Within Safety Zones
Why THOR Cannot Fire Everywhere
Airbase defenders need approved engagement directions so microwave shots avoid aircraft, maintenance zones and mission-critical infrastructure.
On this page
- How exclusion zones differ from simple safety circles
- Aircraft and ground operations inside hazard areas
- How firing sectors shape real counter swarm use
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Introduction
THOR was designed to protect airbases from drone swarms, but an airbase is one of the most crowded electromagnetic environments in military operations. Aircraft, maintenance facilities, communications networks, navigation systems, radar installations and command centres often operate within a relatively small area. As a result, THOR cannot simply be pointed in any direction whenever a threat appears. Its microwave beam must be employed within carefully planned firing sectors that define where engagements are permitted and where they are prohibited. The purpose is not merely operator convenience; it is to ensure that counter-drone operations do not create unacceptable risks to friendly aircraft, mission-critical electronics or personnel. THOR’s wide-beam, high-power microwave design makes these sector controls especially important because the system is intended to affect electronics across an area rather than a single point target. Air Force Research Laboratory+2Air Force Research Laboratory [afrl.af.mil]afrl.af.milAir Force Research Laboratory AFRL conducts swarm technology demonstrationAir Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective a…
Why THOR Cannot Fire Everywhere
THOR is fundamentally an airbase-defence system. The Air Force Research Laboratory developed it specifically to counter multiple drones approaching a protected site, and public demonstrations have highlighted its ability to engage groups of drones using a broad microwave effect rather than a narrowly focused kinetic interceptor. Air Force Research Laboratory+2The War Zone [afresearchlab.com]afresearchlab.comPhoto credit: AFRL Directed Energy Directorate.Read more…
That same characteristic creates an implementation challenge. A conventional gun or missile system primarily raises concerns along a physical trajectory. A high-power microwave weapon introduces electromagnetic considerations as well. Modern aircraft contain dense avionics suites, data buses, communications systems and sensors. Airbases also rely on fixed electronic infrastructure that cannot simply be shut down whenever a drone threat appears. High-power microwave systems are specifically intended to disrupt or disable electronics by coupling energy into vulnerable circuits. [Inzpire+2Office of Naval Research]inzpire.comhigh power microwaves more than just a hot lunchHigh power microwaves – more than just a hot lunch!3 Mar 2025 — High-power microwaves are an emerging class of directed energy wea…
For this reason, airbase operators need approved engagement directions rather than unrestricted 360-degree firing. A safe direction for engaging an incoming drone swarm may be one that points away from parked aircraft, maintenance hangars, air-traffic facilities or communications nodes. The result is a map of authorised sectors and prohibited sectors rather than a simple rule allowing engagement in any direction.
How Exclusion Zones Differ from Simple Safety Circles
A common misunderstanding is that microwave safety can be managed through a fixed-radius buffer around the weapon. In practice, airbase planning is usually more complex.
A simple safety circle assumes that risk decreases uniformly in every direction. THOR’s operational reality is different because the concern is not only distance but also what lies inside the beam path and beyond the target area. A parked fighter aircraft directly downrange may represent a higher concern than a location at a similar distance but outside the authorised engagement sector.
Controlled firing sectors therefore combine several layers of restriction:
- Directional limits, defining where the system may be pointed.
- Infrastructure exclusion zones, protecting sensitive facilities and electronics.
- Aircraft protection zones, preventing engagements through areas containing parked or operating aircraft.
- Operational restrictions, temporarily closing sectors when maintenance or other activities are underway.
The distinction matters because airbases are dynamic. A sector that is safe during one period may become restricted when aircraft are being refuelled, tested or repaired. Sector management therefore becomes part of routine base operations rather than a one-time engineering calculation.
This approach mirrors broader electromagnetic compatibility practices used around military systems. The objective is not simply preventing personnel exposure but ensuring that critical equipment continues operating as intended while the counter-drone system remains available for defence. [Inzpire+2Office of Naval Research]inzpire.comhigh power microwaves more than just a hot lunchHigh power microwaves – more than just a hot lunch!3 Mar 2025 — High-power microwaves are an emerging class of directed energy wea…
Aircraft and Ground Operations Inside Hazard Areas
Aircraft are the most obvious reason for sector control. Modern military aircraft contain extensive electronic systems that are essential for navigation, communications, mission management and flight operations. Even when an aircraft is parked, technicians may be conducting diagnostics, software updates or maintenance procedures involving sensitive equipment.
Because THOR is intended to create electronic effects, operators cannot assume that a parked aircraft is an acceptable background object. Airbases therefore have strong incentives to keep microwave engagement paths separated from aircraft parking aprons, maintenance ramps and hangars whenever possible. [Inzpire+2Air University]inzpire.comhigh power microwaves more than just a hot lunchHigh power microwaves – more than just a hot lunch!3 Mar 2025 — High-power microwaves are an emerging class of directed energy wea…
Ground operations create similar constraints. Airfields contain:
- Mobile command vehicles.
