In mid-October 2025, the European Space Agency (ESA) pushed the boundaries of preparedness by simulating one of the most extreme space weather events imaginable – a catastrophic solar storm modeled after the infamous Carrington Event of 1859. This exercise, conducted at ESA’s European Space Operations Centre (ESOC) in Darmstadt, Germany, was designed to test how mission control teams, satellites, and ground infrastructure would fare against a solar onslaught that could disrupt global communications, power grids, and satellite operations. With the upcoming launch of the Sentinel-1D satellite on November 4, 2025, the timing couldn’t have been more critical, highlighting the agency’s proactive stance on space safety.
Space weather refers to the dynamic conditions in the space environment driven by the Sun’s activity, including solar flares, coronal mass ejections (CMEs), and streams of high-energy particles. These phenomena can wreak havoc on Earth’s technological systems, from GPS navigation to electrical power distribution. While minor solar events occur regularly, extreme ones like the Carrington Event are rare but inevitable. As Jorge Amaya, ESA’s Space Weather Modelling Coordinator, aptly put it, “It’s not a question of if this will happen but when.”
Revisiting the Carrington Event: A Historical Wake-Up Call
The 1859 Carrington Event, named after British astronomer Richard Carrington who observed the massive solar flare, remains the benchmark for solar storm intensity. It caused widespread telegraph disruptions, with operators reporting sparks flying from equipment and auroras visible as far south as the Caribbean. In today’s hyper-connected world, a similar event could lead to trillions in economic losses, blacking out power grids and crippling satellite-dependent services.
ESA’s simulation drew directly from this historical precedent, scaling it up to an X45-class flare – one of the most powerful classifications – to explore modern vulnerabilities.
The Simulation: A Triple Threat from the Sun
The exercise unfolded in phases, mimicking the real progression of a solar storm. It began with a massive solar flare erupting on the Sun, its radiation reaching Earth in just eight minutes and immediately fuzzing radar systems, dropping communications, and rendering GPS and Galileo navigation offline. Next came a barrage of high-energy particles – protons, electrons, and alpha particles – arriving 10 to 20 minutes later, causing “bit flips” in electronics, false readings, and potential permanent hardware failures on satellites.
The climax arrived about 15 hours after the initial flare: a colossal CME, a cloud of charged plasma hurtling toward Earth at speeds up to 2,000 km/s. This impact swelled Earth’s upper atmosphere, increasing satellite drag by up to 400% and shifting orbits unpredictably. Collision risks with space debris skyrocketed, and ground effects included surging currents in power lines, collapsed grids, and auroras visible as far south as Sicily.
Participants, including ESA’s Space Weather Office, Space Debris Office, and operations managers from various Earth-orbiting missions, had to make split-second decisions amid chaos. Gustavo Baldo Carvalho, Lead Simulation Officer for Sentinel-1D, noted that the drill provided “valuable insights into how to better plan, approach, and react” to such crises.
Key Challenges and Insights
One stark finding was that no spacecraft would emerge unscathed from such an event. Even low-Earth orbit satellites, partially shielded by Earth’s magnetic field, faced overwhelming radiation surges, degraded signals, blinded star trackers, and battery issues. Jan Siminski from the ESA Space Debris Office highlighted the difficulty in predicting collisions under these conditions, where avoidance maneuvers might trade one risk for another.
The simulation also underscored broader societal impacts, akin to preparing for a global pandemic, emphasizing the need for resilient infrastructure.
Looking Ahead: Building Resilience
Despite the grim scenario, the teams regained control and mastered the challenge, building confidence for real contingencies. Thomas Ormston, Deputy Spacecraft Operations Manager for Sentinel-1D, stressed the goal of keeping satellites safe and minimizing damage, as “there are no good solutions” in such extremes.
ESA is advancing tools like the Distributed Space Weather Sensor System (D3S) for real-time monitoring and the Vigil mission, set to launch in 2031 at the Sun-Earth L5 Lagrange point, to provide early warnings of solar eruptions. This simulation not only readied teams for Sentinel-1D but also paved the way for European-wide space weather services, ensuring better forecasts and quicker recoveries.
As solar activity ramps up in the current cycle, ESA’s exercise serves as a timely reminder: the Sun’s fury is a force we must respect and prepare for.
For more details, see the ESA press release.
