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What THOR Shows About Microwave Air Defence

THOR is a useful case for understanding how wide-beam microwave systems may disable multiple drones.

On this page

  • THOR as a counter drone microwave system
  • Wide beams and swarm engagement
  • What tests can and cannot prove
Preview for What THOR Shows About Microwave Air Defence

Introduction

THOR, the Tactical High-power Operational Responder, is a US Air Force Research Laboratory high-power microwave system built to test a specific idea: whether a directed-energy weapon can disable several small drones at once rather than shooting them down one by one. Its value as a case study is not that it proves microwave air defence is solved. It shows why wide-beam microwave systems are attractive against drone swarms, what a realistic counter-drone demonstration can reveal, and where the public evidence still leaves gaps. AFRL describes THOR as a counter-swarm electromagnetic weapon for airbase defence that fits inside a 20-foot transport container, can be moved by C-130, can be set up within about three hours, and uses high-power microwaves to produce a counter-electronic effect on drones. [afresearchlab.com]afresearchlab.comTACTICA L HIGH POWER OPERATIONAL RESPONDERLaboratory developed for defense of airbases. stows completely in a 20 foot transport container, which can…

Overview image for THOR The key point is that THOR belongs to the microwave branch of directed energy weapons, not the laser branch. Lasers concentrate energy on a small spot and usually defeat targets individually; THOR’s appeal is its ability to put an electromagnetic effect across a wider area of sky, making it more relevant to multiple small unmanned aircraft approaching together. That same feature also explains the caution around the technology: wide-area electromagnetic effects can be powerful, but they raise questions about range, selectivity, friendly electronics, safety zones and whether trial results translate cleanly to messy operational settings. [GAO]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — For example, wider beam DEWs, such as high power microwave or millimete…Published: May 2023

THOR as a counter-drone microwave system

THOR was developed by AFRL’s Directed Energy Directorate as a transportable counter-swarm demonstrator for defending airbases against small unmanned aircraft systems. In AFRL’s own fact-sheet language, it provides “non-kinetic defeat of multiple targets”, operates from a wall plug, and disables drones using energy rather than missiles, bullets, nets or explosive interceptors. The same official material says the development cost was approximately $18 million, a useful reminder that THOR was framed as a prototype demonstrator rather than a fielded air-defence network by itself. [afresearchlab.com]afresearchlab.comTACTICA L HIGH POWER OPERATIONAL RESPONDERLaboratory developed for defense of airbases. stows completely in a 20 foot transport container, which can…

The mechanism is described in deliberately broad public terms. AFRL says THOR uses high-power microwaves to cause a counter-electronic effect: the target is identified, the weapon discharges in a nanosecond, and the impact is “instantaneous”. That does not mean every drone is affected in exactly the same way. In high-power microwave counter-drone systems, the intended effect is usually disruption or damage to electronics through electromagnetic coupling into vulnerable circuits, wiring or components. Public sources do not provide THOR’s classified waveform, power, frequency, range or detailed failure modes, so the safest reading is that the system demonstrates a class of electronic defeat rather than a single universally guaranteed kill mechanism. [afresearchlab.com]afresearchlab.comCOUNTER-SWARM HIGH POWER WEAPONTHOR is a counter-swarm electromagnetic weapon stows completely in a 20 foot transport container, which ca…

What makes THOR distinct inside the directed-energy category is its “one-to-many” purpose. A conventional gun, interceptor missile or many laser systems normally prosecute targets in sequence. THOR was built around the possibility that a microwave pulse and beam-steering system could engage multiple small drones in a short time window. That is why the public descriptions emphasise airbase defence, swarms and fast engagement rather than precision strike against one hardened military asset. [afrl.af.mil]afrl.af.milR L conducts swarm technology demonstrationRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm with it…Published: May 16, 2023

THOR illustration 1

Why wide beams matter against drone swarms

The central problem THOR is trying to solve is saturation. A small drone may be cheap, expendable and difficult to justify engaging with an expensive missile. A group of drones can be worse: even if each one is individually fragile, the defender must detect, track, prioritise and defeat enough targets quickly enough to stop the attack. High-power microwave systems are attractive because a broader beam can affect multiple drones within the engagement area, giving them a theoretical advantage over point-by-point systems when many small aircraft arrive together. The US Office of Naval Research summarises the HPM appeal in similar terms: speed-of-light attack, deep magazines, modest electrical power from a host platform, broad beams for wide-area coverage, and comparatively simple targeting. [Office of Naval Research]onr.navy.milNavy many benefits including speed of light attack, deep magazines and modest electrical power from the host platform.Read more…