- Air-defence coordination centres.
- Communications shelters.
- Radar and surveillance systems.
- Fuel-handling facilities with electronic monitoring equipment.
- Maintenance workshops using test instruments and networked systems.
Many of these functions must continue during a drone attack. A defensive system that inadvertently disrupts friendly operations could reduce the base’s ability to respond to the threat. Controlled sectors therefore help separate the engagement volume from the electronic infrastructure that the base depends upon.
The issue is particularly significant because THOR’s role is point defence. Public descriptions consistently place it in the short-range defence layer protecting bases from approaching drone swarms. That means engagements occur close to the defended installation rather than far away from friendly assets. [The War Zone+2Popular Mechanics]twz.comthor microwave anti drone system downs swarms in testThe War ZoneTHOR Microwave Anti-Drone System Downs Swarms In Test19 May 2023 — The demonstration pitted the service's high-power microwav…
How Firing Sectors Shape Real Counter-Swarm Use
The existence of controlled sectors affects how THOR would actually be employed during an attack.
In an idealised scenario, operators would engage a swarm from any angle. On a real airbase, planners are more likely to identify preferred engagement corridors before an attack occurs. These corridors direct incoming threats into areas where microwave engagement presents the lowest risk to friendly assets.
This can influence several operational decisions:
Sensor placement. Surveillance systems may be arranged to provide early warning in directions that align with authorised firing sectors.
Base layout. THOR may be positioned so that its safest engagement directions face open approaches rather than dense infrastructure.
Threat prioritisation. Operators may choose to engage a swarm when it enters a preferred sector rather than immediately upon detection.
Layered defence integration. Threats approaching through restricted sectors may require alternative counter-drone measures if microwave employment would create excessive risk.
The fact that THOR uses a gimballed system capable of tracking and engaging targets does not eliminate these constraints. Public demonstrations have emphasised the weapon’s ability to aim rapidly and affect multiple drones, but the question on an operational airfield is not simply whether the target can be tracked. It is whether the engagement direction is compatible with the base’s safety and electromagnetic-control plan. [Air Force Research Laboratory+2Unmanned Airspace]afrl.af.milAir Force Research Laboratory AFRL conducts swarm technology demonstrationAir Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective a…
Controlled Sectors Are an Enabler, Not a Limitation
At first glance, restricting where THOR can fire may appear to reduce its usefulness. In practice, controlled firing sectors are what make deployment on a working airbase possible.
Without sector management, commanders would face uncertainty about the effects of high-power microwave engagements near aircraft, maintenance facilities and critical infrastructure. By defining approved engagement directions, protected areas and temporary operational restrictions, airbases can integrate THOR into daily operations while preserving the systems they are defending.
The result is a defence posture in which the weapon’s wide-area counter-electronics capability remains available against drone swarms, but only within carefully managed corridors that balance effectiveness against the need to protect friendly aircraft, electronics and ongoing airfield operations. epirusinc.com+3Air Force Research Laboratory+3Inzpire [afresearchlab.com]afresearchlab.comPhoto credit: AFRL Directed Energy Directorate.Read more…
Amazon book picks
Further Reading
Books and field guides related to Why THOR Cannot Fire Everywhere. Use these as the next step if you want deeper reading beyond the article.
Air base defense in the Republic of Vietnam, 1961-1973
First published 1979. Subjects: Aerial operations, Air bases, American Air bases, History, United States.
Introduction to Electronic Defense Systems
First published 1991. Subjects: Electronics in military engineering.
Directed Energy Weapons: Technologies, Applications and Impacts
Relevant to firing envelopes and operational limitations.
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Endnotes
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Source: inzpire.com
Title: high power microwaves more than just a hot lunch
Link: https://www.inzpire.com/news/high-power-microwaves-more-than-just-a-hot-lunchSource snippet
High power microwaves – more than just a hot lunch!3 Mar 2025 — High-power microwaves are an emerging class of directed energy wea...
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Source: epirusinc.com
Link: https://www.epirusinc.com/electronic-warfareSource snippet
N) semiconductors for unmatched counter-electronics effects.Read more...
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Source: afrl.af.mil
Title: Air Force Research Laboratory AFRL conducts swarm technology demonstration
Link: https://www.afrl.af.mil/News/Article-Display/Article/3396995/afrl-conducts-swarm-technology-demonstration/Source snippet
Air Force Research LaboratoryAFRL conducts swarm technology demonstrationMay 16, 2023 — 16 May 2023 — “THOR was exceptionally effective a...
Published: May 16, 2023
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Source: afresearchlab.com
Link: https://afresearchlab.com/counter-swarm-high-power-weapon/Source snippet
Photo credit: AFRL Directed Energy Directorate.Read more...
