In January 1994, enhanced fluxes of energetic electrons caused anomalies in three geosynchronous communications satellites, Intelsat-K, Anik E-1, and Anik E-2. All three suffered a loss of attitude control caused by a failure in their momentum wheel circuitry. Although none suffered permanent damage, television, radio, telephone, and satellite operations were affected for hours to days. These satellites provide critical communication functions to Canadian news, weather, and entertainment programming.
Subsequent analysis has shown that the failures were due to deep dielectric charging, an anomaly produced by the impact of highly energetic electrons. The enhanced fluxes of these electrons are associated with high speed solar wind streams. Although large magnetic storms tend to occur during solar maximum conditions, these highly energetic electrons are more common during solar minimum. The enhanced fluxes can persist for days and tend to repeat at the 27-day rotational period of the sun. The improved understanding and predictive capabilities resulting from the National Space Weather Program will help satellite operators prepare for the potential effects these events may have on space systems.