AFRL’s April 2023 THOR demonstration is the most important public case. At the Chestnut Test Site at Kirtland Air Force Base, New Mexico, AFRL said THOR simulated a real-world swarm attack and successfully demonstrated effectiveness against multiple targets. The official release called it the first test of that scale in AFRL history. Adrian Lucero, THOR programme manager, said the system was effective because of its wide beam, high peak powers and fast-moving gimbal used to track and disable targets. [afrl.af.mil]afrl.af.milR L conducts swarm technology demonstrationRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm with it…Published: May 16, 2023

The practical meaning is straightforward: THOR was not merely shown knocking down a single hovering drone for a camera. It was tested against numerous drones in a swarm-like scenario, with the engagement concept relying on rapid pointing and a beam wide enough to produce effects across more than one target path. Specialist coverage at the time noted that AFRL did not disclose the number or types of drones, the range, or whether every drone in the swarm was defeated. That absence matters, because those details determine how much the demonstration says about real combat performance. [Air & Space Forces Magazine]airandspaceforces.comair forces thor drone swarm demoair forces thor drone swarm demo

THOR or TACTICAL HIGH POWER MICROWAVE OPERATIONAL RESPONDER KNOCKS OUT DRONE !

Channel: Defense Updates

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What the public tests show

The public THOR record supports three cautious findings.

First, the system reached a level of maturity beyond a laboratory curiosity. AFRL’s fact sheet describes a containerised system that can be transported, set up and used with minimal operator training; reporting in 2020 described plans for operationally relevant testing by troops rather than only engineering trials. Those features matter because counter-drone systems are judged not just by whether they can produce an effect, but by whether they can be moved, powered, aimed, maintained and used under time pressure. [afresearchlab.com]afresearchlab.comTACTICA L HIGH POWER OPERATIONAL RESPONDERLaboratory developed for defense of airbases. stows completely in a 20 foot transport container, which can…

Second, THOR demonstrated the core counter-swarm promise under controlled conditions. AFRL’s April 2023 release says the system defeated a simulated real-world swarm attack, and Air & Space Forces Magazine reported that the test exceeded earlier single-drone demonstrations by pitting THOR against “numerous” drones of a kind it had not previously faced. That is a meaningful step for the evidence base, because swarm defence is the very use-case that makes microwave weapons especially interesting. [afrl.af.mil]afrl.af.milR L conducts swarm technology demonstrationRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm with it…Published: May 16, 2023

Third, the tests did not publicly establish an operational envelope. Open sources do not reveal THOR’s reliable defeat range, minimum and maximum engagement geometry, recharge or firing cadence under stress, performance against shielded or hardened drones, false-target behaviour, effects on friendly systems nearby, or results in poor weather and cluttered electromagnetic environments. The official record says the demonstration was successful; it does not provide the data needed to compare THOR quantitatively with guns, lasers, jammers, nets or interceptor drones. [Air & Space Forces Magazine]airandspaceforces.comair forces thor drone swarm demoair forces thor drone swarm demo

THOR illustration 2

What tests cannot prove on their own

A live demonstration can prove that a system works under the conditions chosen for that event. It cannot, by itself, prove that the system will work against every drone, in every swarm pattern, at every defended base, with friendly radios, radars, aircraft, vehicles and personnel nearby. This is especially important for high-power microwave weapons because their strength is also their complication: the effect is not a neat physical projectile with a visible path and impact point. It is an electromagnetic interaction between an emitter, a beam pattern, the target’s electronics, the target’s orientation and the surrounding environment.

The US Government Accountability Office identifies the broader limitation clearly. Directed-energy weapons can become less effective with distance; power and cooling can constrain performance; and wider-beam systems such as high-power microwave or millimetre-wave weapons may affect assets in an area whether friend or foe. That does not make THOR unusable. It means deployment would require careful integration with base layouts, exclusion zones, friendly electronic systems, command authority and rules for when a microwave engagement is acceptable. [GAO]gao.govgao 23 106717Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — For example, wider beam DEWs, such as high power microwave or millimete…Published: May 2023

