A satellite is an object that occurs in the orbit of another object. The term was initially used to describe a moon, or a celestial body that orbits a planet. Today, the term also refers to man-made objects that are placed in the orbit of the Earth or other planets. By analogy, the term can also refer to a dependent country called satellite state.
Artificial satellites can be used for many purposes, which most commonly include communication, navigation, weather forecasting and research. Real time vehicle tracking systems usually require data relayed by satellites to function properly. However, satellites can also provide internet, radio, telephony and television services.
The first human made satellite to be launched into Earth’s orbit was the Soviet Sputnik 1 in 1957. Since then, more that 50 countries have contributed to the construction and launch of artificial satellites.
The largest artificial satellite orbiting the Earth today is the habitable International Space Station. The ISS is a joint project uniting the efforts of five space agencies: the US NASA, the Russian RKA, the Japanese JAXA, the European ESA, and the Canadian CSA. The ISS has been continuously occupied for over 11 years.
You’ll find bloggers talking about satellites at sites like blogs.usda.gov.