# Space Weather Effects on Satellites
## 1 Introduction
Alternatively, permanent damage on the optical system is possible, as well as loss of position/control of the entire spacecraft because the stability is ensured by the pointing towards a few (fixed) stars. The loss of stability can be easily corrected when the spacecraft is relatively near, as in the case on for STEREO mission during the solar storm on 2014-09-01. However, if the satellites are traversing the solar system any misalignment could lead to their loss since longer times are needed to register the problem and send a correcting command. In addition to the limited reaction time, the lack of well-developed mission scenarios for trouble-shooting could be another reason for spacecraft loss. The galactic counterpart of the energetic particle populations, know as galactic cosmic rays (GCRs, consisting of high-energy particles accelerated at shock fronts of distant supernova explosions) is modulated inversely with the strength of solar activity [25]. This is why, weak solar cycles are accompanied by increased fluxes of GCRs. Their SW effects can be traced to enhanced levels of the total ionization dose received by astronauts [26] and airrews [27]. The solar energetic particles can contribute by adding extra doses during their sporadic occurrences [28, 29]. The danger of radiation exposure to humans in space is considered as the primary obstacle of space travel. Recently, the radiation dose received during a single flight to Mars and back is estimated to contribute up to 60% of the lifelong limit of astronauts [30]. When ICMEs, fast solar wind plasma streams, and/or IP shocks reach the planetary magnetospheres, various atmospheric (and ground-based) effects are possible [31], auroras being the most spectacular ones. Apart from Earth, auroras have been observed around the magnetic poles of Jupiter, Saturn, and Uranus. Due to the localized (surface) magnetic field on Mars, none on Venus, and lack of atmosphere on Mercury, large scale SW effects are not expected there. The planetary (with a focus here on the terrestrial) perspective of SW [32] refers to the effects of the solar activity drivers from the magnetosphere down to ground. If the ICME magnetic field is oppositely directed to the one of the planetary magnetosphere, a process of magnetic reconnection can take place. During the field line reconstruction, injected streams of electrons and protons form a ring current, which finally leads to a depression of the horizontal terrestrial magnetic field [33]. This cascade of processes is known as a GS with ICME or fast solar wind stream as its primary driver [34]. Apart from changes in the surface magnetic field, other ground-based effects are also known as a consequence of SW phenomena. One such type is termed ground-level enhancement (GLE) [35], which is the secondary particle products (i.e., neutrons, muons) of high-energy SEP events after their interactions with atmospheric atoms and molecules. Thus, particle events can be the driver of atmospheric radiation storms as they can generate a shower of secondary particles in the Earth's atmosphere down to lower altitudes. The high-energy secondary particles cause additional radiation dose at the cruising altitudes for aircraft [5]. The consequences of SW can be traced to different (conducting) devices located on/under the ground [32]. The problems experienced in these equipment systems include telluric currents in pipelines, induced effects in submarine cables, and ground-based magnetic interference. Due to their practical importance, a large amount of research is devoted to the geomagnetically induced currents (GICs) [36], which are intense, low-frequency currents induced in large conductive systems like power lines and pipelines [37]. In rare cases, transformer damage also occurred, as, for example, during the GS in March 1989 in Quebec, Canada. The SW severity ranges from weak to extreme events [38] without strict definitions, as large intensity in one of the parameters does not ensure large values for the accompanied phenomena.