Meteorologists need sensors that are on the ground directly measuring local weather conditions, as well as in orbit high above Earth’s atmosphere observing the "big picture" remotely. The United States has a network of ground stations for measuring surface and upper-air weather conditions at particular locations and times. However, this network leaves gaps in the information about the geographical extent of weather phenomena, their speed and direction of movement, and their duration. Satellite data are also needed to provide a complete and continuous picture of atmospheric conditions. Forecasting the approach of severe storms since 1975, GOES are a cornerstone of weather observing and forecasting.
Geostationary satellites rotate with Earth from west to east directly over the equator at an altitude of 35,800 km (22,300 statute miles). Because the satellite orbits in the same direction as Earth turns on its axis and matches the speed of Earth’s rotation at the equator, the satellite always has the same view of the Earth’s surface. Geostationary satellites are in position to maintain a constant vigil over nearly half the planet.
NOAA’s forecast responsibilities cover the area from Guam to the coast of Africa – the largest being marine and aviation route forecasts. NOAA’s GOES satellites observe the Western Hemisphere on Earth from an equatorial view approximately 22,300 miles high. Because they orbit in the same direction as Earth turns on its axis and match the speed of Earth’s rotation at the equator, the satellites always have the same view of the Earth’s surface. They are positioned to view the west coast of the United States and Pacific Ocean (GOES West) and the contiguous United States and Atlantic Ocean (GOES East).
Geostationary weather satellites work by sensing electromagnetic radiation to indicate the presence of clouds, water vapor, and surface features. Unlike ground-based radar systems and some other types of satellites, these satellites do not send energy waves into the atmosphere and analyze returning signals. Rather, GOES work by passively sensing energy. GOES sense visible (reflected sunlight) and infrared (for example, heat energy), from Earth’s surface, clouds, and atmosphere. Earth and the atmosphere emit infrared energy 24 hours a day, and satellites can sense this energy continuously. In contrast, visible imagery is available only during daylight hours when sunlight is reflected.
The instruments on GOES that measure electromagnetic energy are called radiometers. GOES carry two types of imagers: One measures the amount of visible light from the sun that Earth’s surface or clouds reflect back into space. The second measures the infrared energy that Earth’s surface and clouds radiate back to space. Because GOES can sense infrared radiation, they can operate at night.
Most visible light passes right through the atmosphere, but not so much through the clouds. Clouds reflect some of the visible light back into space. How much depends upon the thickness and height of the cloud. Earth’s surface absorbs the visible light energy, gets warmer, and re-radiates the energy as infrared radiation. Clouds also absorb some of the visible light energy, as well as the infrared energy re-radiated from Earth. Satellite sensors are particularly sensitive to those wavelengths of infrared energy re-radiated up through to the atmosphere to space. Scientists can measure the height, temperature, moisture content (and more) of nearly every feature of Earth’s atmosphere, ocean, and land surface, with and without vegetation.
Communications, transportation, and electrical power systems can be disrupted and damaged by space weather storms. Exposure to radiation can threaten astronauts and commercial air travelers alike, and has affected the evolution of life on Earth. Geomagnetic storms and other space weather phenomena pose a serious threat to all space operations, and can result in total mission failure.
Beginning with GOES-I, the Search and Rescue subsystem has been carried on each of the GOES. Distress signals are broadcast by Emergency Locator Transmitters carried on general aviation aircraft, aboard some marine vessels, and by individuals, such as hikers and climbers. A dedicated transponder on each GOES detects and relays signals to a Search and Rescue Satellite-Aided Tracking (SARSAT) ground station. GOES-R’s transponder is able to operate at a lower uplink power than previous GOES transponders, enabling GOES-R satellites to detect weaker beacon signals. Through a rescue coordination center, help is dispatched to the aircraft, ship, or individual in distress. SARSAT is an international program, with many satellites making up a world-wide network of emergency beacon transponders. Since 1982, SARSAT helped save more than 43,000 lives worldwide.
