In February 2023, news spread of weather-balloon-like crafts from China entering continental US airspace. Although the purpose of the balloons was likely reconnaissance or metrological data collection, it raised concerns that a similar system could deliver a high-altitude electromagnetic pulse (HEMP) attack, largely undetected.

Balloon-borne high-altitude EMP (HEMP) weapons are capable of crippling vital infrastructure and sensitive electronics. Compared to other aerial offenses, the prospect of using balloons as platforms for deploying HEMP weapons seems advantageous due to their low-cost, ease of deployment, and potential ability to deliver a powerful electromagnetic pulse over a large area. Balloon-borne HEMP weapons, if technically feasible, could represent a unique and challenging threat that demands serious consideration.

Technical Feasibility

To evaluate the technical feasibility, experts consider several factors. First and foremost, the altitude reached by these balloons is the determining variable of the affected radius on the ground. Attaining an altitude of 30 kilometers (about 18.64 mi) or higher is necessary to maximize the effectiveness of the EMP effect across an entire country.

Another consideration is the payload required to generate an EMP with significant destructive potential. HEMP weapons generally employ a nuclear detonation or a non-nuclear device that can produce a similar EMP effect. Russia purportably has possession of a “Super-EMP” weapon that potentially could generate 100,000 volts/meter or higher.

While engineering these maximums in altitude and pulse magnitude are conceivably achievable, weaponized balloons in practice would still represent a sizable warfare gamble because of unpredictable trajectories. Accurate targeting poses a formidable obstacle for large-scale HEMP attacks when compared to aircraft or missile delivery systems. Though methods of controlling and directing balloons exist, a payload could easily go off course from its intended route due to meteorological events, especially at extreme altitudes.

Although larger military powers may have developed plans for large balloon-delivered HEMP devices, the 2023 balloon incidents have spurred speculation that cheaper, lower-altitude weapons in the hands of a rogue state or terrorist group could implement attacks, albeit to a narrower geographic area.

Vulnerability Assessment

How vulnerable are North American countries to balloon-borne HEMP weapons?

To civilian society, a HEMP attack would be devastating in its consequences. Most modern electronic devices—those with chip processors—would get short-circuited and fail. A car would likely not start, not due to its battery, but because its electronic control systems cease to function. The supply of electricity, and all other utilities that depend on it, such as mobile communication, datacenters, water pumps and treatment plants, public transportation, might experience catastrophic failure.

The resulting chaos would be on par with a natural disaster, where populations are left with dwindling supplies of food and water and cut off from medical aid and security protections. HEMP events can do permanent damage to large-scale equipment and to repair nodes of the electric grid could require more than a year. Sen. Ron Johnson (R-Wis.) stated in Power Magazine that a HEMP attack across the continent could kill 90 percent of the population. While this estimate is debatable, it is easy to imagine the destructive repercussions of a HEMP event would be widespread and protracted.

Fortunately, compared to other regions, North America has more extensive shielding and other mitigation measures in place, like high-frequency filters and underground power lines at points of critical infrastructure, in particular around military command, communications and relay capabilities. If the pulse were less than maximal strength, these facilities would survive, allowing the government some degree of military and humanitarian response.

Beyond military networks, North American nations have made substantial progress in bolstering their resilience against EMP events. Governments, utilities, and critical infrastructure providers have undertaken various initiatives, such as implementing EMP protection standards, conducting vulnerability assessments, and developing contingency plans. These measures provide a reasonable level of defense against the balloon-borne HEMP threat.

Mitigating the Risk

Ongoing research and development efforts are focused on improving early warning systems for detecting balloons carrying potential HEMP weapons. Satellite-based monitoring systems, advanced radar technology, and collaboration between intelligence agencies all contribute to early detection of high-altitude threats.

In parallel, robust investments have been made in technologies that harden infrastructure and deflect the excess current that pulses induce in power lines. TSS USA Manufacturing has developed a medium-voltage-capable HEMP filter that is the first of its kind, able to protect large scale infrastructure up to 5000 volts. Similarly, TSS low-voltage filter solutions protect sensitive equipment from EMP surges.

Governments have also undertaken new initiatives that can more rapidly assess and repair damaged infrastructure and minimize the effects of any successful attack.

Offense and Defense Up in the Air

While the idea of HEMP weapons delivered through balloons may capture the imagination, their practical feasibility remains uncertain. The technical challenges, including achieving the required altitude, miniaturizing EMP devices, and ensuring accurate targeting, are significant obstacles to overcome for a large-scale attack. Moreover, North American countries have taken proactive steps to fortify their infrastructure and enhance resilience against EMP attacks.

Nonetheless, constant vigilance, continued research, and the strengthening of defensive measures are still needed. As technology evolves and new potential threats emerge, North American nations must remain at the forefront of innovation to ensure the security and protection of their critical infrastructure and citizens in a changing geopolitical landscape.