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Recent simulations have revealed a worrying prospect: no satellite currently orbiting Earth would be safe during the next solar superstorm of Carrington Event magnitude. This revelation comes as scientists prepare for the launch of ESA's Sentinel-1D satellite, using hypothetical scenarios to bolster preparedness for severe space weather events. The original Carrington Event, observed by British astronomer Richard Carrington in 1859, remains the benchmark for extreme solar activity. Carrington witnessed a massive solar flare from a sunspot roughly the size of Jupiter, followed by a week-long geomagnetic storm that lit up skies globally with auroras. This historical episode now serves as a warning for what could happen if a storm of similar or greater intensity hit our modern, satellite-dependent civilization.
In the simulated scenario, an X45 magnitude solar flare erupts suddenly, unleashing intense radiation waves that strike Earth with almost no warning. This initial radiation hits satellites, especially those far from the Earth's protective inner magnetic field. Approximately 15 hours later, a coronal mass ejection (CME) — a massive plasma cloud traveling at over 4.4 million mph — crashes into Earth's magnetosphere, triggering geomagnetic storms on par with the Carrington Event. These storms dramatically expand the upper atmosphere, increasing drag on satellites by up to 400%. This increased atmospheric drag risks pulling satellites down into the atmosphere, where they could burn up or crash, effectively wiping out entire satellite constellations.
The triple threat satellites face includes the initial radiation burst from the flare, a follow-up radiation wave that disturbs navigation systems and heightens collision risks, and finally the geomagnetic storm caused by the CME-induced swelling of Earth's atmosphere. Low-Earth orbit satellites enjoy some natural protection from Earth’s atmosphere and magnetic field, but even they would likely be vulnerable during such an intense event. A taste of this vulnerability was witnessed during a powerful geomagnetic storm in May 2024, which caused significant GPS disruptions and knocked some satellites out of orbit, resulting in nearly $500 million in damages for U.S. farmers due to malfunctioning equipment.
The potential damage from a full-scale Carrington-level event dwarfs these recent impacts. A 2013 study estimated that such a storm could cost the U.S. up to $2.6 trillion in damages, especially to power grids. Globally, the costs would be astronomical and difficult to fully comprehend, given the increasing reliance on satellite technologies. Experts warn that such an event is not a matter of if, but when. Statistically, Carrington-level storms occur roughly every 500 years, with about a 12% chance of one hitting this century. As satellite numbers are projected to increase tenfold by 2050, the stakes only get higher.
Tabletop exercises like those conducted by ESA are critical in training experts to respond effectively to these worst-case scenarios. While preparing to protect Sentinel-1D, researchers gained insights into how global satellite networks might be affected and learned valuable lessons on mitigation strategies. These drills emphasize the urgent need for robust contingency plans to manage the cascading effects of solar superstorms. As Jorge Amaya, ESA’s space weather modeling coordinator, notes, while we won’t see the full impact until such an event occurs, readiness now can prevent catastrophic outcomes later. The escalating threat posed by solar superstorms underscores the importance of continued investment in space weather research, satellite hardening technologies, and international coordination to safeguard humanity’s space assets.
