The file that argues against itself, why the release includes its own debunking material

Mikey · 21 May 2026

THE DOCUMENT

Two documents from PURSUE Release 01. DOW-UAP-D48, a Research Triangle Institute final report titled “Modeling Unlikely Space-Booster Failures in Risk Calculations”, prepared for the US Air Force and dated September 1996. DOW-UAP-D49, the “Vandenberg AFB Launch Summary 1958 to 2000”, compiled by the 30th Space Wing Office of History. Both published by the U.S. Department of War at war.gov/ufo.

What this briefing is

Every document briefed in this series so far has been, in some sense, about an unidentified object. This one is about two documents that are not.

D48 and D49 are not UAP encounter reports. They contain no sightings, no aircrew descriptions, no sensor footage. D48 is a technical risk-analysis study about how rockets fail. D49 is an administrative register of rocket launches. They were both, however, placed inside an official UAP release. This briefing is about why, and about what their inclusion says about the release as a whole.

The short version: a government archive that contains its own conventional explanations is behaving like an honest archive. The presence of mundane, debunking-adjacent material in PURSUE Release 01 is a point in the release’s favour, not against it.

This is tier 2, primary documents. Both are authentic and official. Read on for what each one actually is.

DOW-UAP-D48, the booster-failure study

D48 is a 1996 final report from the Research Triangle Institute, an established American research organisation, prepared under contract for the US Air Force, specifically the safety offices of the 30th Space Wing at Vandenberg and the 45th Space Wing at Patrick. Its title is “Modeling Unlikely Space-Booster Failures in Risk Calculations.”

The subject is narrow and technical. When a launch vehicle fails catastrophically, most of its debris falls close to the intended flight path. The report’s own introduction lists the usual causes: “premature thrust termination, stage ignition failure, tank rupture or explosion, or rapid out-of-control tumble.” But the report is interested in a rarer outcome. It calls these “Mode-5 failure responses”: cases where a malfunction causes the vehicle “to execute a sustained turn away from the flight line”, for example “control failures that cause the rocket engine to lock in a fixed position”, or “erroneous orientation of the guidance platform.” A booster failing in this way does not just fall straight down. It can fly a curving path well off course before it breaks up or impacts.

The report builds a mathematical model for where the debris from such failures would land, inside a risk-analysis program the report calls DAMP, and tunes the model against simulated and real failure data. Crucially for this briefing, the report’s appendices contain “a listing and brief narrative failure history of the Atlas, Delta, and Titan missile and space-vehicle launches” from the beginning of each programme through August 1996, classifying each flight by how, if at all, it went wrong.

The relevance to the UAP question is indirect but real. A document like this is a catalogue of the ways a rocket can behave abnormally in the sky: turning, tumbling, breaking up, scattering burning debris on an unexpected path. Those behaviours, seen from the ground or from a cockpit by someone who does not know a launch failure is underway, are exactly the kind of thing that gets reported as a strange, manoeuvring, fragmenting object. D48 is, in effect, a reference text for one large family of conventional explanations.

It is worth being precise about what D48 is not. It is not a UAP study. It does not mention unidentified phenomena. It is an engineering risk document, and the framing for this briefing, that it points toward conventional explanations, is an inference about why it was included, not a claim the document makes about itself. The honest description is that D48 is technical source material that helps explain how some sightings could arise, included alongside the encounter reports rather than instead of them.

DOW-UAP-D49, the Vandenberg launch summary

D49 is even plainer. It is the “Vandenberg AFB Launch Summary 1958 to 2000”, compiled by the 30th Space Wing History Office. Its own foreword describes it as “the official registry of all major launch operations conducted from Vandenberg Air Force Base, California”, presented “in chronological order beginning with the first launch on 16 December 1958.”

The bulk of the document is exactly that: a launch-by-launch table, running to well over a thousand numbered entries, each giving a date, a nickname, a launch facility, a vehicle type, a programme and a running count. Thor, Atlas, Titan, Minuteman, Delta, Pegasus, Scout, Peacekeeper. It includes summary matrices of launches by year and by command, a glossary of acronyms, and a guide to the launch facilities themselves.

