WEATHER SATELLITES

WEATHER SATELLITES are robotic spacecraft that observe changes in terrestrial weather patterns. Their forecasting sharply reduces deaths from hurricanes and other violent weather. The first weather satellite, TIROS I, was launched in 1960 and functioned only eighty-nine days. TIROS (an acronym for Television and Infrared Observation Satellite) recorded television images of cloud patterns below, enabling meteorologists to track the movement of weather patterns and fronts. Weather satellites have since grown much more durable and can register more data, including wind speeds, atmospheric and surface temperatures, water temperatures, wave heights, and height of the polar ice caps. The U.S. government operates separate weather satellite programs for civilians and the military.

Weather satellites fall into two types. A geostationary satellite remains parked over a given point of the earth's equator, keeping continuous watch over a large portion of the earth from an altitude of 22,000 miles. A polarorbiting satellite flies at about 500 miles in an orbit that carries it nearly over the earth's north and south poles. This satellite views a much smaller portion of Earth than a geostationary satellite but can make more detailed observations. The U.S. government typically has maintained two geostationary satellites and two polar-orbiting satellites in orbit at all times, but satellite weather forecasting ran into a snag in 1989, when the GOES-6 failed in orbit. A replacement, GOES-8, was to have been launched on a space shuttle mission, but the Challenger shuttle explosion interrupted all shuttle launches. The replacement was further delayed until 1994 by technical problems. To fill the gap a European weather satellite was repositioned over the Atlantic Ocean to provide coverage of the eastern United States.

WEATHER SATELLITES

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