Future U.S. warfighters may not have god-like or even superhero powers, but the United States Air Force Research Laboratory (AFRL) has developed a new platform dubbed THOR – or Tactical High Power Operation Responder. Still in the prototype stage, it isn’t quite a mighty hammer, but the technology could be employed to disable the electronics of drones. It utilizes directed energy in a way that can even counter multiple targets including drone swarms with superhero efficiency.
THOR is also compact enough that the platform can be housed in a 20-foot-long shipping container, which could enable it to be stowed and transported via a military cargo plane. Back on the ground it can be assembled by mere mortals.
It came about as the culmination of an Avengers-style team effort involving both the Air Force and the U.S. Army.
“The Army’s directed energy capabilities will need to provide a layered defense with multiple ways to defeat incoming threats,” U.S. Army Lt. Gen. L. Neil Thurgood, director for Hypersonics, Directed Energy Space and Rapid Acquisition, said in a statement. “High energy lasers kill one target at a time, and high powered microwaves can kill groups or swarms, which is why we are pursuing a combination of both technologies for our Indirect Fire Protection Capability rapid prototyping effort.”
Combating Drone Swarms
THOR and similar high-power microwave (HPM) or direct energy weapons (DEWs) can be extremely effective at combating drone swarms, as it generates very short pulses of extremely high peak-power density at multiple kilometer ranges. The technology has the promise to be far more effective than other efforts to stop such attacks.
“Drone swarms are a risk that we should be prepared for not science fiction,” explained David Stoudt, senior executive advisor at Booz Allen Hamilton.
“In October of 2020, China unveiled a truck that could rapidly launch 48 explosive suicide drones that can swarm against ground targets,” Stoudt told ClearanceJobs. “The developer indicated that these drones, which appear to be a variant of the CH-901 loitering munition that can fly at a cruise speed of between 40 and 75 mph for up to two hours, and can be launched from a helicopter or a truck.”
HPM could be the answer to this very real threat. However, it is safe to say that this is still very much the early days.
“The ultimate effectiveness of an HPM weapon depends heavily on its output power level, the size of the antenna, the distance required by a given scenario to cause an effect, and ultimately the required power density on the targeted drones,” added Stoudt. “The HPM lethality study of drones is an ongoing and complex process, but in most cases, the time required to cause a desired effect is a small fraction of a second. Therefore, one could imagine sweeping the very large HPM beam across the sky to defeat a drone swarm.”
Future Standard Issue Weapon
Just as drone swarms shouldn’t be seen as science fiction, the use of THOR and other directed energy weapons could soon become the norm. It must be noted that less than two centuries ago, a trained soldier could only fire three to four rounds from the rifles of the day. A century later, machine guns transformed the ability of a single soldier to literally hold off an attack made by dozens or even hundreds of enemy troops.
“Current deployment would likely be similar to fortified artillery batteries or ship-based heavy guns,” suggested Anika Torruella, senior analyst, electronic warfare at Janes.
However, unlike those guns that required just ammunition, direct energy weapons could require substantial operational power.
“A lot of it,” Torruella told ClearanceJobs.
“For instance, pulse power weapons that need to repeatedly generate high energy output in very short periods of time require generous stored energy and demanding recharge and cooling capabilities,” she added. “When considering the flexibility and agility of DEWs such as the U.S. Airforce Tactical High Power Microwave Operational Responder (THOR) or Counter-Electronic High-Power Microwave Extended-Range Air Base Air Defense (CHIMERA) or the U.S. Navy solid-state Laser Weapon System Demonstrator (LWSD), the electrical generation capacity of the deploying platform and the size, weight, and power (SWaP) limits of those platforms are top considerations.”
Thus while such platforms like THOR can be easily transported and set up by a small team, it will still require ground power and is thus designed for fixed base defense.
THOR part of a Layered Defense
As all electronic devices can be disrupted or damaged by microwave energy at least in principal, these weapons could be a part of a layered defense.
“An HPM weapon developer must identify appropriate targets – i.e., UAS, computers/networks, industrial controls, missiles, etc. – identify desired kill mechanisms and outcomes, and field an operationally viable weapon that achieves those objectives,” explained Stoudt.
However, in many instances, it may not be feasible to generate a sufficient power density on target with a remote HPM weapon on a land or sea platform.
“To overcome this issue, government and industry developers have explored the concept of taking the HPM source closer to the target to overcome the range loss and increase the incident power density,” added Stoudt. “As an example, such a concept was explored by the Air Force Research Laboratory under the Counter-electronics High Power Microwave Advanced Missile Project (CHAMP), which prototyped the integration of an HPM source capability into an air-launched cruise missile.”
As such platforms could be used with high energy lasers (HEL), which could form an outer layer for a swarm defense, whereas the HPM weapon could be used to defeat a much larger number of suicide drones at closer ranges.
“For drone swarms, kinetic weapon capabilities typically are not very effective, cause significant collateral damage, and are often not a cost-effective option,” noted Stoudt.
“In some ways, these weapons are analogous to machine guns,” he suggested. “Once the operational utility of machine guns was demonstrated, they were integrated into everything from tanks and other land vehicles, to ships and small boats, and even aircraft. The same will hold true for future HPM capabilities as their operational viability is proven.”
And while all DEWs capabilities are undeniably game-changing, at least in their current form, these energy weapons are still rather lousy offensive weapons.
“The beams can only propagate on straight vectors and are susceptible to rain, smoke, haze, and dust, particularly when engaging long-range targets,” said Torruella. “And while decision-makers at this point can only imagine what weapons and new requirements will be called for in near-future engagements, they know that agile beam pointing technology and robust, reliable, and cost-effective power sources still require further research.”
