NASA's STEREO-A spacecraft happened to be sitting in the path of the July 2012 Carrington-class storm and took the full hit instead of Earth — the only reason we have detailed measurements of a blow we never felt

On July 23, 2012, NASA’s STEREO-A spacecraft was drifting ahead of Earth in its solar orbit when a coronal mass ejection tore off the Sun and slammed directly into its instruments — a blast that would later be measured…