# Defense Secretary Pete Hegseth Authorizes 'Heat Ray' Testing at US-Mexico Border

> Defense Secretary Pete Hegseth has authorized the Department of Homeland Security to test a non-lethal Active Denial System, a 'heat ray' weapon, for potential use at the U.S.-Mexico border.

By PrimaryBrief newsroom · Published 2026-10-25T20:28:11.818486Z
Canonical: https://primarybrief.com/article/defense-secretary-pete-hegseth-authorizes-heat-ray-testing-at-us-mexico-border-9b25df7b

Defense Secretary Pete Hegseth authorized the Department of Homeland Security (DHS) in September 2026 to test the Active Denial System (ADS), a "heat ray" weapon, for potential use at the U.S.-Mexico border [1][2][3]. This authorization involves a temporary, seven-month loan of one ADS unit to DHS [1].

The decision revives a controversial weapon system previously considered for border use but rejected due to ethical concerns and questions about treating individuals like enemy combatants [17][18]. Its potential deployment could ignite further debate over border security and human rights implications [3].

## What the records show
A memorandum, reportedly obtained by CNN, states that Secretary Hegseth's authorization began a temporary seven-month loan of one ADS unit to DHS in September 2026 [1][2][3][9]. The document permits testing and tactical development for potential border operations, but it does not confirm the system will be used against migrants or other groups [1]. The memo stipulates that Department of Defense (DoD) personnel will not operate the system, transferring full responsibility for its "system employment, use and development of tactics, techniques and procedures" to DHS [2][3].

The ADS is a non-lethal directed-energy weapon that emits an invisible beam of 95 gigahertz millimeter waves [3][4]. This beam penetrates approximately 1/64th of an inch into the skin, activating superficial pain receptors to create an intense, temporary burning sensation without causing physical injury [3][4]. The sensation ceases when a person moves out of the beam and subsides within 10 to 15 minutes [3].

## The timeline
Pete Hegseth was confirmed as the 29th United States Secretary of Defense on January 24, 2025, and sworn in on January 25, 2025, during Donald Trump's second term [7][15][16]. He signed the memo authorizing the ADS loan in September 2026 [3][10]. The ADS was previously deployed to Afghanistan around 2010 for testing but was returned without operational use in combat due to political and public concerns [4][12]. Domestically, Customs and Border Protection (CBP) officials had considered using the ADS at the border in 2018, but then-Homeland Security Secretary Kirstjen Nielsen reportedly rejected the proposal [17][18][19]. Nielsen reportedly refused to authorize its use and demanded it not be discussed again due to concerns about treating immigrants and citizens like enemy combatants, public perception, and international conventions [17][18].

## What changed and for whom
The current authorization by Secretary Hegseth marks a shift from previous rejections of the ADS for border use. Former Homeland Security Secretary Kirstjen Nielsen had explicitly refused to authorize the system in 2018, reportedly citing ethical concerns about its application [17][18]. The transfer of full operational responsibility for the ADS to DHS indicates a significant move toward potentially integrating this military-developed technology into civilian border enforcement strategies [2][3].

## What the subject has said publicly
A U.S. Customs and Border Protection (CBP) spokesperson stated that the agency is "continually evaluating new technology" [3]. However, CBP has not disclosed specific operational plans or locations for testing the ADS at the border [3]. A Pentagon spokesperson referred inquiries about the matter to DHS [3].

## What we could not confirm
The specific operational plans or locations for testing the ADS at the U.S.-Mexico border have not been disclosed [3]. The initial CNN report that obtained the memo also did not confirm if the system would be used against migrants, protesters, or any other group [1].

