Here's What You Need to Know: Lasers are particularly effective as short-range air defense systems against Unmanned Aerial Vehicles because most of them are fairly slow.

After decades of being confined to experimental prototypes and Star Wars movies, laser weapons today are on the verge of entering wide-scale service, whether in the hands of infantry, mounted on trucks, armored vehicles, warships and even Air Force fighters.

Lasers focus beams of light to produce intense heat. They have virtually inexhaustible “ammunition” and are very cheap per shot compared to a missile or even a cannon shell. They are also extremely quick and precise, though they tend to lose coherence over distance. The more powerful the laser, the further it can go and the quicker it burns through its target—but the larger its power supply and cooling system have to be.

The Army hopes that ground-based lasers will provide an effective and cost-efficient means to defend against two major new threats which threaten to overwhelm existing air defenses: drones and surface-skimming cruise missiles. Both are proliferating rapidly around the globe, and both were employed in a recent attack that knocked out half of Saudi Arabia’s daily oil production—despite the facilities being covered by both short- and long-range air defense systems.

Lasers are particularly effective as short-range air defense systems against Unmanned Aerial Vehicles because most of them are fairly slow. That gives a laser ample time to burn through the drone’s skin and damage critical bits of the airframe. Anti-drone lasers have been extensively tested (see a video here), and were recently reportedly used in combat for the first time when a Turkish laser used by a faction in Syria shot down an enemy drone.

By 2022, the Army plans to deploy its first four-vehicle platoon of eight-wheel Stryker armored vehicles equipped with a turret-mounted 50-kilowatt laser. These will eventually become a standard support asset in U.S. brigade combat teams, alongside a Stinger-missile armed Strykers.

Turning Up the Heat to Stop Cruise Missiles

However, jet-powered cruise missiles pose a bigger challenge to lasers. Even slower cruise missiles tend to scream towards their targets at 500–600 miles per hour. That leaves a laser little time to burn through the missile’s skin target.

Furthermore, because a laser exerts no kinetic force to “push” a missile of target, it must somehow inflict heat damage to a component which will prevent the missile from sailing forward on sheer momentum to hit its target. That may involve detonating the missile’s warhead, frying its terminal seeker (if it has one), or damaging its engine and flight control fins.

The Army has already been mandated by Congress to deploy an Indirect Fire Protection Capability (IFPC) that can shield troops on the ground from cruise missile attacks. As an interim measure, the Army announced early in 2019 it would procure two batteries of Israel’s Iron Dome air defense system as Increment 1 of the IFPC program. Iron Dome was designed for shooting down unguided projectiles, but has some applicability to cruise missile defense.

However, for Increment 2, the Army wants a mobile laser system more powerful than that on the Stryker. Originally, that looked like that would come in the form of the 100 KW High Energy Laser (HELAS) which would be mounted on a tactical truck. 

In May 2019, the Army $130 million contract to Lockheed and Dynetics to develop a HELAS combined fiber laser. Rolls-Royce would furnish an integrated power & thermal management system.

However, in August 2019 an article on Army.mil revealed that the Army now sees the 100 KW system as merely an interim step to developing either a 250 or 300 KW weapon that can handle “more stressing threats”—by which they surely mean cruise missiles. Furthermore, they expect the first four-vehicle HEL-IFPC prototype platoon to be ready by 2024.

According to Sydney Freedberg of Breaking Defense, the Center for Strategic & Budgetary Analysis had earlier reported that a 300 to 600-kilowatt laser was necessary to reliably burn down cruise missiles before they reach their target. That level of power would allow the laser to begin toasting an incoming missile from further away, and inflict more damage in a shorter amount of time. That could significantly increase the odds of disabling a cruise missile before it can cause much harm. 

The odds of a successful shoot-down might remain lower against supersonic cruise missiles or forthcoming hypersonic weapons (which exceed five times the speed of sound), but most of the former at least are designed for use against ship, not land targets.

The potentially threefold power increase from the current HELAS laser seems ambitious. However, the 100 KW HELAS reportedly combines a battery with an M250 turboshaft helicopter engine (used in the OH-58 and OH-6 scout helicopters) that generates 300 KW of power, and has thermal management for up to 200 kilowatts. Therefore, it’s possible scaling up the HELAS laser’s power may be feasible without starting with a new design.

The HEL-IFPC laser system will be mounted on a truck, rather than an armored vehicle. Thus, if it enters service, it would likely primarily be deployed behind the frontlines defending headquarters, ammunition and fuel dumps, fixed radars, and key bases or facilities. Those all happen to be attractive targets for expensive land-attack cruise missiles.

The Army is not the only service seeking land-based directed energy weapons. The Air Force is reportedly testing three different microwaves defensive weapons which could be used to disrupt or disable drones.

Sébastien Roblin holds a Master’s Degree in Conflict Resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring.

This article first appeared in 2019.

Image: Reuters