There is also an evidence problem common to many directed-energy systems: the most important performance data are often not public. A reader can know that THOR demonstrated counter-swarm effects, but not the classified details that would settle harder questions. For example, “successful demonstration” could mean all drones were disabled quickly, most drones were disabled, or the test met a defined but undisclosed threshold. It could involve drone types that are representative of likely threats, or types selected for a specific engineering question. Without those details, THOR is best treated as strong evidence that wide-beam microwave counter-drone defence is technically plausible, not proof that any single deployed system can reliably stop all swarm attacks. [Air & Space Forces Magazine]airandspaceforces.comair forces thor drone swarm demoair forces thor drone swarm demo

THOR (Tactical High-power Operational Responder) Destroys Swarms of Enemy Drones

Channel: AFResearchLab

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Why THOR led to follow-on microwave programmes

One sign that THOR mattered is that AFRL moved from the demonstrator into follow-on work. In February 2022, AFRL awarded Leidos a $26 million contract for Mjölnir, a next-generation high-power microwave weapon system explicitly described as building on THOR. AFRL said THOR’s overseas operational testing had produced lessons that would define the requirements for Mjölnir, while the new prototype would improve capability, reliability and manufacturing readiness. [afrl.af.mil]afrl.af.milR L awards contract for drone killer, Mjölnir; brings newR L awards contract for drone killer, Mjölnir; brings new

That transition is important because prototypes often fail at the stage between a successful demonstration and a repeatable, supportable military product. Mjölnir’s stated purpose was not simply to make another dramatic microwave test. AFRL framed it as a step towards a blueprint for future counter-UAS high-power microwave systems, with enhanced range and improved detection and tracking. In other words, THOR appears to have served as the evidence-gathering platform that helped define what a more deployable microwave air-defence system would need. [afrl.af.mil]afrl.af.milR L awards contract for drone killer, Mjölnir; brings newR L awards contract for drone killer, Mjölnir; brings new

THOR also sits in a wider family of high-power microwave counter-drone efforts. Raytheon’s Phaser has been presented as a wide-beam microwave system able to down single drones or swarms by damaging electronics, while AFRL has separately pursued longer-range counter-electronics microwave work such as CHIMERA. These adjacent systems should not be treated as identical to THOR, but they show that the “wide-beam microwave against drones” idea is not a one-off curiosity. It is a continuing line of counter-UAS development within directed energy. [RTX]rtx.comOpen source on rtx.com.

THOR illustration 3

The real lesson from THOR

THOR shows why microwave air defence is compelling in the drone era: a defender facing many small unmanned aircraft needs something faster, deeper-magazined and less target-by-target than conventional interceptors alone. A containerised high-power microwave system that can rapidly slew across the sky and create counter-electronic effects fits that requirement in a way a single-shot kinetic weapon does not. The April 2023 swarm demonstration is therefore a meaningful data point for directed energy weapons, especially for airbase defence against small drones. [afrl.af.mil]afrl.af.milR L conducts swarm technology demonstrationRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm with it…Published: May 16, 2023

But THOR also shows why the field should be discussed carefully. The public evidence supports the concept, not a blanket claim of invulnerability against swarms. Microwave systems must still solve integration, range, discrimination, safety, hardening and operational-command problems. Their wide beam is the reason they may defeat multiple drones quickly; it is also the reason planners must think hard about what else sits inside or near the engagement zone. That trade-off is the core lesson: THOR is not a magic drone eraser, but it is one of the clearest public demonstrations of why high-power microwaves have become a serious branch of directed-energy air defence.

AFRL's THOR Tracks and Disables Drone Swarm

Channel: AFResearchLab

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Endnotes

  1. Source: afresearchlab.com
    Title: TACTICA L HIGH POWER OPERATIONAL RESPONDER
    Link: https://afresearchlab.com/counter-swarm-high-power-weapon/
    Source snippet

    Laboratory developed for defense of airbases. stows completely in a 20 foot transport container, which can...

  2. Source: afresearchlab.com
    Link: https://afresearchlab.com/wp-content/uploads/2019/09/AFRL_THOR_FS_0122.pdf
    Source snippet

    COUNTER-SWARM HIGH POWER WEAPONTHOR is a counter-swarm electromagnetic weapon stows completely in a 20 foot transport container, which ca...

  3. Source: gao.gov
    Title: gao 23 106717
    Link: https://www.gao.gov/products/gao-23-106717
    Source snippet

    Science & Tech Spotlight: Directed Energy Weapons25 May 2023 — For example, wider beam DEWs, such as high power microwave or millimete...

    Published: May 2023

  4. Source: afrl.af.mil
    Title: R L conducts swarm technology demonstration
    Link: https://www.afrl.af.mil/News/Article-Display/Article/3396995/afrl-conducts-swarm-technology-demonstration/
    Source snippet

    RL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective at disabling the swarm with it...

