SAINT-MANDRIER-SUR-MER (83) 23.05.2019

On 23 May 2019, at 07:30, the witness, on board his boat, about 5 nautical miles (approximately 9.3 km) off and south of Cap-Cepet, in the commune of Saint-Mandrier-sur-Mer (83), observed a black ball emerging from the west at an elevation of 15°. This ball seemed to evolve at an altitude comparable to that of an airliner, but at a higher speed. Halfway along its path, the object changed colour to become "very bright chrome" and accelerated considerably while climbing southeast, thus tripling its initial speed. The witness lost sight of the object to the south, at an elevation of 45°. The observation lasted between 5 and 7 seconds, without any noise, halo, trail, smoke or spark being noticeable. The evidential quality* of the account is considered medium, due to the presence of a single witness, the absence of photos or videos of the UAP, and the witness's incomplete or missing data, including the apparent size of the UAP and the angular distance travelled. *according to the GEIPAN criteria, evidential quality is the amount of information considered reliable, collected for testimony. GEIPAN examined a novelty-balloon hypothesis, supported by the following: - The observed colours, "black and chromed", are typical of novelty balloons, which can have two different types of finishes: a painted or aluminized Mylar® envelope. -The round shape is characteristic of balloons, allowing illumination by the Sun on the east side, thus creating a brilliant appearance due to reflection from its aluminized Mylar® surface. - Analysis of the weather data revealed that the initial displacement of the UAP from west to east is perfectly aligned with the wind orientation from an altitude of 750 m upward. We also observe that this wind describes a wide curve at sea, suggesting a possible origin along the coasts of Marseille, Martigues or Port-Saint-Louis-du-Rhône. Given that the weather conditions were otherwise very good, it is plausible that the novelty balloon was released or lost from a beach or calanque located along the coast. The strangeness perceived by the witness is mainly due to his perception of the speed and altitude of the UAP, which he considers to be very high, as well as to changes in colour, trajectory and speed. The investigation provides the following explanations: -The change in colour, from "black to chrome", can be attributed to the mixed composition of the ball, with a dark face and a bright face exposed to the Sun. The perception of the two distinct parts can be influenced by the change of perspective or rotation of the ball during its displacement. - The estimation of speed, distance (and thus altitude), as well as the dimensions of an unknown object observed in the sky is difficult to establish precisely without visual reference points. The witness compares the object to the fighter aircraft he knows, assimilating the characteristics of the UAP to those of these aircraft. However, it is plausible that the UAP is a more modest object, at an altitude below that of an airliner or military aircraft. Consequently, the speed perceived by the witness may seem very high, since he assumes that the UAP is moving at a much higher altitude. - The change in trajectory and speed can be explained by a balloon climb in an area where the winds are stronger and more oriented towards the west-northwest. This may give the witness the impression that the object is following a final path visually oriented towards the southeast. However, the imprecise data on the angular size of the UAP and the angular distance it has travelled do not allow the correspondence to be checked any further. The GEIPAN classifies this case in "B", a very probable observation of a novelty balloon.