Like D48, D49 contains no UAP content of any kind. It is a historical and administrative record. Its relevance to the UAP question, again, is as context. Vandenberg sits on the California coast and launches south over the Pacific. Its rockets and their re-entering or de-orbiting hardware have, for decades, been a documented and recurring source of “strange lights” reports along the western United States. A complete, dated register of every launch from a major spaceport is a tool: given a sighting date and location, you can check whether a launch could account for it.

So D49 belongs in the same category as D48. It is not a sighting. It is reference material that helps separate conventional events from genuinely puzzling ones.

Why including this material strengthens the release

Here is the argument, stated plainly.

A collection assembled to push a particular conclusion would contain only the material that supports that conclusion. If PURSUE Release 01 had been curated to make the UAP phenomenon look as dramatic as possible, documents like D48 and D49 would have been left out. They are unglamorous, they contain no anomalies, and they quietly widen the range of ordinary things a sighting might turn out to be.

Their inclusion points the other way. It indicates that whoever assembled the release was gathering the government’s UAP-adjacent records broadly, including the material that helps explain sightings away. Rocket launches, booster failures and re-entries genuinely do account for a real share of what people report as UAP. A release that hands the reader the tools to make that case, a failure-mode reference and a launch register, is behaving like an archive rather than an argument.

This is the same principle Briefing 1 set out and the same principle behind the deliberately sceptical NASA briefing earlier in this series. A record that only contains its most exciting items is a highlight reel. A record that also contains its own debunking material is a record. The second is more trustworthy, and PURSUE Release 01 is, on the evidence of D48 and D49, the second kind.

There is a caveat worth keeping. We do not know for certain why these two specific files were placed in the release. The framing here, that they were included as candidate conventional explanations, is the most reasonable reading, and it matches how the project’s own inventory work characterised them. But it remains an inference. What is not an inference is the plain fact: the release contains substantial, official, non-anomalous reference material, and that fact is to its credit.

What it reliably establishes

It establishes that PURSUE Release 01 is not composed solely of UAP sighting reports. It contains at least two substantial documents, an Air Force-commissioned booster-failure risk study and an official Vandenberg launch register, that describe entirely conventional aerospace activity. It establishes that the release therefore includes the raw material for conventional explanations, the ways rockets fail and a complete record of when they launched, alongside the encounter reports. And it establishes, by that inclusion, that the release behaves like a broad archive rather than a curated case for a predetermined conclusion.

What it does not establish

It does not establish anything about UAP directly. D48 and D49 contain no sightings and no anomalies, and nothing in them should be read as evidence either for or against the phenomenon.

It does not establish that booster failures or rocket launches explain any specific case in the rest of the release. These documents are general reference material. Applying them to an individual sighting would require matching dates, locations and trajectories, which is a separate exercise.

And it does not, strictly, establish the intent behind including these two files. That they were included as conventional-explanation material is a reasonable and well supported inference, but the documents do not state their own purpose, and this briefing has been careful to mark that as inference rather than fact.

Related wiki entries

The wiki entries below give background on the people, programmes and document types behind this briefing.

PURSUE · Department of War · AARO

References and further reading

• DOW-UAP-D48, Research Triangle Institute, “Modeling Unlikely Space-Booster Failures in Risk Calculations”, final report for the US Air Force, September 1996, hosted at war.gov
• DOW-UAP-D49, “Vandenberg AFB Launch Summary 1958 to 2000”, 30th Space Wing Office of History, hosted at war.gov
• Presidential Unsealing and Reporting System for UAP Encounters, U.S. Department of War, war.gov/ufo
• AARO UAP Records, All-domain Anomaly Resolution Office, aaro.mil/UAP-Records
• Briefing 1 in this series, on how to read PURSUE Release 01 and the evidence-tier system
• Briefing 8 in this series, the deliberately sceptical NASA briefing, on the same honest-framing principle