UK engineers have carried out a detailed assessment of the risks from solar superstorms, and say governments need to do more to protect against them.
Such superstorms occur very rarely - perhaps once every century or two. The last one, known as the 'Carrington event', was in 1859, and led to telegraph stations catching fire.
However, the Royal Academy of Engineering's report, 'Extreme space weather: impacts on engineered systems and infrastructure' points out that another one is inevitable at some point. And, it says, it will degrade the performance of the electricity grid, satellites, GPS systems and aviation.
"The two challenges for government are the wide spectrum of technologies affected today and the emergence of unexpected vulnerabilities as technology evolves," says Professor Paul Cannon, Chair of the Academy's working group on extreme solar weather.
Mobile communications could be affected, and the Academy recommends that they should be able to operate without global navigational satellite systems (GNSS) timing for up to three days.
A solar superstorm could knock GPS and Galileo out for between one and three days, the report says, due to disruption of radio transmission paths between the satellites and the ground. This could potentially affect aircraft and shipping.
And, during a solar superstorm of the size of the Carrington event, air passengers and crew already airborne would be exposed to a one-off dose of radiation, giving a marginal increase in cancer risk.
Satellites will also be affected by the solar superstorm, and the Academy expects as many as one in ten to be fully or partially inoperative for a period of a few days. A small number will never recover.
"Our message is: Don't panic, but do prepare - a solar superstorm will happen one day and we need to be ready for it," says Cannon.
"Many steps have already been taken to minimise the impact of solar superstorms on current technology and by following the recommendations in the report we anticipate that the UK can further minimise the impact."