Sighting in Nantes, June 25, 2015

At around 3:15 a.m., a witness watched a point of light cross the night sky in a straight line for 10 to 15 seconds. The witness themself recognized it as a satellite. They then saw a second, larger light, white and orange, moving very fast without blinking and without a sound. It seemed to stop, abruptly changed course and vanished.

The investigation checked the satellite-pass simulators Calsky and Heavens-above. That night, many satellites were visible on paths close to a north-south or south-north line. The first light was probably COSMOS 2428, visible between 3:00 and 3:12 a.m. moving from north-north-west toward the south, though this was not certain since other satellites could fit. The second phenomenon, much brighter and travelling south to north, matched a flash from the Iridium 52 satellite, which both tools showed as visible from Nantes at 3:25 a.m. on a south-to-north orbit.

According to GEIPAN, a right-angle turn and a sudden acceleration before disappearing are common descriptions for satellites entering the Earth's shadow, or whose brightness stops abruptly because their orientation relative to the Sun changes. The sudden drop in brightness is unconsciously interpreted as the object moving away. The case was classified A: observation of an Iridium 52 satellite flash.