From Energy Input to Orbital Decay: Thermospheric Density and LEO Satellite Response to the May 2024 Gannon Geomagnetic Storm

The May 2024 super geomagnetic storm provided a rare opportunity to investigate the full-chain impact of extreme space weather on the thermosphere and Low Earth Orbit (LEO) satellites. This study presents, for the first time, an end-to-end quantitative analysis that links high-latitude energy input, thermospheric density response, multi-model performance evaluation, and satellite orbital decay. High-latitude Joule heating increased from ~2 mW/m2 during the quiet period to 112 mW/m2 during the main phase. The hemispherically integrated heating peaked at 1822 GW, and the enhanced heating persisted for approximately 18–20 h. Swarm-A observations show that the orbital-mean neutral density at ~470 km increased by a factor of 4.5 relative to quiet-time levels. However, DTM2020, JB2008, NRLMSIS 2.0, and TIEGCM2.0 all underestimated the magnitude of this enhancement, with mean absolute percentage error (MAPE) values of 32.6%, 39.0%, 60.8%, and 40.6%, respectively. Coupling these models to the High Precision Orbit Propagator (HPOP) shows that the China Space Station (CSS) decay rates are 0.5–0.7 km/day during the main phase, about 2–3 times the quiet-time values. These predictions agree with Two-Line Element (TLE) derived semi-major axis decay trends, but significant magnitude discrepancies persist among different models, indicating that thermospheric model selection is a crucial uncertainty source in orbit prediction. A statistical analysis of Space-Track TLE data for LEO population (<1000 km) quantifies decay distribution across altitudes, providing direct references for space situational awareness and orbit maintenance strategies.