The Geostationary Operational Environmental Satellites (GOES) maintain orbital positions over the same Earth location along the equator at about 22,300 miles above Earth, giving them the ability to make nearly constant observations of weather patterns over and near the United States. GOES satellites provide both visible-light and infrared images of cloud patterns, as well as "soundings," or indirect measurements, of the temperature and humidity throughout the atmosphere. These data are essential for the operations of the National Weather Service--such data provide advance warning of emerging severe weather, as well as storm monitoring. The vantage point of GOES satellites allows for the observation of large-scale weather events, which is required for forecasting small-scale events. Data from GOES satellites may be received for free directiy from the satellite by individuals or organizations possessing a relatively inexpensive receiver.
In order to supply complete coverage of the continental United States, Alaska, and Hawaii, the GOES geostationary satellite program requires two satellites, one nominaliy placed at 75deg. west longitude and one at 135deg. west longitude. The first SMS/GOES was placed in orbit in 1974. However, from 1984-1987 and from 1989 to the present time, as a result of sensor failures and a lack of replacements, only one GOES satellite has been available to provide coverage. GOES-7 is currently located at 112deg. west longitude, which provides important coverage for the eastern and central United States. Unfortunately, this single satellite is nearing the end of its "design life" and could fail at any time, leaving the United States with no GOES satellite in orbit. The United States has borrowed a Meteosat satellite from Europe to cover the East Coast and serve as a backup should GOES-7 fail. Meteosat-3 is now positioned at 75deg. west longitude.
SOURCE: National Oceanic and Atmospheric Administration and Office of Technology Assessment, 1993.