Satellite applications
- an overview of the many uses or applications for
satellites in today's world
There are many applications for satellites in today's world.
Ever since the first satellite, Sputnik 1, was launched in 1957, large numbers
of satellites have been launched into space to meet a variety of needs. As
satellite technology has developed over the years, so ahs the number of
applications to which they can be put. Whatever the type of satellite it is
necessary to be able to communicate with them, and in view of the large
distances, the only feasible technology is radio. As such radio communication is
an integral part of any satellite system, whatever its application.
Satellite applications
Astronomical satellites - these satellites are used
for the observation of distant stars and other objects in space. Placing an
observation point in space removes the unwanted effects of the atmosphere and
enables far greater levels of detail to be seen than would be possible on earth
where many observatories are placed on mountain tops that experience low levels
of cloud. The most famous astronomical satellite is the Hubble Telescope.
Although now reaching the end of its life it has enabled scientists to see many
things that would otherwise not have been possible. Nevertheless it did suffer
some major design setbacks that were only discovered once it was in orbit.
Communications satellites - these satellites possible
form the greatest number of satellites that are in orbit. They are used for
communicating over large distances. The height of the satellite above the Earth
enables the satellites to communicate over vast distances, and thereby
overcoming the curvature of the Earth's surface.
Even within the communications field there are a number of sub-categories. Some
satellites are used for point to point telecommunications links, others are used
for mobile communications, and there are those used for direct broadcast. There
are even some satellites used for mobile phone style communications. Even though
these satellites did not take the market in the way that was originally expected
because terrestrial mobile phone networks spread faster than was originally
envisaged, some mobile phone satellite systems still exist.
Earth observation satellites - these satellites are
used for observing the earth's surface and as a result they are often termed
geographical satellites. Using these satellites it is possible to see many
features that are not obvious from the earth's surface, or even at the altitudes
at which aircraft fly. Using these earth observation satellites many
geographical features have become obvious and they have even been used in
mineral search and exploitation.
Navigation satellites - in recent years satellites
have been used for accurate navigation. The first system known as GPS (Global
Positioning System) was set up by the US DoD and was primarily intended for use
as a highly accurate military system. Since then it has been adopted by a huge
number of commercial and private users. Small GPS systems are available at costs
that are affordable by the individual and are used for car navigation, and they
are even being incorporated into phones in a system known as A-GPS (Assisted
GPS) to enable accurate location of the phone in case of emergency.
Further systems are planned for the future. The Russian system known as Glonass
and the European and Chinese system Galileo are planned for the future.
Reconnaissance satellites - these satellites, are able
to see objects on the ground and are accordingly used for military purposes. As
such their performance and operation is kept secret and not publicized.
Weather satellites - as the name implies these
satellites are used to monitor the weather. They have helped considerably in the
forecasting of the weather and have helped provide a much better understanding
not only of the underlying phenomena, but also in enabling predictions to be
made. A variety of these satellites are in use and include the NOAA series.
Summary
There are now many thousands of satellites in orbit around
the Earth. Many are in operations, while some that have not yet fallen out of
orbit are still circling the Earth. The operational satellites provide many of
the services on which we rely today. Without them many of the services which we
have come to accept as normal would not be so nearly to achieve by other means.
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