## Evidence cited
1. Heat Ray for Border? Pentagon Authorizes DHS to Test Active Denial System (gadgetreview.com) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQG7Rbv9rRnFmCI_KeBQFUCetl9xLLHx8CqZsEoCsKvAB_2r_TnzNXE6kSIPmB4oUOgB1RzFSzz00RHq4kIh4jnU8OkG5mZyu8Hy2E0YUD_1Ga4AHllLvyWqSb_mYx6V39LyWxsEwvnCYeM6tju_YKb2XPvgAbpKaTT5_TJHAOxDa6Fc8chg6ewQBpr6686M8QobKQ==
2. US military gives DHS permission to test 'heat ray' weapon on migrants at southern border | Latin Post (latintimes.com) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQH7zhtiGQvw2aNcS0kgyH4jcnUmJnRQPRqb5Uy7vLk7EfmZM5YFDipEYTOOTqHKK-7tZplF95XnHN3CaL8ra3UmejQWIsyj2MwTc-Svuy6kW-Yyc8WRhj5mNixF6Nn4PHzELw3AcbTw5pEA1Hb7NzbEkuepi1dzfkac2Z9MrTdM0dw8Ya-KsY6zHn0vz230R_ACOCtHfvYvDcrlW6xon7Tf8yqk
3. What The U.S. Military's 'Heat Ray' Weapon Does To Your Body (newsweek.com) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQE-5A-upg5T_6zwwLvYqqwC-KscfMsbejhXA4dvBSVR8AjdlqBWVyttDcjCWwyxhlUOq2XMIndJcnfhOgooaB9JIxEnBGNY9BiYUgpl7WTQAT9h3mhbwxaRJRkyM1r2hxq5XUMWvvmVAyYEL_3UMpH19GfsMFI1UWVuImvAJu6tv2wiFn88BUgt_Do=
4. Explained: What is Active Denial System (ADS) or 'Heat Ray'? Why is US considering its deployment at Mexico Border? (gktoday.in) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQFnewGuEbysCsUYhB6YIIaY5pXzk6jtMGw8A-mWZ5f8FXlNnKDGgay3COy903CgizsuFAi87Ce_o6bMkpKYAcCCR2oZWeedqjJcz-PQ88TuS0jfCFJzcZRtPmvtgtTkyWFs3P3UtD6Y
5. ‘Heat ray’ was sought for use on Lafayette Square protesters, whistleblower says (washingtonpost.com) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQGv2QVPszk-HohWyHuMMnDeJejqq9nnWnimLAxfO5zt1izA1Tsj_l4TArkSaLD9JFnIkG8GqIXz41rYlcifVDl4jZsgVHTYsIABiG240BLjRubFtJgHUJB2G4vBoheaV354Eo8jU1M9rWE1hdRKVkpp_0eOVGO9omIk-dCZt5TUa0Cnk9pDw5dQQQ=
6. Ethics and the Active Denial System: An Analysis of the Morality of the 'Heat Ray' (case.edu) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQEs0xERxnwZmbBylVxUnBtvZY-03ahRzBeKHPWQc-N7D5WDS6BLqyq1Ib9d8MypeVbIqOAz6AsDML90mWutAH0HS7RkadRKZqHc4trgz6c1vNh6qwadSnT7Npqrb-4XQBeKmBIh_TvHQYwXLo8FOdyA27dwY980rvU_DC6sH978_oRo3JBkSzQszWZtju_YKb2XPvgAbpKaTT5_TJHAOxDa6Fc8chg6ewQBpr6686M8QobKQ==
7. Pete Hegseth - Wikipedia (wikipedia.org) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQGMboYo63wyu055V-rz1A0Zcf0l7pY7QCq7n_RPGeIiRrMTx4uJLWf-UfwCGVZ7M8HRCIhAXzkCcesvMhwqrChEEF8eiJPX5kJMbTeq7YgeII1UsRzWpd99SMELE7aAD0P0_VqpBQ==
8. Pete Hegseth | Biography, Fox News, Secretary of Defense | Britannica (britannica.com) — https://vertexaisearch.cloud.google.com/grounding-api-redirect/AUZIYQGvV4H6IMmY1idOS4X2NrE37AvVUMWW5LxBGgpcAatfH0mc3-qlVGpQkogfKf6HS5j5vnbDhdHS7CqAlBHB7_rsD01buGd39Kl_z6RXU3SnfiwqhdzGj5PeQpi1We9bkSHU0IQLH6jgtvuqXbM=
9. Heat Ray for Border? Pentagon Authorizes DHS to Test Active Denial System (gadgetreview.com) — https://gadgetreview.com/heat-ray-for-border-pentagon-authorizes-dhs-to-test-active-denial-system
10. US military gives DHS permission to test 'heat ray' weapon on migrants at southern border | Latin Post (latintimes.com) — https://www.latintimes.com/us-military-gives-dhs-permission-to-test-heat-ray-weapon-on-migrants-at-southern-border-523170
11. What The U.S. Military's 'Heat Ray' Weapon Does To Your Body (newsweek.com) — https://www.newsweek.com/what-us-militarys-heat-ray-weapon-does-to-your-body-1836647
12. Explained: What is Active Denial System (ADS) or 'Heat Ray'? Why is US considering its deployment at Mexico Border? (gktoday.in) — https://www.gktoday.in/current-affairs/explained-what-is-active-denial-system-ads-or-heat-ray-why-is-us-considering-its-deployment-at-mexico-border/
13. ‘Heat ray’ was sought for use on Lafayette Square protesters, whistleblower says (washingtonpost.com) — https://www.washingtonpost.com/national-security/2020/08/26/active-denial-system-lafayette-square-protesters/
14. Ethics and the Active Denial System: An Analysis of the Morality of the 'Heat Ray' (case.edu) — https://case.edu/med/pbl/ethics/Active%20Denial%20System.pdf
15. Pete Hegseth - Wikipedia (wikipedia.org) — https://en.wikipedia.org/wiki/Pete_Hegseth
16. Pete Hegseth | Biography, Fox News, Secretary of Defense | Britannica (britannica.com) — https://www.britannica.com/biography/Pete-Hegseth
17. Kirstjen Nielsen, DHS Officials Discussed Deploying Brutal 'Heat Ray' on Migrants: NYT (thedailybeast.com) — https://www.thedailybeast.com/kirstjen-nielsen-dhs-officials-discussed-deploying-brutal-heat-ray-on-migrants-nyt
18. Deploying Heat Ray for Border Patrol: Pentagon Authorizes DHS to Test Weapon for Possible Use at Southern US Border - CBS58 (cbs58.com) — https://cbs58.com/news/pentagon-authorizes-dhs-to-test-heat-ray-weapon-for-possible-use-at-southern-us-border
19. Intolerable burning: Defense Secretary Pete Hegseth approves Homeland Security testing of the military's Active Denial heat ray for potential use at the U.S.-Mexico border, memo shows (knewz.com) — https://knewz.com/defense-secretary-pete-hegseth-approves-homeland-security-testing-of-active-denial-heat-ray-for-potential-use-at-us-mexico-border/
20. Pentagon lends DHS a 'heat ray' weapon to test for border use (us-brief.com) — https://us-brief.com/pentagon-lends-dhs-a-heat-ray-weapon-to-test-for-border-use/
21. Nonlethal heat ray weapon approved for testing by US pending border deployment (jpost.com) — https://www.jpost.com/international/article-770020
22. El “rayo de calor”, un arma polémica: el Ejército de EE.UU. la prueba en la frontera con México (clarin.com) — https://www.clarin.com/mundo/rayo-calor-arma-polemica-ejercito-prueba-frontera-mexico-eeuu_0_sVzH19N46.html
23. Active Denial System - Wikipedia (wikipedia.org) — https://en.wikipedia.org/wiki/Active_Denial_System