Space Weather Scale for Solar Radiation Storms
Physical measure* | (1 cycle=11 years) |
|||
---|---|---|---|---|
S1 | ![]() |
|
10 | 50 per cycle |
S2 | ![]() |
|
102 | 25 per cycle |
S3 | ![]() |
|
103 | 10 per cycle |
S4 | ![]() |
|
104 | 3 per cycle |
S5 | ![]() |
|
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.