What Is Satellite?

While most people think of a satellite as a complex instrument that orbits the earth for various scientific purposes, the truth is that a satellite can be anything that orbits another object. Technically, the moon could be a satellite of the earth, while the planets might be considered satellites of the sun. So, there can be natural satellites or artificial/man-made satellites.

The dictionary definition of the word explains that a few hundred years ago a satellite was someone who served as an attendant to another person or someone who was a member of the entourage of a well-known person. Their live revolved around that individual.

This definition was extended over the years to include a country that might be less powerful nation militarily so it became a willing satellite of a larger, stronger country. In communications, a satellite is indeed a device that orbits the earth to send and receive signals or take photographs, for example.

Russian scientists were working on the concept of sending an object in to earth orbit via a rocket as far back as 1903. A man named Tsiolkovsky even envisioned the use of hydrogen and liquid oxygen as fuels, well ahead of the commonly known plans of a few decades later. These ideas were enhanced in 1928 by another man from Slovenia.

I wasn’t until the first artificial satellite was successfully launched in 1957 by Russian scientists (Sputnik) that the idea of a useful, scientific satellite became a reality. This satellite was successful in its simple mission of temperature and pressure information gathered during the orbit.

It wasn’t long before the United States followed suit, finally getting a satellite into orbit after planning and discussing the idea for nearly two decades. The success of the two countries led to what was commonly called the space race, during which both countries attempted to put satellites both scientific and military use. In fact the United States had a formal name for their program: Space Surveillance Network.

Today there are dozens of specific uses for the many man-made satellites orbiting the Earth, with some rotating in a fixed position above the Earth’s surface to relay voice communications, data such as computer and television information, and in more recent years, quality video of almost any place on Earth that wasn’t out of the satellite’s view.

Satellite positions and direction can be changed from Earth-based stations, allowing for adjustments in areas under surveillance or changes in which areas of the globe are served by the satellite’s signals.
But some satellites don’t transmit information on a constant basis. Rather, these scientific-data orbiters gather information for research purposes and transmit it back on request from the Earth station. In addition, some information-gathering satellites are useful as scientific instruments when they return to earth with the information gathered during orbit.

Satellites can be geocentric, in that they orbit the Earth in a regular path. There are many other types of orbiting satellites designed to move with or around the planet for whatever purpose the designers intended. The list of countries that have launched orbiting satellites has grown to include several dozen nations.

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