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Intelsat 2 F-4 (Intelsat IID) was a COMSAT Corporation commercial communications satellite upgraded to support the Apollo program and to provide 24-hour transoceanic service. It was launched on a Delta booster from Cape Canaveral on 28 September at 00:45 UT into a geosynchronous orbit above the Pacific Ocean. The satellite was retired in 1971.

The Intelsat II series of satellites was based on the Early Bird (Intelsat I) and Syncom 3 designs. The microwave communications capability was upgraded in response to NASA's need for improved quality and reliability due to the needs of the Apollo program. Multichannel communications were used on these satellites to link with overseas and shipborne tracking systems, as well as allowing additional capacity for Department of Defense and commercial traffic.

The satellite was a Hughes HS303 cylindrical bus, 142 cm (56 in.) in diameter and 67.3 cm (26.5 in.) in height, with an orbital mass of 87 kg (192 lbs). The spacecraft sides were aluminum honeycomb construction. It was powered by 12,756 n/p solar cells and NiCd batteries at 85 W initially (75 W or more after 5 years). The spacecraft was spin-stabilized and had a solid rocket apogee motor. It used passive thermal control. Telemetry was provided by two VHF transmitters and two encoders with two frequencies near 136 MHz via eight monopole antennas, command was received on an omnidirectional antenna.

It had a single wide bandwidth (130 MHz) single conversion repeater. Two redundant receivers (one on standby) were used to pick up signals from 6280 to 6410 MHz. The transmitter comprised four 6-W travelling wave tube amplifiers, which transmitted at 4055 to 4185 MHz. The receiving antenna was a 4-dB gain biconical horn, the transmission antenna was a four-element omnidirectional biconical horn array with a 5-dB gain, a radiated power of 15 W, and a 12 x 360 degree beam. The satellite had a capacity of 240 two-way voice channels and was designed so the beam was centered on the equator with equal coverage of the northern and southern hemispheres.

Alternate Names

  • 02969
  • I2F4
  • Pacific 2

Facts in Brief

Launch Date: 1967-09-28
Launch Vehicle: Thrust Augmented Delta
Launch Site: Cape Canaveral, United States
Mass: 87 kg
Nominal Power: 85 W

Funding Agency

  • International Telecommunications Satellite Corporation (International)


  • Communications

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Mr. C. P. Smith, Jr.Project ManagerNASA Goddard Space Flight Center
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