The Sun is angry. At least, that’s how it might feel for SpaceX’s Starlink satellites as they hurtle through our planet’s upper atmosphere, buffeted by ferocious solar storms. With over 7,000 Starlink spacecraft now orbiting Earth—and many more on the launchpad—scientists suddenly have a unique, unprecedented laboratory to study how solar activity can dramatically shorten the lifespans of these minimalist, mass-produced satellites. What they’ve found is a stark reminder that, even hundreds of kilometers above us, the Sun still holds immense sway.

Every eleven years, the Sun goes through a period of heightened activity known as solar maximum, marked by more frequent and intense sunspots, solar flares, and coronal mass ejections (CMEs). When a CME or high-speed solar wind stream slams into Earth’s magnetic field, it can trigger a geomagnetic storm: the magnetosphere is compressed, the upper atmosphere heats and expands, and the density at satellite altitudes—typically between 200 and 1,000 km—increases substantially. As atmospheric particles climb to these heights, they create extra drag on any spacecraft trying to maintain its orbit, hastening its descent and eventual reentry. This phenomenon isn’t new—Skylab famously fell back to Earth in 1979 because of unexpectedly high solar activity—but the sheer scale of Starlink has thrust it into the spotlight like never before.

Researchers have known for decades that satellites in low Earth orbit (LEO) are vulnerable to space weather. During the great geomagnetic storm of March 1989, for instance, the upper atmosphere ballooned, forcing over a thousand tracked objects to be reclassified, and even knocking one satellite—the Solar Maximum Mission—out of orbit later that year. But with Starlink’s mega-constellation currently dwarfing any prior fleet, we’re now witnessing hundreds of simultaneous reentries linked to the same solar activity. “It’s the first time in history we have so many satellites re-entering at the same time,” says NASA Goddard Space Flight Center scientist Denny Oliveira, who has been meticulously tracking Starlink deorbits.

In a NASA-led study recently highlighted by New Scientist, Oliveira and his colleagues examined two-line element (TLE) data for 523 Starlink satellites that reentered between 2020 and 2024. They performed a superposed epoch analysis, a statistical technique that aligns multiple events around a common trigger—in this case, geomagnetic storms—and averages their effects. The result was unmistakable: during periods of heightened geomagnetic activity, satellites experienced significantly elevated drag forces, causing them to lose altitude faster and reenter Earth’s atmosphere days or even weeks sooner than predicted under quiet conditions.

More concretely, as the Sun ramped up toward its solar maximum in late 2024, a single Starlink satellite’s effective lifetime could shrink by up to ten days compared to its expected orbital duration absent major solar storms. That might not sound like much on paper, but when multiplied by thousands of satellites, it represents a substantial operational and logistical headache for SpaceX. “We found that when we have geomagnetic storms, satellites re-enter faster than expected [without solar activity],” Oliveira told New Scientist.

University of Regina astrophysicist Samantha Lawler, another co-author on the study, emphasizes the novelty of the situation: “This is the first solar maximum that we’ve had in the mega constellation era,” she explains. “So it is important to do these measurements.” Indeed, while early solar cycles saw only dozens or hundreds of satellites, Solar Cycle 25 ushered in thousands at speeds never seen before, creating a perfect storm—quite literally—for studying space weather’s impact on orbital debris.

Two particularly eye-opening events highlight just how fierce space weather has become. On May 10, 2024, a potent geomagnetic storm—triggered by a fast-moving CME—swept past Earth and unexpectedly “pre-conditioned” the thermosphere, increasing its density well before the main event. Researchers found that a dozen Starlink satellites experienced rapid orbital decay immediately afterward, reentering over the subsequent weeks rather than persisting for months as planned. The May 10 storm’s effects rippled through April as well, hinting at complex interactions between enhanced extreme ultraviolet flux, Joule heating, particle precipitation, and the equatorial neutral anomaly.

Fast-forward to October 10, 2024, and Solar Cycle 25 flexed its muscles again. A geomagnetic storm that peaked around that date wrought havoc on Starlink-1089 (SL-1089), a satellite slated to reenter on October 22. Instead, it plunged back to Earth on October 12—ten days early. Denny Oliveira and colleagues documented a precipitous drop in altitude coinciding with the storm’s onset, underscoring how even a “moderate” storm during peak solar activity can have outsized effects on low-orbit satellites.

