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GOES D - H mission graphic

Geostationary Operational Environmental Satellite

Phase: Past

Launch Date: September 09, 1980

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Program(s):GOES / POES

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GOES-4 (D) Launch Date: September 9, 1980

GOES-4 advanced meteorologists’ capabilities by continuously profiling vertical temperature and water vapor. This major advancement permitted, for the first time, the monitoring of frame-to-frame movement of water vapor concentrations, a technique introduced by the European Meteosat-1 satellite. Meteosat-1 did not have profiling capability, but pioneered water vapor imaging in 1977. This new capability led to a greatly improved knowledge of global atmospheric circulation by revealing motions in clear areas where no visible clouds were present.

The GOES-4 and GOES-5, spacecraft developed by the Hughes Aircraft Corporation, are significantly different from the earlier SMS/GOES spacecraft. Onboard were a visible and infrared spin scan radiometer (VISSR) atmospheric sounder (VAS). This instrument is a more sophisticated version of the VISSR on board the earlier GOES spacecraft. The VAS had a new capability, atmospheric temperature sounding for gathering infrared (IR) radiation data which can be used, with known atmospheric properties, to calculate atmospheric temperature profiles over a selected geographic area. With the positioning of GOES-4 as the GOES-West satellite, and the positioning of GOES-5 as the GOES-East operational satellite, the users receiving the WEFAX broadcasts from either of these satellites were required to change the polarity of their antennas. While the S-band antennas on SMS/GOES spacecraft through GOES-3 had linear horizontal polarization (polarization parallel to the place of the Equator), the GOES-4 and -5 spacecraft have parabolic antennas which have linear vertical polarization (perpendicular to the plane of the Equator). During the time of three simultaneous WEFAX transmissions, this difference required a user switching reception of broadcasts from either the GOES-East or -West to the GOES-Central, to change the polarity of the user's antenna.

GOES-4 was placed in a geostationary orbit directly over the equator over the Pacific (135W).

GOES-5 (E) Launch Date: May 22, 1981

GOES-5 carried an instrument compliment identical to GOES-4 and was placed in a geostationary orbit directly over the equator over the western Atlantic (75W).

GOES-6 (F) Launch Date: April 28, 1983

GOES-6 was designed to replace GOES-4 and was placed in a geostationary orbit directly over the equator over the Pacific (136W) and was referred to as GOES-WEST. After GOES-5 failed, it was moved to a central location 98W. When GOES-7 was placed into service, it was returned to its original location. The VAS imager failed on January 21, 1989, so direct readout images and soundings are no longer available. It is, however, still acting as the west WEFAX relay satellite, although its orbit is unstable.

GOES-G Launch Date: May 3, 1986

The spacecraft (to be named GOES-7, or GOES EAST) was lost in a Delta 3914 launch vehicle failure. The rocket was struck by lightning shortly after liftoff.

GOES-7 (H) Launch Date: February 26, 1987

GOES-7 was placed in a geostationary orbit directly over the equator (over the Atlantic at 75W) and was referred to as GOES-EAST. The satellite is still operational; however, it has been moved several times to cover both the west and east coasts of the U.S. due to the failure of the imager on GOES-WEST. The current position (112W) allows coverage of the US West coast, while the METEOSAT-3 geostationary satellite is currently being leased from the European Space Agency for coverage of the US East coast. Unfortunately, the spin of the GOES-7 satellite is no longer stable, resulting in a 'figure-8' orbit which grows by 0.9 deg. latitude each year. After GOES-I was deployed in Spring of 1994, as GOES 8 (GOES-East), GOES-7 remained in geostationary orbit, at 105 W, and is still used for satellite communications.