MARECS was a version of the European Space Agency's ECS communications satellite, adapted for maritime communications. It was used by Inmarsat. 

MARECS A was launched in 1981 and placed over the Atlantic Ocean. It was deactivated in August 1996.

MARECS B was lost due to launch problems in 1982, while MARECS B2 (also known as MARECS C) was launched in 1984 and placed over the Pacific Ocean. MARECS B2/C was active until 2002.

They were among Europe's first telecommunications satellites.

References

External links
 Documentary

Communications satellites
European Space Agency satellites