In the context of spaceflight, 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 Union in 1957. By 2009 thousands of satellites had been launched into orbit around the Earth. These originate from more than 50 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 Earth as space debris. A few space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Venus, Mars, Jupiter and Saturn.
Satellites are used for a large number of purposes. Common types include military and civilian Earth observation satellites, communication 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.
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.
Some houses transcend the basic functionality of providing a roof over one head or of serving as a family. When a house becomes a display case for wealth and fashion and conspicuous consumption. The residence of a feudal lord or of a ruler may require defensive structures and thus turn into a fort or a castle.
The house of a monarch may come to house courtiers and officers as well as the royal family this sort of house may become a palace. Compare the popularity of the holiday house or cottage, also known as a crib.
In contrast to a relatively upper class or modern trend to ownership of multiple houses, much of human history shows the importance of multi purpose houses.
Thus the house long served as the traditional place of work or of commerce. During the Industrial Revolution there was a separation of manufacturing and banking from the house, though to this day some shopkeepers continue to live over the shop.
goodbye letter for co workers
