A major solar storm does not need to directly destroy satellites to trigger an orbital crisis. It is enough that it disrupts the tracking systems, commands, and avoidance maneuvers that today manage an increasingly crowded orbital environment.
This risk grows as low Earth orbit fills up with mega-constellations, those large networks of satellites launched and replaced in rapid cycles. These craft provide internet access, communications, weather, navigation, and other services. But they also add congestion to a region where objects fly and cross paths at about 27,000 kilometers per hour (16,777 mph).
To quantify this vulnerability, a paper led by Sarah Thiele at Princeton introduces a new metric: the CRASH clock (Collision Realization And Significant Harm). It estimates the time needed for a serious collision to occur if satellites can no longer maneuver or if operators lose a reliable view of object positions.
The results of this analysis are striking. Using data from the satellite catalog of June 2025, the team calculated that if operators lost the ability to send commands for avoidance maneuvers, a catastrophic collision could happen in about 2.8 days. In 2018, before the rapid expansion of mega-constellations, that value was 164 days.
Solar storms pose a systemic threat. Satellites in low orbit do not simply follow fixed paths. They depend on maintaining their position, tracking updates, and collision avoidance maneuvers. According to the latest SpaceX semiannual report cited in the study, Starlink satellites performed 144,404 avoidance maneuvers between December 2024 and May 2025. That averages 41 maneuvers per satellite per year, or one maneuver every 1.8 minutes across the entire Starlink network.
During a strong solar storm, this carefully managed system becomes harder to control. Solar storms heat Earth's upper atmosphere, causing it to expand. This increases drag on satellites, pushes them off their intended trajectories, forces operators to use fuel to maintain altitude, and makes orbital predictions less reliable.
The May 2024 storm, called the "Gannon storm," showed just how disruptive this can be. Nearly half of all active satellites in low orbit maneuvered due to increased atmospheric drag. The study notes that this widespread repositioning, combined with unpredictable drag, made collision assessment much more difficult during and after the storm.
Paths of Starlink satellites as of February 2024.
Credit: NASA Scientific Visualization Studio
The danger grows if the storm also disrupts navigation, communications, or ground control. In that case, satellites may become harder to track while also becoming less able to react.
The Kessler syndrome is the best-known version of this type of catastrophe, where cascading collisions fill orbit with debris and make it extremely difficult to launch or operate new craft.
Even a single high-speed impact can have lasting consequences. A collision between large objects can create thousands of fragments, each becoming a new hazard. The current debris environment is still marked by the 2007 Chinese antisatellite test targeting Fengyun 1C and the 2009 collision between Iridium 33 and Kosmos 2251.
Researchers estimate that across low Earth orbit, approaches closer than one kilometer (0.62 miles) occur every 36 seconds. Encounters involving at least one satellite happen about every 41 seconds, and those involving Starlink and another orbiting object happen every 47 seconds.
An approach is not a collision. Operators weigh distance, uncertainty, object size, and collision probability before deciding to move a satellite. Still, the frequency of these encounters shows how dependent orbit has become on fast, precise, and coordinated control.
Major solar storms are rare, but not hypothetical. The May 2024 Gannon storm was the strongest geomagnetic storm in decades. The Carrington event of September 1859 was at least twice as intense, according to the paper, and included two violent storms within a few days. Such a storm could have dramatic consequences today.