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Anything in orbit around another object can be called a satellite.
The Moon, for example, is a natural satellite of Earth. Since 1957,
hundreds of artificial satellites have been launched into orbit
around the Earth. They come in many shapes and sizes and occupy
different types of orbits, depending on what they are designed to
do. Many communications satellites occupy geostationary orbit, for
example, while many weather satellites are in polar orbit. Whichever
orbit they follow, satellites must remain stable so that their
instruments always point in the right direction.
TYPES
OF ORBITS
Most
satellites are launched into one of these four main orbits:
Low-Earth
Orbits - A nearly circular orbit that is up to about 250 km above
Earth.
Polar
Orbits - Often 800 km high.
Highly
Elliptical Orbits - Has a much lower altitude at it's closest
approach to Earth (its perigee) than when it is most distant (its
apogee).
Geostationary
Orbits - Is 36,000 km above the equator.
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SATELLITES
& ORBITS
