Within Project Mogul Balloon
The Diary Entry Behind the Flight 4 Claim
A brief diary entry about a cancelled operation and later balloon release became central evidence for identifying the disputed Flight 4 launch.
On this page
- What Crary recorded on June 4
- Why the launch was not formally documented
- Competing readings of the diary evidence
Page outline Jump by section
Introduction
Albert Crary’s field diary occupies a unique place in the debate over Project Mogul Flight 4 because it is the principal surviving contemporaneous record for the activities of the Mogul team on 4 June 1947. Since no complete launch documentation for Flight 4 has been found, later investigators relied heavily on Crary’s handwritten notes to reconstruct what happened. The diary has therefore become both a cornerstone of the US Air Force’s explanation of the Roswell debris and the main source of criticism directed at that explanation. Rather than settling the question, the brief entry leaves room for competing interpretations about whether a significant balloon launch occurred, whether it qualified as Flight 4, and whether it could plausibly have produced the debris later recovered near Roswell.[Muller Lab]muller.lbl.govMuller Lab Project MogulMuller Lab Project Mogul
What Crary recorded on 4 June
The key diary entry describes the day’s work in concise operational language. In summary, Crary recorded that:
- acoustic charges were fired during the early morning hours;
- there was “no balloon flight again on account of clouds”;
- a “regular sonobuoy mike” was nevertheless flown in a cluster of balloons;
- reception of the signal was successful on the ground but poor from the aircraft involved in the experiment;
- further explosive tests were carried out later that day.[ResearchGate]researchgate.netResearch Gate(PDF) A Grounded Theory Update on the Roswell UFO IncidentResearch Gate(PDF) A Grounded Theory Update on the Roswell UFO Incident
The wording is significant because it appears internally inconsistent at first glance. The statement that there was “no balloon flight” is immediately followed by a note describing a sonobuoy microphone being lifted by a cluster of balloons. This apparent contradiction has driven decades of historical debate.
The entry also reflects the practical focus of a working scientist rather than someone preparing a formal operational record. Crary’s diary was intended as a personal field log, recording observations and experimental results rather than producing an official chronology of Project Mogul launches. That distinction is important when assessing how much weight can be placed on individual phrases.[ResearchGate]researchgate.netResearch Gate(PDF) A Grounded Theory Update on the Roswell UFO IncidentResearch Gate(PDF) A Grounded Theory Update on the Roswell UFO Incident
Why the launch was not formally documented
The absence of a surviving Flight 4 launch report is one of the central evidential gaps in the Mogul explanation for Roswell.
The 1994 US Air Force investigation concluded that the debris most probably came from Mogul Flight 4 despite acknowledging that the normal launch documentation was missing. Instead, investigators reconstructed the event using Crary’s diary, surviving NYU progress reports, witness descriptions of the recovered debris and knowledge of the experimental programme’s operating practices.[Muller Lab]muller.lbl.govMuller Lab Project MogulMuller Lab Project Mogul
According to this reconstruction, the planned full constant-level balloon flight was disrupted by poor weather, but the team still released a simpler cluster of meteorological balloons carrying a sonobuoy. Because tracking was unsuccessful and the experiment differed from a standard operational flight, no complete launch record survived. In this interpretation, the diary preserves the only surviving contemporary evidence that the balloon release actually occurred.[Muller Lab]muller.lbl.govMuller Lab Project MogulMuller Lab Project Mogul
This reliance on reconstruction rather than complete documentation explains why Flight 4 remains more controversial than other Mogul launches whose records are substantially intact.
Competing readings of the diary evidence
The Air Force interpretation
The Air Force and researchers such as Charles Moore argued that the diary should be read as distinguishing between two different activities.
In this interpretation, “no balloon flight” refers to the cancellation of the originally planned constant-level Mogul mission because cloud conditions prevented it. The following sentence records that the already-prepared cluster of ordinary meteorological balloons carrying a sonobuoy was nevertheless released for a reduced experiment. Moore later suggested that Crary may have copied several days of field notes into the diary afterwards, potentially explaining why the wording appears compressed or awkward.[lbl.gov]muller.lbl.govMuller Lab Project MogulMuller Lab Project Mogul
This reading allows investigators to identify the balloon release as the event later designated Flight 4, even though no conventional launch report survives.