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Source: airuniversity.af.edu
Title: army partners with air forces thor for base defense
Link: https://www.airuniversity.af.edu/News/Display/Article/2511792/army-partners-with-air-forces-thor-for-base-defense/Source snippet
Air UniversityArmy partners with Air Force's THOR for base defense23 Feb 2021 — THOR is a prototype directed energy weapon used to disabl...
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Source: twz.com
Title: thor microwave anti drone system downs swarms in test
Link: https://www.twz.com/thor-microwave-anti-drone-system-downs-swarms-in-testSource snippet
The War ZoneTHOR Microwave Anti-Drone System Downs Swarms In Test19 May 2023 — The demonstration pitted the service's high-power microwav...
Published: May 2023
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Source: onr.navy.mil
Link: https://www.onr.navy.mil/organization/departments/code-35/division-353/directed-energy-weapons-high-power-microwavesSource snippet
Office of Naval ResearchDirected Energy Weapons: High Power MicrowavesDirected energy weapons (DEWs) are defined as electromagnetic syste...
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Source: popularmechanics.com
Title: laser microwave weapons
Link: https://www.popularmechanics.com/military/weapons/a32083799/laser-microwave-weapons/Source snippet
air bases from the threat of drone strikes, shooting down any unauthorized drone that comes...Read more...
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Source: unmannedairspace.info
Link: https://www.unmannedairspace.info/counter-uas-systems-and-policies/us-air-force-research-laboratory-demonstrates-anti-drone-swarm-c-uas-technology/Source snippet
US Air Force Research Laboratory demonstrates anti-...“THOR was exceptionally effective at disabling the swarm with its wide beam, high...
Additional References
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Source: s3.us-east-1.amazonaws.com
Link: https://s3.us-east-1.amazonaws.com/files.cnas.org/hero/documents/CNAS_Directed_Energy_Weapons_April-2015.pdfSource snippet
DIRECTED-ENERGY WEAPONS:by JD Ellis — High- energy [lasers]({{ 'lasers/' | relative_url }}) often operate within the visible or infrared portions of the spectrum; high-pow...
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Source: jedonline.com
Title: high power microwave systems getting much much closer to operational status
Link: https://www.jedonline.com/2023/01/24/high-power-microwave-systems-getting-much-much-closer-to-operational-status/Source snippet
High-Power Microwave Systems – Getting (Much...24 Jan 2023 — AFRL's THOR demonstrator system, developed by Leidos, BAE Systems and Verus...
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Source: youtube.com
Link: https://www.youtube.com/watch?v=JGzL3fZgPZY -
Source: potomacofficersclub.com
Title: afrl demonstrates microwave powered defense system against drone swarms
Link: https://www.potomacofficersclub.com/afrl-demonstrates-microwave-powered-defense-system-against-drone-swarms/Source snippet
AFRL Demonstrates Microwave-Powered Defense System...23 May 2023 — The Air Force Research Laboratory recently demonstrated the Tactical...
Published: May 2023
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Title: microwave weapons principles and applications
Link: https://www.aivon.com/blog/aerospace-electronics/microwave-weapons-principles-and-applications/Source snippet
Microwave Weapons: Principles and Applications20 Jan 2026 — Technical overview of microwaves, microwave weapons, and counter-UAS systems...
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Source: gpsworld.com
Title: power of thor ready to down enemy drones
Link: https://www.gpsworld.com/power-of-thor-ready-to-down-enemy-drones/Source snippet
GPS WorldPower of THOR ready to down enemy drones14 Aug 2020 — THOR stands for Tactical High-power Operational Responder, a counter-swarm...
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Source: droneshield.com
Link: https://www.droneshield.com/blog/a-counter-to-drone-swarms-high-power-microwave-weaponsSource snippet
sive, mass-produced drones can overwhelm defences...
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Source: science.gc.ca
Title: directed energy weapons
Link: https://science.gc.ca/site/science/en/safeguarding-your-research/guidelines-and-tools-implement-research-security/emerging-technology-trend-cards/directed-energy-weaponsSource snippet
11 Feb 2025 — Directed energy weapons (DEWs) use concentrated energy from electromagnetic or particle technology, rather than kinetic ene...
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Source: airandspaceforces.com
Link: https://www.airandspaceforces.com/air-forces-thor-drone-swarm-demo/Source snippet
Air & Space Forces MagazineTHOR Hammers Drone Swarm with High-Power Microwaves19 May 2023 — THOR uses bursts of high-power microwave ener...
Published: May 2023
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Source: youtube.com
Title: THOR (Tactical High-power Operational Responder) Destroys Swarms of Enemy Drones
Link: https://www.youtube.com/watch?v=QjHGxKb6W1cSource snippet
Air Force Research Lab unleashed THOR on drone swarm...
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