was developed. Known as System 2, it is a containerized version of the ADS that can be transported via a tactical cargo vehicle. LeVine notes that the ACTD ended in 2007. The program currently is transitioning to a formal acquisition program.

The key part of the ADS is an antenna that produces 95-gigahertz millimeter waves that penetrate the outer layers of a target’s skin, up to a depth of 1/64th of an inch. The waves cause a heating sensation that becomes intolerable within seconds, forcing targets to move out of the beam’s path instinctively. According the JNLWP, the sensation immediately stops when an individual leaves the beam. The Defense Department also notes that the beam does not cause injury because of its shallow penetration depth and the safety features designed into the system. The system’s hardware allows the operator to view the entire beam path and target area while the millimeter waves require no adjustments for ballistics or wind. The ADS also features computer safety systems to limit shot duration to several seconds. Other safety measures include engagement procedures, software upgrades, checklists and a multiperson validated compliance and enhanced training process.

LeVine adds that extensive research has been conducted to determine the weapon’s effects on the human body. The AFRL Human Effectiveness Directorate at Brooks City-Base, Texas, conducted more than 12 years of tests to understand the full effects of millimeter waves. According to the Defense Department, no adverse effects were found after thorough testing for potential short-term and long-term damage. More than 700 military and civilian volunteers have participated in the ADS testing. An independent agency review concluded that there is a very low risk of injury, including eye damage or cancer, from the beam.

The Raytheon Company, which developed the ADS technology, has produced its own version of the system. Silent Guardian is smaller and lighter than the JNLWP version. The smaller signature allows the system
to be mounted on civilian vehicles for use by law enforcement agencies.
Only two injures have been associated with the testing. Both incidents resulted in second-degree burns because of overexposure to the beam. The JNLWP says that both victims quickly and fully recovered. As a result of these accidents, the program instituted new procedures to prevent further incidents. In 2004, an independent Human Effects Advisory Panel review determined that the bioeffects of the ADS set a benchmark for nonlethal weapons testing and found no issues to delay the program’s progress.

The program is continuing to work on developing the ADS technology to make it lighter and smaller. LeVine says that one goal of the miniaturization effort is to install the beam into armored vehicles, where space is at a premium. One version of the ADS mounted on a Stryker armored combat vehicle has been delivered to the Office of Force Transformation in the Office of the Secretary of Defense. Raytheon also has developed a short-range tripod-mounted version of the ADS.

Although the ADS has been in development for years, much work remains because it still is a new technology that is barely beyond the proof-of-concept stage, LeVine says. The key challenge remains in efforts to miniaturize the system. She notes that the subsystem that helps the ADS generate millimeter waves is based on vacuum tube technology. The program is now working on a solid-state version that is lighter and smaller. Developers are addressing power generation because the vehicle-based versions of the ADS require a generator to power the weapon. The program is looking into alternate battery sources and technology. “The part that we have down is the effect and its range,” LeVine emphasizes.

Although it is located at the U.S. Marine Corps base at Quantico, LeVine notes that the JNLWP supports all of the services. She adds that the lead services for the ADS are the Air Force and the Army. The services are establishing their own funding lines to acquire ADS, but she notes that this is still a work in progress.

Marine Corps forces urgently requested the weapon for use in Iraq in 2006, but LeVine explains that the ADS was not yet ready for operational deployment. ADS System 2 was developed in response to these requests, but it is still undergoing operational tests. Critics of Defense Department policy claim that the delay of the system’s deployment had less to do with the technology’s maturity and was more about fears that the public would negatively perceive the ADS as a “pain ray” in the highly charged period following the Abu Ghraib torture scandal.

Raytheon, which helped to develop ADS, has produced a smaller, shorter-range version of the system that soon may be acquired by military or law enforcement organizations. Called Silent Guardian, it features a smaller beam footprint than the version the company developed with the Air Force. Another advantage is that Silent Guardian’s antenna is half the size of the System 1 and 2 versions, which makes it less conspicuous, says George Svitak, director of business development for Raytheon’s directed energy product and nonlethal systems, Phoenix, Arizona. He adds that the company used its experience in developing the ADS and its background in miniaturization to develop a more compact version of the technology. “The services realize that a smaller emitter is better,” he says.

Silent Guardian fits into a container that can be mounted on the back of a light commercial truck or a HMMWV. Svitak explains that the small size allows the system to be used by civilian and military organizations. The Defense Department has set aside $23 million from the Global War on Terrorism supplemental fund to purchase the system. He says that Raytheon is now working with the Defense Department on a formal contract, but he could not provide any details. A company spokesman notes that this process is separate from the JNLWP’s effort to initiate acquisition contracts with the services.

The funding was part of a request by the Marine Corps for the system. Svitak says that Raytheon is working with the service, the JNLWP and the Air Force to determine the system’s exact configuration.

Svitak describes the ADS technology as a “game changer” because it allows U.S. forces to react nonlethally to a range of situations. Besides U.S. forces, a number of other nations have shown interest in the technology. Although he could not provide names, Svitak notes that a number of the interested nations are U.S. coalition allies. Another role for the system is to protect ships, military bases and civilian infrastructure such as nuclear power plants where security personnel must be prepared to repel terrorists and demonstrators.

U.S. law enforcement agencies also are looking at Silent Guardian. Svitak notes that Raytheon is working with the U.S. National Institute of Justice and the Los Angeles County Sheriff’s Department. One potential use of the system is to put down riots in prisons.

Web Resources
Joint Non-Lethal Weapons Program: https://www.jnlwp.com/
Raytheon Company: www.raytheon.com


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