Accurate Optical Observations on Low Earth Orbit Satellites During the May 2024Severe Solar Storm: Analysis of the O-C Values and their Causes

Abstract

In May, 2024 a severe solar storm with strong geomagnetic storm components was recorded.Based on optical observation of low Earth orbit (LEO) satellites during and after the solar event, we describe and make available a database featuring topocentric observations for more than 300 LEOs, and present the analysis of the storm's impact on the satellites' orbital positions.Between May 10 and May 15, on several nights, we performed a series of observations on LEOs from Cluj-Napoca, Romania, and the Feleacu Station of the Astronomical Observatory Cluj-Napoca.Two instruments were used: a wide Field of View instrument based on an 85 mm lens with a DSLR camera, and a narrow Field of View instrument based on an Orion ShortTube 80 refractor telescope, with a SBIG STT 1603ME CCD camera.These observations were gathered in a database with information about the instrument used and location, the satellite's identifier, time of observation, and the topocentric position.This database contains over 300 satellites.In the second part of this study, we used these observations to compare the observed apparent positions with the predicted positions computed from the up-to-date Two-Line Elements (TLEs), available in the USSPACECOM catalog.An initial investigation of this comparison leads us to identify satellites that underwent active space maneuvers (ASM), with most satellites belonging to the Starlink constellation.Additionally, we plotted and investigated the distribution of O-C values for ASM and non-space maneuvered (NSM) satellites during the solar storm.Among all surveyed satellites, prediction errors for ASM satellites were significantly larger when compared to NSM satellites.These differences are illustrated in plots of ASM versus NSM satellites.We found that O-C errors were driven primarily by active maneuvers, rather than by the G5 geomagnetic storm itself.