Strong electrical currents driven along the Earth’s surface during auroral events disrupt electric power grids and contribute to the corrosion of oil and gas pipelines. Changes in the ionosphere during geomagnetic storms interfere with high-frequency radio communications and Global Positioning System (GPS) navigation. During polar cap absorption events caused by solar protons, radio communications can be compromised for commercial airliners on transpolar crossing routes. Exposure of spacecraft to energetic particles during solar energetic particle events and radiation belt enhancements cause temporary operational anomalies, damage critical electronics, degrade solar arrays, and blind optical systems such as imagers and star trackers.