'Satellites more at risk from solar wind than space storm'

Satellites are more likely to be at risk from high-speed solar wind than a major geomagnetic storm, according to a study.

Researchers, including those from British Antarctic Survey, investigated the space weather risks to orbiting satellites and calculated electron radiation levels within the Van Allen radiation belts.

This ring-doughnut-shaped zone wraps around the Earth, trapping charged particles.

Geostationary orbit lies inside the Van Allen radiation belts, according to the study published in the Journal Space Weather.

The study, which analysed years of satellite data, found that electron radiation levels at geostationary orbit could remain exceptionally high for five days or more, even after the solar wind speed had died down.

As a result, electronic components on satellites could charge up to dangerously high levels and become damaged.

"Until now we thought that the biggest risk to orbiting satellites was geomagnetic storms, said Professor Richard Horne, lead author of the study.

"Our study constructed a realistic worst-case event by looking at space weather events caused by high-speed solar wind flowing away from the Sun and striking the Earth.

"We were surprised to discover just how high electron radiation levels can go. This new research is particularly interesting to the satellite industry," Horne said.

Fast solar wind is more dangerous to satellites because the geomagnetic field extends beyond geostationary orbit and electron radiation levels are increased all the way round the orbit.

In a major geomagnetic storm the field is distorted and radiation levels peak closer to the Earth, researchers said.

"Electronic components on satellites are usually protected from electrostatic charges by encasing them in metal shielding," Horne said.

"There are well over 450 satellites in geostationary orbit and so in a realistic worst case we would expect many satellites to report malfunctions and a strong likelihood of service outage and total satellite loss," he said.