The Geostationary Operational Environmental Satellite (GOES) is a system of spacecraft and ground systems that provide a continuous stream of environmental data. It is operated by the National Oceanic and Atmospheric Administration (NOAA)’s Environmental Satellite, Data, and Information Services division to support weather forecasting, severe storm tracking, and meteorology research. The system’s spacecraft and sensors produce a full picture of the Earth, day or night, covering an area extending from 20° W to 165° W longitude.

The first GOES satellite was launched on October 25, 1975. It carried a Visible Infrared Spin-Scan Radiometer (VISSR) to provide imagery of Earth’s clouds and other atmospheric phenomena. It relayed this data to the National Weather Service and other government agencies for use in meteorological forecasting. GOES images help to detect and monitor the development of local severe storms and tropical cyclones, as well as other meteorological phenomena, including squalls and fog.

After a period of sleepless nights and countless hours of testing, the NOAA team declared GOES-17 operational on February 12, 2018. This advanced satellite will cover the GOES-West slot over the Pacific Ocean from a location 22,300 miles above the surface of the Earth. The GOES-R series will continue to provide critical weather and climate data into the 2030s.

GOES-R uses the same basic design as previous GOES satellites, with two primary instruments: the Imager and the Sounder. The Imager will sense the radiance of the Sun on the Earth’s atmosphere and its cloud tops, measuring brightness and color. It will also measure the vertical distribution of temperature and moisture in the atmosphere. The Sounder will detect radiance from the sun’s surface and atmosphere, as well as the presence of ozone.

In addition to the aforementioned instrument suites, GOES-R will carry the Space Environment Monitoring (SEM) package of sensors that monitor the near-Earth solar-terrestrial electromagnetic environment. These sensors will detect and alert NOAA/SESC to high-energy particles that could impact the safety of spacecraft and astronauts. The GOES-R Imager and Sounder will continue to be processed and distributed to users in real time from the NOAA/SESC Geostationary Operations Control Center at Suitland, MD.

The EPS and HEPAD sensors on GOES-R will provide additional information about the physical state of the solar atmosphere, as well as the space environment, by sensing high energy protons, alpha particles, and galactic cosmic rays. The HEPAD instrument will detect these particles by the phenomenon of Cerenkov radiation, which occurs when an incident particle carries more energy than its speed of light in a medium with a high refractive index—in this case, fused silica. Unlike the previous GOES satellites, GOES-R will be capable of transmitting these data to the NOAA/SESC in real-time.