Development of Satellites
Tara M / Physics 336 / 19 May 1997
The term satellite refers essentially to one thing--a small body, natural
or artificial, that revolves around a larger astronomical object. Data
gathered from these satellites help promote an awareness of the environment,
the world, and the universe. The new technologies developed from these
satellites have additional applications that benefit life on Earth.
Satellites During
the Cold War
Satellites were used as spies during the Cold War to photograph the
activities of the Soviet Union and China. These photographs can be used
to study desertification, urbanization, and other environmental changes.
They can also help scientists spot many surface features from space.
Many once-super secret Cold War spy satellite photographs began to
be released under an executive order by President Clinton. The pictures
were collected by the first generation of photo-reconnaissance satellites
from their advent in August 1960 through May 1972. This is when more advanced
systems took over. Included in the photographs was the image of the Corona
series of spy satellites--a shot of a military airfield in northeastern
Russia. The reconnaissance pictures, taken regularly to monitor arms developments
and produce maps, will help establish a baseline in the 1960s for measuring
changes, such as global warming, desertification, and forest shrinkage
(Wolf 1).
First Early Communications
Satellites
National Aeronautics and Space Administration (NASA) was created in
October 1958 and took control of space activities. It is exploring ways
to provide frequent flight opportunities for inexpensive space missions.
NASA hopes to continue learning about the balance of life on our planet.
NASA, though, has confined itself to experiments with "mirror"
or "passive" communications satellites, while the Department
of Defense was responsible for "repeater" or "active"
satellites, which amplify signals, that they receive, at the satellite.
In 1960, American Telephone and Telegraph (AT&T) filed with the Federal
Communications Commission (FCC) for permission to launch an experimental
communications satellite. Communications Satellite Corporation (COMSAT)
was formed in 1962 as a result of the Communications Satellite Act and
was in the process of contracting to build a system of dozens of medium-orbit
satellites. Other companies that provide service to the United States include
GE Americom, Alascom, GTE, and Hughes Communications (Whalen 1).
Satellites are put to a wide variety of uses. Applications range from
scientific research to military reconnaissance. The first satellites were
used to study the Earth's upper atmosphere and inner space. Today, scientific
satellites study a far greater range of objects. The major application
of artificial satellites has been to provide long-distance communication
links. Telephone companies, cable television stations, newspapers, and
magazines use communications satellites to transmit data to various parts
of the globe. Meteorological satellites use highly sensitive instruments
for modern weather forecasting. Navigation satellites use laser-beam signals
to determine the exact location of a ship on Earth. The technique used
by navigation satellites are also used to make accurate maps of remote
areas of the Earth. Countries use military surveillance or spy satellites
to monitor the activity of other nations (Demeis 72).
Important Satellites
Several well-known satellites were used to experiment the cutting-edge
of satellite technologies. In 1962, AT&T launched Telestar I. This
satellite transmitted phone calls and photos between Europe and America.
Telestar was the first satellite to transmit black-and-white color between
two continents. It was capable of 600 telephone channels or one television
channel. In 1963, Telestar 2 was launched and established the first direct
link between Japan and Europe.
Echo, a silvery balloon that orbited Earth every 114 minutes, was launched
August 12, 1960 by NASA. It was a passive satellite that reflected radio
signals back to Earth. Echo 2 was launched January 1964.
Relay I was NASA's first active experimental satellite and was launched
December 13, 1962. It handled simultaneous two-way telephone conversations
or one television channel. It provided the first satellite communication
link between North and South America and Europe. Relay 2, an improved version,
was launched in January 1964 ("Early Communications Satellites"
1).
The Syncoms were three experimental active satellites. Syncom I was
launched February 14, 1963, but did not reach synchronous orbit and communications
failed. Syncom II was launched July 26, 1963. It was the first satellite
placed in synchronous orbit. Syncom III was launched August 19, 1964. It
was the first stationary Earth satellite. In orbit near the International
Date Line, it was used to telecast the 1964 Olympic Games in Tokyo to the
United States. It was the first television program to cross the Pacific.
A French satellite, SPOT, helped illustrate the damage caused by the
explosion of the former Soviet Union's nuclear reaction in Chernobyl ("Satellites"
2).
Television Infrared Observation Satellite (TIROS) was the first series
of meteorological satellites to carry television cameras to photograph
the Earth's cloud cover and demonstrate the value of using spacecraft for
meteorological forecasting. The first TIROS was launched in 1960. It returned
data that showed a large degree of organization within the cloud cover
over the Earth.
Nimbus 1, a meteorological satellite, had a one-month life span. It
tracked the storm pattern of Hurricane Cleo and helped prevent severe damage.
Nimbus 7 operated from 1978 to 1993. It played a major role in the study
of the global ozone and the "ozone hole" over the Atlantic Ocean.
Present Satellites
Satellites today have improved tremendously since the first satellite
and are continuing to rapidly progress into the future. Around the world,
satellites put people and their computers on the information super highway.
They are used in our everyday lives and will continue to improve life on
Earth.
References
Brown, Stuart F. "America's First Eyes in Space." Popular
Science. Feb. 1996: cover.
Campanella, Joseph S. "Communications Satellite." Microsoft
Encarta '95 Multimedia Encyclopedia.
CD-ROM. Microsoft Corporation, 1994.
Demeis, Richard. "Satellite." Compton's Encyclopedia and
Fact Index. Chicago: World Book Inc.,
1996.
"Early Communications Satellites." http://www.csde.asde.aces.k12.ct.us/friends/;green/earlcom.html.
1/2/97.
Magill's Survey of Science Space Exploration Series, Vol. 1.
Pasadena: Salem Press, 1989.
Redmond, Charles. "Artificial Satellite." Merit Students
Encyclopedia. New York: MacMillan Education Co., 1989.
"Satellites." NASA Fact Sheets. http:// www.pao.gsfc.nasa.gov
/gsfc /service /gallery /factsheets /general /satsum.htm. 1/3/97.
Whalen, David J. "Communications Satellites: Making the Global
Village Possible." Communications Satellites Short History.
http://www.hq.nasa.gov/office/pao/history/satcomhistory.html. 1/2/97.
Wolf, Jim. "U.S. Lifts Veil on Spy Shots." Centerpiece.
http://www.sjmercury.com.:80/spy.htm. 1/5/97.