The GOES system of geostationary weather satellites is a vital tool for meteorologists working to provide forecasts and warnings. The satellites, operated by the National Oceanic and Atmospheric Administration (NOAA), are in an orbit 35,790 kilometres (22,240 miles) above Earth and continuously scan the continental United States, Pacific and Atlantic Oceans, Central America, South America and Canada. GOES spacecraft have two main payload instruments: the Imager and the Sounder. The Imager observes the atmosphere using visible and infrared wavelengths, analyzing a variety of information to create images of clouds and atmospheric phenomena. The Sounder measures vertical profiles of atmospheric temperature and moisture to help understand how weather systems develop.

GOES satellites also monitor solar activity and the interaction of solar wind with Earth’s magnetosphere and ionosphere, which may impact satellite communications and navigation systems, power grids, electric and nuclear facilities, and even the missions of Space Station astronauts and high-altitude aviators. The system transmits real-time data from its instruments to the Space Environment Services Center (SESC) in real time, providing critical information about space weather conditions.

Until the GOES-R series was launched in 2016, there were six satellites in the GOES series, designated by their letters before launch and their numbers once they reached geostationary orbit. The GOES-R series consists of four satellites, GOES-16, GOES-17, GOES-T and GOES-U that are designed to operate through 2036. The GOES-R series features new, more advanced sensors to support short-term and long-range weather forecasting and emergency management.

Launched in 1994, GOES-I satellites introduced significant improvements in the quantity and quality of data available. These advances were made possible by advancements in two technologies: three-axis stabilization of the spacecraft and separate optics for imaging and sounding. The ability to continuously obtain both imaging and sounding data allowed forecasters to better pinpoint the location of severe storms and other events. The GOES-I series could also temporarily suspend its routine scanning of the hemisphere to concentrate on a small area of quickly evolving events to improve short-term weather forecasts.

The GOES-R series, which includes GOES-16 and GOES-17, is equipped with more sophisticated sensors that produce sharper, clearer imagery than the older GOES-I and GOES-J satellites. GOES-R also carries the GOES-R Advanced Baseline Imager (ABI), which enables the observance of different atmospheric phenomena with high spatial and temporal resolution.

In addition to observing the Earth’s surface and atmosphere, GOES-R carries the Geostationary Lightning Mapper (GLM), which tracks thunderstorms and the build-up of lightning over an entire region. This capability is critical for improving tornado forecasts.

GOES-R’s Advanced Baseline Imager (ABI) provides multispectral imagery with very detailed cloud coverage and surface reflectivity. This information is used for severe storm evaluation, fire detection and monitoring, and the assessment of water-vapor and cloud cover. The GOES-R series is also able to detect volcanic ash and monitor ocean surface winds and waves. GOES-R also contains the Geostationary Operational Environmental Satellite Sensor (GOES-S) to collect and broadcast high-rate data for emergency managers, including a geostationary view of active volcanoes.