Halloween solar storms, 2003
The Halloween Solar Storms were a series of solar flares and coronal mass ejections that occurred from mid-October to early November 2003, peaking around October 28–29.[1][2] Satellite-based systems and communications were affected, aircraft were advised to avoid high altitudes near the polar regions,[3] and a one-hour-long power outage occurred in Sweden as a result of the solar activity.[2] Aurorae were observed at latitudes as far south as Texas[2] and the Mediterranean countries of Europe.[3]
The SOHO satellite failed temporarily, and the Advanced Composition Explorer was damaged by the solar activity.[2] Numerous other spacecraft were damaged or experienced downtime due to various issues. Some of them were intentionally put into safe mode in order to protect sensitive equipment.[3] Astronauts aboard the International Space Station had to stay inside the more shielded parts of the Russian Orbital Segment to protect themselves against the increased radiation levels.[4] Both the Ulysses spacecraft which was near Jupiter at the time, and Cassini, approaching Saturn, were able to detect the emissions. In April 2004, Voyager 2 was also able to detect them as they reached the spacecraft.[4]
These events occurred during Solar cycle 23, approximately three years after its peak in 2000, which was marked by another occurrence of solar activity known as the Bastille Day Flare.
