| FACTS |
| It all started with the launch of Sputnik by the USSR in 1957. The ensuing space race led to the development of satellites. Why are they important, you ask? Satellites are vital in technology, they serve us in navigation through the GPS (Global Positioning System), they are the key factor in communications, environmental monitoring, and weather forecasting. They are important in just about everything, and were (are) a vital tool in the development of the modern times. What exactly is a satellite? It as an object that orbits a larger object such as a planet. There are two very important and distinct classes of satellites, being the natural and artifical satellites. The natural satellites are objects such as our moon, meanwhile the artificial ones are man made. The important components of a satellite include: *communication capabilities with earth *a power source *a control system to accomplish its mission The communications antenna, the radio recievers and transmitters enable satellites to communciate with one or more of its ground stations. The messages sent from an satellite to earth are downlinked, meanwhile those sent from the earth to a satellite are uplinked. Many satellites are solar powered, the most effective method as they are much closer to the sun and have direct contact with its' unobstructed energy. Other satellites have fuel cells that convert chemical engery to electrical energy, while still others depend heavily on nuclear energy. The energy is required for the small thrusters which provide altitude and propulsion controls to modify and stabelize the satellite's position in space. How are satellites launched? The trick is to launch them at the ideal speed of 17,000 MPH, so they don't escape into space or fall back to the earth. If the speed is higher than 23,500 MPH the satellite will travel into space, out of the gravitational pull of the earth, if it is lower than 17,500 MPH it will fall back to the earth. A satellite stays in orbit due to the the balancing of two important factors, being the velocity at which the satellite would travel in a stratigh line and the gravitational pull of the earth. This is well demonstrated in the following picture, courtesy o |
