Category |
Effect |
Physical measure |
Average Frequency |
|
---|---|---|---|---|
Scale |
Descriptor |
Duration of event will influence severity of effects |
||
Solar Radiation Storms |
Flux level of >= 10 MeV particles (ions)* |
Number of events when flux level was met (number of storm days**) |
||
S 5 |
Extreme |
Biological: unavoidable high radiation hazard to astronauts on EVA (extra-vehicular activity); high radiation exposure to passengers and crew in commercial jets at high latitudes (approximately 100 chest x-rays) is possible. 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 |
S 4 |
Severe |
Biological: unavoidable radiation hazard to astronauts on EVA; elevated radiation exposure to passengers and crew in commercial jets at high latitudes (approximately 10 chest x-rays) is possible. 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
|
S 3 |
Strong |
Biological: radiation hazard avoidance recommended for astronauts on EVA; passengers and crew in commercial jets at high latitudes may receive low-level radiation exposure (approximately 1 chest x-ray). 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
|
S 2 |
Moderate |
Biological: none. 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 |
S 1 |
Minor |
Biological: none. Satellite operations: none. Other systems: minor impacts on HF radio in the polar regions. |
10 |
50 per cycle |
* Flux levels are 5 minute 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.