NOAA’s geostationary satellites have been used to support other needs, should they remain fully or partially operational beyond their expected life. For example, GOES-10 was repositioned to provide timely access to critical GOES data for meteorologists in South America. In 2010, GOES-12 replaced GOES-10 for South American coverage until it was decommissioned in 2012. The longest operating GOES satellite, GOES-3, was in service for nearly 40 years. Once GOES satellites are decommissioned, we move them to a “graveyard” orbit, at least 300 km higher than operational orbit, out of the way of the busier operational orbits below.
The GOES-R Series is the next generation of NOAA geostationary Earth-observing systems. The satellite’s advanced spacecraft and instrument technology support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Learn more on the Mission page of this site.
NOAA funds and manages the GOES-R Series Program and is responsible for operating the satellites as well as the science and applications of the data. NASA oversees the acquisition of the GOES-R Series spacecraft, instruments, and launch vehicle. Lockheed Martin is responsible for the design, creation and testing of the satellites and the spacecraft launch processing. Harris Corp. provided GOES-R’s main instrument payload, the Advanced Baseline Imager, and the ground system, including the antenna system for data receipt. Launch management is provided by NASA’s Launch Services Program based at the agency’s Kennedy Space Center.
The lifecycle budget ($10.8 billion) includes the entire life of the development, launching, operation, and eventual decommissioning of the four satellites in the GOES-R Series, which spans more than 30 years, from 2005-2036. This includes the spacecraft, all instruments, the four launch vehicles, ground segment work, antenna systems, construction of a remote back-up satellite data facility in Fairmont, West Virginia, new construction to the primary satellite station in Wallops Island, Virginia, and upgrades to the NOAA Satellite Operations Facility in Suitland, Maryland. The budget is also used to fund the Environmental Satellite Processing and Distribution System and a Comprehensive Large-Array Stewardship System to process and archive GOES-R Series data and ultimately make it available to end users.
GOES satellites are designated with a letter (ex.: GOES-R, GOES-S, etc.) prior to launch. Once a GOES satellite has successfully reached geostationary orbit, it is renamed with a number (GOES-16, GOES-17, etc.). If a satellite fails to reach orbit, it does not receive a number designation.
The launch window for a GOES satellite is determined such that the satellite would have favorable power and thermal conditions after separation from the launch vehicle. The two-hour window was designed to place the sun at the optimal location at the middle of the launch window. The launch window is selected to be +/- one hour to the “optimal” time to launch for the best geometry between Earth, the sun and the spacecraft needed to optimize the power and thermal conditions.
There are four satellites in the GOES-R Series Program: GOES-R, GOES-S, GOES-T and GOES-U. They are not launched at the same time; rather they are built and launched sequentially over many years. These satellites continue a more than 40 year legacy of geostationary weather satellites going back to GOES-A. Operationally, NOAA maintains two satellites on orbit, GOES East and GOES West, and maintains a backup satellite in a central position to ensure a robust constellation should a problem occur with an operational satellite. For example, in GOES-14, the on-orbit spare, was used to cover the GOES East location following a GOES-13 issue and again in 2013 following a micrometeroid collision.
After launch, GOES-R Series satellites reach orbit approximately two weeks later. At that time, they are renamed with a number. For example, GOES-R became GOES-16 when it reached geostationary orbit. The satellite then travels to a checkout orbit of 89.5 degrees west where it undergoes a period of checkout and validation. During that time, it undergoes instrument outgassing (an operation that prevents contamination from collecting on the instruments’ optical surface) and on-orbit calibration tests. Once data starts to flow, instrument-level testing and product validation begins. Once checkout and validation are complete, the satellite drifts to its operational location.
GOES-R Series advanced spacecraft and instrument technology supports expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. The Advanced Baseline Imager (ABI) collects three times more data and provides four times better resolution and more than five times faster coverage than previous GOES. The GOES-R Series satellites also carry the first lightning mapper flown from geostationary orbit. The Geostationary Lightning Mapper, or GLM, detects the light emitted by lightning at the tops of clouds day and night and collects information such as the frequency, location and extent of lightning discharges. The instrument measures total lightning, both in-cloud and cloud-to-ground, to aid in forecasting developing severe storms and a wide range of high-impact environmental phenomena including hailstorms, microburst winds, tornadoes, hurricanes, flash floods, snowstorms and fires. The satellites also host a suite of instruments that provide significantly improved detection of space weather for more accurate monitoring of energetic particles responsible for radiation hazards, improved power blackout forecasts, increased warning of communications and navigation disruptions, and more.
