High solar wind poses higher threat to satellites than space storms

Satellites are more at risk from high-speed solar wind than from geomagnetic storms, reveals a UK-US study.

Titled “Realistic worst case for a severe space weather event driven by a fast solar wind stream,” the study was carried out by the British Antarctic Survey in collaboration with the University of Surrey, UK, and Boston University, US.

The study was partially funded by the Natural Environment Research Council, UK, as part of the Rad-Sat project to safeguard satellites from space weather.

Scientists, who are probing the space weather risks to orbiting satellites, have calculated electron radiation levels within the Van Allen radiation belt. This zone, which looks like a ring doughnut, surrounds the Earth. Charged particles are trapped in the zone, and the geostationary orbit sits in this radiation belt.

The study, which assessed satellite data for years, concluded that electron radiation levels at geostationary orbit could be high for more than five days even after the speed of solar wind slows down considerably.

As a result, electronic components on satellites could get charged up to very high levels, leading to damage.

British Antarctic Survey professor and lead author of the study Richard Horne said: “Until now we thought that the biggest risk to orbiting satellites was geomagnetic storms.

“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.

“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”.