Directed Energy: The Focus on Laser Weapons Intensifies

In the constant race between measure and countermeasure, military powers have also developed jammers, spoofing tools, and other increasingly sophisticated means of conducting electronic attack or using electronic countermeasures to gain a battlefield advantage. This back-and-forth is still playing out today in Ukraine, with both Russian and Ukrainian forces deploying a wide range of EW capabilities as part of their reconnaissance-strike and air defense systems.

Militaries and societies have also become aware of the potential threat from electromagnetic pulses such as those generated through high-altitude detonations of a nuclear warhead. An undirected rather than directed energy weapon, these have fortunately not yet been used in war because they indiscriminately damage all unshielded electronics in a target area and can be confused with—and thus lead to an escalation to—a nuclear exchange.

Building on these trends, technology programs have sought to make DEW a reality. In the 1980s, the Reagan administration famously sought to develop more-powerful lasers to defend the United States against Soviet missiles as part of the Strategic Defense Initiative. Ultimately, this did not work—a costly and failed effort often derisively dubbed “Star Wars”. Yet after decades of low-power devices being rolled out globally, recent years have seen increasing military investment and technological advances in high-energy lasers (HEL) and high-powered radiofrequency (HPRF) or microwave (HPM) systems.

These emerging categories of weapons are designed for a variety of targets. Emitting a stream of photons, HELs are useful for engaging fast-moving targets within line-of-sight, such as destroying aerial or missile threats to ships, a base, or ground forces. Even at lower power settings, lasers can dazzle the sensitive electro-optical sensors on their targets (or, indeed, the human eye), blinding them and making it harder to maneuver safely or carry out their mission. Emitting radiofrequency waves, meanwhile, HPRFs and HPMs are useful for disrupting electronic systems, making them especially useful against military equipment, drones, and robotic systems. Unlike HELs, which focus on one target at a time, HPRFs and HPMs can engage multiple threats within a wide beamwidth simultaneously.

There is thus substantial interest in DEWs to help counter the proliferation of unmanned systems in the air, on land, and at sea, as well as for targeting missiles in-flight or satellites in orbit. The U.S. military and others have also looked at nonlethal DEWs for crowd control, perimeter security, and area denial purposes—for example by inducing a temporary and nondamaging sensation of extreme heat on human skin or using sonic devices to force people to leave an area—though this remains controversial. Beyond military applications, several companies have proposed using ground-based lasers for civil and commercial purposes, such as active debris removal missions to shoot at ‘space junk’ posing a risk to nearby satellites in an increasingly congested low-Earth orbit.

Balancing Benefits, Drawbacks, and Countermeasures
Competing nations are pouring so much investment into DEWs because, if the technology can be matured, such systems hold the potential to tip both the military and economic calculus of modern warfare in their users’ favor. HEL and HPRF/HPM systems deliver an effect on target at the speed of light, drawing on an energy source rather than traditional munitions. Compared with traditional gun- or missile-based alternatives, these characteristics of DEW promise increased accuracy, speed of engagement, magazine depth, and flexibility to re-task the weapon against a variety of targets.

Currently, DEWs are comparatively large, relying on large power sources and stable platforms such as a ground battery or naval ship. But in future, miniaturized and more-efficient energy storage systems could enable their rollout across all domains—with the U.S. and European next-generation fighter programs envisaging integrating such weapons into the fighter aircraft of the future. Reducing reliance on kinetic munitions that must be constantly replenished would similarly take pressure off military logistics and industrial production, enabling forward deployed forces to operate for longer without resupply of ammunition, so long as they had access to suitable energy sources.

These military considerations in turn have important cost implications. After its recent DragonFire trial, the UK Ministry of Defense reported that the HEL could hit a target the size of a small coin at a kilometer, and that firing it for 10 seconds used equivalent energy to running a domestic portable heater for an hour—meaning each shot of the laser costs around £10 ($12–13). This stands in stark contrast to the hundreds of thousands, or even millions, of dollars that a sophisticated air defense or missile interceptor can cost. These are currently being expended in large numbers by Israel, Russia, and Ukraine; and by U.S. and UK naval forces deployed to protect commercial shipping from Iran-backed Houthi attacks in the Red Sea.