GLM captures the momentary changes in an optical scene, indicating the presence of lightning. The instrument is sensitive to the in-cloud lightning that is most dominant in severe thunderstorms. Trends in total lightning available from GLM provide critical information to forecasters, allowing them to focus on initial thunderstorm development and intensifying severe storms before these storms produce damaging winds, hail or even tornadoes. Such storms often exhibit a significant increase in total lightning activity, particularly in-cloud lightning. GLM provides insights beyond the presence of a lightning strike, revealing the spatial extent and distance lightning flashes travel.
In general, visible imagery is mainly used in the identification of clouds. Visible images are frequently used for weather forecasting but are only available during the daytime. Infrared imagery is available 24 hours a day because it monitors emitted radiation. Each band has many uses, for example the visible and near-IR bands are used for monitoring aerosols, clouds, hurricanes, snow cover, and atmospheric motion, while the IR bands monitor aerosols, clouds, hurricanes, rainfall, moisture, atmospheric motion and volcanic ash. The GOES-R Series Advanced Baseline Imager has 16 bands, including two visible channels, four near-infrared channels, and ten infrared channels. The ABI Technical Summary provides information on what each of the 16 bands is used for.
The ability to observe targeted areas of severe weather every 30-60 seconds allows forecasters to see what is happening in near real-time and provide information not captured in previous satellite imagery, such as the formation and evolution of rapidly developing severe weather. This enables more advanced warnings and effective evacuations.
On September 20, 2017, when Hurricane Maria struck Puerto Rico as a powerful Category-4 storm, it shattered the island’s two FAA Doppler radars, which were critical forecasting tools for the National Weather Service. Without the radars, it would be impossible to forecast subsequent severe weather and flooding for the foreseeable future. Fortunately, GOES-16 came to the rescue to mitigate the devastating loss of radar data. GOES-16 has the ability to scan targeted areas of severe weather every 30-60 seconds, a capability previous GOES satellites didn’t have. The satellite provided forecasters real-time imagery, with scans every minute on 16 different channels at high resolution. These scans actually provide forecasters with more detailed and frequent information than they received from radar about development of cumulus clouds that cause rain and thunderstorms. Warning lead time is key for public safety in devastated area like Puerto Rico, and GOES-16 is providing for longer lead times.
GOES-R Series satellites offer four times the resolution of previous GOES satellites. The Advanced Baseline Imager (ABI) provides greater accuracy of feature attributes, allowing for better characterization of small hurricane eyes. Use of GOES-16 to get precise view of the eye of Hurricane Harvey allowed emergency managers to react and make decisions on a block by block basis: As Hurricane Harvey parked over Texas for days on end, causing torrential downpours and flooding, NWS personnel used GOES 16 data to provide impact-based decision support to emergency managers. As Harvey made landfall, our forecasters in Corpus Christi, Texas, tracked the eyewall to alert emergency managers when they would have a window of opportunity as the eyewall was passing over the region to evacuate 200 people to safety before the back end of the hurricane struck.
The ABI also has additional channels not available on previous GOES. For instance, Band 13, or the “clean” longwave infrared band is used to monitor clouds and storm intensity. The GOES-16 infrared channels are helping forecasters determine how cold the cloud tops are and how rapidly they are cooling, which aids predictions for rainfall intensity, potential flash flooding and severe thunderstorms. GOES-16 infrared imagery also provides estimations of hurricane central pressure and maximum sustained winds.
