In the world of geostationary weather satellites, two of the most recognizable are GOES and POES. Both have an extensive 40+ year legacy and specialize in observing atmospheric conditions that are critical to weather forecasting and environmental applications. They share a lot in common, including a huge fleet of satellites, a long heritage, and extensive image collection capabilities. However, the differences between these two satellites lie in their orbital type – GOES is geostationary, while POES has a polar orbit.

GOES (Geostationary Operational Environmental Satellite) satellites are the National Weather Service’s flagship fleet of weather observation satellites. GOES satellites continuously monitor meteorological and space environment data, providing a constant vigil over North America to identify the atmospheric “triggers” of severe weather conditions like tornadoes, hailstorms and hurricanes.

With sensors designed to detect light-emitting radiation, the GOES fleet can also measure surface temperature, wind speed and moisture from Earth’s surface to the atmosphere. It is because of these instruments that GOES satellites are vital to the safety and protection of electric power networks, astronauts in the Space Station and high-altitude aviators, as well as military radar systems, communications and navigation systems and the nation’s telecommunications and broadcasting services.

Each satellite is designated a letter prior to launch, and once it enters its operational geostationary orbit, the letter is dropped and replaced by a number. The GOES-R series consists of GOES-16, currently NOAA’s operational GOES East satellite, and GOES-17, which began operating at 135° West over the Pacific Ocean on 10 December 2018.

Both GOES-16 and -17 are equipped with a new spectral imaging sensor called the Advanced Baseline Imager (ABI), which provides sharper and more defined imagery than previous GOES models. GOES-16 also has another important new capability, the Geostationary Lightning Mapper (GLM), which can detect lightning strikes at very high spatial resolution. This information can be useful for both storm forecasting and fire behavior monitoring, particularly when determining the best location to deploy helicopters and airplanes to spray fire retardant to contain wildfires.

The GOES-R series also includes a Geostationary Orbit Experiment (GOES-SXI), which will provide high-cadence observations of large-scale solar structures and flares. GOES-SXI will provide valuable information for the National Weather Service, as well as other government agencies, to support their mission to protect people and property from solar hazards.