The MARECS (Maritime European Communications satellite) satellites were members of
Inmarsat's first generation global maritime communications 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 is operated by ESA for Inmarsat.
Based on 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 provide 0.04 deg knowledge. Two sun-tracking solar
arrays provide 955 W (BOL) with 2 NiCd batteries for eclipse power. Hydrazine propulsion
system for station-keeping.
Three repeaters: shore-to-ship with 5 MHz bandwidth, ship-to-shore with 6 MHz
bandwidth, shore-to-shore with 0.5 MHz bandwidth. These provide 35 two-way voice channels
plus search and rescue capabilities. One 2 m diameter L-Band antenna and 2 horns (one
transmit, one receive) for 4/6 GHz channels. All antennas have full Earth coverage.
