GOES (pronounced “goes”) is a series of NOAA weather satellites that provides continuous images and soundings of Earth’s surface and atmosphere. The GOES series has a long history of enhancing operational services and improving support for atmospheric science research, numerical weather prediction model development, environmental sensor design and testing. GOES is controlled by NOAA’s Satellite Operations Control Center in Suitland, Maryland. The satellites also serve as platforms for the NOAA Space Environment Monitoring (SEM) instrument package and the Solar X-ray Imager (SXI).
The SEM instruments on GOES are designed to detect and provide data on solar wind particles. This information is critical for the operation of military and civilian radio wave and satellite communications, telecommunications systems, high-altitude aviators and astronauts at the International Space Station, power distribution networks and the mission of geophysical explorers.
SEM detects ions and electrons produced by the Sun as it interacts with its magnetic field. These instruments are flown on the GOES-13, GOES-16, and GOES-18 satellites and provide data that help meteorologists forecast severe thunderstorms and other atmospheric events, and also to monitor air quality and water vapor levels, ocean currents, cloud cover and fog.
In addition to SEM, the GOES 13- and 16-series satellites carry two imaging instruments called Imager and Sounder. The Imager instruments use a servo-driven, two-axis gimballed mirror system in conjunction with a 31 cm Cassegrain telescope to capture and display Earth’s visible light, infrared and near-infrared radiation. The Sounder instruments utilize a spectroradiometer to measure the brightness and temperature of clouds, as well as surface temperatures. Both instruments can be scanned quickly, covering a small area, or at a slower rate to capture the full disk of the Earth, as required by meteorologists.
Both instruments are capable of determining the type of clouds that are in an area by observing their “albedo.” A cloud that reflects more light, such as snow, has a higher albedo, while one that absorbs more light, such as rain, has a lower albedo. Meteorologists can then determine the speed and direction of a moving storm by viewing a series of images from a GOES satellite.
The next generation of GOES satellites, GOES-19 and 20, will be powered by solar arrays to achieve greater energy efficiency and to enable them to operate in harsher conditions. The satellites will also be able to perform more observations and scans when they are needed. The new GOES satellites will launch in 2022 and be positioned as GOES East at 75° West longitude and GOES West at 135° West longitude. This positioning will allow the satellites to provide comprehensive coverage for North America, Alaska and Hawaii. Both GOES satellites will be able to detect and track hurricanes, and provide data for coastal flooding, volcanic eruptions and wildfires. GOES-T will also carry the Search and Rescue Satellite-Aided Tracking (SARSAT) system, which detects signals from 406 MHz emergency beacons carried by aircraft, boats, yachts and individuals in distress and relays them to rescuers.