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The SMS 2, a NASA-developed, NOAA-operated spacecraft, carried (1) a visible-infrared spin-scan radiometer (VISSR) to provide high-quality day/night cloudcover data and to take radiance temperatures of the earth/atmosphere system, (2) a meteorological data collection and transmission system to relay processed data from central weather facilities to small APT-equipped regional stations and to collect and retransmit data from remote earth-based platforms, and (3) a space environment monitor (SEM) system to measure proton, electron, and solar X-ray fluxes and magnetic fields. The spin-stabilized, earth-synchronous, and cylindrically shaped spacecraft measured 190.5 cm in diam 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 honeycomb equipment shelf and a 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. 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. Both UHF-band and S-band frequencies were used in the telemetry and command subsystems. A low-power VHF transponder provided telemetry and command during launch, and then served as a backup for the primary subsystem after the synchronous orbit was attained. For more detailed information, see "The GOES/SMS User's Guide."

Alternate Names

  • 07648
  • ME02
  • PL-731E
  • SMS-B
  • SMS2
  • Synch. Meteorol. Sat. B

Facts in Brief

Launch Date: 1975-02-06
Launch Vehicle: Delta
Launch Site: Cape Canaveral, United States
Mass: 243 kg

Funding Agencies

  • NASA-Office of Space Science Applications (United States)
  • NOAA National Environmental Satellite Service (United States)


  • Space Physics
  • Solar Physics
  • Earth Science

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Mr. Thomas J. KarrasProject ManagerNOAA National Environmental Satellite, Data and Information Service
Mr. William E. ShenkProject ScientistNASA Goddard Space Flight Center
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