A trio of heliophysicists and satellite trackers at NASA Goddard Space Flight Center and the Goddard Planetary Heliophysics Institute at the University of Maryland has found evidence showing that Starlink satellites reenter Earth’s atmosphere faster during heightened solar activity. For their paper posted on the arXiv preprint server, Denny Oliveira, Eftyhia Zesta and Katherine Garcia-Sage analyzed Starlink satellite data over the years 2020 and 2024, during a rising phase of the solar cycle.

Every 11 years, the sun undergoes a cycle where the frequency and intensity of storms on its surface intensifies and then lessens. Such activity tends to lead to more geomagnetic activity in Earth’s upper atmosphere, which can have an impact on satellites circulating the planet. The team at Goddard wondered what sort of impact the solar cycle has on Starlink satellites.

Looking at their data, the research team found that as geomagnetic activity increased, Starlink satellites tended to reenter the atmosphere sooner than they would have during quieter periods. Such satellites are designed to stay in orbit for about five years, but the study found that during periods of intense geomagnetic storms, the final descent phase—from a reference altitude of about 280 km to atmospheric reentry—was shortened by 10 to 12 days compared to quieter times.

The research team suggests that increased heat in the atmosphere due to an increase in geomagnetic activity leads to more drag on the satellites, which leads them to lose altitude. They also suggest the same drag could result in more collisions between the satellites that make up constellations that are deployed.

Also, the unexpected reentry of the satellites can interfere with controlled reentry. The increased drag results in the satellites falling faster, which makes it more likely they will hit the ground before burning completely—such was the case when a chunk of debris from one of the satellites crashed onto a farm in Canada in 2024—which happened to be at the peak of a solar cycle.

The team concludes that as the number of satellites in orbit continues to grow, careful monitoring and prediction will become even more important during periods of high solar and geomagnetic activity to safeguard against both orbital collisions and potential debris impacts on Earth.

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