How do satellites work?
The first satellites may
only have been launched into orbit less than 60 years ago, but many facets of
the modern world and day-to-day life have come to depend on their presence.
Although the term
‘satellite’ also refers to natural objects in Earth’s orbit - the Moon in
particular - it has come to be generally associated with artificial satellites
sent into orbit to perform a variety of tasks, which are facilitated by the
high vantage point and being outside interfering elements of the Earth’s
atmosphere.
The first satellites
The Soviet Union was the
first country to succeed in establishing an orbital satellite when Sputnik I
was launched on 4 October 1957, shortly followed by Sputnik II that carried the
first living creature, the dog Laika, beyond the Earth’s atmosphere.
The Sputnik launch is
commonly viewed as the major catalyst in the Space Race that ensued between the
USSR and USA, but it also inspired people around the world as possibilities
that were previously consigned to science fiction started to become more
tangible.
The United States
launched its first satellite, Explorer I, in January 1958, which discovered the
presence of magnetic radiation belts around the Earth and was succeeded by
other satellites in the Explorer program designed for scientific research. This
led to the establishment of the National Aeronautics and Space Administration
(NASA) later that year.
Satellite operation
Communication satellites
are primarily responsible for sending and receiving radio signals to and from
points on the Earth’s surface, and this is accomplished in a number of ways.
The simplest satellites reflect or ‘bounce’ these signals at greater strength
than they were received, and can convert the information into different
frequencies and data, where it will be received by antennas on the ground.
These may be large earth stations that broadcast signals over a wide area, such
as radio and television towers, or compact antennas inside mobile phones and
other devices.
Satellites do not
broadcast signals indiscriminately, and are designed to send and receive
information according to specified geographical locations. By working on
dedicated frequencies, satellite users can also ensure that signals will not be
mistakenly picked up by other receivers.
Research satellites
A number of orbiting satellites
were designed for carrying out scientific and meteorological research. Weather satellites monitor changing cloud
patterns, fluctuations in pressure and temperature levels and other factors to
predict likely weather events, and have proven invaluable in providing early
warnings for natural disasters such as typhoons and hurricanes.
Other research
satellites are concerned with different aspects of the Earth, such as changes
in the atmosphere or terrain, while others direct their attentions away from
the planet entirely to study outer space. One of the most notable of these is
the Hubble Space Telescope, which has taken some of the most spectacular images
of the universe that would not have been possible from the Earth’s surface.
Navigation satellites
More breakthroughs came
in the area of navigation, as satellite technology became ever more
sophisticated and capable of pinpointing accurate locations on the Earth’s
surface. This technology revolutionised search and rescue operations and
eventually trickled down to passenger vehicles, many of which can now benefit
from comprehensive maps, directions and real-time traffic updates.
Communication satellites
The first satellite
dedicated to communications and entertainment was Telstar 1, which was launched
in 1962. It made the live broadcasting of global news events, sports and other
TV shows possible for the first time.
This basic satellite
laid the groundwork for others that followed in Telstar’s wake, which made
long-distance telephone calls and household satellite TV broadcasting a reality
- these satellite services are of course now common place. HBO was the first
television network to offer satellite TV services to subscribers in 1975, and
satellites became the primary means for broadcasting by the 1990s.
Author Bio:
Roger Lane is a keen
blogger with a passion for writing. Roger works with various
organisations creating unique content ranging from business growth to satellite
communications.