Imager
is a five-channel (one visible, four infrared) imaging radiometer
that senses radiant energy and reflected solar energy from the
Earth’s surface and the atmosphere. Position and size of an
area scan are controlled by command, so the instrument is
capable of full-Earth imagery and various area scan sizes
within the Earth scene. The Imager also provides a star-
sensing capability, used for image navigation and
registration purposes.
Sounder
is a 19-channel discrete-filter radiometer that senses
specific radiant energy for vertical atmospheric temperature and moisture profiles,
surface and cloud top temperature, and ozone distribution. As does the Imager,
the Sounder can provide full-Earth imagery, sector imagery, or local region scans.
Communications Subsystem
Includes Weather Facsimile (WEFAX) transmission and the Search and Rescue (SAR)
transponder. Low-resolution WEFAX transmission includes satellite imagery from
GOES and polar-orbiting satellites and meteorological charts uplinked from the
Command and Data Acquisition (ground) Station. The SAR subsystem detects the
presence of distress signals broadcast by Emergency Locator Transmitters carried on
general aviation aircraft and by Emergency Position Indicating Radio Beacons
aboard some classes of marine vessels. GOES relays the distress signals to a SAR
Satellite-Aided Tracking ground station within the field-of-view of the spacecraft.
Help is dispatched to downed aircraft or ship in distress.
Space Environment Monitor (SEM)
consists of a magnetometer, and X-ray sensor, a high-energy proton and alpha
detector, and an energetic particles sensor, all used for in-situ surveying of the near-
Earth space environment. The real-time data is provided to the Space Environment
Services Center—the nation’s space weather service—which receives, monitors,
and interprets solar-terrestrial data and forecasts special events such as solar flares
or geomagnetic storms. That information is important to the operation of military
and civilian radio wave and satellite communication and navigation systems, as
well as electric power networks, Space Shuttle astronauts, high-altitude aviators,
and scientific researchers.
