We don't pay too much attention to the weather in space, except when it affect such vital parts of our lives as our television and radio reception. But space weather does affect many people and it's watched and forecast just as closely as our terrestrial weather systems are. While many of us were cleaning up after last Friday's petulant weather, high over our heads the Earth was in the grip of another major storm. People who noticed this particular storm were mariners and aviators, who found their positioning and communication equipment weren't working well for about an hour. A satellite in orbit during a solar radiation storm is similar to a small water craft at the mercy of the winds and waves.
Satellites can experience problems with their memory devices and star tracking equipment.
High frequency radio communications shut down. A major coronal mass ejection, when a large amount of material of thrown away from the sun, followed on the heels of the flares and reached earth this past Saturday. The resulting G5 geomagnetic storm topped the chart, the largest since 1989. In that year, a similar storm was responsible for knocking out Montreal's power grid and plunging nearly 6 million people into darkness. Geomagnetic storms can also knock satellites out of commission, black out communications, and disrupt even low-frequency radio navigation.