A study of a May 2024 solar storm reveals significant disruptions to SpaceX's Starlink constellation, including altitude drops and network outages. Researchers warn that as satellite numbers increase, the threats from solar activity could worsen, potentially leading to collisions and communication failures. The findings highlight vulnerabilities during the sun's 11-year activity cycle.
The number of satellites in orbit has surpassed 10,000 for the first time in history, with SpaceX's Starlink mega-constellation accounting for a large share. Since May 2019, SpaceX has launched more than 10,000 Starlink satellites, though about 1,000 have re-entered Earth's atmosphere at a rate of one or two per day. These satellites form a global mesh at around 550 kilometers altitude, making them susceptible to solar storms and the resulting geomagnetic disturbances.
In May 2024, during a moderate solar storm, researchers led by Eunju Kang at the University of California, Irvine, analyzed public tracking data. They observed that satellites on the sun-facing side of Earth experienced altitude drops of up to half a kilometer due to atmospheric drag from solar radiation. Regions near Earth's poles and the South Atlantic Anomaly—where the magnetic field is weaker—saw even greater effects, as charged particles were funneled more intensely.
This disruption created a cascading 'undulating' wave across the constellation. 'If one satellite loses its altitude, the neighbouring satellite would also have to compensate,' Kang explained, using ion thrusters to maintain laser-based communication links. 'It’s kind of like waves,' added team member Sangeetha Abdu Jyothi. Such unpredictability raises collision risks for other spacecraft. 'When we have less predictability of trajectories, it can increase the risk of collisions,' Abdu Jyothi noted.
Network impacts were evident too, with RIPE Atlas data showing spikes in packet loss and outages. 'There was an immediate spike in packet loss,' Kang said. This storm was about three times weaker than the 1859 Carrington Event, yet it echoed a February 2022 incident that destroyed 40 newly launched Starlink satellites.
Experts predict challenges will intensify with the sun's next activity peak in the 2040s, when tens or hundreds of thousands more satellites could orbit. 'The problem goes up the more satellites you have,' said Scott Shambaugh of Leonid Space. Predictive models for short-term drag remain inadequate, and substorms—small atmospheric variations—are particularly hard to forecast, according to Mathew Owens at the University of Reading. Starlink's scale now serves as a vast probe network for studying these effects.