CORROBORATED
CF-GEI-20111008238 CORROBORATED
The Fleury-Mérogis ISS Misidentification
CASE FILE — CF-GEI-20111008238 — CASEFILES CLASSIFIED ARCHIVE
Date Date when the incident was reported or occurred
2011-10-20
Location Reported location of the sighting or event
Fleury-Mérogis, Essonne, Île-de-France, France
Duration Estimated duration of the observed phenomenon
several seconds to disappearance
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
1
Country Country where the incident took place
FR
AI Confidence AI-generated credibility score based on source reliability, detail consistency, and corroboration
85%
On October 20, 2011, at approximately 21:10 local time, an amateur astronomer in Fleury-Mérogis, France, observed a slow-moving, particularly bright luminous point traveling from west to east across the night sky. The witness, who possessed astronomical expertise, watched as the object ascended toward the celestial vault before suddenly disappearing within seconds. The witness reported the object reached a maximum elevation of 60-70 degrees above the horizon.
GEIPAN (the official French UFO investigation unit operated by CNES, the French space agency) investigated this sighting and classified it as Category B—a probable identification with good consistency. Their analysis determined the observation characteristics precisely matched the passage of the International Space Station (ISS) disappearing into Earth's shadow, which creates the characteristic sudden vanishing effect reported by the witness.
The investigation noted minor discrepancies between the witness account and orbital simulation data: the simulator indicated the ISS should have disappeared at 21:03 versus the reported 21:10 observation time, and the predicted maximum elevation was 50 degrees compared to the witness's estimate of 60-70 degrees. GEIPAN attributed these variances to the ISS's orbital bulletins evolving significantly day-to-day during this period, likely due to station-keeping maneuvers, making precise orbital predictions challenging. Despite these small timing and elevation differences, the overall characteristics firmly pointed to an ISS observation.
02 Timeline of Events
21:03
Predicted ISS Shadow Entry
Orbital simulator predictions indicated the International Space Station should have entered Earth's shadow at this time, creating the sudden disappearance effect
21:10
Witness Observation Begins
Amateur astronomer notices a particularly bright luminous point moving slowly from west to east across the night sky
21:10+
Object Ascends to Maximum Elevation
The light rises toward the celestial vault, reaching an estimated elevation of 60-70 degrees above the horizon (simulator predicted 50 degrees)
21:10+ (seconds later)
Sudden Disappearance
The luminous object vanishes abruptly within seconds, consistent with a satellite entering Earth's shadow rather than gradually fading from view
Post-incident
GEIPAN Investigation Initiated
Official investigation analyzes witness testimony against ISS orbital data and simulation software, identifying minor discrepancies attributed to station maneuvers
03 Key Witnesses
Anonymous Amateur Astronomer
Amateur astronomer
high
An amateur astronomer with sufficient observational training to provide detailed sky position data and accurate trajectory descriptions. The witness's astronomical background lends credibility to the precision of the reported details, though they appear unfamiliar with satellite tracking specifically.
"Point lumineux particulièrement brillant, se déplaçant d'Ouest en Est qui s'élève vers la voûte céleste et disparaît en quelques secondes"
04 Analyst Notes -- AI Processed
This case demonstrates the value of witness expertise cutting both ways—the amateur astronomer's observational skills provided detailed, reliable data, yet even experienced sky watchers can misidentify familiar objects under certain conditions. The witness's description of a 'particularly brilliant' light moving west to east in a slow, steady trajectory is textbook ISS behavior. The sudden disappearance is the key diagnostic feature: satellites don't simply fade away but vanish abruptly when entering Earth's shadow cone.
The credibility of this report is enhanced by GEIPAN's thorough analysis using orbital simulation software to cross-reference the ISS trajectory. The 7-minute time discrepancy and 10-20 degree elevation variance are actually consistent with the dynamic nature of ISS orbital parameters during periods of active maneuvering. The witness's lack of familiarity with ISS pass characteristics, despite astronomical knowledge, suggests they may have specialized in other areas of amateur astronomy (deep sky objects, planets) rather than satellite tracking. This case received a Classification B rating—GEIPAN's second-highest confidence level for probable identifications—indicating strong but not absolute certainty due to the minor orbital prediction discrepancies.
05 Theory Comparison
BELIEVER ANALYSIS
SKEPTIC ANALYSIS
Observer Unfamiliarity with Common Satellite Passes
Despite being an amateur astronomer, the witness appears to have specialized in other areas of astronomy rather than satellite tracking. The ISS is the most commonly reported 'UFO' due to its brightness and visibility, making multiple passes over any given location monthly. The lack of recognition of this routine phenomenon by someone with astronomical training suggests specialization in deep-sky observation, planetary astronomy, or other fields. This case exemplifies how expertise in one domain doesn't automatically transfer to another—a skilled telescope user may never have learned satellite pass prediction or recognition.
06 Verdict
ANALYST VERDICT
This sighting is almost certainly a misidentification of the International Space Station entering Earth's shadow. The classification as GEIPAN Category B (probable identification) is well-justified given the characteristic ISS behavior: slow west-to-east trajectory, exceptional brightness, high elevation pass, and sudden disappearance rather than gradual fading. While the 7-minute timing offset and elevation discrepancy prevent absolute confirmation, these variances fall within expected margins when ISS orbital parameters are evolving due to station maneuvers. The case holds minimal significance as a UFO/UAP event but serves as an excellent educational example of how even trained observers can be unfamiliar with satellite pass characteristics, and demonstrates the rigor of GEIPAN's investigation methodology using orbital simulation validation.
AI CONFIDENCE SCORE:
85%
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