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The two antennas of the OTC Earth Station in
1971.
At left is the (then) two-year old 97 foot antenna and
at right is the older 42 foot antenna.
Photo: Tom Sheehan.
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Background
By 1963 a number of countries had begun discussions on creating
of a global satellite communications system.
In Washington in August 1964, eleven Governments, including Australia,
agreed to form an International Telecommunications Satellite Consortium
(INTELSAT). The aim was to have a global communications satellite system in
place by 1967 (later revised to 1968).
By 1968, 63 member countries were involved. Australia, through
its government owned international carrier, The
Overseas Telecommunications Commission, had an ownership share of 2.5%
of the space segment and was the sixth largest contributor.
In April 1965 the first internationally-owned commercial communications
satellite, INTELSAT I (also known as Early Bird), was placed in a geosynchronous
orbit above the Atlantic Ocean and enabled reliable telephone communication
between North America and Europe.
Also in 1965, NASA approached INTELSAT with the aim of
acquiring a satellite communications network for its rapidly expanding needs.
An agreement was reached – INTELSAT would launch and manage two INTELSAT
II satellites for NASA’s purposes – one above the Pacific, and the
other to serve the Atlantic area and part of the Indian Ocean area.
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An Intelsat II satellite.
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In addition to the satellites, a network of earth stations was
needed to relay voice and data from the NASA tracking stations, ships and the
ARIA aircraft, back to NASA centres in the US.
This background explains why Australia’s first satellite
earth station was built at Carnarvon. It was at the end of Brown’s Range,
just 4 kilometres north of the existing NASA Carnarvon Tracking Station. It
was purpose built to support the NASA station’s communications needs for
the Gemini and Apollo Programs. The two stations were linked by landlines.
Until this time, the Carnarvon Tracking Station had to rely on
tropospheric scatter radio links to Geraldton – and before that, telephone
lines. (The two troppo-scatter antennae are seen behind the NASA 30 foot USB antenna in this photo by Alan Gilham.)
The initial OTC Earth Station
Initially, the OTC Carnarvon earth station had one 42
foot (12.8m) antenna, serviced by three semi-transportable vans (operations,
maintenance and emergency power), housing the major equipment.
Permanent fixtures included two buildings, one for supplementary
equipment and stores, and another for primary power.
The whole station, including equipment, buildings and staff housing,
cost $3 million, and was completed in under 12 months. It was opened in late
1966.
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The initial 42 foot casshorn antenna of the OTC
Earth Station.
From a 1969 OTC publication.
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All this helps explain why many people confuse the two Carnarvon
stations. The NASA Tracking Station was built to support Gemini and Apollo
– and the OTC Earth Station was built to facilitate communication
between the NASA Tracking Station and the US.
The OTC Station expands
During 1967 a further three INTELSAT II satellites were placed
in geosynchronous orbit; two above the Pacific and another above the Atlantic
Ocean.
As these satellites had capacity to spare after meeting NASA’s
requirements, OTC went on to build Earth Stations at Moree
in northern NSW (to communicate with the Pacific Ocean satellites) and at Ceduna
in South Australia (to communicate with Europe via the Indian Ocean satellite).
These were used for Australian commercial voice, telex and TV traffic.
In 1969, the larger 97 foot (29.6m) steerable
antenna was completed. This released the 42 foot casshorn antenna to be
modified (at a cost of $600,000) for use as one of four Tracking, Telemetry
and Command stations in the worldwide network to control the new Intelsat III
satellites.
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One of the Intelsat III satellites.
This illustration of an Intelsat III communications satellite
was published in an OTC information booklet.
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Tom Sheehan
was on a NASA visit to the nearby tracking station in 1971 when he took these
photos of the OTC installation –
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View from the NW Coastal Highway of the staff houses.
Photo: Tom Sheehan.
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Sign on the entry road to the OTC station.
Photo: Tom Sheehan.
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The 97 foot antenna.
Photo: Tom Sheehan.
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The 42 foot casshorn antenna is at left.
Photo: Tom Sheehan.
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