SMS-2 was launched in February 1975 and was a NASA-developed, NOAA-operated, second prototype spacecraft for the geosynchronous series of meteorological satellites. 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 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 orbit. This spin-stabilized spacecraft carried a visible infrared spin-scan radiometer, meteorological data collection and relay system, space environment monitor, and a biaxial fluxgate magnetometer. Throughout its history, it operated at 75 (replaced SMS-1 in April 1979), 115, and 135 degrees West.
Taken from the NSSDC System for Information Retrieval and Storage (SIRS). For
more information contact the NSSDC Coordinated Request and User Support Office,
301-286-6695 (NASA Goddard Space Flight Center, Code 933.4, Greenbelt, Maryland
20771, USA, https://nssdc.gsfc.nasa.gov/).