Space weather is a general term for the radiation in the near-Earth environment; outside the planet’s protective aura, satellites and spacecraft feel the full brunt of the sun’s rays, and a solar storm can interfere with or disable them. The type and intensity of this radiation shifts and flows just like atmospheric weather, but being invisible and moving at the speed of light, it’s considerably more difficult to observe and predict.
There are numerous satellites and deep-space missions that monitor solar radiation, but they are necessarily limited; imagine trying to predict the path of a storm using only a handful of wind and rain sensors scattered across the ocean. And while historically this has been sufficient, the growth of the new space economy has transformed space weather from an occasional inconvenience to a constant and quantifiable threat.