Communications satellite

The invention: Telstar I, the world’s first commercial communications
satellite, opened the age of live, worldwide television by
connecting the United States and Europe.
The people behind the invention:
Arthur C. Clarke (1917- ), a British science-fiction writer
who in 1945 first proposed the idea of using satellites as
communications relays
John R. Pierce (1910- ), an American engineer who worked
on the Echo and Telstar satellite communications projects
Science Fiction?
In 1945, Arthur C. Clarke suggested that a satellite orbiting high
above the earth could relay television signals between different stations
on the ground, making for a much wider range of transmission
than that of the usual ground-based systems. Writing in the
February, 1945, issue of Wireless World, Clarke said that satellites
“could give television and microwave coverage to the entire
planet.”
In 1956, John R. Pierce at the Bell Telephone Laboratories of the
American Telephone & Telegraph Company (AT&T) began to urge
the development of communications satellites. He saw these satellites
as a replacement for the ocean-bottom cables then being used to
carry transatlantic telephone calls. In 1950, about one-and-a-half
million transatlantic calls were made, and that number was expected
to grow to three million by 1960, straining the capacity of the
existing cables; in 1970, twenty-one million calls were made.
Communications satellites offered a good, cost-effective alternative
to building more transatlantic telephone cables. On January 19,
1961, the Federal Communications Commission (FCC) gave permission
for AT&T to begin Project Telstar, the first commercial communications
satellite bridging the Atlantic Ocean.AT&T reached an
agreement with the National Aeronautics and Space Administration
(NASA) in July, 1961, in which AT&T would pay $3 million for each Telstar launch. The Telstar project involved about four hundred
scientists, engineers, and technicians at the Bell Telephone
Laboratories, twenty more technical personnel at AT&T headquarters,
and the efforts of more than eight hundred other companies
that provided equipment or services.
Telstar 1 was shaped like a faceted sphere, was 88 centimeters in
diameter, and weighed 80 kilograms. Most of its exterior surface
(sixty of the seventy-four facets) was covered by 3,600 solar cells to
convert sunlight into 15 watts of electricity to power the satellite.
Each solar cell was covered with artificial sapphire to reduce the
damage caused by radiation. The main instrument was a two-way
radio able to handle six hundred telephone calls at a time or one
television channel.
The signal that the radio would send back to Earth was very
weak—less than one-thirtieth the energy used by a household light
bulb. Large ground antennas were needed to receive Telstar’s faint
signal. The main ground station was built by AT&T in Andover,
Maine, on a hilltop informally called “Space Hill.” A horn-shaped
antenna, weighing 380 tons, with a length of 54 meters and an open
end with an area of 1,097 square meters, was mounted so that it
could rotate to track Telstar across the sky. To protect it from wind
and weather, the antenna was built inside an inflated dome, 64 meters
in diameter and 49 meters tall. It was, at the time, the largest inflatable
structure ever built. A second, smaller horn antenna in
Holmdel, New Jersey, was also used.International Cooperation
In February, 1961, the governments of the United States and England
agreed to let the British Post Office and NASAwork together
to test experimental communications satellites. The British Post Office
built a 26-meter-diameter steerable dish antenna of its own design
at Goonhilly Downs, near Cornwall, England. Under a similar
agreement, the French National Center for Telecommunications
Studies constructed a ground station, almost identical to the Andover
station, at Pleumeur-Bodou, Brittany, France.
After testing, Telstar 1 was moved to Cape Canaveral, Florida,
and attached to the Thor-Delta launch vehicle built by the Douglas Aircraft Company. The Thor-Delta was launched at 3:35 a.m. eastern
standard time (EST) on July 10, 1962. Once in orbit, Telstar 1 took
157.8 minutes to circle the globe. The satellite came within range of
the Andover station on its sixth orbit, and a television test pattern
was transmitted to the satellite at 6:26 p.m. EST. At 6:30 p.m. EST, a
tape-recorded black-and-white image of the American flag with the
Andover station in the background, transmitted from Andover to
Holmdel, opened the first television show ever broadcast by satellite.
Live pictures of U.S. vice president Lyndon B. Johnson and
other officials gathered at Carnegie Institution inWashington, D.C.,
followed on the AT&T program carried live on all three American
networks.
Up to the moment of launch, it was uncertain if the French station
would be completed in time to participate in the initial test. At 6:47
p.m. EST, however, Telstar’s signal was picked up by the station in
Pleumeur-Bodou, and Johnson’s image became the first television
transmission to cross the Atlantic. Pictures received at the French
station were reported to be so clear that they looked like they had
been sent from only forty kilometers away. Because of technical difficulties,
the English station was unable to receive a clear signal.
The first formal exchange of programming between the United
States and Europe occurred on July 23, 1962. This special eighteenminute
program, produced by the European Broadcasting Union,
consisted of live scenes from major cities throughout Europe and
was transmitted from Goonhilly Downs, where the technical difficulties
had been corrected, to Andover via Telstar.
On the previous orbit, a program entitled “America, July 23,
1962,” showing scenes from fifty television cameras around the
United States, was beamed from Andover to Pleumeur-Bodou and
seen by an estimated one hundred million viewers throughout Europe.Consequences
Telstar 1 and the communications satellites that followed it revolutionized
the television news and sports industries. Before, television
networks had to ship film across the oceans, meaning delays of
hours or days between the time an event occurred and the broadcast of pictures of that event on television on another continent. Now,
news of major significance, as well as sporting events, can be viewed
live around the world. The impact on international relations also
was significant, with world opinion becoming able to influence the
actions of governments and individuals, since those actions could
be seen around the world as the events were still in progress.
More powerful launch vehicles allowed new satellites to be placed
in geosynchronous orbits, circling the earth at a speed the same as
the earth’s rotation rate. When viewed from the ground, these satellites
appeared to remain stationary in the sky. This allowed continuous
communications and greatly simplified the ground antenna
system. By the late 1970’s, private individuals had built small antennas
in their backyards to receive television signals directly from the
satellites.