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GOES-7
Objectives:
The satellite was designed to sense meteorological conditions from
a fixed location above the Earth, and to provide this data to operational
forecasters and private interests on the ground. It was designed to replace
GOES-5 and provide continuous vertical profiles of atmospheric temperature
and moisture.
Description:
The spacecraft was a cylinder 85
inches in diameter, 138 inches high and weighed 874 pounds. The sides of
the cylinder were covered by 15,000 solar cells which, along with nicad
batteries, provided the power for the craft. Contained within, but
protruding from the base was the primary instrument - the VAS (Visible
Infrared Spin Scan Radiometer (VISSR) Atmospheric Sounder) and its sunshade.
This instrument provided both day and night imagery of cloud conditions as
well as temperature and moisture profiles over the full-disk.
Unfortunately, the dwell times of sounder versus imager do not permit these
two operations to occur simultaneously; however, soundings are still
available on an hourly basis.
The satellite also used new despun
S-band and UHF antennas to improve the relay of meteorological data from
over 10,000 surface locations into a central processing center for
incorporation into numerical weather prediction models, and to perform
fax transmission of processed images and weather maps to WEFAX field
stations. In addition, a Space Environment Monitor (SEM) and Data
Collection System (DCS) similar to those on the previous GOES were
installed.
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.
Participants: NASA, NOAA, Hughes Aircraft,
McDonnell Douglas
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Launch Date
April 28, 1983
Operational Period
1983-1996 due to unstable orbit
Launch Vehicle
Delta 3914
Launch Site
Cape Canaveral, FL
Type
Weather Satellite
GOES missions
1968 - 1977
1978 - 1987
1988 - 1997
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