A spike in solar activity has been creating problems for anything orbiting close to Earth, and Starlink satellites have been hit especially hard. Since SpaceX launched the first units in 2019, more than 500 Starlink satellites have made unplanned atmospheric reentries, according to an analysis as reported by BGR.
These reentries aren’t dramatic crashes. Starlink satellites burn up high in the atmosphere long before reaching the ground. What the rising number really shows is how the sun can change the conditions in orbit. When solar activity heats and expands the upper atmosphere, satellites experience more drag, and low orbiting spacecraft slow down until gravity pulls them into reentry.
The sun is currently in Solar Cycle 25, an 11 year stretch during which its magnetic poles flip. As it moves toward solar maximum, our star unleashes more solar flares, sunspots, and coronal mass ejections. Streams of charged particles from these events pour into Earth’s upper atmosphere and act like fuel, heating it and causing it to balloon outward. A team led by space physicist Denny Oliveira notes that this cycle is far more active than early forecasts predicted, and that intensity has put pressure on Starlink’s enormous fleet.
SpaceX has launched 8,873 Starlink satellites so far, with 7,669 still operating. That leaves 1,204 that are no longer functioning, a number that includes both failures and intentional deorbits. Hundreds of those reentries happened during this unusually energetic phase of the solar cycle, making it one of the busiest periods ever for atmospheric burn ups.
Not all of these losses were caused by the sun. SpaceX regularly retires older satellites to refresh the network, and the company programs them to deorbit after about five years. These satellites are built to fully disintegrate during reentry, and while rare fragments occasionally survive, they almost never reach the surface. It is a built in part of managing such a massive constellation.
Still, the sun adds unpredictability. Operators can design for heat, radiation, and orbital decay, but they can’t cool down the upper atmosphere when it swells. As solar activity increases, so does drag, and spacecraft operators across the globe have to adjust.
For SpaceX, it is simply the cost of maintaining a network in low Earth orbit and a reminder that even the most advanced technology still answers to the forces of nature.