| The television we watch at home, the weather | | | | in 1965. |
| updates we receive, the knowledge we acquire of | | | | There are very many different types of satellites |
| other planets in the universe, are all possible due | | | | and each one serves a different purpose. Earth |
| to satellites. Artificial satellites are man-made | | | | observation satellites are specifically designed to |
| objects that orbit the Earth. These satellites are | | | | observe the Earth. They are used for |
| launched for specific purposes. A satellite is lifted | | | | environmental monitoring, meteorology and map |
| from the earth's surface by a rocket and, once | | | | making. Astronomical satellites are used for |
| placed in orbit, maintains its motion without further | | | | observing distant planets, galaxies and other space |
| rocket propulsion. The first artificial satellite, | | | | objects. Navigation satellites were developed |
| Sputnik I, was launched on Oct. 4, 1957, by the | | | | primarily to satisfy the need for a navigation |
| USSR, which triggered the space race between | | | | system for nuclear submarines. Today they use |
| the Soviet Union and the U.S. The first U.S. | | | | radio time signals transmitted to enable mobile |
| satellite, Explorer I, was launched on Jan. 31, 1958. | | | | receivers on the ground to determine their exact |
| During the first decade of space exploration, | | | | location. Reconnaissance satellites are either |
| satellites were launched from either the United | | | | observation or communication satellites deployed |
| States or USSR. Today, there are more than | | | | for military intelligence applications. |
| three dozen launch sites in use or under | | | | Weather satellites are used to monitor the |
| construction in more than a dozen countries. | | | | weather and climate of the Earth.. They provide |
| Communications satellites are stationed in space | | | | continuous, up-to-date information about |
| to provide a worldwide linkup of radio, telephone | | | | large-scale atmospheric conditions such as cloud |
| and television. Echo 1 was the first | | | | cover and temperature profiles. Tiros 1, was the |
| communications satellite to be launched in 1960. It | | | | first weather satellite that was launched in 1960. |
| was a large metal balloon that reflected radio | | | | Not so long ago, satellites were exclusive, |
| signals striking it. The first commercial | | | | top-secret devices. Today, they are an essential |
| geosynchronous satellite, Intelsat 1 was launched | | | | part of our daily lives. |