GOES 2 was a NASA-developed, NOAA-operated, geosynchronous, and operational
spacecraft. The spin-stabilized spacecraft carried (1) a visible infrared spin-scan radiometer
(VISSR) to provide high-quality day/night cloudcover data and to take radiance-derived
temperatures of the earth/atmosphere system, (2) a meteorological data collection and
transmission system to relay processed data from central weather facilities to APT-equipped
regional stations and to collect and retransmit data from remotely located earth-based
platforms, and (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 cylinder 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 out from the thrust tube and was affixed to the solar panels, which formed
the outer walls of the spacecraft and provided 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 attained synchronous orbit.