Circle around larger, more massive objects (the Earth is
technically a satellite of the Sun, and the Moon is a natural
satellite of the Earth).
Satellites orbit the Earth to provide links between places on
the planet (TV, phone, internet) and to study the Earth and space.
They provide information to the military, to weather forecasting,
to geologists, and more. The orbiting space telescopes examine
other planets and stars.
Satellites orbit in a variety of directions, but most circle
west-tp-east at various heights above the Earth's atmosphere.
Geostationary satellites seem to stay in one place, but they only
in very high orbits. Geosynchronous satellites orbit exactly once a
day, so they stay over the same location on the ground.
(see related question)
Communications - This includes television,
phones (cellular as well as others), and internet. Satellite
television providers, for example, broadcast a one-way signal with
audio and video programming to their customers. This is of great
use for customers who are in areas too remote to use cable or other
wired means, or for mobile users in vehicles and boats. Customers
simply tune their in-home receivers to the sub-channel they desire
and watch digital programming direct from space.
Earth Observation and
Surveillance - Military reconnaissance satellites and
civilian mapping satellites use high-resolution cameras to take
photos of the earth's surface for mapping or intelligence purposes.
Further, these cameras are not limited to the visible light
spectrum, and so some are dedicated to infrared or ultraviolet
sensing, which are used by environmental researchers and
agriculturists; this can help them determine the temperature,
quantity of foliage, chemical composition of the air in different
locales, changing height of the polar ice caps, shoreline erosion,
or mapping of warm and cold ocean currents. Other uses include
popular web applications, surveying, real-time weather observation,
and natural resource detection and management.
Navigation - Global Positioning System (GPS)
satellites function by emitting a specific signal pattern.
Variations in this signal can be detected by GPS receivers to
determine a GPS user's location relative to the satellite by using
a principle called the Doppler Effect. The Doppler effect is the
apparent compression or decompression of signals that occurs when
the signal source is in motion, relative to a listener, for
example, why a train whistle changes pitch when it approaches or
departs from the listener. By calculating the amount of compression
in the signals for multiple satellites, a GPS receiver can pinpoint
the user's location.
Because of the large distance between satellites, distances from
Earth to distant stars and planets can be determined more
accurately (greater parallax). Also, on board cameras can better
view objects on Earth in 3 dimensions.
There are many purposes for placing satellites in orbit. First
and foremost, communications satellites exploit their great
distance from the earth to transmit their signals the greatest
distance possible. Many modes of communication, chief among them
microwave, travel by 'line of sight,' meaning that one must be in a
direct, unobstructed sight line in order to receive a signal. The
earliest communications satellite received and relayed microwave
communications from large ground stations. Today, we have
technology to communicate directly through such satellites using
satellite phones. Satellite communication permits direct
communication beyond the horizon that might not otherwise be
possible with conventional VHF (Very High Frequency) communication
Still other satellites are used for assorted experimental
purposes, exploiting the lack of vibration, low temperature and low
gravity of space as an ideal location for extremely sensitive
instruments, such as the Hubble Space telescope and similar
projects, which are able to see much deeper and more clearly into
the cosmos without having to look through the earth's atmosphere
A special category of satellite is one that is manned, such as
the International Space Station (ISS), and they are used for
exploration and research into the effects of long-term low gravity,
international cooperation and the promotion of peace, among other
Communication satellites can be used to send telephone messages
or TV pictures. A satellite can be used for working out what the
weather will be like in a few days. It has a sensor which send a
television call to earth telling us what's going to happen. They
can also be used for spying and navigation and they can spot forest
fires and water pollution.
1st letter is S and ends with E!
it transmits radio/ televideo/etc. waves
It helps us by like if we atrapped some where and u have afone on u
u can call 911 or someone who willhelp u
They are used for exploring different planets in our solar system,
transmitting radio, telephone, and television signals, and to tell
what the weather is going to be like.
many sencitest send artifical satalites some revolving around the
earth. it is used dish antena
The primary uses for an artificial satellite, given our current
Communication (television and cell phone satellites)
Observation (the Hubble Space Telescope, weather satellites,
Location (the GPS system)
Habitation (Skylab, Mir, the International Space Station)
As our technology continues to expand, it's likely that uses for
artificial satellites will as well. For example, a military
satellite might provide a way to defend specific nations, or even
the Earth as a whole (from a meteor strike, for example). Or, as
seen on sci-fi TV shows, a space dock could allow the repair and
refueling of space vehicles, without the need to return to our
planet's surface. There could eventually be space hotels, low- and
zero-gravity tourist attractions, zero-gee factories,
controlled-gravity hospitals... The list is bounded only by our
imagination, and economic considerations.