Two significant geomagnetic storms in 2024 triggered unprecedented “mass migrations” of thousands of satellites in low Earth orbit, raising serious concerns about space traffic coordination. The phenomenon was initially observed in May during the Gannon storm, notable for auroral displays at unusually low latitudes.
The storm drastically increased atmospheric density at low Earth orbit altitudes, as noted by William Parker of the Massachusetts Institute of Technology. This heightened density led to increased drag, significantly affecting satellite orbits. The initial problem was the low accuracy of storm forecasts. “As a result of this low skill in our forecasts, SpaceX saw 20 kilometers of position error in their one-day computations” of Starlink satellite orbits, Parker explained. “If we’re uncertain in where our spacecraft are by 20 kilometers, then you can throw collision avoidance out the window.”
The situation worsened due to a lack of awareness regarding the forecast inaccuracies. “We were pretty confident in those bad solutions,” Parker stated. “Being confident in the wrong answer fundamentally changes the decisions that we’re making whether or not to maneuver the spacecraft.” Following the storm’s peak, increased drag caused orbital decay, prompting numerous automated maneuvers to restore altitudes. The Gannon storm resulted in approximately 5,000 satellites, mostly Starlink, performing orbit-raising maneuvers in a single day—a stark contrast to the usual baseline of around 300.
Parker described this as “the largest mass migration in history,” a record later broken in October by another geomagnetic storm. This increase was partially due to additional Starlink satellites launched between the two events. These mass maneuvers further complicated collision avoidance, already compromised by positional errors. “Then we have no idea when a collision is going to happen. We lose that capability for days at a time,” he noted.
Many satellite operators, unaware of the position errors and mass migration, continued unnecessary maneuvers. “Lots of operators continued to maneuver as if nothing was wrong, but all of those maneuvers were pointless because they didn’t represent reality,” Parker said. The events highlight the urgent need for improved space weather models and forecasts. “This is a significant impact,” Parker concluded. “This is critical infrastructure to all of our space operations moving forward, and it will only become more important as time goes on.”