Mariana Vázquez Pierina Cabo

1. SATELLITES Mariana Vázquez Pierina Cabo

2. Definition of astronautics 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.

3. Some historical facts about satellites • 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

4. This proved that artificial satellites could be used for that purposes in spite of the fact that they had a disadvantage, they depended one the time of the day to obtain the reflected signals. • Since that time a new project emerged. It consisted in a huge balloon recovered with aluminum to act as a mirror and to reflect the signals from earth, this device was the first passive artificial satellite, the active ones would come later with the technological advances and the experiences obtained in this area.

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

6. What are they used for? • They are the main elements to communicate around the world. Thanks to them we receive signals of television, radio, and telephone. We can also get information about weather, environment and outer space. • We can also get to know the difference between clean air and contaminated one the elements of the soil and the results of its harvests, marine and terrestrial fauna, cities, set ups by man overland routes and much more. • Satellites are getting more and more complex, they due in orbit more time and they offer better services.

7. Different kinds of satellites They can be classified in different ways: • The (TIU) divides them according to the sort of service they give. • There are permanent mobiles, radio diffuse , radio navigation and exploration of earth.

8. 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.

9. 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.

10. Scientific satellites: • Their main purpose is to study earth, its surface, its atmosphere, its surroundings and the other bodies of space. • These devices allowed a more precise knowledge of the Universe.

11. Navigation satellites: • They are used as global systems to identify terrestrial places by means of three satellites and a manual input device that can point exactly to the place they are looking for and obtain in this way the coordinates of its geographical place. • They were originally developed for military purposes pointing to the direction of the missiles, submarines, bombers and troops.

12. Meteorologic satellites: • These satellites are very specialized devices, that are exclusively dedicated to observe the atmosphere. • The first meteorologic satellite was first launched in April 1960. • To these satellites we owe the discovery of the ozone hole. They allowed the scientists to detect the cold fronts, pressure, distribution of steam water the reason of the droughts or the results of contamination.

13. Communication satellites: • It’s an artificial satellite stationed in space with the purpose of being used for telecommunications using radio frequencies and microwaves. Many of these satellites are orbiting the earth, although some of the most recent ones use lower orbits. • A communication satellite works as a receptor and transmisor of a signal in different frequencies and is received by antennas that are becoming smaller everyday, in a different places at the world that can be used for several technologies as Internet, telephones, mobile phones, etc.

14. Teledetection satellites: • They allow the observation of the environment and evaluate its natural resources, control the crops connections, the deforestation rate, pollution in seas, etc. • To take advantage of their capacity, these satellites can be placed in low and polar orbits, often synchronized with the sun. • The satellite takes images, it takes them constantly. • The most important of these is Landsat program.

15. BIBLIOGRAFIA Libros: • Elementos de astrofisica – Aldo A.Cassinelli. • Astrolabio • Diccionario Enciclopedico Básica Internet: • http://www.cuentame.inegi.gob.mx/medios/satelites/textos/texto_artificial.htm