Sighting in Moulézan, December 26, 2018

Around 6:45 one morning, a witness who was having breakfast in their living room noticed an object moving across the sky. They first took it for a satellite, but its size surprised them. They went outside for a better look and saw four points of light that suggested a square shape. The object travelled from the south/south-west toward the east, with no particular sound. Its path was straight at first, then it seemed to "undulate" before making a long turn and passing out of the witness's sight.

The investigation concluded that this was very probably a pass of the International Space Station (ISS). A check showed that, that morning, the station followed a south-west to east track during the exact time window of the sighting. It looks much bigger and brighter than an ordinary satellite, almost as bright as Venus. The curve has an explanation: the path of a satellite that does not pass overhead really is curved, and here the maximum elevation was 40°, which the witness perceived as "almost overhead". At that height, judging direction against the cardinal points becomes difficult. The undulations match the autokinetic effect, a known perceptual phenomenon with a point of light in the dark. The number of points seen is not fully explained: it exceeds the eye's average resolving power, but the strong contrast against a black sky and better-than-average eyesight could account for it. The resupply vehicles present were docked to the station and do not explain these points. Still, this detail does not contradict the hypothesis. GEIPAN therefore classified the case as B, probably identified as the ISS.