This post has been updated to clarify the nature of pallet delivery for the weapon system.

Under a clear sky on a distant battlefield in a not-too-distant future, American soldiers may find themselves beset by a surprise swarm of drones. Signalling for help, their salvation may come in the form of a specially equipped dune buggy, its lasers blasting multiple drones out of the sky every minute.

The scene, as easily imagined by a child with a G.I. Joe playset, is one set into motion by defense giant Raytheon. On Oct. 22, 2019, the Massachusetts-based company announced the Air Force had accepted delivery of a High Energy Laser Weapon System, or HELWS, to be deployed overseas.

HELWS isn’t the first laser to be deployed as a counterdrone tool in modern times.

That distinction goes to the Laser Weapon System (LaWS), developed by Kratos and mounted on the USS Ponce when it deployed to the Persian Gulf in 2014. That laser demonstrated an ability to burn through mortar rounds, small boat engines, and the wings of drones. It also drew on the power supply of a whole ship.

For its demonstrator, Raytheon chose to mount HELWS on a Polaris RZR dune buggy.

“It’s diesel and it’s the appropriate size,” said Michael Hofle, program manager at Raytheon. “It’s not too big, but it is able to to carry unmodified your entire laser weapons system and it’s cool; everybody loves it.”

Mounting on a vehicle was the easiest way to make it portable, but Hofle said Raytheon has told customers it is possible to deliver on a pallet, so the military can transport it how they like. The emphasis being, the laser weapon itself was portable enough it doesn’t come with many constraints on how its brought to battle.

The costs of laser weapons are primarily bound up in their development and manufacture. Once deployed, they can become a counterdrone weapon that bends the asymmetry of attacks by cheap drones back in favor of the defender.

“Basically, your cost of shot is the cost of electricity,” said Hofle. “The other advantage to the weapon system is that it’s a kinetic effect that travels at the speed of light, and it’s also a very precise weapon. You can effectively project a beam the size of a dime damage onto a moving target.”

That emphasis on vehicle damage and low cost means lasers are designed, ultimately, as a cost-per-shot effective alternative to not just missiles, but also bullets. That makes laser weapons a possible complement to existing counterdrone systems, but not a holistic answer in and of themselves.

“The other thing to consider is the weather conditions,” said Hofle. “If you're in a rainstorm, then the laser's not your most effective or really an effective weapon system. You may want to use something else.”

And while a laser cannot down an entire swarm of drones at once, it can make short work of many drones in sequence. Paired with a targeting system to track the vehicles, the laser can burn one enough to disable it in a matter of seconds, and then move to another.

The HELWS is designed to work with Raytheon’s Multi-spectral Targeting System, modified so that it can direct the beam and keep it on target. Detecting, tracking and targeting drones is done largely autonomously, but designed with a human in the loop to decide when and if to fire on a target.

“Typically, what happens is your radar will send a cue directly to the weapon system,” said Hofle. “You’ll get you get a cue spot on to where the drone is. And then the operator, using just a standard game controller, pushes a button and it locks on and can use different sensors to make positive identification.”

The systems will keep tracking the object while the human evaluates that it is, in fact, the kind of flying object appropriate to shoot with a laser. For example, the military doesn’t want to target and then down a bird, a task a human could help avoid.

Or think about when the laser is tasked with intercepting incoming projectiles, like mortar rounds. In that case, the immediate need of stopping an imminent munition is one where Hofle sees autonomous laser firing as more likely.

Countering mortars will likely fall to other weapon systems. This laser is, instead, built to defeat the small and medium-sized drones typical of modern warfare, either developed by states or modified from commercial models.

“We've tested against class 1, class 2, your typical drones, fixed wing drones,” said Hofle. “Certainly if [targeted at] a larger drone with some sensors or ISR assets on it you could potentially blind them or damage them, but you for a hard kill, for you're looking at class 1, 2.”

For now, HELWS will go abroad, and the real learning process will happen among its handlers. Because so much of the cost of a laser system is front-loaded into its development, to realize the comparative savings that come on a per-shot basis the system will need to prove effective for a long time. Key to that will be feedback from the service members actually using the laser dune buggy.

“The soldiers, they're smart, and they know the landscape better than anyone,” said Hofle. “A lot of times what happens is we deploy the systems and the soldiers find new and even better ways to use the weapons, right things that maybe we didn't even anticipate when we designed and tested the system.”

The use of small and cheap drones on the battlefield, the kind HELWS is specifically designed to counter, is only likely to increase in the near future. And for one small, two-kilometer radius, HELWS will be there, ready to burn robots out of the sky.

So long as it isn’t raining.

Kelsey Atherton blogs about military technology for C4ISRNET, Fifth Domain, Defense News, and Military Times. He previously wrote for Popular Science, and also created, solicited, and edited content for a group blog on political science fiction and international security.

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