Military & Aerospace

Directed-Energy Weapons: Mirage or Reality? Light at the end of the Tunnel
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Issue Vol. 36.3, Jul-Sep 2021 | Date : 25 Oct , 2021

No doubt, much remains to be done before Directed-Energy Weapons (DEWs) make a convincing transition from laboratory wonders to effective and reliable weapons of war. But there is finally light at the end of the tunnel and technologists believe that most if not all issues facing DEWs, can be resolved. Not only are DEWs becoming more powerful, they are also becoming more affordable. In addition, countering the growing global threat to aviation safety posed by commercially available unarmed and armed drones is an important factor spurring DEW research. By the end of this decade, DEWs will, in all likelihood, be widely deployed for a range of missions by all the three services as well as to protect vital civilian facilities.

In 213–212 BC, the Greek city of Syracuse was under siege by the forces of the Roman Republic. The mighty Romans would have overrun Syracuse, but for the determination of the mathematician Archimedes who turned his remarkable mind to weapons of war. One new contraption was what today might be called a Directed Energy Weapon (DEW). According to the 12th century Byzantine historian Joannes Zonaras, “At last, in an incredible manner, he (Archimedes) burned up the whole Roman fleet. For by tilting a kind of mirror, he ignited the air from the beam and kindled a great flame, the whole of which he directed at the ships at anchor in the path of the fire, until he consumed them all.” However, attempts within the past 20 years to validate this flaming feat have been singular failures. When a team from the Massachusetts Institute of Technology (MIT), using a specially constructed reflective device of 300 square feet of highly polished bronze and glass, took aim at a small boat 150 feet away, all they could do was to make the boat’s wooden surface smoulder a little. They could not kindle even a tiny open flame.

Fast forward over 2,200 years from Syracuse to the United States. Since November 2016, speculation has been growing that foreign spies or their agents have been aiming mysterious energy weapons at United States (US) personnel, mainly diplomatic staff on overseas duty. As of May 2021, more than 130 US spies, diplomats, soldiers and others are reported to have displayed symptoms such as headaches, nausea and hearing loss as a result. Some have even suffered traumatic brain injuries. Although many experts dismiss the possibility that a mysterious type of DEW is to blame, the US government is believed to be actively investigating the theory.

Some analysts believe that DEWs are among the most overhyped military devices ever. Take the Strategic Defence Initiative (SDI), the mother of all DEW projects. Mockingly called “Star Wars” by its critics, this proposed missile defence system was announced in March 1983 by US President Ronald Reagan to protect the nation from attacks by strategic nuclear weapons. The SDI would have depended mainly on various types of space and ground-based DEW. It was abandoned after more than two decades of effort and an estimated expenditure of over $35 billion. Huge sums spent on DEW research in other countries too have mostly failed to deliver tangible results.

Still, recent tests of prototype DEWs make it clear that they are no longer just theoretical concepts. Many DEWs are now nearing technological maturity. Will they become effective weapons of war in the near future or will they remain forever impractical, like Archimedes’ mirror or Reagan’s Star Wars?

DEW Fundamentals

A DEW system achieves its destructive effect by emitting highly-focused energy and transferring that energy to a target. The energy may be in the form of lasers, microwaves, electro-magnetic radiation, radio waves, sound or particle beams. However, particle-beam weapons technically are not DEWs because they use micro-projectiles, not pure energy. When it comes to actual war-fighting, High-Power Lasers (HPL) and High-Power Microwaves (HPM) are likely to prove the most effective. While HPL can be used against vital components of satellites, radar systems, and Unmanned Aerial Vehicles (UAVs) to render them inoperable, HPM could pose a serious threat to computer and other electronic systems on which every nation and military force now relies. In the defensive mode, both types can be used to prevent incoming UAVs or missiles from reaching their targets. HPL and HPM can also work in tandem. While HPL can be used to shoot down approaching drones one by one, HPM can be employed to simultaneously counter a swarm.

According to the Lexington Institute, a think tank in Arlington, Virginia, “Directed-energy weapons have several advantages over conventional munitions. First, they transmit lethal force at the speed of light (about 300,000 kilometres per second). Second, their beams are not affected by the constraining effects of gravity or atmospheric drag. Third, they are extremely precise. Fourth, their effects can be tailored by varying the type and intensity of energy delivered against targets.”

There is also the cost factor. A defender trying to shoot down an incoming hostile aircraft or missile needs to fire an expensive missile against it. This is starkly illustrated in Israel’s conflict with the Palestinians, where Israel often launches a missile costing $50,000 or more against an incoming Hamas rocket that may come for $1,000 or less. And defensive missiles could quickly run out. In contrast, a laser DEW system could dramatically lower the cost of engagement and its “magazine” would be limited only by fuel capacity. At $1 per shot, it would be an extremely cost-effective defence against drones.

