BackForward Satellite Programme: TIROS Operational System 

Programme details
Programme description
  • Series of 9 satellites for operational meteorology, follow-on of the experimental TIROS series.
  • From a historical viewpoint, considered as the 2nd generation of NOAA polar orbiting satellites.  Main improvements: operational adoption of the "cartwheel" configuration (as in TIROS-9), of the sunsynchronous orbit (as in TIROS-9 and TIROS-10) and of the real-time dissemination function (as in TIROS-8).
  • USA programme: ESSA, the predecessor of NOAA, responsible of the overall programme and the operations, NASA responsible of the development of the space segment.
  • Spin-stabilised satellites, with the spin axis perpendicular to the orbital plane ("cartwheel" configuration) and the cameras mounted on the side, activated when facing the earth.
  • Design lifetime 1 year.
  • Sunsynchronous orbits around 9:30 exploited, with two satellites at any time: ESSA 1, 3, 5, 7 and 9 equipped with instruments for stored data, ESSA 2, 4, 6 and 8 equipped for real-time transmission.
  • Replacement policy based on launching satellites of each series (odd-numbered or even-numbered) at yearly intervals.
  • See detailed description at
Data circulation
  • Selected data of odd-numbered satellites stored onboard and downlinked to the CDA (Command and Data Acquisition station) at Fairbanks.
  • Data from the even-numbered satellites downlinked in real time to APT receiving stations.
Programme lifetime 1966 - 1976
Associated satellites and instruments

Note: red tag => no longer operational , green tag => operational , blue tag => planned