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Gorizont 21



Gorizont 21 was a Soviet geosynchronous communications satellite. It was launched to provide telephone, telegraph and fax communications services, in addition to relaying TV and radio broadcasts. It was stationed at 90 deg E.

The Gorizont spacecraft possessed an initial mass in excess of 2.1 metric tons and have demonstrated a lifetime of nearly 10 years, although a 5-year service life was more common. The 3-axis stabilized satellite was approximately 2 m in diameter and 5 m long with two large solar arrays capable of generating 1.3 kW of electrical power for the first 3 years. Seven separate transmission antennas allowed a variety of reception patterns for both broad and localized terrestrial regions.

A typical Gorizont communications payload included six general purpose (TV, audio, facsimile) 6/4 GHz transponders (five 12.5 W and one 60 W), one Luch 14/11 GHz transponder (15 W), and one Volna 1.6/1.5 GHz transponder (20 W). The Volna transponders were INMARSAT-compatible and were extensively used by the Russian merchant marine fleet via the primary GEO television rebroadcasting system, supporting all five Federation time zones: Zone 1 from 140 deg E, Zone 2 from 90 deg E, Zone 3 from 80 deg E, Zone 4 from 53 deg E, and Zone 5 from 14 deg W. These transmissions were handled by Orbita (12-m receiving antenna) and Moskva (2.5-m receiving antenna) ground stations in the 6/4 GHz band. The Moskva Globalnaya system was inaugurated in 1989 using 4-m receiving antennas and serviced by Gorizonts at 96.5 deg E and 11 deg W.

Alternate Names

  • 20923
  • Gorizont21

Facts in Brief

Launch Date: 1990-11-03
Launch Vehicle: Proton
Launch Site: Tyuratam (Baikonur Cosmodrome), U.S.S.R
Mass: 2125 kg

Funding Agency

  • Unknown (U.S.S.R)


  • Communications

Additional Information

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

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