What would happen if a solar superstorm hit Earth? ESA just found out

Solar storms occur when the Sun releases giant waves of radiation and charged particles. Most of the time, Earth’s magnetic field protects us – but during extreme events, that shield can be overwhelmed.

In 1859, a storm known as the Carrington Event knocked out telegraph systems, ignited fires, and illuminated the skies with auroras visible as far south as the Caribbean.

Today, a similar storm could interfere with satellites, shut down power grids, and disrupt GPS signals worldwide.

This is the kind of storm the European Space Agency (ESA) aims to prepare for with its Sentinel-1D mission, scheduled to launch on November 4, 2025.

The fake solar storm hits

To simulate the unthinkable, ESA’s team designed a space weather disaster modeled after the Carrington Event. During the drill, the satellite had barely separated from its rocket when trouble struck.

An enormous solar flare – classified as X45, one of the most intense levels – blasted radiation that reached Earth in just eight minutes. Radar systems went fuzzy. Communication dropped. GPS? Gone.

Then came a second hit. This time, high-energy particles followed, slamming into satellites and causing glitches in electronics.

“The solar flare took team members by surprise,” said Gustavo Baldo Carvalho, lead simulation officer for Sentinel-1D. “But once they regained composure, they knew a countdown had begun. In the next 10 to 18 hours, a coronal mass ejection would strike, and they had to brace for it.”

Riding out the chaos

Fifteen hours later, the main event arrived: a coronal mass ejection (CME), a giant cloud of hot, charged plasma, traveling at speeds up to 1,240 miles per second (2,000 kilometers per second). It hit Earth hard.

While people on the ground enjoyed rare auroras as far south as Sicily, power grids overloaded. Surge currents ran through pipelines and long cables. And in space, things got worse.

The Earth’s upper atmosphere ballooned from the heat, dragging satellites out of place and increasing the chance of crashes.

“Should such a storm occur, satellite drag could increase by 400 percent, with local peaks in atmospheric density,” said Jorge Amaya, space weather modeling oordinator at ESA. “This not only affects collision risks but also shortens satellite lifetimes due to increased fuel consumption to compensate for the orbit decay.”

An event of such magnitude would severely degrade the quality of conjunction data, making collision predictions increasingly difficult to interpret as probabilities shift rapidly.

“In this context, decision-making becomes a delicate balance under significant uncertainties, where an avoidance maneuver to reduce the risk of one potential collision could slightly increase the risk of another,” said Jan Siminski, from the ESA Space Debris Office.

Electronics didn’t stand a chance

Radiation levels surged. Satellites started to fail. Navigation signals dropped out. Star trackers – used to keep satellites oriented – stopped working. Charging systems went haywire.

“The immense flow of energy ejected by the Sun may cause damage to all our satellites in orbit,” said Amaya.

“Satellites in low Earth orbit are typically better protected by our atmosphere and our magnetic field from space hazards, but an explosion of the magnitude of the Carrington Event would leave no spacecraft safe.”

Not if, but when

Training for this type of disaster isn’t about fear. It’s about preparation. ESA wanted to see how different departments – from mission controllers to space weather experts – would react together.

“Conducting it in a controlled environment gave us valuable insights into how we could better plan, approach and react when such an event occurs,” said Carvalho. “The key takeaway is that it’s not a question of if this will happen but when.”

According to Amaya, simulating the impact of such event is similar to predicting the effects of a pandemic. We will feel its real effect on our society only after the event, but we must be ready and have plans in place to react in a moment’s notice, he noted.

“The scale and variety of the impacts pushed us and our systems to the limit, but the team mastered the challenge and that taught us that if we can manage that we can manage any real-life contingency,” said Thomas Ormston, deputy spacecraft operations manager for Sentinel-1D.

New systems to track solar storms

ESA isn’t stopping at drills. The agency is working on new tools to help Europe get ahead of space weather.

One major project is the Distributed Space Weather Sensor System (D3S), a network of space-based instruments that will continuously monitor the environment around Earth. More data means better forecasts and faster responses.

Another key mission is called Vigil. Launching in 2031, it will orbit at a special location known as Lagrange Point 5 – about 93 million miles (150 million kilometers) from Earth, positioned off to the side of the Sun.

From there, Vigil can watch solar eruptions before they swing toward Earth, giving operators more time to respond.

Our world runs on satellites – from internet and weather forecasts to GPS and global banking, space technology underpins daily life. A strong solar storm could disable these systems and cause billions of dollars in damage.

ESA is working to ensure that when the Sun misbehaves, we’re not caught off guard.

Image Credit: NASA’s Solar Dynamics Observatory

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