The critical interpretation
Critics reach a different conclusion from the same text.
They argue that the plain reading of “no balloon flight again on account of clouds” indicates that Flight 4 was cancelled altogether. In their view, the later reference to a sonobuoy lifted by a cluster of balloons describes only a limited acoustic test rather than a complete Mogul balloon train. If that smaller experiment lacked the long balloon array, radar reflectors and other characteristic components associated with a standard Mogul flight, then identifying it as the source of the Roswell debris becomes substantially more uncertain.[Kevin Randle's Blog]kevinrandle.blogspot.comKevin Randle's Blog A Different Perspective: Project Mogul and RoswellKevin Randle's Blog A Different Perspective: Project Mogul and Roswell
From this perspective, the diary does not positively identify the Roswell material with Flight 4 but instead highlights the weakness of the documentary record.
How much can the diary establish?
The evidential value of Crary’s diary is both considerable and limited.
It is valuable because it is the closest surviving contemporary account of the Mogul team’s activities on the crucial date. Without it, historians would know far less about what happened on 4 June 1947. It confirms that weather disrupted planned operations, that balloon-based acoustic experiments continued despite those disruptions, and that the team remained active throughout the day.[ResearchGate]researchgate.netResearch Gate(PDF) A Grounded Theory Update on the Roswell UFO IncidentResearch Gate(PDF) A Grounded Theory Update on the Roswell UFO Incident
At the same time, the diary cannot answer every question. It does not explicitly state that a formal Project Mogul Flight 4 was launched, nor does it clearly distinguish between a full operational balloon train and a more limited experimental balloon cluster. Because the entry is brief and informal, later interpretations necessarily rely on inference as well as the diary’s literal wording.
Why the diary remains central to the Flight 4 debate
The importance of Crary’s diary stems less from what it definitively proves than from what is missing elsewhere. With no complete Flight 4 launch file available, the diary became the foundation on which competing historical reconstructions were built.
Supporters of the Mogul explanation regard it as evidence that a balloon release compatible with Flight 4 occurred despite weather-related changes to the planned mission. Critics regard the same entry as evidence that the official Flight 4 launch was cancelled and that later investigators stretched an ambiguous field note into a more definite historical claim than the surviving documentation supports.[lbl.gov]muller.lbl.govMuller Lab Project MogulMuller Lab Project Mogul
For that reason, the debate over Flight 4 is ultimately less about the authenticity of Crary’s diary—which is generally accepted—and more about how much historical certainty can legitimately be extracted from a few lines written by a scientist recording a busy day’s fieldwork.
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Endnotes
1.
Source: muller.lbl.gov
Title: Muller Lab Project Mogul
Link:https://muller.lbl.gov/teaching/physics10/Roswell/USMogulReport.html
2.
Source: researchgate.net
Title: Research Gate(PDF) A Grounded Theory Update on [the Roswell UFO]({{ ‘the-roswell-ufo/’ | relative_url }}) Incident
Link:https://www.researchgate.net/publication/362854511_A_Grounded_Theory_Update_on_the_Roswell_UFO_Incident
3.
Source: kevinrandle.blogspot.com
Title: Kevin Randle’s Blog A Different Perspective: Project Mogul and Roswell
Link:https://kevinrandle.blogspot.com/2007/07/project-mogul-and-roswell.html
4.
Source: kevinrandle.blogspot.com
Title: Kevin Randle’s Blog A Different Perspective: Mogul Flight No. 4
Link:https://kevinrandle.blogspot.com/2022/11/mogul-flight-no-4-end.html
Source snippet
Kevin Randle's BlogA Different Perspective: Mogul Flight No. 4 - The End...
5.
Source: kevinrandle.blogspot.com
Title: Kevin Randle’s Blog A Different Perspective: Mogul and Roswell
Link:https://kevinrandle.blogspot.com/2013/07/mogul-and-roswell.html
6.
Source: nexusnewsfeed.com
Title: The Observer anti-Roswell article: A brief response by Kevin D
Link:https://nexusnewsfeed.com/article/unexplained/the-observer-anti-roswell-article-a-brief-response-by-kevin-d-randle/
Source snippet
Randle - Nexus NewsfeedJuly 5, 2025 — Image Charles Moore reviewing winds aloft data. Photo by Kevin Randle. Image The ladder to which Mo...
