History of Satellites
The advent of rockets in the 1950s led engineers to think seriously about putting orbiting satellites into space. Writer Arthur C. Clark first suggested the idea of communications satellites in geosynchronous in the October 1945 issue of Wireless World. Clarke realized that a radio relay station in space could serve a huge area of the earth’s surface. Because the space relay would be so far above the surface, it would be like having a radio tower thousands of miles high. In In the April 1955 issue of Jet Propulsion, J.R. Pierce of Bell Labs presented his ideas on communications satellites in an article entitled "Orbital radio relays"; he discussed both passive satellites and ones with powered repeaters, calculating that microwave communications between points on earth should be possible by means of orbiting satellites. Pierce subsequently became a major advocate of using artificial “satellites” (objects that circle the earth) for communication purposes.
The first satellite to contain a radio transmitter was the USSR’s Sputnik, launched in 1957. The U.S rushed to end a Sputnik-like transmitter into space in early 1958. Later that same year the U.S put into orbit the first radio relay capable of both transmitting and receiving messages (called Project SCORE). The military continued to develop military satellites and, today, military command and control operations in many countries rely extensively on satellites, although the functions of many of them remain secret. These satellites have included spy satellites, those used for voice and data communication, weather information, navigational information, and the Global Positioning System (GPS).
The first communication satellite was launched on December 18, 1958. Signal Communication by Orbital Relay (SCORE), which broadcasted a Christmas message from President Eisenhower - "Peace on Earth, Good will toward men" - orbited the earth for 12 days until the batteries failed. The main purpose of the SCORE project was to prove that an atlas missile could be put into orbit.
Combined, the U.S. and U.S.S.R. launched six satellites in 1958, 14 satellites in 1959, 19 in 1960 and 35 in 1961. In 1962, the United Kingdom and Canada launched satellites of their own, along with the 70 satellites launched by the U.S. and U.S.S.R.
On August 12, 1960, the United States launched Echo 1, a passive reflector satellite with no amplification possibilities. Echo 1 could only reflect the radiation back to earth. At the time of its launch, it was thought that passive reflector satellites could serve a purpose in communications, but the technology was soon abandoned.
Bell Telephone Laboratories assisted in the Echo 1 project. Knowledge gained working on Echo 1 helped Bell to develop Telstar, an experimental satellite that relayed television signals. Telstar was launched into medium earth orbit in 1962. In the six months following the launch, stations in the United States, Britain and France conducted about 400 transmissions with multichannel telephone, telegraph, facsimile and television signals, and they performed over 250 technical tests and measurements.
Near complete Earth coverage (excluding polar areas) was achieved with the development of Intelsat and the launching of satellites into geosynchronous earth orbit over the Atlantic (1965), Pacific (1967), and Indian oceans (1969). A combination of more than 130 governments and international organization control Intelsat. Intelsat, along with Inmarsat, which is used in international shipping, is open to use by all nations. The Intelsat consortium owns the satellites, but each nation owns their own earth stations. In 1997 Intelsat had 19 satellites in geostationary orbit.
The advent of rockets in the 1950s led engineers to think seriously about putting orbiting satellites into space. Writer Arthur C. Clark first suggested the idea of communications satellites in geosynchronous in the October 1945 issue of Wireless World. Clarke realized that a radio relay station in space could serve a huge area of the earth’s surface. Because the space relay would be so far above the surface, it would be like having a radio tower thousands of miles high. In In the April 1955 issue of Jet Propulsion, J.R. Pierce of Bell Labs presented his ideas on communications satellites in an article entitled "Orbital radio relays"; he discussed both passive satellites and ones with powered repeaters, calculating that microwave communications between points on earth should be possible by means of orbiting satellites. Pierce subsequently became a major advocate of using artificial “satellites” (objects that circle the earth) for communication purposes.
The first satellite to contain a radio transmitter was the USSR’s Sputnik, launched in 1957. The U.S rushed to end a Sputnik-like transmitter into space in early 1958. Later that same year the U.S put into orbit the first radio relay capable of both transmitting and receiving messages (called Project SCORE). The military continued to develop military satellites and, today, military command and control operations in many countries rely extensively on satellites, although the functions of many of them remain secret. These satellites have included spy satellites, those used for voice and data communication, weather information, navigational information, and the Global Positioning System (GPS).
The first communication satellite was launched on December 18, 1958. Signal Communication by Orbital Relay (SCORE), which broadcasted a Christmas message from President Eisenhower - "Peace on Earth, Good will toward men" - orbited the earth for 12 days until the batteries failed. The main purpose of the SCORE project was to prove that an atlas missile could be put into orbit.
Combined, the U.S. and U.S.S.R. launched six satellites in 1958, 14 satellites in 1959, 19 in 1960 and 35 in 1961. In 1962, the United Kingdom and Canada launched satellites of their own, along with the 70 satellites launched by the U.S. and U.S.S.R.
On August 12, 1960, the United States launched Echo 1, a passive reflector satellite with no amplification possibilities. Echo 1 could only reflect the radiation back to earth. At the time of its launch, it was thought that passive reflector satellites could serve a purpose in communications, but the technology was soon abandoned.
Bell Telephone Laboratories assisted in the Echo 1 project. Knowledge gained working on Echo 1 helped Bell to develop Telstar, an experimental satellite that relayed television signals. Telstar was launched into medium earth orbit in 1962. In the six months following the launch, stations in the United States, Britain and France conducted about 400 transmissions with multichannel telephone, telegraph, facsimile and television signals, and they performed over 250 technical tests and measurements.
Near complete Earth coverage (excluding polar areas) was achieved with the development of Intelsat and the launching of satellites into geosynchronous earth orbit over the Atlantic (1965), Pacific (1967), and Indian oceans (1969). A combination of more than 130 governments and international organization control Intelsat. Intelsat, along with Inmarsat, which is used in international shipping, is open to use by all nations. The Intelsat consortium owns the satellites, but each nation owns their own earth stations. In 1997 Intelsat had 19 satellites in geostationary orbit.
References:
- What is communication satellite? [online] Available at: http://www.webopedia.com/TERM/C/communications_satellite.html
- Space age. [online] Available at: http://en.wikipedia.org/wiki/Space_Age
- Communication Satellites. [online] Availabe at: http://www.ieeeghn.org/wiki/index.php/Communications_Satellites