The US Air Force (USAF) has successfully defeated a so-called “drone swarm” in recent tests using a microwave energy weapon.

AFRL THOR Anti swarm weapon

Source: US Air Force Research Laboratory

Tactical High-power Operational Responder, or THOR, uses high-power microwaves to defeat small UAVs flying at low altitude

The Air Force Research Laboratory (AFRL) on 16 May said a system known as the Tactical High-power Operational Responder (THOR) was able to down multiple small aerial targets in a simulated attack.

“THOR was exceptionally effective at disabling the swarm with its wide beam, high peak powers and fast-moving gimbal to track and disable the targets,” says Adrian Lucero, programme manager with the AFRL’s directed energy directorate.

The demonstration occurred on 5 April, the AFRL says, but was only recently reported.

With the global proliferation of dedicated military unmanned aerial vehicles (UAVs) and small commercial quadcopter drones, military planners in Washington have been seeking options to defeat them on the battlefield.

While lone UAVs can provide powerful battlefield effects, such as kinetic strikes, reconnaissance or artillery spotting, generals at the Pentagon are particularly concerned about large numbers of cheap, small craft operating in unison against ground troops or stationary air bases.

The US Army has already demonstrated that dozens of commercial quadcopters can be synchronised into drone swarms via artificial intelligence algorithms and controlled by a single soldier.

While traditional air defences and some counter-UAV systems use guided munitions to destroy aerial targets, the small size of quadcopters and numerous potential targets present a challenge for projectile weapons.

Systems like THOR use electronic warfare measures to jam, disrupt or even destroy the many UAVs making up a swarm. In the case of the recent tests, AFRL researchers “flew numerous drones at the THOR system to simulate a real-world swarm attack”, according to Lucero.

While the USAF declined to disclose how many or what type of UAVs were employed in the test, citing security concerns, the service says the microwave weapon system was effective at defeating the swarm.

“THOR was extremely efficient, with a near continuous firing of the system during the swarm engagement,” says USAF Captain Tylar Hanson, THOR deputy programme manager.

“It is an early demonstrator, and we are confident we can take this same technology and make it more effective to protect our personnel around the world,” he adds.

The presence of cheap, easy to obtain commercial drones and military UAVs has already become a defining trait of the 15-month-old Russia-Ukraine war; Europe’s largest conflict in decades.

The technology has also appeared in conflicts including the Syrian civil war and the Second Nagorno-Karabakh war between Armenia and Azerbaijan.

The former commander of US Special Operations Command, retired General Richard Clarke, in 2022 described the proliferation of UAVs and commercial drones as having the ability to disrupt the global military order.