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The NOAA 3 was one in a series of improved TIROS-M type satellites with new meteorological sensors onboard to expand the operational capability of the ITOS system. The primary objective of NOAA 3 was to provide global daytime and nighttime direct readout cloudcover data on a daily basis. The sun-synchronous spacecraft was also capable of supplying global atmospheric temerature soundings and very high resolution infrared cloudcover data of selected areas in either a direct readout or a tape recorder mode. A secondary objective was to obtain global solar proton flux data on a routine daily basis. The primary sensors consisted of a very high resolution radiometer (VHRR), a vertical temperature profile radiometer (VTPR), and a scanning radiometer (SR). The VHRR, VTPR, and SR were mounted on the satellite baseplate with their optical axes directed vertically earthward. The nearly cubical spacecraft measured 1 by 1 by 1.2 cm. The satellite was equipped with three curved solar panels that were folded during launch and deployed after orbit was achieved. Each panel measured over 4.2 m in length when unfolded and was covered with 3420 solar cells measuring 2 by 2 cm. The ITOS dynamics and attitude control system maintained desired spacecraft orientation through gyroscopic principles incorporated into the satellite design. Earth orientation of the satellite body was maintained by taking advantage of the precession induced from a momentum flywheel so that the satellite body precession rate of one revolution per orbit provided the desired 'earth looking' attitude. Minor adjustments in attitude and orientation were made by means of magnetic coils and by varying the speed of the momentum flywheel. The spacecraft became the operational ITOS spacecraft on March 19, 1974. Operations terminated in August 1976.

Alternate Names

  • 06920
  • ITOS-F
  • NOAA3

Facts in Brief

Launch Date: 1973-11-06
Launch Vehicle: Delta
Launch Site: Vandenberg AFB, United States
Mass: 746 kg

Funding Agencies

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


  • Space 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. Charles M. HunterGeneral ContactNASA Goddard Space Flight Center
Mr. Stanley WeilandProject ManagerNASA Goddard Space Flight Center
Mr. Isidore L. GoldbergProject ScientistNASA Goddard Space Flight Center
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