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As a follow-up to Does cosmic dust pose a problem for long-term satellites, telescopes and probes?, assuming satellite's long duration stay in Earth's orbit – let's for the sake of argument assume a run-of-the-mill communications satellite in Geostationary Orbit (GEO) – would its solar panels gather dust and require cleaning?

What is the rate at which this dust would gather, or if that is unknown, how fast do solar panels of GEO satellites deteriorate due to external causes that can't be attributed to material degradation due to exposure to solar radiation, solar wind, micrometeorites and other causes unrelated to persistent dust covering solar cells?

Additionally, assuming this can be identified as a genuine concern, what techniques can they employ to clean their solar panels or help mitigate persisting dust problem?

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Settling dust is not a problem. Keep in mind that dust in space does not settle on surfaces like it does on Earth--it's not slowly sinking, it hits the surface at relative speeds measured in km/s. It's basically a micro-meteoroid bombardment and the allowed degradation is derived from the performance requirements over the design lifetime of the solar array.

Here's an ESA image of dust grain impact on aluminum (from http://space-env.esa.int/madweb/hdebris.php) to give you an idea what space dust does to thin foils.

enter image description here

That said, there are situations where specific satellites take precautions to not expose delicate parts to excess degradation. In particular, satellites with optical components (think telescopes, laser communication) which also use thrusters for attitude control will protect mirrors from thruster exhaust contamination by covering their aperture prior to firing attitude thrusters.

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Satellites do not have any capacity to clean the solar arrays. The solar arrays degrade over life due to many factors: radiation damage, UV darkening, micrometeroids, etc. The manufacturers have models of degradation and design for it. Adhering dust is the least of it.

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  • $\begingroup$ In particular, at least in LEO, radiation damage is the single largest contributor for solar array degradation. Meteoroid and orbital debris impacts are a moderate second, and for most modern construction types, the remaining factors are relatively minor. $\endgroup$ – Tristan Jun 22 '16 at 17:55

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