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MARECS 1 was a geostationary communications satellite, which formed part of INMARSATs world-wide maritime communications satellite network. The program began as the experimental Maritime Orbital Test Satellite (MAROTS) in 1973, but was subsequently changed to an operational system resulting in a name change, a satellite redesign, and delayed development. MARECS was operated by ESA for INMARSAT. The spacecraft was based on the British Aerospace ECS platform, 3-axis stabilized to 0.2 deg (pitch, roll) using fully redundant momentum wheels, thrusters, and nutation dampers. Redundant sun sensors provided 0.04 deg knowledge. Two sun-tracking solar arrays provided 955 W (BOL) with 2 NiCd batteries for eclipse power. It had a hydrozine propulsion system for station-keeping. The payload consisted of 3 repeaters: shore-to-ship with 5 MHz bandwidth, ship-to-shore with 6 MHz bandwidth, and shore-to-shore with 0.5 MHZ bandwidth. These provided 35 two-way voice channels plus search and rescue capabilities. It had one 2 m diameter L-Band antenna and 2 horns (one transmit, one receive) for 4/6 GHz channels. All antennas had full Earth coverage.

Alternate Names

  • 13010

Facts in Brief

Launch Date: 1981-12-20
Launch Vehicle: Ariane
Launch Site: Kourou, French Guiana
Mass: 582 kg

Funding Agency

  • European Space Agency (International)


  • Communications

Additional Information

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

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