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Mission description

GOES 7 was the tenth satellite of the GOES series (Geostationary Operational Environmental Satellite).

GOES 5-7 were a series of NASA-developed, NOAA-operated, geosynchronous, and operational spacecraft. The spin-stabilized spacecraft carried

  1. a Visible/Infrared Spin-Scan Radiometer (VISSR) Atmospheric Sounder (VAS) to provide high-quality day/night cloudcover data, to take radiance-derived temperatures of the Earth/Atmosphere system, and to determine atmospheric temperature and water vapor content at various levels;
  2. a meteorological data collection and transmission system to relay processed data from central weather facilities to APT (Automatic Picture Transmission)-equipped regional stations and to collect and retransmit data from remotely located Earth-based platforms;
  3. a Space Environment Monitor (SEM) system to measure proton, electron, and solar X-ray fluxes and magnetic fields.
The cylindrically shaped spacecraft measured 190.5 cm in diameter and 230 cm in length, exclusive of a magnetometer that extended an additional 83 cm beyond the cylindrical shell. The primary structural members were a honeycombed equipment shelf and thrust tube. The VISSR telescope was mounted on the equipment shelf and viewed the Earth through a special aperture in the side of the spacecraft. A support structure extended radially from the thrust tube and was affixed to the solar panels, which formed the outer walls of the spacecraft to provide the primary source of electrical power. Located in the annulus-shaped space between the thrust tube and the solar panels were stationkeeping and dynamics control equipment, batteries, and most of the SEM equipment. Proper spacecraft attitude and spin rate (approximately 100 rpm) were maintained by two separate sets of jet thrusters mounted around the spacecraft equator and activated by ground command. The spacecraft used both UHF-band and S-band frequencies in its telemetry and command subsystem. A low-power VHF transponder provided telemetry and command during launch and then served as a backup for the primary subsystem once the spacecraft had attained synchronous orbit.

Detector description

The implemented data set consists of averaged SEM measurements.

The energetic particle monitor consisted of three detector assemblies, each covering limited regions of the overall energy spectrum. The first two detector assemblies monitored protons in seven energy ranges between 0.8 and 500 MeV and alpha particles in six energy ranges from 4 to > 400 MeV. There was also one channel for the measurement of electrons in the energy range above 500 keV. The third detector, High Energy Proton and Alpha Detector (HEPAD), monitored protons in four energy ranges above 370 MeV and alpha particles in two energy ranges above 640 MeV/nucleon. In all, there were 25 channels of data, each channel sampling at a slow rate of once in a few seconds, or once in a few minutes.

The X-ray monitor consisted of two ion chambers, mounted behind a slim rectangular field-of-view (48° x 3°) collimator made of lead-lined aluminium. The chamber for the lower wavelength band of 5 to 30 nanometer was filled with Xe-He mixture with an entry aperture made of 20 mil Be sheet. For the other band, 10-80 nm, the gas was Ar-He mixture and the aperture was a 2 mil Be. The threshold sensitivities were 10-13 J cm-2 s-1 for the lower wavelength band, and 10-12 J cm-2 s-1 for the higher band; each had a dynamic range of four decades.

The spinning twin-fluxgate magnetometer, located at a few meters away from the spacecraft was designed to provide the orthogonal components of the magnetic field: Hp was parallel to the spin axis that was held nearly in the direction of Earth's axis, He was directed toward Earth center, and Hn pointed eastward. The magnetometer had a range of +/- 400 nT (without saturation) and a resolution of 0.1 nT over a range of +/- 50 nT. The sensitivity of the magnetometer was about 0.2 nT. The instrument and its electronics were carried on board GOES-4, -5, -6, and -7, without significant changes. Since May 1993, He and Hn components of the magnetic field could not be obtained. Only Hp data are available, but with uncertainty about the absolute values.

GOES 7
Mission
NameGOES 7 (GOES-H)
Orbit typeGEO at longitude:
OperatorNOAA
Launch date/time26 February 1987
Instrument
InstrumentSEM (Space Environment Monitor)
Data coverage03/1987 - 08/1996
Data resolution5-minute averaged
PIEPS: Herbert H. Sauer (SEL/NOAA)
X-ray monitor: Howard A. Garcia (NOAA)
Magnetometer: Harold Leinbach (SEL/NOAA)
Dan Wilkinson (NGDC/SPIDR)
SourceSPIDR
L-coverage6.5 - 7.5 RE
Data set
VariableDescription
AltitudeFixed value: 35790 km
LatitudeFixed value: 0°
LongitudeInterpolated from daily averages
Measured BMagnetometer data
HpMagnetometer data
HeMagnetometer data
HnMagnetometer data
Calculated BCalculated at BISA with UNILIB
  • Internal magnetic field: DGRF/IGRF
  • External magnetic field: Olson & Pfitzer quiet
McIlwain's L parameterCalculated at BISA with UNILIB
  • Internal magnetic field: DGRF/IGRF
  • External magnetic field: Olson & Pfitzer quiet
X-ray flux (1-8 Å)X-ray monitor data
X-ray flux (.5-4 Å)X-ray monitor data
Electron channele-: > 2 MeV uncorrected
Proton channelsp+: > 1 MeV corrected
p+: > 5 MeV corrected
p+: > 10 MeV corrected
p+: > 30 MeV corrected
p+: > 50 MeV corrected
p+: > 60 MeV corrected
p+: > 100 MeV corrected

The mission and instrument description are provided by NSSDC's Master Catalog.

Last update: Mon, 12 Mar 2018