Within Alpine UFO Files
Was the Sciliar Light a Distant Space Launch?
A huge silent light near the Sciliar became a lasting test of witness perception against a plausible rocket-fuel explanation.
On this page
- What the witnesses reported
- How the launch explanation arose
- Why the public evidence remains incomplete
Page outline Jump by section
Introduction
The Sciliar light was most probably connected with the launch of the American military weather satellite DMSP F18 on 18 October 2009. That evening, observers across Europe saw exceptionally bright clouds produced by the Atlas V rocket’s Centaur upper stage as it burnt and vented propellant high above Earth. Specialist satellite watchers had predicted the display before it occurred, and their timed observations closely match the account from Aica di Fiè near the Sciliar massif.[af.mil]af.milOpen source on af.mil.
That does not mean every detail of the local testimony has been satisfactorily explained. Actress Monica Trettel and three companions described an enormous, silent white light that appeared stationary over the Bolzano basin for roughly ten minutes before moving rapidly in a zigzag direction towards Renon. Other local witnesses reportedly described a similar phenomenon. No photograph, measured bearing, original observatory log or complete reconstruction has been published alongside the explanation. The case therefore matters less as evidence of an extraordinary craft than as a revealing dispute over how a real aerospace event can be perceived against an Alpine landscape—and how an explanation can remain unpersuasive when its supporting work is not shown.[Franz Magazine]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
What the witnesses reported
Trettel’s account was published in January 2012 as publicity for a theatrical presentation about UFOs. She said the sighting had occurred “two years” earlier while she was at her home in Aica di Fiè, which overlooks the valley west of the Sciliar. According to her recollection, four people watched a huge white light apparently suspended over the Bolzano basin. It was completely silent and, in her comparison, looked powerful enough to illuminate a football pitch. After about ten minutes, it seemed to vanish quickly towards Renon with a zigzag movement. No one in the group took a photograph.[Franz Magazine]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
She said that she contacted the amateur astronomical observatory at Collepietra the next day. In her telling, the observatory had also noticed the phenomenon and had received several reports. She further referred to a priest in the Braies valley who had reportedly seen a similar light descending slowly and silently about fifteen minutes before her own observation. A local newspaper subsequently carried an explanation linking the light to a launch from Vandenberg Air Force Base in California.[Franz Magazine]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
Several features made the experience compelling to those present:
- Apparent size: the light was remembered not as a point resembling a star or aircraft lamp, but as a vast luminous area.
- Silence: no engine noise accompanied it, reinforcing the impression that it was neither a conventional aircraft nor a nearby helicopter.
- Duration: roughly ten minutes gave the witnesses time to watch rather than merely glimpse it.
- Apparent manoeuvring: the reported zigzag departure suggested controlled local motion rather than a diffuse astronomical phenomenon.
- Multiple observers: Trettel was not alone, and she believed reports from elsewhere in South Tyrol referred to the same object.[Franz Magazine]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
These points establish that the experience was vivid and shared. They do not, by themselves, establish the light’s distance, physical size or trajectory. Those are precisely the quantities that are hardest to judge when a bright object is seen without a known reference distance.
How the launch explanation arose
The strongest technical match is the DMSP F18 mission. The United States Air Force confirms that an Atlas V launched the Defence Meteorological Satellite Program spacecraft from Vandenberg at 9.12 am local time on 18 October 2009, equivalent to 16.12 UTC and 18.12 summer time in Italy. The satellite was intended for a near-polar, Sun-synchronous orbit used to gather military meteorological and environmental data.[Air Force]af.milOpen source on af.mil.
The rocket did not simply disappear from relevance once the satellite reached orbit. The mission used a Centaur upper stage powered by liquid hydrogen and liquid oxygen. United Launch Alliance’s mission material identifies this cryogenic stage and shows that it remained active after the initial ascent.[ULA]ulalaunch.comULAAV017_mob:Layout 1.qxdULAAV017_mob:Layout 1.qxd
Satellite observer Ted Molczan calculated on the day of the launch that a Centaur burn and propellant dump should become visible from a large part of Europe shortly after 19.17 UTC—21.17 in Italy. His alert was posted before the predicted event, which makes it more valuable than an explanation constructed only after reports appeared. French observers were warned in advance because their viewing position was expected to be favourable.[SatObs]satobs.orgOpen source on satobs.org.
