Environmental effects in space
are subtle,
but often determine the end of life for a spacecraft.
See the article, "No
Safe Place for Satellites," on the Van
Allen belts.
Environmental
Effects
Low
Earth Orbit (LEO) satellites
fly through the ionosphere's plasma, which causes
spacecraft charging detrimental to sensitive electronics;
the Van Allen belts are a design concern above about
500 km, dependent on solar activity. This also gives
rise to ram and wake effects, where electrochemical
reactions erode surface coatings. Atmospheric drag
against LEO satellites may cause orbital decay,
requiring periodic maintenance burns to stay on
altitude.
Geosynchronous
Earth Orbit (GEO)
satellites are well above the atmosphere, so orbital
maintenance burns are not required. They are also
above the ionosphere, so spacecraft charging and
the ram-wake effects like those found in LEO do
not occur.
Interplanetary
trajectory environmental effects apply to
spacecraft traveling outside the magnetosphere to
another planet. The interplanetary medium is more
benign than around the Earth. However, solar photon
and flare-accelerated particle radiation is present.
Nonetheless, this level of exposure is small compared
to the Van Allen radiation belts.
