Communications Satellite Corporation (COMSAT), a private corporation, was a leading provider of communications satellite services in the United States and overseas during the late 1900's. COMSAT was the U.S. participant in INTELSAT, a global communications satellite system. Through INTELSAT, COMSAT enabled telephone messages, television signals, and other forms of communication to be sent between the United States and other countries. COMSAT also provided services to the shipping and offshore oil-drilling industries through INMARSAT, an international maritime satellite system.