These accelerated reentries haven’t just been academic curiosities. Late last year, as a formidable solar storm pummeled Earth, Elon Musk himself warned Starlink users of “degraded” broadband service. Although the fleet weathered that particular event, a March 2022 storm knocked out forty Starlink satellites—a stark reminder that space weather can disrupt not only lifespans but also real-time communications.

SpaceX designs each Starlink satellite with an onboard propulsion system and a planned deorbit sequence: when a satellite reaches the end of its mission or experiences a critical failure, it intentionally lowers its orbit to burn up. But when the upper atmosphere is superheated and expanded, that decay process accelerates uncontrollably. NASA’s Oliveira worries that fragments could survive reentry: “By accelerating this process, pieces of the satellites may survive reentry, allowing bits to plummet back to the ground,” he says. Last summer, one such fragment was recovered on a Canadian farm, confirming that not everything vaporizes.

“If we found one [piece] here, how many did we miss?” asks Samantha Lawler. As storms grow more intense, thousands more Starlink satellites are slated for launch—and potentially premature reentry. The prospect of more debris reaching Earth raises not only safety concerns for people on the ground but also environmental questions about what happens when tiny shards of spacecraft pepper the planet.

The timing of reentries matters not only for ground debris but also for collision avoidance in space. When hundreds of satellites experience sudden drag, predicting their exact trajectories becomes more difficult. “Prediction errors, defined as the difference between the epochs of actual reentries and predicted reentries at reference altitudes, increase with geomagnetic activity,” Oliveira and team report. In other words, when the Sun throws a tantrum, the usual models start to break down, making it harder to forecast where each satellite will be hours—or even minutes—down the road.

This uncertainty has ripple effects. Space traffic management relies on accurate TLE data to plot conjunctions (close approaches) and issue collision warnings. If a satellite suddenly drops in altitude without warning, it could skirt too close to another vehicle, forcing emergency maneuvers. And with SpaceX planning to grow Starlink to over 30,000 satellites in the coming years, that collision risk only magnifies. We’re already seeing satellites reentering “every day,” warns Oliveira—and sometimes without warning.

Solar Cycle 25 is projected to peak sometime in mid-2025, and the scientific community expects even more intense storms as the Sun reaches its apex. Satellite operators are scrambling to improve forecasting and refine drag models. Some proposed strategies include equipping future Starlink satellites with more robust propulsion systems to counteract unexpected drag, adjusting deployment altitudes, or employing more sophisticated space weather forecasts to plan for storm seasons. Yet, despite these efforts, Nature has shown once again that it remains a formidable force.

Researchers also see opportunities in this period of record-high solar and orbital activity. “This is a very exciting time in satellite orbital drag research,” says Oliveira. By analyzing hundreds of co-orbiting satellites undergoing simultaneous decay, scientists can refine our understanding of how the thermosphere responds to extreme space weather—insights that could benefit everything from climate studies to the design of future Earth-observing missions.

In the end, the saga of the Sun and Starlink serves as a vivid reminder that even our most advanced technologies remain subject to the whims of our nearest star. As SpaceX and other operators push toward megaconstellations, understanding—and predicting—solar-driven atmospheric dynamics is no longer an academic luxury but a pressing necessity. The Sun’s “anger,” manifested as blazing streams of charged particles, highlights an eternal truth: in the space between Earth and the heavens, human ambition and cosmic forces are locked in a continuous tug of war. Whether we’re streaming video, monitoring the environment, or exploring other worlds, we’re all, in a very real sense, passengers on a tiny craft navigating the steering currents of our Solar System’s powerhouse.

In the months ahead, as Solar Cycle 25 reaches full fury, scientists will watch closely to see whether our models hold up—or whether the Sun has more surprises in store. One thing is certain: for every satellite that falls prematurely, and for every piece of hardware that survives reentry to remind us of space weather’s power, we’ll be learning more about the complex dance between Earth, its atmosphere, and the star at the center of it all.