NOAA and 1974 Tornado Outbreak


Weather Satellite Technology, Then and Now

Applications Technology Satellites

Today, the Geostationary Operational Environmental Satellite (GOES) provides cloud images seen daily on television weather forecasts. But, it 1974, GOES, as we know it today, had not yet been developed. Cloud images over Xenia, Ohio, were taken by the Applications Technology Satellite 3 (ATS 3), which was launched on November 5, 1967.

The Applications Technology Satellite series was a set of six NASA spacecraft created to explore and flight-test new technologies and techniques for communications, meteorological and navigation satellites. ATS was a multi-purpose engineering satellite series, testing technology in communications and meteorology from geosynchronous orbit. The major objective of the early ATS satellites was to test whether gravity would anchor the satellite in a synchronous orbit (22,300 statute miles above the Earth), allowing it to move at the same rate the Earth is turning, thus seeming to remain stationary. Although the ATS satellites were intended mainly as testbeds, they also collected and transmitted meteorological data and functioned at times as communications satellites.

ATS was launched to investigate spin stabilization techniques and VHF and C-band communications experiments. In addition to fulfilling its primary mission, it also provided regular communications service to sites in the Pacific basin and Antarctica. It provided the first color images from space as well as regular cloud cover images for meteorological studies.

Synchronous Meteorological Satellites

Two Synchronous Meteorological Satellites (SMS) were launched by NASA: SMS-1, launched on May 17, 1974, and SMS-2, launched on February 6, 1975. The purpose of the SMS was to provide improved meteorological data on worldwide weather phenomena for improved forecasting. After the successful launch of these satellites, NASA turned over the geostationary satellite program to the National Oceanic and Atmospheric Administration (NOAA) for operation. NOAA bought additional spacecraft identical to SMS with the new name Geostationary Operational Environmental Satellite (GOES). The SMS series included the first operational satellite in the NOAA system.

Geostationary Operational Environmental Satellites

The early GOES satellites, built by Philco-Ford, were spin-stabilized, which meant they viewed the earth only about ten percent of the time. These satellites were in operation from 1975 until 1994.

A new generation of three-axis stabilized spacecraft (GOES I-M) is currently in operation. GOES-8, the first of the new generation, was launched in 1994. These satellites view the earth 100 percent of the time, taking continuous images and soundings. GOES satellites provide data for severe storm evaluation, information on cloud cover, winds, ocean currents, fog distribution, storm circulation and snow melt, using visual and infrared imagery. The satellites also receive transmissions from free-floating balloons, buoys and remote automatic data collection stations around the world.

GOES satellites are a mainstay of weather forecasting in the United States. They are the backbone of short-term forecasting or nowcasting. The real-time weather data gathered by GOES satellites, combined with data from Doppler radars and automated surface observing systems, greatly aids weather forecasters in providing warnings of thunderstorms, winter storms, flash floods, hurricanes, and other severe weather. These warnings help to save lives, preserve property, and benefit commercial interests.

The United States operates two meteorological satellites in geostationary orbit, one over the East Coast and one over the West Coast with overlapping coverage over the United States. NOAA's National Environmental Satellite, Data, and Information Service operates the GOES series of satellites from its Suitland, Md., facility. The GOES satellites are a critical component of the ongoing National Weather Service modernization program, aiding forecasters in providing more precise and timely forecasts. Satellites in the GOES series will be launched as required to support NOAA's dual-satellite geostationary observing system. The contractor for development of GOES I-M is Space Systems/Loral (formerly Ford Aerospace).

March 1999