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INTELSAT 3F-4 was launched by NASA for Communications Satellite Corporation. It provided service over the Pacific Ocean through November 1972.

The Intelsat 3 program comprised a series of eight nearly identical communications satellites, it was the first to provide global coverage. They were put in geosynchronous orbits over various equatorial areas and provided reception and retransmission capabilities with 1200 two-way voice circuits or four television circuits.

The satellite was a 150 kg spinning cylinder, 142 cm in diameter and 104 cm high. It had a despun conical horn antenna protruding from the top axis, total height including the antenna was 198 cm. The outside was covered with solar cells, which provided 160 W power to NiCd batteries. A solid rocket motor was used for apogee maneuvers with a hydrazine monopropellant thruster for use on-orbit.

Communication was channeled through two 225-MHz bandwidth single-conversion repeaters, consisting of two tunnel-diode amplifier receivers (5930-6155 MHz and 6195-6420 MHz) and two TWTA transmitters (3705-3930 MHz and 3970-4195 MHz). The horn antenna had a flat reflector angled 45 degrees to the axis and a 19.3 degree beamwidth with circular polarization. Telemetry was at 3933 and 3967 MHz using an omnidirectional or Earth coverage antenna. Command was at 6175 MHz via an omnidirectional antenna.

Alternate Names

  • 03947

Facts in Brief

Launch Date: 1969-05-22
Launch Vehicle: Delta
Launch Site: Cape Canaveral, United States
Mass: 647 kg

Funding Agency

  • International Telecommunications Satellite Corporation (International)


  • Communications

Additional Information

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



NameRoleOriginal AffiliationE-mail
Mr. Robert R. ZiemerProject ManagerNASA Goddard Space Flight Center
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