Solar Radiation Storms (Current)

GOES Proton Flux (5 minute)

Space Weather Scale for Solar Radiation Storms

Space Weather Scale for Solar Radiation Storms
level
Effect
 Physical measure*
Average Frequency
(1 cycle=11 years)
S1
  • Biological : none
  • Satellite operations : none
  • Other systems : minor impacts on HF radio in the polar regions
 10 50 per cycle
S2
  • Biological : passengers and crew in high-flying aircraft at high latitudes may be exposed to elevated radiation risk.***
  • Satellite operations : : infrequent single-event upsets possible.
  • Other systems : small effects on HF propagation through the polar regions and navigation at polar cap locations possibly affected.
 102 25 per cycle
S3
  • Biological : radiation hazard avoidance recommended for astronauts on EVA; passengers and crew in high-flying aircraft at high latitudes may be exposed to radiation risk.***
  • Satellite operations : single-event upsets, noise in imaging systems, and slight reduction of efficiency in solar panel are likely.
  • Other systems : degraded HF radio propagation through the polar regions and navigation position errors likely.
103 10 per cycle
S4
  • Biological : unavoidable radiation hazard to astronauts on EVA; passengers and crew in high-flying aircraft at high latitudes may be exposed to radiation risk.***
  • Satellite operations : may experience memory device problems and noise on imaging systems; star-tracker problems may cause orientation problems, and solar panel efficiency can be degraded.
  • Other systems : blackout of HF radio communications through the polar regions and increased navigation errors over several days are likely.
 104 3 per cycle
S5
  • Biological : unavoidable high radiation hazard to astronauts on EVA (extra-vehicular activity); passengers and crew in high-flying aircraft at high latitudes may be exposed to radiation risk.***
  • Satellite operations : satellites may be rendered useless, memory impacts can cause loss of control, may cause serious noise in image data, star-trackers may be unable to locate sources; permanent damage to solar panels possible.
  • Other systems : complete blackout of HF (high frequency) communications possible through the polar regions, and position errors make navigation operations extremely difficult.
105 Fewer than 1 per cycle

* Flux levels are 5 minutes averages. Flux in particles·s-1·ster-1·cm-2. Based on this measure, but other physical measures are also considered.
** These events can last more than one day.
*** High energy particle measurements (>100 MeV) are a better indicator of radiation risk to passenger and crews. Pregnant women are particularly susceptible.

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