1. INTRODUCTION
A satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon. The first artificial satellite, Sputnik 1, was launched by the Soviet nion in 1!"#. $y %&1& thousands of satellites have been launched into orbit around the 'arth. These originate from more than "& countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the 'arth as space debris. A few space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, (enus, Mars, )upiter and Saturn. Satellites are used for a large number of purposes. *ommon types include military +spy, and civilian 'arth observation satellites, communication satellites, navigation satellites, weather satellites, and research satellites. Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. -ell.known +overlapping, classes include low 'arth orbit, polar orbit, and geostationary orbit. Satellites are usually semi.independent computer controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.
1
2. History of artificial satellites
The first artificial satellite was Sputnik 1, launched by the Soviet
nion on /ctober 0
1!"#, and initiating the Soviet Sputnik program, with Sergei 1orolev as chief designer and 1erim 1erimov as his assistant. This in turn triggered the Space 2ace between the Soviet nion and the nited States. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio.signal distribution in the ionosphere. $ecause the satellite3s body was filled with pressuri4ed nitrogen, Sputnik 1 also provided the first opportunity for meteoroid detection, as a loss of internal pressure due to meteoroid penetration of the outer surface would have been evident in the temperature data sent back to 'arth. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the within the *old -ar. nited States and ignited the so.called Space 2ace
Sputnik 1 Sputnik % was launched on 5ovember 6, 1!"# and carried the first living passenger into orbit, a dog named 7aika. 8n May, 1!09, :roject 2A5; had released the :reliminary ;esign of a 'ollowing pressure by the American 2ocket Society, the 5ational Science >oundation, and the 8nternational @eophysical Aear, military interest picked up and in early 1!"" the Air >orce and 5avy were working on :roject /rbiter, which involved using a )upiter * rocket to launch a satellite. The project succeeded, and '
A satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon. The first artificial satellite, Sputnik 1, was launched by the Soviet nion in 1!"#. $y %&1& thousands of satellites have been launched into orbit around the 'arth. These originate from more than "& countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the 'arth as space debris. A few space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, (enus, Mars, )upiter and Saturn. Satellites are used for a large number of purposes. *ommon types include military +spy, and civilian 'arth observation satellites, communication satellites, navigation satellites, weather satellites, and research satellites. Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, and are classified in a number of ways. -ell.known +overlapping, classes include low 'arth orbit, polar orbit, and geostationary orbit. Satellites are usually semi.independent computer controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control and orbit control.
1
2. History of artificial satellites
The first artificial satellite was Sputnik 1, launched by the Soviet
nion on /ctober 0
1!"#, and initiating the Soviet Sputnik program, with Sergei 1orolev as chief designer and 1erim 1erimov as his assistant. This in turn triggered the Space 2ace between the Soviet nion and the nited States. Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio.signal distribution in the ionosphere. $ecause the satellite3s body was filled with pressuri4ed nitrogen, Sputnik 1 also provided the first opportunity for meteoroid detection, as a loss of internal pressure due to meteoroid penetration of the outer surface would have been evident in the temperature data sent back to 'arth. The unanticipated announcement of Sputnik 1's success precipitated the Sputnik crisis in the within the *old -ar. nited States and ignited the so.called Space 2ace
Sputnik 1 Sputnik % was launched on 5ovember 6, 1!"# and carried the first living passenger into orbit, a dog named 7aika. 8n May, 1!09, :roject 2A5; had released the :reliminary ;esign of a 'ollowing pressure by the American 2ocket Society, the 5ational Science >oundation, and the 8nternational @eophysical Aear, military interest picked up and in early 1!"" the Air >orce and 5avy were working on :roject /rbiter, which involved using a )upiter * rocket to launch a satellite. The project succeeded, and '