US may test a military heat ray at the Mexico border. How the ‘pain beam’ works and why it raises questions

The US government has plans to implement a technology which seems more like science fiction than normal border control tactics: the deployment of a military heat ray which will have people step back from the invisible beam of energy. The Pentagon has granted the Department of Homeland Security (DHS) approval to use the Active Denial System, which is a directed-energy weapon causing the sensation of burning to the exposed skin. CNN reports that through a memo signed by Defence Secretary Pete Hegseth, the one-month transfer of the system was approved.

The decision does not mean the weapon has been deployed at the US-Mexico border, or that officials have settled on how it might be used.

The department has been permitted to assess the system and develop possible operational tactics, leaving open questions about where testing would take place and whether it could eventually become part of border enforcement.


Also Read | Can race-neutral school admissions policies still discriminate? What’s at stake in the US Supreme Court’s Maryland school case

The proposal is notable because the US military has previously explored the technology for crowd control but ultimately declined to use it in several situations.

Its possible introduction into domestic border operations raises questions about the limits of nonlethal weapons, the treatment of migrants and the government's approach to managing crowds.

How the military's Active Denial System makes people flee

Active Denial System, which is referred to as a heat ray or "pain beam", relies on electromagnetic radiation, which produces an extreme burning sensation once the energy touches the skin of humans.

As far as the range of the weapon, the United States Army claims that it could work from about half a mile away and would allow influencing people without touching them.

Also Read | America's $1 trillion annual interest bill is growing as national debt surges, so why isn't the US facing a debt crisis like France?

According to CNN reporting, this sensation is similar to the one when you open a very hot oven and feel the heat wave. The energy passes through the outer layer of skin and burns it.

The military has stated that the resultant feeling typically persists for around 10 to 15 minutes.

The idea behind such a weapon is to induce an instantaneous response from those at whom the beam is directed and not inflict any permanent damage on them. It has been described by officials as an instinctive need to get away from the light source, thereby making it suitable for use in cases where there is a need to disperse a crowd without using normal projectiles.

The classification of a weapon as a non-lethal one does not automatically make it safe in all possible conditions. The results will be a function of how the weapon is handled, its duration of usage, and the conditions under which it will be employed.

The system's potential use at the border remains under consideration. CNN reported that the DHS request did not spell out exactly where or how the weapon would be tested.

Why DHS is getting access to the weapon now

The Pentagon's memorandum authorises a temporary loan of one Active Denial System for seven months. It also specifies that Department of War personnel will not operate the equipment, assigning DHS responsibility for its use and for developing tactics, techniques and procedures.

A defence official told CNN that DHS could seek an extension after the loan period if it determines that further use is necessary for border operations.

Under the arrangement, the weapon would be held by a department concerned with immigration enforcement and border control, instead of staying in the confines of the military test programs. The Department of Homeland Security’s Customs and Border Protection said that it is always on the lookout for new technologies to enhance its effectiveness, in a statement to CNN.

The department has yet to outline its deployment strategy. The memo also does not state that the weapon will be deployed against migrants, in a certain crossing area or situation.

Still, the possibility is not entirely new.

According to CNN, officials at the U.S. Customs and Border Protection have talked about using the weapon to clear crowds in regions where there is an exceptionally high number of illegal immigrants crossing into the United States from Mexico.

The military has also considered the weapon for crowd control outside of actual battlegrounds. According to CNN, the weapon has been considered during instances of unrest within the country towards the end of Donald Trump’s presidency after the 2020 murder of George Floyd.

The system was not deployed for that purpose.

A controversial technology with a history of limited use

The Active Denial System has been examined by the US military for years, but its operational history has remained limited.

CNN reported that the military briefly deployed the technology to Afghanistan nearly two decades ago but ultimately chose not to use it in active combat.

The officials also evaluated the crowd control technology used at US facilities overseas which housed the detainees suspected of being terrorists, but the use of the technology was never implemented in this context.

The above decisions are relevant to the proposal put forward as they demonstrate that developing technology and then utilising it are two distinct processes. A weapon can seem like an alternative to firearms or other forms of violence, but its practicality and effectiveness in a certain situation have to be analysed.

There are particular difficulties in the case of borders.

Crowds can include families, children and people who may have limited ability to move quickly away from an affected area. Questions would also arise over how officers distinguish between individuals posing an immediate threat and people who are simply present in a crowd.

The Pentagon's decision transfers responsibility for operational planning to DHS, but it does not settle those questions. CNN's report also leaves unclear whether the department will ultimately request an extension beyond the initial seven-month period.

For now, the heat ray remains a technology being considered for possible border use, not a weapon confirmed to be operating along the southern frontier. Whether DHS moves beyond testing will depend on its assessment of the system and the tactics it develops.

The larger issue is how far US authorities are prepared to go in adopting military technologies for domestic enforcement. A beam that causes people to flee without bullets may be presented as a less lethal option, but its use would still demand clear rules, effective oversight and careful scrutiny of the risks.