Early Bird, also known as Intelsat I, the world's first commercial communications satellite, was built for the
Communications Satellite Corporation (COMSAT) by the Space and Communications Group of
Hughes Aircraft Company, later Hughes Space and Communications Company. The satellite was
launched into synchronous orbit on 6 April 1965. It was placed in commercial service on
June 28. Early Bird's design stemmed from the Syncom satellites Hughes had built for the
National Aeronautics and Space Administration to demonstrate the feasibility of
communications from synchronous orbit. On station in orbit 22,300 miles above the equator,
Early Bird provided line of sight communications between Europe and North America. As a
communications repeater, Early Bird handled communications that were representative of all
types of common carrier network traffic, including telephone, television, telegraph, and
facsimile transmissions.
As the forerunner of a synchronous satellite system that would furnish communications
to all the populated areas of the world, Early Bird, with capability of 240 circuits or
one TV channel, successfully demonstrated the concept of synchronous satellites for
commercial communications. While designed for an operational lifetime of only 18 months,
the satellite was in continuous, full-time service for nearly 4 years. It was placed on
reserve status in January 1969, but recalled into service in June of that year for use
during the Apollo 11 mission. Two months later the satellite was again retired from active
service and placed in orbital reserve by COMSAT. The satellite is currently inactive.
Features:
- Spin stabilized-gyroscopic action eliminated need for complex attitude control systems
- Solar power for constant operation
- Provided point-to-point communications
The primary advantage of a synchronous orbit communications satellite is that ground
installations are greatly simplified. By virtue of the satellite's "fixed"
position, complex and expensive tracking antennas are not required. However, in order to
hold its position in relation to the Earth's axis, the satellite must be placed directly
above the equator. Since Early Bird was launched from Cape Kennedy, which is north of the
equator, certain maneuvers were necessary to properly position the satellite. These were
performed by means of commands from the Earth station located at Andover, Maine. The
launch vehicle for Early Bird was the Delta-D, a
three-stage rocket built by Douglas Aircraft Company. Launched with its apogee motor in a
forward position, Early Bird was aligned by the Delta's third stage at an angle of 16.7
degrees to the equator and spin stabilized. It was separated from the third stage at 26
minutes, 32 seconds after liftoff and coasted to its first apogee of 23,081 miles. During
the elliptical orbits, Early Bird was precisely oriented by ground control.
With the firing of the apogee motor on the sixth apogee, Early Bird was thrust into an
almost circular equatorial orbit near 32 degrees W longitude with an eastward drift rate
of 1.5 degrees per day. Final synchronization to slow the drift rate and more nearly match
the earth's rotation rate was accomplished on 14 April 1965. This maneuver placed Early
Bird at its planned position, 28 degrees W longitude. The attitude of the satellite was
then changed to concentrate the antenna beam on the Andover and European earth stations.
The earth station at Andover was equipped with Hughes-developed telemetry and command
equipment. Launching services and facilities were provided by NASA in accordance with an
agreement with COMSAT.