Solar storms heat and puff up the upper atmosphere, dragging low satellites down, and their fast particles can charge, glitch or damage satellite electronics.
A big solar storm does not knock satellites out of the sky with a blast. It works in quieter ways. Some effects hit a satellite's electronics; others change the air it flies through.
During a geomagnetic storm, energy from the Sun heats the upper atmosphere and it expands upward. Low satellites suddenly fly through denser gas, feel more drag and lose height faster. NOAA's storm scale warns that from G2 drag changes can upset orbit predictions, and that from G3 drag may increase for satellites in low Earth orbit.
That matters for tracking too. Positions on this site are estimated from published orbital data. When drag jumps, a satellite drifts away from its predicted position until fresh data comes out.
On 3 February 2022 SpaceX launched 49 Starlink satellites into low Earth orbit. A geomagnetic storm — which NOAA-led researchers later described as minor — heated the upper atmosphere in the following days. Drag rose, and 38 of the 49 satellites fell back and burned up.
A study led by NOAA's Space Weather Prediction Center found that its physics-based model, WAM-IPE, captured the conditions behind the loss better than the model the Starlink team had used before launch. The lesson: even a modest storm can doom freshly launched satellites that are still flying low.
Fast particles cause other trouble. NOAA's scales list:
India's satellites feel the drag effect directly. ISRO reports that 2024's many strong storms sped up orbital decay in the year a record 2,095 catalogued objects re-entered, 335 of them Starlink satellites.
Every Starlink position shown is estimated from orbital data; after a strong geomagnetic storm, extra drag can make such estimates drift until fresh data is published. Open the Starlink tracker
NASA's drag equation is D = Cd × ρ × V² × A / 2, where ρ is air density, V speed, A a reference area and Cd a drag coefficient. Dividing by the satellite's mass m gives its deceleration: a = ½ × Cd × (A/m) × ρ × V².
Two lessons follow. First, drag is directly proportional to density. A storm that doubles the density at a satellite's height doubles the drag, and roughly doubles how fast it sinks. Second, A/m matters: a large, light object — a flat satellite with big solar panels, or a thin fragment — feels more drag per kilogram than a compact, dense one.
Speed barely changes during a storm. For a circular orbit, v = √(GM/r). With GM = 398,600 km³/s² and r = 6,378 + 400 = 6,778 km, v = √58.8 ≈ 7.67 km/s, close to ESA's rule of thumb of 7.8 km/s for low orbit. So the term that jumps is ρ, not V.
Losing energy to drag lowers the orbit, and a lower orbit meets denser air, so decay speeds up as it goes. That is why the February 2022 Starlink batch, already low, was lost within days. ESA puts the practical lower limit of low Earth orbit at about 180 km because of drag.
Radiation effects scale differently. They depend on the flux of particles above 10 MeV, and NOAA's S scale steps up by a factor of ten in that flux at each level, from S1 to S5.
A geomagnetic storm heated and expanded the upper atmosphere, increasing drag on the newly launched, low-flying satellites until they re-entered and burned up.
Surface charging of its components, and single event upsets that flip bits in its electronics. Strong radiation storms can also confuse star trackers and degrade solar panels.
Drag needs air. Low satellites fly through the thin upper atmosphere that a storm heats and thickens; geostationary satellites at 35,786 km are far above it.