GOES - Geosynchronous Operational Environmental Satellite

Geosynchronous Operational Environmental Satellite

The National Oceanic and Atmospheric Administration (NOAA) operates a series of meteorology observing satellites that is a continuation of the Synchronous Meteorological Satellite (SMS) series.

This GOES program formally began in 1975 with the launch of the first operational spacecraft, GOES-A, renamed GOES-1 when it reached orbit. The GOES spacecraft circle the Earth in a geosynchronous orbit, which means they orbit close to the equatorial plane of the Earth at a speed matching the Earth’s rotation. This allows them to appear to hover continuously over one position on the surface of the Earth at an altitude of 35,800 km (22,300 miles).

In addition to providing systematic, continuous observations of terrestrial weather, GOES also provides observations of space weather through its Space Environment Monitor (SEM) system. The three main components of space weather monitored by GOES are: X-rays, energetic particles, and the magnetic field. The initial series of satellites maintained attitude control by spinning. This is known as “spin-stabilized.” With the advent of GOES-8, launched in 1995, the basic platform design became “3-axis stabilized.” In 2001 GOES-12 was launched with a new X-ray instrument onboard — the Solar X-ray Imager (SXI)**. This instrument creates images of the Sun, whereas the original XRS instrument only generated whole disk flux measurements.

GOES Geosynchronous Operational Environmental Satellite

  • X-ray Sensor (XRS) is an ion chamber that provides whole-Sun X-ray fluxes in the 0.5-to-4 and 1-to-8 Angstrom (Å) wavelength bands. These observations provide a sensitive means of detecting the start and evolution of solar flares. Two bands are measured to allow the hardness of the solar spectrum to be estimated and hence also the temperature and emission measure of the emitting hot flare plasma.
  • Energetic Particle Sensor (EPS) is a solid-state detector with pulse-height discrimination to measure proton, alpha-particle, and electron fluxes.
  • Magnetometer is a twin-fluxgate spinning sensor that provides measures of three mutually perpendicular components of the Earth’s magnetic field.
  • Soft X-ray Imager (SXI) (only on GOES-12 and 13) provides a continuous sequence of full-Sun X-ray images at a 1-minute cadence with a 512×512 intensified CCD. Broadband filters are employed to obtain images in several wavelength bands between about 6 and 60 Å.
Table 5. List of GOES Spacecraft
Launch Date Status
GOES-1 (A) October 16, 1975 Decommissioned
GOES-2 (B) June 16, 1977 Decommissioned
GOES-3 (C) June 16, 1978 Decommissioned
GOES-4 (D) September 9, 1980 Decommissioned
GOES-5 (E) May 22, 1981 Decommissioned
GOES-6 (F) April 28, 1983 Decommissioned
GOES-G May 3, 1986 Failed*
GOES-7 (H) February 26, 1987 Decommissioned
GOES-8 (I) April 13, 1994 Decommissioned
GOES-9 (J) May 23, 1995 Decommissioned
GOES-10 (K) April 25, 1997 In Operation
GOES-11 (L) May 3, 2000 In Operation
GOES-12 (M) July 23, 2001 In Operation**
GOES-13 (N) May 24, 2006 In Orbit Storage***
GOES-O November 5, 2008
GOES-P 2010
GOES-Q Cancelled
GOES-R 2014

* GOES-G failed to make it into orbit when its Delta rocket lost control after being struck by lightening shortly after liftoff.

**The SXI instrument is out of commission indefinitely due to a GOES 12 X-ray Sensor (XRS) anomaly on April 12, 2007.

***No GOES 13 SXI images are available after December 2006 due to a detector anomaly that occurred in conjunction with an X-class flare.