While going towards earth, the radiations, the mass coronal ejections and the SEPs will have drawbacks at the upper atmosphere level and deal huge damages.
First of all, this particles projection can deteriorate internal electric circuits and therefore create a malfunction of the control software
Moreover, satellites have solar panels. The particles damage these solar panels. To prevent it, the satellites solar panels are covered by gallium arsenide and germanium (instead of silica) making them also more efficient, lighter and increase their durability.
Satellites are not continually touched by solar wind (as they are inside the magnetosphere) but the latter gets stronger when there is a solar storm. It’s actually compressing the Earth magnetosphere which no longer protects the satellites. They will also be affected because of radiations from a solar storm.
However, that’s not all, under a solar storm’s X-ray’s influence, the atmosphere is going to get warmer, which will inflate it. This swelling of the atmosphere or expansion will increase the satellite drag force (the intensity of the drag force is based depending on the speed, the shape and size of the moving object and the fluid in which it interacts, cf. Figure 11). This increase in drag force will cause the loss of control on the satellite (a consequence of an augmentation of the drag). We must, at all costs, avoid this because if the satellite enters the atmosphere it will disintegrate. This is the case for Skylab, a space station, which had a deflected trajectory. It entered the Earth’s atmosphere in 1979, and disintegrated itself.
So, we can see that this type of event can easily cause the destruction of all the satellites, even those that are at a low altitude (less than 600km).
A study was conducted by Sten F. Odenwald and James L. Green (Forecasting the impact of an 1859-caliber super storm on geosynchronous Earth-orbiting satellites: Transponder resources, Space Weather) to estimate the cost that could result from a solar storm. A thousand simulations were made and the damage caused would be evaluated in between 15 and 50 billion euros, considering that 20 satellites would be damaged.
During a solar storm, astronauts located in the upper atmosphere are the first affected and are exposed to radiation levels four times superior to nuclear workers on earth.
The astronauts are only protected by few centimetres of aluminium (protection usually found in spaceships). The astronaut’s suit will therefore not protect him. The radiation emitted can pass through living tissues and damage the cells of his body, which can lead to create cancer cells. However, this should not alarm astronauts in the International Space Station (ISS), which have a sufficient shield for a Carrington-like event. This shielding is applied to only one ISS module. Furthermore, the sun’s activity is very well monitored and alerts are transmitted to astronauts in case of major event.
Moreover, plane’s passengers, even not being in upper atmosphere, would be affected by those radiations, which would, however, have less consequences. They would be similar to a dose received during a scan. For further information, the dose received during a flight can be evaluated on the following website:https://www.sievert-system.org.