Every 11 years, the Sun’s activity peaks in a solar maximum, unleashing powerful geomagnetic storms that heat and expand Earth’s upper atmosphere. This extra heating increases atmospheric drag on satellites. Starlink (SpaceX’s network of thousands of satellites) is designed for about a five-year orbital lifespan. NASA scientists asked whether solar storms might trim these orbits. In a new arXiv study, researchers analysed tracking data for 523 Starlink satellites reentering between 2020 and 2024 (rising Solar Cycle 25). They found that during active solar periods, the satellites lost altitude and re-entered sooner than under quiet conditions.
NASA Study of Starlink Re-entries
According to the study, researchers used public TLE tracking data to investigate hundreds of Starlink deorbit events. By aligning each satellite’s descent around a reference altitude (280 km), they showed that higher geomagnetic activity drives faster orbital decay. During a severe storm, the final drop from 280 km took on average only 7 days, compared to 16 days under calm conditions. In practice, this means intense storms shaved roughly 10–12 days off the satellites’ final descent phase.
The team attributes the effect to increased thermospheric heating and drag during storms. For example, one storm prompted 37 Starlinks to re-enter in just 5 days (versus 15 days normally). With thousands more satellites planned, the authors stress that improved orbital prediction during solar maxima will be crucial to manage these accelerations.
Implications and Monitoring
The findings highlight new risks for large constellations. Greater atmospheric drag not only shortens mission life but can raise collision danger in crowded orbits. Unplanned, rapid re-entries also complicate disposal plans: satellites falling unexpectedly may not burn up completely. In fact, a fragment of a Starlink satellite landed on a Canadian farm in August 2024 during the last solar maximum.
The researchers conclude that as megaconstellations expand, accurate tracking and prediction will be vital. Close monitoring during solar storms can help avert in-orbit collisions and ensure debris burns up safely before reaching Earth.