n orbit is the path in space along which
an object moves around a primary
body. In the case of environmental
satellites, the satellite moves
around the primary body Earth.
Bodies in space or low-Earth orbit
a re governed by laws of gravity
and motion, just as life on Earth is.
These laws make it possible to
d e t e rmine how, where, and why
satellites will be. Orbital mechanics
utilizes a standard set of re f e re n c e
points and terms that make it pos-
sible to pinpoint a body in space
and describe its unique location
and motion.
The ability to understand and pre-
dict the location of satellites is
essential for obtaining direct read-
out from polar-orbiting environ-
mental satellites. Geostationary
orbits must also be located.
However, because they remain in
the same position relative to Earth,
orbital information doesn’t need to
be regularly updated.
This section describes the basics of
orbital mechanics, the Keplerian ele-
ments, pro c e d u res for tracking satel-
lites, and re s o u rces for orbital data.
OR B I T S
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