    Published: May 16, 2023

  5. Source: afrl.af.mil
    Title: R L awards contract for drone killer, Mjölnir; brings new
    Link: https://www.afrl.af.mil/News/Article/2945744/afrl-awards-contract-for-drone-killer-mjlnir-brings-new-drone-hammer-to-the-fig/

  6. Source: rtx.com
    Link: https://www.rtx.com/raytheon/what-we-do/integrated-air-and-missile-defense/phaser-high-power-microwave

  7. Source: afrl.af.mil
    Link: https://www.afrl.af.mil/News/Photos/igphoto/2003223867/

  8. Source: afrl.af.mil
    Link: https://www.afrl.af.mil/

  9. Source: af.mil
    Title: rls drone killer thor will welcome new drone hammer
    Link: https://www.af.mil/News/Article-Display/Article/2713908/afrls-drone-killer-thor-will-welcome-new-drone-hammer/

  10. Source: afrl.af.mil
    Link: https://www.afrl.af.mil/News/Video/?dvpTag=drone&dvpmoduleid=69743&videoid=800274

  11. Source: afrl.af.mil
    Title: mil News
    Link: https://www.afrl.af.mil/News/Tag/187/thor/

  12. Source: afresearchlab.com
    Link: https://afresearchlab.com/

  13. Source: afresearchlab.com
    Link: https://afresearchlab.com/thor/

  14. Source: afresearchlab.com
    Link: https://afresearchlab.com/wp-content/uploads/2019/09/AFRL_THOR_FS_0719.pdf

  15. Source: afresearchlab.com
    Title: AFRL FY21 Annual Report Digital
    Link: https://afresearchlab.com/wp-content/uploads/2022/03/AFRL-FY21-Annual-Report-Digital.pdf

  16. Source: onr.navy.mil
    Link: https://www.onr.navy.mil/organization/departments/code-35/division-353/directed-energy-weapons-high-power-microwaves
    Source snippet

    Navy many benefits including speed of light attack, deep magazines and modest electrical power from the host platform.Read more...

  17. Source: airandspaceforces.com
    Title: air forces thor [drone swarm]({{ ‘swarm-limits/’ | relative_url }}) demo
    Link: https://www.airandspaceforces.com/air-forces-thor-drone-swarm-demo/

  18. Source: Wikipedia
    Title: Air Force Research Laboratory
    Link: https://en.wikipedia.org/wiki/Air_Force_Research_Laboratory

  19. Source: usfk.mil
    Link: https://www.usfk.mil/What-We-Do/Exercises/Freedom-Shield/?dvpTag=Thor&videoid=904340

Additional References

  1. Source: breakingdefense.com
    Title: troops in theater to test afrls thor drone killer this fall
    Link: https://breakingdefense.com/2020/08/troops-in-theater-to-test-afrls-thor-drone-killer-this-fall/
    Source snippet

    Breaking DefenseTroops To Test AFRL's THOR Drone Killer This Fall4 Aug 2020 — This Fall THOR puts high-powered microwaves to fry drone sw...

  2. Source: arxiv.org
    Link: https://arxiv.org/abs/2602.08477

  3. Source: researchgate.net
    Link: https://www.researchgate.net/publication/358274981_C277_Recent_Trends_in_High_Power_Microwave_Counter_Measure_Against_Drone_Swarm_Attack

  4. Source: droneshield.com
    Link: https://www.droneshield.com/blog/a-counter-to-drone-swarms-high-power-microwave-weapons

  5. Source: dvidshub.net
    Link: https://www.dvidshub.net/video/904353/afrls-thor-tracks-and-disables-drone-swarm

  6. Source: instagram.com
    Link: https://www.instagram.com/reel/C4aV7pKt26e/

  7. Source: facebook.com
    Link: https://www.facebook.com/AFResearchLab/videos/afrls-tactical-high-power-operational-responder-or-thor-system-%EF%B8%8F-is-swarming-int/1138955837220051/

  8. Source: linkedin.com
    Link: https://www.linkedin.com/company/air-force-research-laboratory

  9. Source: facebook.com
    Link: https://www.facebook.com/ArmedWithScience/posts/building-a-drone-killer-the-air-force-research-laboratory-afrl-is-building-a-cou/3833287916896360/

  10. Source: market.us
    Link: https://market.us/report/directed-energy-weapons-market/

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