When a catastrophic storm hits, the resulting floods can be deadly and cost billions of dollars in economic losses. In the U.S., floods are responsible for more loss of life and property than any other severe weather event. NOAA’s GOES-16 and NOAA-NASA Suomi NPP satellites mapped flooding during the 2017 hurricane season. Images from the two satellites were merged to create detailed and comprehensive flood zone maps which helped FEMA and first responders plan for evacuations and determine where to focus recovery efforts. The flood maps also showed where water was receding. This highly valuable information helped officials determine, in combination with other critical resources, when it was safe for people to return to their homes.
The GOES-R Series Solar Ultraviolet Imager (SUVI) is an improvement over the Solar X-ray Imager (SXI) in many ways. SUVI provides improved resolution compared to the Solar X-ray Imager (SXI) for more detailed observations of the sun’s atmosphere. SUVI also utilizes six carefully-chosen extreme ultraviolet (EUV) channels that are known to correspond to the drivers of space weather. In addition, SUVI provides data faster than SXI, allowing NOAA space weather forecasters to capture both slowly-evolving events such as coronal holes and those that happen rapidly, such as solar flares and eruptive events. SUVI also has a larger field of view, which allows allow NOAA scientists to observe distinctive features of the corona out to distances rarely observed in the EUV portion of the spectrum.
SUVI data are complementary to the datasets produced by other space weather missions and observatories such as SOHO and DSCOVR. SUVI observes the entire solar disk and allows scientists and forecasters to characterize complex active regions of the sun, solar flares, and the eruptions of solar filaments which may give rise to coronal mass ejections. SUVI observations of solar flares and solar eruptions can provide early warning of possible impacts to Earth’s space environment and enable better forecasting of potentially disruptive events on the ground. Depending on the size and the trajectory of solar eruptions, the possible effects to near-Earth space and Earth’s magnetosphere can cause geomagnetic storms which can disrupt power utilities and communication and navigation systems. These storms may also cause radiation damage to orbiting satellites and the International Space Station. Solar flares in particular have large-scale, immediate effects at Earth that start as soon as the light from the flare reaches Earth. This means that forecasters must issue alerts and warnings for potential effects as soon as a large flare is detected. SUVI provides high-quality, timely imagery that is extremely important for these forecasting efforts.
SOHO is an aging joint NASA/ESA solar observatory at the L-1 Lagrangian point and hosts many solar observing instruments. Unfortunately, many of these instruments are no longer operating or operate at a diminished capacity. Most of the data obtained by SOHO is from the LASCO coronagraph instrument. Coronagraphs block out the sun and image the reflected sunlight from the material in the solar wind. The coronagraph data is used for tracking eruptive events from the sun and providing initial estimates of the likelihood and severity of any impacts to Earth.
DSCOVR serves as Earth's forward space weather observatory at the L-1 Lagrangian point and serves to identify the imminent arrival of Earth-impacting events. DSCOVR hosts "in-situ" instruments that measure the magnetic and particle conditions at the location of the spacecraft. The in-situ measurements made by DSCOVR (interplanetary magnetic field and solar wind speed/temperature) provide a forecasting (~ 45 minutes) capability and is the last measurement made of any event prior to its arrival at Earth.
The data from all these satellites (GOES, DCSOVR, and SOHO) form a critical chain of forecasting data. SUVI observes the sun and alerts forecasters to energetic eruptive events. Coronagraph data from the SOHO spacecraft allow for tracking of coronal mass ejections as they propagate through space. DSCOVR captures the magnetic and particle properties as the solar wind passes through the L-1 Lagrangian point on its way to Earth. Finally, the in-situ particle and magnetic instruments aboard GOES record how the Earth's magnetosphere is impacted every minute. Data from all these satellites allow NOAA forecasters to provide up-to-date forecasts and alerts to our military, commercial sectors, and the general public.
GOES satellites see the entire Western Hemisphere, not just the United States. There are a number of ways that other countries in the Western Hemisphere are able to access GOES-R Series data. GOES Rebroadcast (GRB) is the primary space relay of full resolution, near real-time direct broadcast data. These data are available to all users with GRB receivers in view of a GOES-R Series satellite at the East or West operational longitudes. The Product Distribution and Access (PDA) system receives and store real time environmental satellite data and makes them available to authorized users. The Comprehensive Large Array-data Stewardship System (CLASS) is a web-based data archive and distribution system for NOAA’s environmental satellite data. Users in North, Central and South America (including the Caribbean Basin) are also able to access data through GEONETCast-Americas (GNC-A), which disseminates near real-time data through relatively inexpensive satellite receiver stations.
