UNCLASSIFIED // PUBLIC RELEASERELEASE 06 · SEPTEMBER 18, 2026
PENTAGON UFO FILE · DOCUMENT · DOW-UAP-D122AAWSAP DIRD, Invisibility Cloaking Theory and Experiments, March 2010
Dated March 2, 2010, this Defense Intelligence Reference Document reviews the science of invisibility cloaking as it stood at the time. It is one of the papers commissioned under AAWSAP for the Defense Intelligence Agency, and its subject is optics and materials physics, not UFO reports.
Ways to hide an object
The paper lays out several routes to making something hard to see or to detect with sensors: camouflage, transparency, and true optical cloaking, in which light is steered around an object so it passes as if nothing were there. Most of its attention goes to metamaterials — engineered structures with features smaller than the wavelengths they act on — and to negative refraction and transformation optics, a mathematical method for designing materials that bend light along chosen paths. It reviews experiments that had already achieved limited cloaking at microwave frequencies.
Its judgment draws a clear line. An “imperfect” cloak is physically possible in some parts of the spectrum, especially microwaves. A “perfect” one is not practical, because it would need material properties at odds with the underlying physics. Cloaking in visible light, the paper concludes, will need new theoretical breakthroughs more than steady progress in materials.
Related papers
Metamaterials also feature in the series’ paper on programmable matter, which lists invisibility among its long-range possibilities. A DIRD is a reference synthesis rather than new research, and the release cautions that its summary reflects the paper’s framing at the time, not current validation. The released copy is partly redacted.
The official description
From war.gov/UFO, released September 18, 2026, quoted in full
This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed.
This DIRD surveys the theory and early experiments behind invisibility cloaking, describing several ways an object might be hidden from visual or sensor detection, including camouflage, transparency effects, and optical cloaking that bends light around an object. It focuses mainly on metamaterials, negative refraction, and transformation optics, and reviews experiments that had already demonstrated limited cloaking at microwave frequencies. The report argues that “imperfect” cloaking is physically achievable in some parts of the electromagnetic spectrum, especially for microwaves, but that “perfect” cloaking is not practical because it would require material properties that conflict with the underlying physics. Its overall conclusion is that cloaking is a scientific field with plausible narrow applications, but that useful visible-light cloaking depends more on future theoretical breakthroughs than on conventional advances in materials science.