TRIPLET DE SATELLITES — NATIONAL (FR) 11.08.2018

A witness in Lalinde (24) told GEIPAN that, on 11 August 2018 around 23:10 local time, he followed 3 grouped points of light moving in a straight line across the night sky. Two other accounts described similar sightings that night, giving 3 independent reports from different departments: - Lalinde (24), 11 August 2018. - Argelès-Gazost (65), 11 August 2018. - Lunan (46), 11 August 2018. The investigation report analyzes the Lalinde account in detail. GEIPAN concludes that this principal witness happened to see a recently launched triplet of Chinese surveillance satellites in a temporary configuration favorable to naked-eye observation. Its reasoning is based on: - Brightness, colour, point-like appearance and straight movement entirely consistent with satellites, as the witness himself noted. - Confirmation that the satellites were present in the sky at the observation time. - Other matching observations at the same date and time, including a particularly detailed account by a satellite specialist. - Initial and final elevations matching those given by the specialist for his own sighting and the trajectory reconstructed in Stellarium, corresponding to the triplet near its highest point in the sky. GEIPAN also found that the witness probably substantially overestimated the angular distance traveled and, to a lesser extent, underestimated the duration. Straight movement at an approximately constant elevation of 75° matched the satellite triplet's characteristics. The initial viewing direction was estimated fairly accurately, but the final direction was not. GEIPAN considers this probably due to trees, buildings and other obstructions concealing much of the horizon and making azimuth estimates difficult. The short duration and the triplet's high position likely contributed: sightings near the zenith make the azimuths of appearance and disappearance harder to judge. The witness had seen satellites before. What chiefly puzzled him was seeing 3 moving together, without visible stars. GEIPAN explains that triplets are possible for these particular NOSS-type surveillance satellites, used by the United States and now China. It considers that no stars appeared between the lights because the triplet was probably crossing a part of the sky without stars bright enough to be visible. The Argelès-Gazost and Lunan accounts concerned sightings around 23:00 on the same date. Both also described 3 moving points of light, with the leading one less visible. GEIPAN has little doubt that they involved the same phenomenon. Conditions favored observation: mild temperatures, a very clear, cloudless, moonless sky, and a period when more people were watching for shooting stars. GEIPAN classifies the case A: confirmed observation of the Chinese surveillance satellites Yaogan-31 A, B and C, a few months after launch, in a temporarily favorable configuration.