The GOES series of geosynchronous equatorial weather satellites has been a key element of the United States’ weather monitoring and forecasting system since the launch of SMS-1 in 1974. GOES satellites have provided continuous imagery and data on atmospheric conditions and solar activity (space weather). Moreover, these systems have contributed to better understanding of the evolution of local weather phenomena such as severe thunderstorms and hurricanes.

The GOES system is a collaborative NOAA and NASA program. NASA builds and launches the GOES spacecraft, while NOAA operates them and distributes their data to meteorologists around the world.

GOES provides real-time observations of Earth’s atmosphere and its weather systems using two main instruments, an imager and a sounder. Imagers monitor clouds and other meteorological phenomena, while sounders provide detailed information about the vertical structure of the atmosphere for analysis of weather phenomena including wind velocity, temperature, water vapor, and humidity.

In addition to its traditional weather observation capabilities, the GOES-R Series imager scans the Earth five times faster with four times the resolution and three times more channels than previous GOES satellites for more accurate weather forecasts and severe storm warnings. The GOES-R Series sounder instruments monitor Earth’s surface temperature and water vapor, and provide near-real-time data on the vertical movement of atmospheric phenomena such as clouds and thunderstorms.

Another new capability of the GOES-R Series is the SXI instrument which allows NOAA to quickly and continuously monitor the Sun’s explosive atmosphere. This information can help forecasters issue timely warnings if solar activity is expected to impact satellite and ground-based operations.

The GOES-R Series also includes the EPS and HEPAD instruments which monitor very high energy protons and alpha particles from solar flares, as well as the continuous measurement of galactic cosmic rays in the Earth’s atmosphere. These sensors are based on the phenomenon of Cerenkov radiation, which is emitted when charged particles (mostly electrons) move through high refractive index materials such as fused silica.

A third new capability of the GOES-R is the Disaster/Seismic Signal Relay (DSSR). The DSR is used to broadcast and relay in S-band distress signals from people, aircraft, and marine vessels that are detected by GOES imagers or the sounder instruments. These signals are then sent to search and rescue (S&R) ground stations for transmission to distressed personnel. GOES-R includes both self-timed and random reporting of the distress signal by the DSR.