GOES

A fixed view of a hemisphere

Weather satellites in low orbit see each place once or twice a day. A satellite in geostationary orbit, 35,786 kilometres above the equator, circles the Earth once a day and so stays above the same longitude, giving a continuous view. NASA launched an experimental precursor, SMS-1, in 1974, and GOES-1 followed on 16 October 1975, with its first image on 25 October. NOAA operates the series, with NASA building and launching the satellites.

Two satellites, GOES-East and GOES-West, cover the Americas and the eastern Pacific, with a spare in orbit.

Generations

The first generation was spin-stabilised, scanning the Earth once per rotation of the spacecraft. The second generation, beginning with GOES-8 in 1994, was three-axis stabilised and could image and sound the atmosphere at the same time, with much greater flexibility. GOES-R, launched on 19 November 2016 and renamed GOES-16, began the third generation, with a 16-band Advanced Baseline Imager, the Geostationary Lightning Mapper and instruments for space weather.

GOES-U, launched on 25 June 2024 and renamed GOES-19, became GOES-East on 7 April 2025.

What the data do

The imagery is the backdrop of television weather forecasts and, more important, an input to numerical weather models and to warnings for hurricanes, fires, volcanic ash and floods. Lightning mapping shows where storms are strengthening before radar can. NOAA makes the data openly available to all users, and the archives are held in the cloud for commercial use.

Operational means redundant

A geostationary weather satellite has a life of about ten years, and NOAA keeps spare satellites in orbit, so that the loss of one does not mean the loss of coverage. That redundancy is expensive and is what makes the service dependable. GOES also depends on its ground system, which receives, calibrates and distributes the data, with antennas at Wallops Island in Virginia and a backup site in West Virginia. The programme shows that operational infrastructure includes spare capacity, a ground segment and a plan for replacement.

Instruments and technologies

• Advanced Baseline Imager A 16-band scanning radiometer covering the visible, near-infrared and infrared, with a full disk every 10 minutes and smaller regions every 30 seconds to a minute.
• Geostationary Lightning Mapper A near-infrared camera that detects the flash of lightning in clouds, day and night, over the whole hemisphere.
• Space-weather sensors Solar imagers and particle and magnetic field sensors observe the sun and the space environment.

Timeline

• 1974 NASA launches the precursor SMS-1.
• 1975 GOES-1 launched on 16 October; first image on 25 October.
• 1994 GOES-8 opens the second generation.
• 2016 GOES-R launched on 19 November, becoming GOES-16.
• 2024 GOES-U launched on 25 June, becoming GOES-19.
• 2025 GOES-19 becomes GOES-East on 7 April.

Key lessons for observation today

• Continuity of service is the product The series is built so that a new satellite is always ready for an old one. Planned successors keep a time series unbroken.
• Open data multiplies value GOES data are available to anyone, and the commercial weather industry is built on them. Open access to a public observing system returns more than it costs.
• Detect early, warn faster The ten-minute full disk and lightning mapper shorten the time to a warning. Latency is a design target for observing systems.

Sources

• NOAA NESDIS, 40 Years of GOES: The Anniversary of GOES-1
• NOAA NESDIS, GOES History
• Wikipedia, Geostationary Operational Environmental Satellite