Reports then arrived from observers who were deliberately watching for the spacecraft. In Darmstadt, Germany, Gerhard Holtkamp saw a bright cone-shaped cloud at about 19.13 UTC, followed by another luminous cloud with a red central light. He tracked the Centaur passing close to Vega and described intermittent venting or “puffing”. The clouds remained conspicuous even near a city horizon. Other observers reported expanding rings, a brilliant cone and two bright moving objects associated with the satellite and upper stage. French satellite-watching networks received numerous accounts, photographs and drawings of the display.[SatObs]satobs.orgSat Obs See Sat-L Oct-09: Centaur-CloudsSat Obs See Sat-L Oct-09: Centaur-Clouds
The timing is striking. The European display occurred at roughly 21.13–21.20 Italian summer time, extremely close to the “21.00” time attributed to the launch-related explanation in Trettel’s account. Her published description did not give a precise calendar date, but the combination of a Vandenberg military weather-satellite mission, a spectacular European propellant display and an evening time around 21.00 strongly identifies 18 October 2009 as the likely sighting date.[franzmagazine.com]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
Why a distant rocket cloud could look local
A propellant cloud in near-Earth space can appear enormous because gases released into very low pressure spread across a wide angular area. Sunlight can illuminate the expanding material even after observers on the ground are in darkness. Modern examples show that released propellant or exhaust products can form bright cones, rings, spirals and diffuse white clouds visible across several countries.[EarthSky]earthsky.orgEarth Sky Strange spiral in the night sky was a rocket fuel dumpStrange spiral in the night sky was a rocket fuel dumpAugust 13, 2025 — 12 Aug 2025 — The released fuel can freeze into ice cryst…
The DMSP F18 observations demonstrate that this was not merely a generic possibility. Trained sky watchers recorded large expanding structures at the predicted time. One observer estimated that the concentric rings covered three or four degrees of sky—many times the apparent width of the Moon. Another saw two clouds following different paths, one associated with an earlier Centaur firing and another with later venting. Such changing structures could readily be interpreted as a huge object altering direction, particularly by people who did not know that a rocket stage was crossing the European sky.[SatObs]satobs.orgSat Obs See Sat-L Oct-09: Centaur-CloudsSat Obs See Sat-L Oct-09: Centaur-Clouds
The mountainous setting adds another source of ambiguity. A light viewed above the Bolzano basin or against the outline of Renon and the Dolomites may seem to occupy the landscape even when it is hundreds or thousands of kilometres away. Without binocular tracking, angular measurements or a known foreground crossing, the eye cannot reliably determine whether a luminous patch is above a nearby ridge, over a neighbouring valley or far beyond the atmosphere.
Apparent stationary behaviour is also compatible with a slowly changing line of sight. A distant cloud expanding or moving largely towards or away from an observer may show little obvious sideways motion for several minutes. As different portions brighten, fade or separate, the perceived centre can then appear to jump or zigzag. This does not prove that every reported movement was illusory, but it provides a plausible mechanism that fits the independently documented behaviour of the Centaur clouds.
Silence is not a difficulty for the launch interpretation. The display was produced far from South Tyrol and at orbital or near-orbital altitude. There would be no locally audible rocket sound accompanying the visible cloud.
Why the public evidence remains incomplete
The launch explanation is persuasive at the level of date, time, mission type and observed European phenomenon. It is weaker as a publicly documented reconstruction of the exact view from Aica di Fiè. The surviving article presents the conclusion in a sentence, but not the calculations behind it. It does not provide the witnesses’ exact observation time, compass bearing, elevation, duration measured by a clock or the location of the reported Braies observation. Nor does it reproduce the Collepietra observatory’s original notes or the local newspaper article that first connected the event to Vandenberg.[Franz Magazine]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
That missing material matters because several claims require separate testing:
The ten-minute stationary phase. A proper reconstruction would plot the Centaur and illuminated cloud against the horizon as seen from Trettel’s balcony. It would show whether the predicted angular movement was slow enough to be remembered as stationary.
The movement towards Renon. The reported direction should be compared with the upper stage’s apparent track, not merely with its orbital direction on a world map. Perspective can make an object’s sky path differ markedly from a witness’s geographical description.
The zigzag. A diffuse, changing cloud may create an impression of irregular motion, but that should be demonstrated using photographs or timed observations from comparable locations rather than assumed.
