Inmarsat 2-F4 was a maritime satellite launched using an Ariane launch vehicle from the Kourou Space Center for the International Maritime Satellite Organization. It operated a total of four INMARSAT-2 satellites. Launched between 1990-92, they each had a capacity equivalent to about 250 INMARSAT-A voice circuits.
The spacecraft was built by an international consortium headed by British Aerospace. Subcontractors included Hughes Aircraft Company, Fokker (The Netherlands), Matra (France), MBB (Germany), NEC (Japan), and Spar (Canada). Satellite ground control operations contractors included CLTC (China), CNES (France), SED (Canada), Telespazio (Italy) and Intelsat.
The INMARSAT-2s were three-axis-stabilized spacecraft based on the Matra/B Ae Eurostar platform. With a ten-year design life, each satellite has a 1,300 kg launch mass, reducing to an initial 800 kg in orbit. Initial power rating was 1,200 W.
The communications payload comprised two transponders supporting satellite- to-mobile (service) links in L-band (1.6GHz uplink, 1.5GHz downlink) and satellite-to-earth station (feeder) links in C-band (6.4GHz uplink, 3.6GHz downlink). Effective L-band isotropic radiated power (EIRP) was 39dBW. Each satellite's global beam covered roughly one-third of the earth's surface.
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