UNCLASSIFIED // PUBLIC RELEASERELEASE 06 · SEPTEMBER 18, 2026
PENTAGON UFO FILE · DOCUMENT · DOW-UAP-D127AAWSAP DIRD, An Introduction to the Statistical Drake Equation, March 2010
Among the 38 reference papers written for the AAWSAP program, this one takes up extraterrestrial life, and it does so as mathematics. Dated March 2010, the DIRD takes the Drake Equation, the famous back-of-envelope formula for counting civilizations in the galaxy that could communicate with us, and asks how to handle the fact that almost every term in it is a guess.
From single numbers to distributions
The classic approach multiplies a string of fixed estimates — how often stars form, what share have planets, how many of those develop life, intelligence and technology, and how long such civilizations last. The paper argues this hides the real uncertainty. It instead treats each factor as a probability distribution, so the answer becomes a spread of possible values rather than a single headline number.
The same treatment is applied to the likely distance to the nearest neighboring civilization, which also comes out as a statistical range. The worked examples plug in assumed inputs to show how the method behaves; they are illustrations, not measurements.
What it does not claim
The release is explicit that the paper is a methods exercise. It does not estimate how likely alien civilizations really are or how near the closest might be, and if the Drake framework itself is flawed, the statistics inherit that flaw. For how this program fits the wider story, see the timeline.
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 introduces the Drake Equation, a well-known thought framework for estimating how many communicative extraterrestrial civilizations might exist in the galaxy. It reformulates the equation in statistical terms, arguing that the usual approach of assigning fixed values to its variables is too simplistic because major inputs are uncertain and are better modeled as probability distributions. Using that approach, it concludes that, if one accepts the underlying logic of the Drake Equation, the estimated number of communicating civilizations should be treated as a range of possible values, and that the likely distance between neighboring civilizations can likewise be expressed statistically rather than as a single figure. The document is primarily a mathematical and methodological exercise, and its worked examples rely on assumed values to illustrate the framework rather than to establish a firm astrophysical estimate. Overall, it is an attempt to formalize uncertainty within the Drake framework rather than an attempt to bound the actual likelihood, prevalence, or proximity of extraterrestrial civilizations.