The Braies report. If the priest’s observation occurred roughly fifteen minutes earlier, its direction and timing could either strengthen the launch identification or expose a mismatch. The published retelling supplies too little detail to decide.
The observatory confirmation. An observatory receiving several calls establishes that the phenomenon was widely visible. It would be more informative to know whether staff independently identified the Centaur, recorded its position or merely observed an unusual light.
The absence of this documentation does not place the rocket explanation and an extraordinary-craft hypothesis on equal footing. One side is supported by a confirmed launch, advance predictions and independent observations of the resulting clouds across Europe. The alternative rests on visual impressions without imagery or instrument data. The evidence therefore favours the Centaur explanation, but the lack of a published local reconstruction helps explain why witnesses felt dismissed rather than answered.
Did later reporting strengthen the UFO claim?
Later reporting strengthened the space-launch interpretation more than the UFO interpretation. The Air Force and United Launch Alliance records confirm the correct kind of mission from the named base. Contemporary satellite-observer archives show that the Centaur display was predicted before it occurred and then seen widely at the relevant time. The descriptions of cones, rings, brilliant clouds and intermittent venting resemble the extraordinary appearance reported near the Sciliar.[af.mil]af.milOpen source on af.mil.
By contrast, no publicly accessible photograph, video, radar trace or formal witness file has emerged to establish a separate low-altitude object over Bolzano. Trettel’s later account also moved beyond the local incident into broad claims about historical spacecraft imagery and worldwide secrecy. Those wider arguments do not add evidence to the Sciliar sighting and should not be used to judge what was seen that evening.[Franz Magazine]franzmagazine.comFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo SciliarFranz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
The fairest classification is therefore plausibly explained, but poorly communicated. The sighting was not invented: witnesses in South Tyrol appear to have observed a genuinely unusual and impressive light display. Its most likely cause was not a conventional aircraft and need not have been an astronomical body. It was probably an uncommon human-made phenomenon—the illuminated burn and propellant release of a rocket stage passing over Europe.
Within the UFO history of Trentino-Alto Adige, the Sciliar light remains important because it demonstrates the difference between an unidentified experience and an unexplained event. For the witnesses, the light was unidentified at the time and seemed to behave like something close to the mountains. For investigators with access to launch records and orbital predictions, there was a strong external match. The enduring dispute arose because that match was reported as a conclusion rather than presented as a full, testable reconstruction.
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Endnotes
1.
Source: satobs.org
Link:https://satobs.org/seesat/Oct-2009/0096.html
2.
Source: satobs.org
Title: Sat Obs See Sat-L Oct-09: European observations of the fuel dump
Link:https://satobs.org/seesat/Oct-2009/0111.html
3.
Source: satobs.org
Title: Sat Obs See Sat-L Oct-09: RE: DMSP F18 search elements; Centaur fuel du
Link:https://www.satobs.org/seesat/Oct-2009/0098.html
4.
Source: satobs.org
Title: Sat Obs See Sat-L Oct-09: Centaur-Clouds
Link:https://satobs.org/seesat/Oct-2009/0105.html
5.
Source: satobs.org
Title: Sat Obs See Sat-L Oct-09: Stupendous!!!!
Link:https://satobs.org/seesat/Oct-2009/0103.html
6.
Source: earthsky.org
Title: Earth Sky Strange spiral in the night sky was a rocket fuel dump
Link:https://earthsky.org/space/strange-spiral-in-the-night-sky-rocket-fuel-dump-aug-12-2025/
Source snippet
Strange spiral in the night sky was a rocket fuel dumpAugust 13, 2025 — 12 Aug 2025 — The released fuel can freeze into ice cryst...
Published: August 13, 2025
7.
Source: space.com
Link:https://www.space.com/stargazing/mysterious-white-streak-spotted-over-us-skies-during-surprise-aurora-storm-what-was-it-photos
8.
Source: space.com
Link:https://www.space.com/stargazing/stargazers-in-europe-spot-a-strange-cloud-from-spacex-falcon-9-rocket-launch
9.
Source: weather.com
Title: Air Force Launches New Weather Satellite | The Weather Channel
Link:https://weather.com/science/news/air-force-launches-weather-satellite-20140407
10.
Source: satobs.org
Link:https://satobs.org/seesat/Oct-2009/author.html
11.