The early GOES (A-C) satellites were spin-stabilized, viewing Earth only about ten percent of the time and provided data in only two dimensions. There was no indication of cloud thickness, moisture content, temperature variation with altitude, or any other information in the vertical dimension. 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 1970s, 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, 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, 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 GOES-R Series marks the first major technological advances in geostationary observations since 1994. The GOES-R series (GOES R, S, T and U) imager has three times the spectral channels, four times the resolution and five times faster coverage than previous GOES, allowing for the “nowcasting” of severe storms. GOES-16 flies the first operational lightning mapper flown in geostationary orbit, which measures total lightning, both in-cloud and cloud-to-ground, to aid in forecasting developing severe storms and a wide range of high-impact environmental phenomena including hailstorms, microburst winds, tornadoes, hurricanes, flash floods, snowstorms and fires. The GOES-R Series satellites also offer improved monitoring of solar activity and earlier warnings of hazardous space weather.
The GOES-R ground system is located in two primary locations: the NOAA Satellite Operations Facility (NSOF) in Suitland, Maryland and the Wallops Command Data Acquisition Center (WCDAS) at Wallops, Virginia. A third operations facility in Fairmont, West Virginia, will serve as a backup location in the event of a communications issue at either NSOF or WCDAS. Additional information is available in the ground system overview of this site.
GOES-R (now GOES-16/GOES East) and GOES-S (now GOES-17/GOES-West) carry identical instrumentation: Advanced Baseline Imager (ABI), Geostationary Lightning Mapper (GLM), Extreme Ultraviolet and X-ray Irradiance Sensors (EXIS), Solar Ultraviolet Imager (SUVI), Magnetometer (MAG), and Space Environment In-Situ Suite (SEISS). For GOES-T and GOES-U, the ABI radiator/loop heat pipes were redesigned to decrease the risk of the cooling system anomaly found on GOES-17. GOES-T and GOES-U will also carry Magnetometers built by NASA Goddard Space Flight Center, but the instrument requirements and specifications remain the same. GOES-U will carry an additional space weather instrument, the Compact Coronagraph (CCOR), which will image the solar corona (the outer layer of the sun’s atmosphere) and help detect and characterize coronal mass ejections (CMEs).
GOES-R Series Extreme Ultraviolet and X-ray Irradiance Sensors (EXIS), Magnetometer, Space Environment In-Situ Suite (SEISS), and Solar Ultraviolet Imager (SUVI) data can be accessed through NOAA’s National Centers for Environmental Information space weather data access webpage.
The GOES-R Series Program engaged users early in the process through Proving Ground and NOAA testbed activities, simulated data sets, scientific and user conferences, and other communication and outreach efforts. » Learn more about user readiness efforts here.
The Proving Ground is a collaborative effort between the GOES-R Program Office, NOAA Cooperative Institutes, a NASA center, NWS Weather Forecast Offices, NCEP National Centers, and NOAA testbeds across the country. The Proving Ground is a project in which simulated GOES-R products are tested and evaluated before going into operational use. Additional information is available in the Proving Ground section of this site.
GOES Rebroadcast is the primary space relay of Level 1b products from GOES-R Series satellites and replaces the GOES VARiable (GVAR) service. GRB provides full resolution, calibrated, navigated, near-real-time direct broadcast data. » Learn more about GRB.
Users must either acquire new systems to receive GRB or upgrade components of their existing GVAR systems. At a minimum, GVAR systems will require new receive antenna hardware, signal demodulation hardware, and computer hardware/software system resources to ingest the extended magnitude of GOES-R GRB data. See the GRB Downlink Specifications and GRB Product Users Guide (PUG) documents for more information.