MONTMORENCY (95) 18.12.2020

At nightfall on 18 December 2020 in Montmorency (95), a witness and his daughter noticed a very bright constellation-like group of 3 points forming an almost equilateral triangle. Its brightness began to change and it seemed to move. After a few seconds, less than 1 minute, the points disappeared almost simultaneously. The witness compared it to 3 International Space Stations forming a triangle. GEIPAN judges the evidential strength moderate: a single detailed account, but no photographs or videos. The investigation found that the witnesses had observed a trio of Chinese satellites temporarily positioned to reflect sunlight toward them and thus become visible to the naked eye. GEIPAN bases this conclusion on the following findings. Three satellites moving together are typical of this type of satellite group. Their brightness, color, point-like appearance and straight-line motion matched satellites, as the witness himself noted. Data from CNES's Space Surveillance Operations Center confirmed their presence in the sky at the time. The reported elevations matched the trio's trajectory to within 1.5 minutes. The estimated duration, a few seconds and less than 1 minute, matched the expected visibility of these glints and comparable GEIPAN cases: 30–50 seconds at LE PETIT-QUEVILLY (76), 16.04.2014, and 8 seconds at SOUSTONS (40), 01.12.2019. The witness also correctly estimated the viewing direction and the 5° angular separation between the components. The case is classified as A: definite observation of the Chinese satellites Yaogan-31 A, B and C. The witness saw sunlight reflected from the 3 satellites.