Source: youtube.com
Title: Atlas V
Link:https://www.youtube.com/watch?v=5758RBjNJvg
Source snippet
SpaceX Rocket with glowing light mistaken for UFO...
12.
Source: af.mil
Link:https://www.af.mil/News/Article-Display/Article/118809/vandenberg-officials-launch-atlas-v-rocket/
13.
Source: franzmagazine.com
Title: Franz Magazine Monica Trettel e l’incontro ravvicinato con gli Ufo sullo Sciliar
Link:https://franzmagazine.com/2012/01/26/monica-trettel-e-lincontro-ravvicinato-con-gli-ufo-sullo-sciliar
14.
Source: space.oscar.wmo.int
Title: dmsp f18
Link:https://space.oscar.wmo.int/satellites/view/dmsp_f18
Source snippet
WMO OSCARSatellite: DMSP-F1817 Nov 2025 — 18 Oct 2009, EOL, Sep 2026. Last update: 2025-11-17. Associated satellite programme and related...
Published: November 17, 2025
15.
Source: ulalaunch.com
Title: ULAAV017_mob:Layout 1.qxd
Link:https://www.ulalaunch.com/docs/default-source/news-items/av_dmspf18_mob.pdf
16.
Source: af.mil
Link:https://www.af.mil/News/Article-Display/Article/475221/defense-meteorological-satellite-program-flight-19-launch/
17.
Source: af.mil
Link:https://www.af.mil/News/Article-Display/Article/114752/air-forces-x-37b-historical-landing-advances-space-vehicle-technologies/
18.
Source: af.mil
Title: Vandenberg officials launch Minotaur IV > Air Force > Article Display
Link:https://www.af.mil/News/Article-Display/Article/115478/vandenberg-officials-launch-minotaur-iv/About-Us/vandenberg-officials-launch-minotaur-iv/
19.
Source: af.mil
Title: First Minotaur IV Lite launches from Vandenberg > Air Force > Article Display
Link:https://www.af.mil/News/Article-Display/Article/116892/first-minotaur-iv-lite-launches-from-vandenberg/
20.
Source: af.mil
Link:https://www.af.mil/News/Article-Display/Article/116966/air-force-space-officials-prepare-to-launch-first-minotaur-iv/
21.
Source: af.mil
Title: NAS A WISE Delta II launch successful > Air Force > Article Display
Link:https://www.af.mil/News/Article-Display/Article/118283/nasa-wise-delta-ii-launch-successful/
22.
Source: af.mil
Link:https://www.af.mil/News/Article-Display/Article/130377/defense-weather-satellites-provide-environmental-support/
23.
Source: Wikipedia
Title: Atlas V
Link:https://en.wikipedia.org/wiki/Atlas_V
Additional References
24.
Source: youtube.com
Title: Space X’s Falcon 9 launch creates confusion over mistaken UFO sighting
Link:https://www.youtube.com/watch?v=nSLgsvg_jIw
Source snippet
SpaceX launch creates glowing spiral over UK sky...
25.
Source: youtube.com
Title: Space X Rocket with glowing light mistaken for UFO
Link:https://www.youtube.com/watch?v=43GtQesBTFU
Source snippet
SpaceX's Falcon 9 launch creates confusion over mistaken UFO sighting...
26.
Source: facebook.com
Link:https://www.facebook.com/thejournal.ie/posts/a-blue-and-white-light-spiral-seen-over-europe-was-likely-caused-by-a-spacex-fal/1053145260191767/
27.
Source: facebook.com
Link:https://www.facebook.com/RaiPlay.it/videos/segnali-di-vita-documentario-disponibile-su-raiplay/2278443512599608/
28.
Source: facebook.com
Link:https://www.facebook.com/groups/smartphoneastro/posts/684288370830555/
29.
Source: newitalianbooks.it
Link:https://www.newitalianbooks.it/wp-content/uploads/2025/11/Geopolitica_dello_spazio_mail.pdf
30.
Source: eggental.com
Link:https://eggental.com/it/info/osservatorio-astronomico-max-valier_2455
31.
Source: zur-sonne.it
Link:https://www.zur-sonne.it/it/planetario-alto-adige/
32.
Source: britastro.org
Link:https://britastro.org/forums/topic/potential-visibility-of-a-fuel-dump-from-a-rocket-booster
33.
Source: instagram.com
Link:https://www.instagram.com/reel/DRPrsk5jN5S/