Satellite earth stations are different from previous ground-based installations in that they are intended to transmit to and receive from spacecraft. The first of these were used to track the early vehicles that were launched into orbit and deep space. The function is called tracking, telemetry, and command (TT&C) and often includes a requirement to receive various types of sensor information. Such stations could also be equipped for communication with manned spacecraft and orbiting repeaters (e.g., communication satellites).
Both the United States and the former Soviet Union introduced these capabilities as part of their respective space programs, which began in the mid-1950s. The first TT&C ground stations were, in fact, radio telescopes that had been modified for bidirectional transmission. An example is the 90-m Goldstone, California, tracking station antenna, which was installed in the late 1950s to track Explorer 1 by Jet Propulsion Laboratories (JPL), which at the time was under contract to the U.S. Army. In 1959, JPL was transferred to the National Aeronautics and Space Administration (NASA) as part of the still-operating Deep Space Network (DSN).
Also installed at Goldstone was the 30.5-m earth station for use with the Project Echo passive balloon reflector satellite. Bell Labs in Holmdale, New Jersey, provided the other end of the link with their reflector horn antenna. Horn antennas of this type have the added feature of very low side and back lobe radiation and reception, something that helps reduce noise pickup from extraneous sources. Later, this antenna was the instrument used by Bell Labs’ scientists A. A. Penzias and R. W. Wilson to make the discovery of the cosmic background noise level, produced by the Big Bang.
While experimenting with noise measurements, they were trying to find where about three degrees of excess noise was coming from.
The first active repeater satellite was Bell Laboratories Telstar 1, which allowed the United States and the United Kingdom to communicate realtime TV and voice. As the first true earth stations, these facilities were as large and elaborate as the TT&C stations and large radio telescopes that they emulated. Size did matter because of the low power and antenna gain provided by the little Telstar satellite. Because Telstar 1 was in low earth orbit (LEO), the earth stations required tracking systems; also, the service was interrupted whenever the satellite was not in simultaneous view of the end points.
All of these earth stations were highly customized and experimental in nature. They were not constructed to provide a service to subscribers and certainly were not operated as a business. In the next section, we consider how earth stations evolved into commercial ground segments installed to provide profitable communications services.
Both the United States and the former Soviet Union introduced these capabilities as part of their respective space programs, which began in the mid-1950s. The first TT&C ground stations were, in fact, radio telescopes that had been modified for bidirectional transmission. An example is the 90-m Goldstone, California, tracking station antenna, which was installed in the late 1950s to track Explorer 1 by Jet Propulsion Laboratories (JPL), which at the time was under contract to the U.S. Army. In 1959, JPL was transferred to the National Aeronautics and Space Administration (NASA) as part of the still-operating Deep Space Network (DSN).
Also installed at Goldstone was the 30.5-m earth station for use with the Project Echo passive balloon reflector satellite. Bell Labs in Holmdale, New Jersey, provided the other end of the link with their reflector horn antenna. Horn antennas of this type have the added feature of very low side and back lobe radiation and reception, something that helps reduce noise pickup from extraneous sources. Later, this antenna was the instrument used by Bell Labs’ scientists A. A. Penzias and R. W. Wilson to make the discovery of the cosmic background noise level, produced by the Big Bang.
While experimenting with noise measurements, they were trying to find where about three degrees of excess noise was coming from.
The first active repeater satellite was Bell Laboratories Telstar 1, which allowed the United States and the United Kingdom to communicate realtime TV and voice. As the first true earth stations, these facilities were as large and elaborate as the TT&C stations and large radio telescopes that they emulated. Size did matter because of the low power and antenna gain provided by the little Telstar satellite. Because Telstar 1 was in low earth orbit (LEO), the earth stations required tracking systems; also, the service was interrupted whenever the satellite was not in simultaneous view of the end points.
All of these earth stations were highly customized and experimental in nature. They were not constructed to provide a service to subscribers and certainly were not operated as a business. In the next section, we consider how earth stations evolved into commercial ground segments installed to provide profitable communications services.
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