Geostationary Operational Environmental Satellite (GOES)

Since 1975, Geostationary Operational Environmental Satellites (GOES) have provided continuous imagery and data on atmospheric conditions and solar activity (space weather). They have even aided in search and rescue of people in distress. GOES data products have led to more accurate and timely weather forecasts and better understanding of long-term climate conditions. The National Aeronautics and Space Administration (NASA) builds and launches the GOES, and the National Oceanic and Atmospheric Administration (NOAA) operates them.

The satellites circle the Earth in geosynchronous orbit, which means they orbit the equatorial plane of the earth at a speed matching the Earth’s rotation. This allows them to stay in a fixed position in the sky, remaining stationary with respect to a point on the ground. The satellites continually view the continental United States, Pacific and Atlantic Oceans, Central and South America, and Southern Canada. The satellites operate approximately 22,300 miles above Earth.

GOES satellites are designated with a letter prior to launch. Once a satellite has achieved orbit, it is assigned a number. The following shows the history and status of all GOES satellites.

• GOES A-C (1-3) The early GOES satellites were spin-stabilized, viewing Earth only about ten percent of the time and provided data in only two dimensions (three if you consider time). There was no indication of cloud thickness, moisture content, temperature variation with altitude, or any other information in the vertical dimension.
• GOES D-H (4-7) In the 1980s the capability was added to obtain vertical profiles of temperature and moisture throughout the atmosphere. This added dimension gave forecasters a more accurate picture of the intensity and extent of storms, allowed them to monitor rapidly changing events, and to predict fog, frost and freeze, dust storms, flash floods, and even the likelihood of tornadoes. However, as in the 70s, the imager and sounder still shared the same optics system, which meant the instruments had to take turns. Also, the satellites were still spin-stabilized.
• GOES I-M (8-12) GOES-I, launched in 1994, brought real improvement in the resolution, quantity, and continuity of the data. Advances in two technologies were responsible: three-axis stabilization of the spacecraft and separate optics for imaging and sounding. Three-axis stabilization meant that the imager and sounder could work simultaneously. Forecasters had much more accurate data with which to better pinpoint locations of storms and potentially dangerous weather events such as lightning and tornadoes. The satellites could temporarily suspend their routine scans of the hemisphere to concentrate on a small area of quickly evolving events to improve short-term weather forecasts.
• GOES N-P (13-15) GOES-N, O, and P further improved the imager and sounder resolution with the Image Navigation and Registration subsystem, which uses geographic landmarks and star locations to better pinpoint the coordinates of intense storms. Detector optics were improved and because of better batteries and more available power, imaging is continuous.

The next-generation GOES program — $11 billion in all — includes four satellites, an extensive land system of satellite dishes and other equipment, and new methods for crunching the massive, nonstop stream of expected data. The most advanced weather satellite ever built was launched 19 November 2016, part of an $11 billion effort to revolutionize forecasting and save lives.

The GOES-R spacecraft will track U.S. weather as never before: hurricanes, tornadoes, flooding, volcanic ash clouds, wildfires, lightning storms, even solar flares. Indeed, about 50 TV meteorologists from around the country converged on the launch site — including NBC’s Al Roker — along with 8,000 space program workers and guests. The first in a series of four high-tech satellites, GOES-R was launched on an unmanned Atlas V rocket, delayed an hour by rocket and other problems. NOAA teamed up with NASA for the mission.

The satellite, valued by NOAA at $1 billion, is aiming for a 22,300-mile-high equatorial orbit. There, it will join three aging spacecraft with 40-year-old technology, and become known as GOES-16. After months of testing, this newest satellite will take over for one of the older ones. The second satellite in the series will follow in 2018. All told, the series should stretch to 2036.

GOES-R’s premier imager, one of six science instruments, will offer three times as many channels as the existing system, four times the resolution and five times the scan speed. A similar imager is also flying on a Japanese weather satellite. Typically, it will generate full images of the Western Hemisphere every 15 minutes and the continental United States every five minutes. Specific storm regions will be updated every 30 seconds.

• DATA COLLECTION SYSTEM (DCS) - DCS is a satellite relay system used to collect information from Earth-based data collection platforms that transmit in-situ environmental sensor data from more than 20,000 platforms across the hemisphere.
• GOES REBROADCAST (GRB) - GRB is the primary space relay of Level 1b products, replacing the GVAR (GOES VARiable) service. GRB will provide full resolution, calibrated, navigated, near real-time direct broadcast data.
• HIGH RATE INFORMATION TRANSMISSION/EMERGENCY MANAGERS WEATHER INFORMATION NETWORK (HRIT/EMWIN) - Weather Information Network (HRIT/EMWIN) EMWIN is a direct service that provides users with weather forecasts, warnings, graphics and other information directly from the National Weather Service (NWS) in near real-time. HRIT service is a new high data rate (400 Kpbs) version of today’s LRIT (Low Rate Information Transmission), broadcasting GOES-R satellite imagery and selected products to remotely-located user terminals.
• SEARCH AND RESCUE SATELLITE AIDED TRACKING (SARSAT) - The SARSAT system detects and locates mariners, aviators and other recreational users in distress. GOES-R will continue the legacy function of the SARSAT system on board NOAA’s GOES satellites. This system uses a network of satellites to quickly detect and locate signals from emergency beacons onboard aircraft, vessels and from handheld personal locator beacons. The GOES-R SARSAT transponder will operate with a lower uplink power than the current system (32 bBm), enabling GOES-R to detect weaker beacon signals.

The GOES satellites operate from two primary locations. GOES East is located at 75° W and provides most of the U.S. weather information. GOES West is located at 135°W over the Pacific Ocean. NOAA also maintains an on-orbit spare GOES satellite in the event of an anomaly or failure of GOES East or GOES West.