In an era where satellite observations of Earth are commonplace, it’s easy to forget that only a few decades ago, the amount of information available about the state of Earth’s environment was limited. Observations were infrequent, and data were sparsely located. The advent of the Geostationary Operational Environmental Satellites (GOES) has revolutionized weather forecasting over the past 50 years, providing continuous monitoring and critical data for meteorologists worldwide.
In the late 1950s, primitive numerical weather prediction (NWP) models were capable of producing accurate forecasts given a set of initial conditions. However, the data available to provide those initial conditions were limited. For example, the weather balloon network around 1960 covered only about 10% of the troposphere and did not extend into the Southern Hemisphere, the tropics, or over the ocean.
Weather forecasters of the pre-satellite era typically relied on manual analysis of plotted weather maps, cloud observations, and barometric pressure readings. They combined this limited dataset with their own experience to predict upcoming weather and storm events. The lack of comprehensive data often led to poor forecasts, which usually weren’t accurate beyond two days, particularly in the Southern Hemisphere. As a result, forecasts lacked the specificity and lead time required to adequately prepare communities for severe weather events.
The Dawn of Satellite Observations
The first satellite observations, such as those from the Television Infrared Observation Satellite (TIROS) program or early Nimbus missions, hinted at the potential for improving weather forecasting. However, polar orbiting satellites could only observe a given location twice a day, which was insufficient for tracking rapidly evolving weather phenomena like thunderstorms and hurricanes.
The advent of geostationary observations marked a revolutionary advance in weather forecasting. This approach enabled continuous monitoring of the atmosphere over a particular region on Earth. The development and evolution of NOAA’s GOES have been a major achievement in this regard.
Since 1975, the National Oceanic and Atmospheric Administration (NOAA) and NASA have partnered to advance NOAA satellite observations from geostationary orbit. GOES satellites serve as sentinels in the sky, keeping constant watch for severe weather and environmental hazards on Earth, as well as dangerous space weather.
GOES Heritage Missions: Pioneering Advances
The heritage of GOES can be traced to the Applications Technology Satellite (ATS) series, which consisted of six NASA spacecraft launched between 1966 and 1974. These missions explored and flight-tested new technologies for communications, meteorological, and navigation satellites. Although primarily testbeds, ATS satellites collected and transmitted meteorological data and sometimes functioned as communications satellites.
Following the success of the ATS series, NASA and NOAA developed the Synchronous Meteorological Satellite (SMS), the first operational satellites designed to sense meteorological conditions in geostationary orbit. The SMS missions laid the groundwork for the GOES program, with the first GOES satellite launching in 1975.
First Generation: GOES 1-3
The GOES era began with the launch of GOES-1 in October 1975. The first three GOES missions were spin-stabilized satellites equipped with the Visible and Infrared Spin-Scan Radiometer (VISSR), which provided high-quality day and night observations of cloud and surface temperatures, cloud heights, and wind fields.
The early GOES missions also focused on monitoring space weather, featuring a Space Environment Monitor (SEM) to measure proton, electron, and solar X-ray fluxes, as well as magnetic fields around the satellites. This technology became standard on all subsequent GOES satellite missions.
Second Generation: GOES 4-7
Launched in 1980, the second generation of GOES satellites introduced the VISSR Atmospheric Sounder (VAS), enhancing the study and forecasting of severe storms. The ability to obtain vertical profiles of temperature and moisture allowed forecasters to monitor rapidly changing events and predict severe weather more accurately.
This generation helped forecasters track and forecast impacts from significant events, such as the 1982-1983 El Niño and destructive hurricanes like Juan in 1985 and Hugo in 1989. GOES-7, launched in 1987, added the capability of detecting distress signals from emergency beacons, contributing to the Search and Rescue Satellite-Aided Tracking (SARSAT) system.
Third Generation: GOES 8-12
In 1994, advances in technology enabled another leap forward for GOES capabilities. Improved three-axis stabilization and the separation of the imager and sounder into distinct instruments allowed for more accurate forecasts. Flexible scanning capabilities allowed meteorologists to study local weather trouble spots, improving short-term forecasts.
GOES-12, launched in 2001, included a Solar X-ray Imager (SXI), the first X-ray telescope capable of taking a full-disk image of the Sun, enhancing space weather monitoring and prediction.
Fourth Generation: GOES 13-15
By the mid-2000s, the fourth generation of GOES, known as the GOES-N series, enhanced the mission with improvements in image navigation and registration. GOES-13 monitored the record-breaking tornado outbreak in April 2011, while GOES-14 provided rapid-scan imagery of Tropical Storm Isaac and Hurricane Sandy in 2012.
The GOES-R Series: A New Era
Launched in 2016, the GOES-R Series brought state-of-the-art instruments into orbit, including the Advanced Baseline Imager (ABI) and the Geostationary Lightning Mapper. These satellites provided minute-by-minute information to forecasters, enabling early warnings of severe weather and environmental hazards.
The GOES-R Series also carried sophisticated solar imaging and space weather monitoring instruments. GOES-19, the final satellite in the series, is equipped with NOAA’s first compact coronagraph (CCOR-1), which images the solar corona to detect and characterize coronal mass ejections.
Looking Ahead: GeoXO
NOAA, NASA, and industry partners are developing the next generation of geostationary satellites, known as Geostationary Extended Observations (GeoXO). Scheduled for launch in the early 2030s, GeoXO will advance forecasting and warning of severe weather, continuing the legacy of GOES well into the 2050s.
GeoXO will prioritize the detection and monitoring of environmental hazards, providing earlier warnings to decision-makers and improving short-term forecasting skills.
For 50 years, GOES satellites have been the backbone of short-term forecasts and warnings of severe weather and environmental hazards. Their data are essential for public safety, property protection, and efficient economic activity. As we look to the future, the continued evolution of geostationary satellites promises to enhance our ability to respond to the challenges posed by Earth’s dynamic environment.
