Space weather drill simulates Carrington-level solar storm, challenging satellite safety and mission control response

No communication or navigation, faulty electronics and risk of collision. At ESA's mission control center in Darmstadt, teams faced a scenario unlike any before: a solar storm of extreme severity. Fortunately, this nightmare did not unfold in reality, but rather as part of a Sentinel-1D simulation campaign pushing the boundaries of spacecraft operations and space weather preparedness.

Before each ESA launch, mission teams go through a thorough simulation phase, during which they rehearse the satellite's first moments in space and prepare mission management for any anomaly. Since mid-September, teams at ESA's European Space Operations Center (ESOC) in Darmstadt, Germany, have been immersed in simulations of Sentinel-1D, which is scheduled to launch on November 4, 2025.

To simulate one of the most extreme scenarios, modelers took inspiration from the infamous Carrington Event of 1859, the most powerful geomagnetic storm ever recorded. The exercise simulated the impact of a catastrophic solar storm on satellites to test the team's ability to respond without satellite navigation and under conditions of severe electronic failure.

“If such an event occurs, there are no good solutions. The goal is to ensure the safety of the satellite and limit damage as much as possible,” says Thomas Ormston, deputy director of operations for the Sentinel-1D spacecraft.

The campaign included a rare activation by ESA's Space Weather Office of the Space Security Centre, which opened in 2022 as part of ESA's growing commitment to space security. ESA's Space Debris Office and spacecraft operations managers for other ESA missions in Earth orbit also joined the exercise to improve realism, simulated impacts and coordination between missions.

Get hit by a rogue wave

The time is 22:20 and everything is going according to plan. After successful launch and separation, mission control waits for satellite signal reception. A few minutes later, the noisy transmission reaches mission control. Something's wrong.

The spacecraft, like other ships in orbit, was hit by a solar flare. Traveling at the speed of light, this electromagnetic wave reached our planet just eight minutes after the sun erupted.

The simulation team simulated a massive X45-class flare with intense X-ray and ultraviolet radiation disrupting radar systems, communications and tracking data. Galileo and GPS navigation functions are now disabled and ground stationsespecially in polar regions, have lost tracking capabilities due to peak radiation levels.

Moments later, a second wave hit the Earth, this time consisting of high energy particlesincluding protons, electrons and alpha particles. Accelerated to near-light speeds, these particles took 10–20 minutes to reach our planet and began disrupting onboard electronics with bit flips and potential permanent failures.

“The solar flare took the team members by surprise. But as soon as they regained their composure, they realized that the countdown had begun. In the next 10–18 hours there was coronal mass ejection could strike, and they had to prepare for it,” says Gustavo Baldo Carvalho, lead modeler for Sentinel-1D.

Trip to CME

Fifteen hours after solar flareThe third and most destructive phase began: a massive ejection of coronal mass – a hot plasma of charged particles – moving at speeds of up to 2000 km/s, struck the Earth and caused a catastrophic geomagnetic storm.

On the ground, beautiful auroras were visible as far away as southern Sicily, while the hurricane destroyed the power grid and caused devastating surges of electrical current in long metal structures such as power lines and pipelines.

In space, satellites also experienced difficulties. The storm caused Earth's atmosphere to inflate, increasing drag on satellites in low Earth orbit and knocking them out of their normal trajectories. Mission controllers faced numerous warnings about collisions with space debris and other spacecraft.

“If such a storm occurs, the satellite's drag could increase by 400% with local peaks in atmospheric density. This not only affects the risk of collision, but also reduces the lifespan of satellites due to increased fuel consumption to compensate for orbital decline,” says Jorge Amaya, space weather modeling coordinator at ESA.

“An event of this magnitude will severely degrade the quality of the connection data, making collision forecasts increasingly difficult to interpret as probabilities change rapidly. In this context, decision-making becomes a delicate balance under conditions of significant uncertainty, where an evasive maneuver aimed at reducing the risk of one potential collision may slightly increase the risk of another,” explains Jan Sieminski from ESA’s Space Debris Office.

Radiation levels also increased, damaging electronics and materials. Single failures have become even more frequent, disrupting systems and shortening their service life. GNSS signals deteriorated further, star trackers were blinded, and battery charging events added to the chaos.

“The enormous flow of energy emitted by the Sun could cause damage to all our satellites in orbit. Satellites in low Earth orbit are usually better protected by our atmosphere and our magnetic field from the hazards of space, but an explosion on the scale of a Carrington event would leave no spacecraft safe,” says Jorge.

Training for the big one

“This exercise provided an opportunity to expand the simulation training campaign to include multiple other stakeholders within ESOC, covering all types of missions and task forces. Conducting them in a controlled environment has given us valuable insight into how we can better plan, approach and respond when such an event occurs. The key takeaway is that it is not a question of if, but when,” says Gustavo.

ESA's Space Safety Center played a central role in the exercise and is a key asset in preparing Europe for extreme solar storms. The modeling will provide important information for the establishment of pan-European operational space weather services, helping to improve procedures and increase sustainability.

“Modeling the impact of such an event is similar to predicting the consequences of a pandemic: we will only feel its real impact on our society after the event, but we must be prepared and have plans to respond at any time. This exercise was the first opportunity to address such a major event and integrate the ESA Space Weather Office response into established ESA operations,” says Jorge.

“The scale and variety of impacts pushed us and our systems to the limit, but the team rose to the challenge and it taught us that if we can cope, we can cope with any real contingency,” Thomas concludes.

Infrastructure of the future

In addition to testing space weather resilience during operations, simulations like this highlight the urgent need to improve Europe's ability to forecast space weather events.

ESA's Space Safety Program is developing a Distributed Space Weather Sensor System (D3S). This series of space weather satellites and their payloads will monitor various parameters of space weather around Earth and provide an unrivaled source of data, ready to protect European citizens and critical infrastructure.

Further away from Earth, ESA's Vigil mission will pioneer a revolutionary approach by observing the “side” of the Sun from Lagrange Point 5, opening up the possibility of continuous understanding of solar activity.

Vigil, which will launch in 2031, will detect potentially dangerous solar events before they become visible from Earth, giving us advance knowledge of its features and offering invaluable time to protect spacecraft and ground infrastructure.