Mariana VázquezMariana Vázquez

Pierina CaboPierina Cabo

Astronautics is the Branch of engineering dedicated to space flights and to build also devices that operate manned or unmanned flights out of the earth atmosphere.Astronautics didn’t practically develop this until the ends of 1950s due to the first Sputnik orbital flight.

Some historical facts about Some historical facts about satellitessatellites

In 1945 the British secretary of the Interplanetary Society Arthur C. Clarke proposed to make and artificial satellite that could go arrowed the earth every 24 hours.

This apparatus would be equipped with tools to receive and transmit signals between itself or some other points from earth.

The USA navy some years later, used successfully the natural satellite of earth the moon, to established communication between Washington D.C and Hawaii.

The secretary of the Interplanetary Society Arthur C. Clarke

This proved that artificial satellites could be used for This proved that artificial satellites could be used for that purposes in spite of the fact that they had a that purposes in spite of the fact that they had a disadvantage, they depended one the time of the day disadvantage, they depended one the time of the day to obtain the reflected signals. to obtain the reflected signals.

Since that time a new project emerged. It consisted in Since that time a new project emerged. It consisted in a huge balloon recovered with aluminum to act as a a huge balloon recovered with aluminum to act as a mirror and to reflect the signals from earth, this mirror and to reflect the signals from earth, this device was the first passive artificial satellite, the device was the first passive artificial satellite, the active ones would come later with the technological active ones would come later with the technological advances and the experiences obtained in this area.advances and the experiences obtained in this area.

What is an artificial satellite?What is an artificial satellite?

A satellite is a body that rotates A satellite is a body that rotates around another one. Earth has a around another one. Earth has a natural satellite and nearly 900 natural satellite and nearly 900 artificial ones. With these artificial ones. With these devices a great extension can devices a great extension can be observed because they are be observed because they are much higher from where places much higher from where places normally fly. normally fly.

What are they used for?What are they used for? They are the main elements to communicate around They are the main elements to communicate around

the world. the world. Thanks to them we receive signals of television, radio, Thanks to them we receive signals of television, radio,

and telephone.and telephone. We can also get information about weather, We can also get information about weather,

environment and outer space.environment and outer space. We can also get to know the difference between clean We can also get to know the difference between clean

air and contaminated one the elements of the soil and air and contaminated one the elements of the soil and the results of its harvests, marine and terrestrial the results of its harvests, marine and terrestrial fauna, cities, set ups by man overland routes and fauna, cities, set ups by man overland routes and much more.much more.

Satellites are getting more and more complex, they Satellites are getting more and more complex, they due in orbit more time and they offer better services.due in orbit more time and they offer better services.

Different kinds of satellitesDifferent kinds of satellites

They can be classified in different ways: They can be classified in different ways: The (TIU) divides them according to the The (TIU) divides them according to the

sort of service they give.sort of service they give. There are permanent mobiles, radio There are permanent mobiles, radio

diffuse , radio navigation and exploration diffuse , radio navigation and exploration of earth.of earth.

Military satellites:Military satellites: They are those that support

the military operation of several countries down the national security laws.

During the cold war they built early warning satellites that detected and launching of commercial rockets as well as military ones.

Oceans are places where great battles have happened where ships and submarines of all kinds navigate.

They can be equipped with nuclear missiles and their mobility and their high capacity to hide make them very dangerous.

That’s why so many kinds of satellites have been developed and that’s the reason why some very special satellites, whose identity is very well hidden have proliferated. Among these are the ones that can listen to telephonic conversations from great this distances.

Scientific satellites:Scientific satellites: Their main purpose is to study Their main purpose is to study

earth, its surface, its atmosphere, earth, its surface, its atmosphere, its surroundings and the other its surroundings and the other bodies of space.bodies of space.

These devices allowed a more These devices allowed a more precise knowledge of the precise knowledge of the Universe.Universe.

Navigation satellites:Navigation satellites: They are used as They are used as

global systems to global systems to identify terrestrial identify terrestrial places by means of places by means of three satellites and a three satellites and a manual input device manual input device that can point that can point exactly to the place exactly to the place they are looking for they are looking for and obtain in this and obtain in this way the coordinates way the coordinates of its geographical of its geographical place.place.

They were originally They were originally developed for developed for military purposes military purposes pointing to the pointing to the direction of the direction of the missiles, missiles, submarines, submarines, bombers and troopsbombers and troops..

Meteorologic satellites:Meteorologic satellites:These satellites are very These satellites are very

specialized devices, that are specialized devices, that are exclusively dedicated to exclusively dedicated to observe the atmosphere.observe the atmosphere.

The first meteorologic satellite The first meteorologic satellite was first launched in April 1960.was first launched in April 1960.

To these satellites we owe the To these satellites we owe the discovery of the ozone hole. discovery of the ozone hole. They allowed the scientists to They allowed the scientists to detect the cold fronts, pressure, detect the cold fronts, pressure, distribution of steam water the distribution of steam water the reason of the droughts or the reason of the droughts or the results of contamination.results of contamination.

Communication satellites:Communication satellites: It’s an artificial satellite stationed It’s an artificial satellite stationed

in space with the purpose of being in space with the purpose of being used for telecommunications used for telecommunications using radio frequencies and using radio frequencies and microwaves. Many of these microwaves. Many of these satellites are orbiting the earth, satellites are orbiting the earth, although some of the most recent although some of the most recent ones use lower orbits.ones use lower orbits.

A communication satellite works A communication satellite works as a receptor and transmisor of a as a receptor and transmisor of a signal in different frequencies and signal in different frequencies and is received by antennas that are is received by antennas that are becoming smaller everyday, in a becoming smaller everyday, in a different places at the world that different places at the world that can be used for several can be used for several technologies as Internet, technologies as Internet, telephones, mobile phones, etc.telephones, mobile phones, etc.

Teledetection satellites:Teledetection satellites: They allow the They allow the

observation of the observation of the environment and evaluate environment and evaluate its natural resources, its natural resources, control the crops control the crops connections, the connections, the deforestation rate, deforestation rate, pollution in seas, etc. pollution in seas, etc.

To take advantage of their To take advantage of their capacity, these satellites capacity, these satellites can be placed in low and can be placed in low and polar orbits, often polar orbits, often synchronized with the synchronized with the sun.sun.

The satellite takes The satellite takes images, it takes them images, it takes them constantly.constantly.

The most important of The most important of these is Landsat program.these is Landsat program.

BIBLIOGRAFIABIBLIOGRAFIA

Libros:Libros:Elementos de astrofisica – Aldo Elementos de astrofisica – Aldo

A.Cassinelli. A.Cassinelli. AstrolabioAstrolabioDiccionario Enciclopedico BásicaDiccionario Enciclopedico Básica

Internet:Internet: http://www.cuentame.inegi.gob.mx/medios/satelites/texto

s/texto_artificial.htm