Published: July 5, 2025
7.
Source: kevinrandle.blogspot.com
Title: A Different Perspective: The End of Project Mogul
Link:https://kevinrandle.blogspot.com/2022/03/the-end-of-project-mogul.html
8.
Source: kevinrandle.blogspot.com
Title: A Different Perspective: The Project Mogul Double Standard
Link:https://kevinrandle.blogspot.com/2013/12/the-project-mogul-double-standard.html
9.
Source: kevinrandle.blogspot.com
Title: there was no flight no 4
Link:https://kevinrandle.blogspot.com/2007/08/there-was-no-flight-no-4.html?showComment=1211478480000
10.
Source: kevinrandle.blogspot.com
Title: A Different Perspective: A Roswell Chronology
Link:https://kevinrandle.blogspot.com/2007/05/roswell-chronology.html?showComment=1180847280000
11.
Source: muller.lbl.gov
Title: [Roswell Incident]({{ ‘the-1980-book/’ | relative_url }})
Link:https://muller.lbl.gov/teaching/physics10/Roswell/RoswellIncident.html
12.
Source: youtube.com
Title: Project Mogul
Link:https://www.youtube.com/watch?v=mBcYtSsPIuU
Source snippet
The Roswell Incident Mystery Finally Solved...
Additional References
13.
Source: newspaceeconomy.ca
Link:https://newspaceeconomy.ca/2026/01/04/challenges-to-the-project-mogul-explanation-for-the-roswell-incident/?amp=1
Source snippet
January 4, 2026 — THE PHANTOM FLIGHT 4 HYPOTHESIS The cornerstone of the Air Force’s 1994 report is the assertion that a specific service...
Published: January 4, 2026
14.
Source: marcianitosverdes.haaan.com
Link:https://marcianitosverdes.haaan.com/2026/06/notas-sobre-roswell/
Source snippet
sobre Roswell | Marcianitos VerdesJune 25, 2026 — En primer lugar, permítanme señalar que Charles Moore preparó un informe detallado sobr...
Published: June 25, 2026
15.
Source: londonmail.co.uk
Title: What REALLY happened during Roswell crash?
Link:https://londonmail.co.uk/2024/02/17/what-really-happened-during-roswell-crash-americas-most-famous-ufo-case-is-thrust-back-into-the-spotlight-again-by-former-nasa-scientists-who-say-new-pentagon-report-is-bogus/
Source snippet
America's most famous UFO case is thrust back into the spotlight again by former NASA scientists who say new Pentagon report is 'bogus'...
16.
Source: youtube.com
Link:https://www.youtube.com/watch?v=TV0Xm9ZgiKQ
Source snippet
The Roswell Incident as Told by Thomas Snégaroff...
Published: July 1947
17.
Source: youtube.com
Title: The Roswell Incident Mystery Finally Solved
Link:https://www.youtube.com/watch?v=Pz0vYcc4KiI
Source snippet
8th July 1947: First flying saucer as Roswell Army Air Base reports debris of a 'flying disc'...
Published: July 1947
18.
Source: youtube.com
Title: The Roswell Incident as Told by Thomas Snégaroff
Link:https://www.youtube.com/watch?v=s1FsS-dPc0w
Source snippet
The [Roswell UFO Crash]({{ 'roswell-ufo-crash/' | relative_url }}) (Overview) - Jimmy Akin's Mysterious World...
19.
Source: hangar1publishing.com
Link:https://hangar1publishing.com/blogs/ufos-uaps-and-aliens/mogul-balloon-explanation-roswell
20.
Source: astronomyufo.com
Link:https://www.astronomyufo.com/UFO/flight4.htm
21.
Source: davidhalperin.net
Title: The Roswell Bookshelf – Kevin Randle, “Roswell in the 21st Century” (Part 1)
Link:https://www.davidhalperin.net/the-roswell-bookshelf-kevin-randle-roswell-in-the-21st-century-part-1/
22.
Source: scribd.com
Title: [Roswell Report]({{ ‘the-roswell-report/’ | relative_url }}): Fact vs. Fiction | PDF | Unidentified Flying Object
Link:https://www.scribd.com/document/831210606/Roswel-Fact-or-Fiction