An added advantage is that of plausible deniability. DEWs operate silently and invisibly, in some ways like cyber warfare. It can be difficult, if not impossible, to determine the source of a DEW attack.

Light Strike

Two varieties of laser devices are particularly suitable for weaponisation. In the older chemical laser, the device draws its energy from reactions between two or more chemicals and uses that energy to impel yet another chemical to emit the laser beam. On the other hand, a solid-state laser works by stimulating a laser beam to emerge from a crystal or a piece of glass by pumping electrical energy into it. HPL weapons are difficult and expensive to develop. The challenges that need to be overcome include providing adequate power to the system, accurately directing a focused beam towards a distant moving target, and developing an efficient cooling mechanism to dissipate the intense heat generated by firing the laser.

Solid-state lasers became prominent in 2014, when the USS Ponce, a US Navy vessel deployed in the Persian Gulf, began testing a 30-kilowatt weapon. The system was able to fry some critical components and motors of enemy drones and boats and was later declared operational. Following this successful trial, Lockheed Martin was contracted to install its High Energy Laser with Integrated Optical Dazzler and Surveillance (HELIOS) system on the USS Preble, a Burke-class guided missile destroyer, later the same year. The weapon is likely to have at least 65 kilowatts of power and a lower-power optical dazzler to disable hostile Intelligence, Surveillance, and Reconnaissance (ISR) sensors. The power could potentially be increased to 100 or 150 kilowatts before deployment on other destroyers. The US Army also plans to field its first combat-worthy laser by 2022. It is a 50-kilowatt weapon mounted on Stryker armoured vehicles to defend them against aerial attack from small missiles.

Meanwhile, the US Air Force (USAF) has said that it tested a new ground-based High Energy Laser Weapon System 2 (HELWS2 or H2) counter-UAV DEW, built by Raytheon, in 2020. The USAF Research Laboratory (AFRL) is also working on its Self-Protect High Energy Laser Demonstrator (SHiELD) that aims to develop a laser DEW compact enough to be carried in the pod of a fighter jet such as the F-15. Its first airborne test is planned to be conducted in 2024. If successful, it will significantly enhance the future combat survivability of US military jets that are currently vulnerable to Surface-to-Air Missiles (SAMs) such as the Russian-built S-400. It is more difficult to design a fighter-mounted laser weapon than a ship-based or land-based one, due to the relatively limited space and electrical power generation potential of the jet.

The immediate goal of researchers is to demonstrate 300 kilowatt capability by 2022 and 500 kilowatt by 2024 – the minimum required to neutralise large missiles.

Playing Catch Up

Although US companies such as Lockheed Martin, Raytheon and Boeing lead global weapons grade laser research, China and Russia are fast catching up. China is actively pursuing DEW, both solid-state HPL weapons and microwave ones. Lacking the capability e to take on the US in a conventional war, it considers DEWs and other unconventional weapons as being critical in obtaining some military advantage over the Americans. For the last five years, the Chinese have been marketing a 30-kilowatt mobile, solid-state laser and are developing more powerful land-sea-and air-deployable laser weapons. They are pursuing ground-based Anti-Satellite (ASAT) DEWs that could potentially be used to take down satellites in Low Earth Orbit (LEO).

Russia’s Peresvet is a new HPL weapon unveiled by President Vladimir Putin in March 2018. It is already operational with the Russian Army, most likely to counter UAVs, cruise missiles and low-speed aircraft operating at low altitudes. The vehicle-mounted system features steerable laser cannon. There is speculation that Peresvet’s role may also be to blind ISR systems, UAVs and LEO satellites.

In fact, both China and Russia could be aiming to threaten the American GPS constellation on which the US military is heavily reliant for navigation, timing and precision targeting of conventional and nuclear weapons. China may have already deployed some HPL DEWs capable of incapacitating GPS satellites and may succeed in developing more powerful ones that could physically destroy satellites by the late 2020s.

In September 2020, India’s Defence Research and Development Organisation (DRDO) announced plans to develop DEWs using high-energy lasers and microwaves. It has also formulated short, medium and long-term goals to develop a series of DEW systems with up to 100 kilowatts of power. DRDO has already developed two anti-drone DEW systems. One is a ten-kilowatt trailer-mounted HPL to engage drones at two-km range. Another system is a compact, tripod-mounted DEW with a two-kilowatt laser for a one-km range. Both weapons can bring down micro drones through either jamming of command and control links or by physically damaging them. A classified project, still in the concept stage, is the Directionally Unrestricted Ray-Gun Array II (DURGA II) that is planned to be integrated with platforms operating from land, sea or air. It could result in a 100-kilowatt lightweight DEW system.

