A powerful X8.2 solar flare erupted from Region 2673, located just around the visible disk, at 16:06 UTC on September 10, 2017, causing R3 – Strong radio blackout and a rapid increase in relativistic proton levels. Within just 3 hours, solar radiation storm reached S3 – Strong levels (on a scale of 1 – 5).
The proton flux exceeded the S1 – Minor threshold at 16:45 UTC and continued to increase to a peak flux of 1 040 pfu at 18:45 UTC – R3 – Strong solar radiation storm threshold. Proton levels still remain at those levels at 07:49 UTC on September 11.
An enhancement in the energetic portion of the solar radiation spectrum may indicate increased biological risk to astronauts or passengers and crew in high latitude, high altitude flights. Additionally, energetic particles may represent an increased risk to all satellite systems susceptible to single event effects.