Satellites fall into five principal types – research satellites, communication satellites, weather satellites, navigational satellites, and application satellites. Communication satellites provide a worldwide linkup of radio, telephone, and television. The first communication satellite was Echo 1, launched in 1960. Relay 1 and telstar 1 were the first active communications satellites. They were launched in 1962. Telstar 1 transmitted first live television broadcast across the Atlantic.
Weather satellites, also called meteorological satellites, provide continuous, up-to-date information about large-scale atmospheric conditions such as cloud cover and temperature profiles. Tiros 1 was first weather satellite. It was launched in 1960. It transmitted infrared television pictures and was able to detect the development of hurricanes and to chart their paths. Other weather satellites include geostationary operational environmental satellites (GOES) that send weather data and pictures across the United States, China, Japan and India. The European space agency has also orbited a similar craft. Modern weather satellites can transmit visible or infrared photos, focus on a narrow or wide area, and can be maneuvered in space to obtain maximum coverage. Navigation satellites are mainly intended to help aircraft, ships and nuclear submarines. Transit satellites provide constant signals by which aircraft and ships can determine their positions with great accuracy.
Other important types of satellites are scientific satellites, observation satellites, stationary earth satellites and commercial geosynchronous satellites. Scientific satellites are used to survey the earth and its vicinity. Observation satellites help to observe the various features of the earth’s surface. Observation satellites are also used for the surveying and mapping of the earth’s surface. Stationary earth satellites assist in telecasting programs. Syncom 3 was the first stationary earth satellite. It was launched in 1964.