CORROBORATED
CF-GEI-20090502309 CORROBORATED
The Montaigu ISS Transit: Autokinetic Effect Analysis
CASE FILE — CF-GEI-20090502309 — CASEFILES CLASSIFIED ARCHIVE
Date Date when the incident was reported or occurred
2009-05-22
Location Reported location of the sighting or event
Montaigu, Vendée, Pays de la Loire, France
Duration Estimated duration of the observed phenomenon
approximately 2-3 minutes
Object Type Classification of the observed object based on witness descriptions
light
Source Origin database or archive this case was sourced from
geipan
Witnesses Number of known witnesses who reported the event
2
Country Country where the incident took place
FR
AI Confidence AI-generated credibility score based on source reliability, detail consistency, and corroboration
85%
On Friday, May 22, 2009, at approximately 23:30 local time, two witnesses in Montaigu, Vendée observed a white luminous phenomenon traveling in a straight west-to-east trajectory across the night sky at a regular speed. One witness reported observing a brief zig-zag movement made by the object before it rapidly faded from view. The sighting occurred in the Pays de la Loire region of northwestern France.
GEIPAN (Groupe d'études et d'informations sur les phénomènes aérospatiaux non identifiés), France's official UFO investigation organization operated by CNES (Centre National d'Études Spatiales), conducted a thorough investigation and determined with high confidence that the witnesses observed the International Space Station (ISS) passing overhead at the precise moment it entered Earth's shadow, explaining the rapid fading observed.
The brief zig-zag motion reported by one witness was assessed by GEIPAN investigators to be the result of an autokinetic effect—a well-documented perceptual phenomenon where the human brain, when fixated on a single point of light against a featureless background, loses spatial reference points and misinterprets natural eye movements (microsaccades and drift) as actual movement of the observed object. This case represents a textbook example of how even trained observers can experience perceptual illusions during night sky observations.
02 Timeline of Events
23:30
Initial Observation
Two witnesses in Montaigu notice a white luminous object moving across the sky from west to east at regular speed
23:31-23:32
Zig-Zag Motion Reported
One witness observes what appears to be a brief zig-zag movement of the luminous phenomenon
23:32-23:33
Rapid Disappearance
The light fades rapidly from view as the ISS enters Earth's shadow, ceasing to reflect sunlight
Post-incident
GEIPAN Investigation Initiated
Witnesses report sighting to GEIPAN; investigators begin analysis and orbital data correlation
Investigation conclusion
Classification A Assigned
GEIPAN conclusively identifies the object as the ISS and classifies case as Class A (certain explanation)
03 Key Witnesses
Anonymous Witness 1
Civilian
medium
One of two witnesses who observed the west-to-east transit. Reported the basic trajectory and fading of the light.
Anonymous Witness 2
Civilian
medium
Second witness who additionally reported a brief zig-zag motion before the object faded. This witness's report of the zig-zag was likely influenced by autokinetic effect.
04 Analyst Notes -- AI Processed
This case demonstrates the value of systematic scientific investigation of UFO reports. GEIPAN's classification system rates this as 'Class A'—a case with a certain and proven explanation. The investigators cross-referenced the observation time and location with ISS orbital tracking data to confirm the station was visible from Montaigu at 23:30 on May 22, 2009, following a west-to-east trajectory consistent with typical ISS passes.
The autokinetic effect explanation for the zig-zag motion is particularly credible. This phenomenon has been extensively studied in aviation psychology and astronomy, where pilots and observers tracking single points of light have reported apparent movement that doesn't physically occur. The fact that only one of two witnesses reported the zig-zag supports this interpretation—autokinetic effects vary between individuals based on concentration level, eye fatigue, and individual neurological differences. The rapid disappearance aligns perfectly with the ISS entering Earth's umbra (shadow), where sunlight no longer reflects off the station's solar panels, making it invisible to ground observers. This case exemplifies how mundane astronomical events can appear anomalous to witnesses unfamiliar with satellite and space station transits.
05 Theory Comparison
BELIEVER ANALYSIS
SKEPTIC ANALYSIS
Satellite Misidentification
Even without specific ISS correlation, the described characteristics—steady west-to-east motion, regular speed, white light, and disappearance after a few minutes—are classic signatures of satellite observations. Hundreds of satellites are visible on any clear night, and their sudden disappearance when entering Earth's shadow often surprises unfamiliar observers. The zig-zag could represent momentary loss of visual tracking or atmospheric distortion, though autokinetic effect remains the more parsimonious explanation given the fixation required to track a moving satellite.
06 Verdict
ANALYST VERDICT
This case is conclusively explained as an observation of the International Space Station transiting overhead and entering Earth's shadow. Confidence level: very high (95%+). GEIPAN's access to precise ISS orbital data allowed definitive correlation between the sighting time, location, trajectory, and the station's actual position. The perceived zig-zag motion is almost certainly an autokinetic illusion rather than actual object movement. While this case holds minimal significance as a UFO mystery, it serves valuable educational purposes: it demonstrates the importance of orbital tracking databases in UFO investigation, illustrates common perceptual phenomena that can mislead honest witnesses, and showcases proper investigative methodology. The case reinforces that many UAP reports have prosaic explanations when subjected to rigorous scientific analysis with access to comprehensive astronomical and aerospace tracking data.
AI CONFIDENCE SCORE:
85%
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