The Space Weather Threat Environment

An authoritative assessment of solar activity, geomagnetic storms, and their documented operational consequences for satellite operators, governments, and critical infrastructure. Solar Cycle 25 peaked roughly 50% above the 2019 consensus prediction, driving the most severe geomagnetic storm in over three decades — the May 2024 'Mother's Day Storm', the first G5 event since March 1989. This paper examines the behaviour of Solar Cycle 25 and the limits of solar forecasting; the mechanics of geomagnetic storms and the NOAA scales used to classify them; and the historical record of major storms, including a well-documented case of a storm directly causing the operational loss of an active satellite deployment.