Munitions production capacity is tightly constrained despite ongoing global efforts to ramp it up. Low-cost drones and rockets have swung the economic calculus of offence and defense in favor of those using large volumes of cheap unmanned systems and munitions to overwhelm more-sophisticated air and missile defenses. Maturing DEW technologies therefore promise more cost-efficient ways of engaging a variety of threats, especially these rockets and drones.

At the same time, DEWs are far from a panacea. Such futuristic weapons are the subject of considerable technology hype, and there remain technical, financial, policy, and doctrinal barriers to their successful maturation and deployment at scale on the battlefield.

Physical limitations include the need for HELs to have a clear line of sight to the target. This limits the range of many DEWs and means that optimal performance demands a stable platform, the ability to remain focused on a moving target for sufficient time to deliver effect, and no cloud, rain, smoke, or manmade countermeasures. Electronic systems can also be hardened against attack by HPRFs or HPMs. Conversely, attackers can hope to overwhelm DEWs both through technical means and use of certain tactics—for instance, by forcing defenders to deal with large numbers of different threat vectors at once, or by going after the command and control or sensor systems tasking the DEWs. Users of DEWs must also be mindful of the possibility of collateral damage (e.g., dazzling or damaging a friendly satellite behind an in-atmosphere target), and of safety, ethical, and legal concerns, though such considerations are of course true for kinetic weapons. And while there have been considerable advances in the battery and supercapacitor technologies that power any DEW, generating, storing, transmitting, and using large amounts of energy in austere battlefield conditions remains both a technical and logistical challenge.

Building Towards Integrated Air and Missile Defense
Given these mixed prospects, DEWs are far from a ‘silver bullet’. But, if these technologies continue to progress, they can make a vital and urgently needed contribution within a wider toolkit, helping mitigate the increasing air and missile threat to military forces and civilian targets.

To fulfil this promise, DEWs need to be further developed to become more mobile, reliable, and affordable. This should be combined with all the other lines of development that make up a mature military capability, including appropriate infrastructure, logistics, doctrine, and training. DEWs should then be layered alongside other counter-rocket, artillery, mortar, and air and missile defense systems, including a mix of different sensors, guns, missiles, and platforms, as part of what the UK military calls ‘integrated air and missile defense’. This enables a holistic approach to dealing with different threats from cheap drones to sophisticated aircraft or cruise and ballistic missiles, at varying altitudes, speeds, and levels of cost.

Integrated air and missile defense has emerged as a key priority for NATO and other powers, with alarming shortfalls in the capacity of modern air and missile defenses and the associated production lines exposed by the fighting between Russia and Ukraine since February 2022. Addressing this challenge requires more than just flashy new technical solutions such as DEWs—the United Kingdom’s Missile Defense Centre, for instance, talks of missile defense across five pillars, encompassing nonproliferation, deterrence, counter force, active defense, and passive defense measures. This means tackling threats both ‘left and right of launch’: going after the enemy’s ability and willingness to launch an attack in the first place, or, if that fails, seeking to intercept, deny, or mitigate the effects of an attempted strike once it has been launched.

Still, DEWs offer a potential new layer to this concept and a more cost-efficient means of dealing with fast-proliferating threats. This would free more traditional, kinetic weapons for other purposes, and relieve some of the pressure on the West’s already-stretched munitions production lines. This change could directly benefit operations of the kind currently underway to defend Ukraine or the Red Sea. From the successful DragonFire trial in the United Kingdom to recent U.S. and French naval deployments of shipborne DEWs, it is positive to see such energy being directed at directed energy. Hard-fought progress is being made by NATO Allies in this continuing race for technological advantage.

James Black is assistant director of defense and security at RAND Europe, the European arm of RAND. This article is published courtesy of RAND.