Loss of 12 Starlink Satellites Due to Pre-conditioning of Intense Space Weather Activity Surrounding the Extreme Geomagnetic Storm of 10 May 2024

TL;DR

This paper analyzes how intense space weather activity, especially around the May 2024 geomagnetic storm, caused increased orbital decay and satellite loss, highlighting the complex effects of preconditioning factors like EUV flux and thermospheric changes.

Contribution

It provides the first detailed analysis of preconditioning effects of space weather on satellite orbital decay during an extreme geomagnetic storm.

Findings

Significant increase in decay rates post-storm

Pre-storm decay acceleration linked to EUV flux and O/N2 ratio

Multiple decay mechanisms during storm recovery phase

Abstract

This study investigates the orbital decay and subsequent reentries of 12 Starlink satellites from 16 April to 15 May 2024. By examining Two-Line Element data, we observed a significant increase in orbital decay following the geomagnetic storm on 10 May 2024, consistent with expectations of increased thermospheric density. An unexpected increase in decay rates for 10 satellites was identified around 25 April 2024, while two lower-altitude satellites remained unaffected. Detailed analysis revealed that this enhanced decay rate prior to the storm was influenced by a spike in the O/N2 ratio and an increase in Extreme Ultra Violet (EUV) flux. Moreover, most of the satellites exhibited sharp decay during the early recovery phase of the geomagnetic storm. Based on the positions and local times of changes in decay rates, it is likely that the satellites were affected by various processes during elevated space weather activity, such as enhanced EUV flux, Joule heating, particle precipitation, and the equatorial neutral anomaly. This study highlights the complex role of preconditioning due to enhanced EUV flux and extreme space weather activity in the orbital dynamics of Low-Earth Orbit (LEO) satellites.