Microwave Mayhem

An important factor driving DEW research is the ubiquitous drone. This device that goes all the way from a child’s innocuous toy to a long-range weapon of great lethality has no simple military counter. Over the last few years, threats of attack by drone swarms have begun to assume alarming proportions. For instance, in September 2019, around 20 armed drones were used to attack the state-owned Saudi Aramco oil processing facilities at Abqaiq and Khurais. The Saudi missile defence system failed to neutralise the swarm.

While one or two drones attacking an air base or aircraft carrier can be countered by kinetic weapons or an HPL system, there is no way a hundred can be neutralised even by a sophisticated area defence system. That is why HPM are becoming more important.

Researchers are working on prototype DEWs based on HPM technology that can jam, dismantle, take-out or simply stop multiple attacking drones by disabling their electronics. The Tactical High Power Operational Responder (THOR) is a new weapon developed by the AFRL. It consists of a large microwave dish housed in a 20-foot long container and can engage multiple targets in a broad area by simultaneously jamming their guidance systems and sensors. Field testing is slated for 2024 and possible operational deployment by 2026.

A “set a thief to catch a thief” approach is to deploy an HPM drone against an attacking drone swarm. Lockheed Martin claims its MORFIUS drone equipped with HPM can effectively counter hostile drone swarms. Weighing less than 30 pounds, MORFIUS is a reusable drone that can fit inside a six-inch diameter launch tube and can be operated from a ground station, a vehicle or an aircraft.

The USAF’s PHASER prototype HPM manufactured by Raytheon is an HPM cannon that can emit radio frequencies against hostile UAVs in a conical beam. It instantaneously disrupts or permanently destroys their circuits with a massive burst of energy lasting less than one microsecond. To avoid attacking friendly drones, operators need positive identification before using PHASER. Not only can PHASER attack multiple targets simultaneously, it does not run out of ammunition.

Challenges Galore

However, there is a wide gap between a laboratory laser and an operational weapon. Apart from their sky-high development costs and generally inadequate funding, DEWs face numerous technological challenges. For a practical weapon, especially an aircraft mounted one, the DEW’s Size, Weight, and Power consumption (SWaP) must all be low. Yet it must be a robust system and have enough power output to be effective. Powering the laser could take a considerable amount of energy from the aircraft’s internal generation source. Besides, laser weapons produce enormous amounts of heat as they fire repeatedly and the cooling system must be exceedingly effective. According to technologists, the rule of thumb for an HPL weapon is an efficiency of about one-third, meaning a 300-kilowatt generator can create only a 100-kilowatt laser beam, resulting in 200 kilowatts of waste heat.

To burn a hole in any target, a laser beam must be held steady on it. When both attacker and target are moving at tremendous speeds, sophisticated corrective optics whose complexity can only be imagined, are required. Besides, as the beam passes through the atmosphere, it is subject to diffraction, absorption and turbulence. To maintain its effective range and lethality, it must retain its focus and resist being degraded by the atmosphere – also known as good beam quality.

Finally, sooner or later, there will be a counter weapon. For instance, high-value targets may be given special coatings to reflect or redirect hostile lasers and their skin may be constructed of special materials to dissipate the heat generated by the beam striking the target. Electronic equipment can also be hardened to resist an HPM attack, although at additional cost. Even something as simple as generating copious amounts of black smoke around a target could frustrate a laser weapon.

Not Just a Sound and Light Show

What is clear is that the tools of warfare between the major powers are gradually being transformed from missiles and bombs to exotic new weapons. The May 2021 cyber strike that forced the shutdown of major fuel pipelines in the US was not mounted by Russia or China, but the next one might as well be. DEWs could be another attractive option. In fact, a few such weapons are already in service to defend against drones. In future, they may be employed both to destroy enemy targets and to defend vital infrastructure against air and missile attack. Although it is unlikely that DEWs will ever replace conventional munitions they will increasingly complement them.

No doubt, much remains to be done before DEWs make a convincing transition from laboratory wonders to effective and reliable weapons of war. But there is finally light at the end of the tunnel and technologists believe that most if not all issues facing DEWs can be resolved. Not only are DEWs becoming more powerful, they are also becoming more affordable. In addition, countering the growing global threat to aviation safety posed by commercially available unarmed and armed drones is an important factor spurring DEW research. By the end of this decade, DEWs will, in all likelihood, be widely deployed for a range of missions by all the three services as well as to protect vital civilian facilities.

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The views expressed are of the author and do not necessarily represent the opinions or policies of the Indian Defence Review.

About the Author

Gp Capt Joseph Noronha

Former MiG-21 Pilot and experienced IAF instructor before he turned to writing articles on aviation.

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