Space Regulatory Glossary Industry

radio blackout

noun

1. A temporary loss or degradation of high-frequency (HF) radio communications caused by enhanced ionization of Earth's ionosphere, typically triggered by X-ray and extreme ultraviolet emissions from solar flares.
2. Rated on the NOAA R-scale from R1 (minor, brief HF degradation) to R5 (extreme, complete HF blackout lasting hours with degraded low-frequency navigation). Blackouts affect the sunlit hemisphere of Earth and begin within minutes of flare onset.

Related terms

solar flare A sudden, intense burst of electromagnetic radiation from the Sun's surface, caused by the release of magnetic energy… space weather The variable conditions in the space environment between the Sun and Earth — including solar wind, energetic particles,…

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