Academic journal article Technology and Engineering Teacher

Preparing Students for the Satellite Industry: While the Satellite Industry Is Characterized by Dynamic Innovation, It Has Steadily Matured into a Healthy, Market-Driven Model of Customers, Value Generators, and Supporting Suppliers

Academic journal article Technology and Engineering Teacher

Preparing Students for the Satellite Industry: While the Satellite Industry Is Characterized by Dynamic Innovation, It Has Steadily Matured into a Healthy, Market-Driven Model of Customers, Value Generators, and Supporting Suppliers

Article excerpt

Satellite History

The first satellite went into operation when the Soviet Union dramatically launched Sputnik 7 in 1957. Sputnik orbited the world, transmitting a signal from October to December of that year. A month later the Soviets launched Sputnik 2 and its passenger, Laika, the first living creature to enter Earth orbit. The space race was on, and the United States launched Explorer 1 early in 1958 (Pelton, 1998). The first satellite to serve a communications purpose was launched by the U.S. in December 1958 when the Signal Communication by Orbital Relay (SCORE) satellite broadcasted President Eisenhower's "Peace on Earth, good will toward men" message, The satellite functioned for 12 days until its batteries reached their end. The SCORE project demonstrated that an Atlas missile could achieve a stable orbit and, more importantly, that satellites had the potential to facilitate communications with Earth.

Russia and the U.S. had launched fewer than 20 temporary satellites into orbit prior to the U.S, Telstar project in 1962. Bell Telephone Laboratories constructed Telstar, an experimental satellite that relayed television signals from a medium Earth orbit. Telstar was arguably the most important commercial satellite first developed. For six months, the U.S., Britain, and France conducted about 400 transmissions with multichannel telephone, telegraph, facsimile, and television signals, and performed over 250 technical tests and measurements (Martin, 1991).

Following Telstar, the International Telecommunications Satellite (Intelsat) consortium coordinated the launching of satellites into geosynchronous Earth orbit over the Atlantic, Pacific, and Indian Oceans. Begun in August 1964, Intelsat achieved whole-Earth communications by 1969. A combination of more than 130 governments and international organizations now comprise Intelsat, one of the most enduring space collaborations. Intelsat and Inmarsat (maritime control) are available for use by all participating nations. The Intelsat consortium owns the satellites, but each nation owns its own Earth ground communications stations (Montgomery, 1997).

NASA's Advanced Communications Technology Satellites (ACTS) program began in 1993. ACTS pioneered the use of spot beams, onboard storage and processing, and digital transmission. These innovations combined to enable the creation of a satellite constellation, a network of interconnected satellites that work in concert to serve a communications purpose. Following the successful demonstration of the constellation, the Federal Communications Commission (FCC) began to issue licenses to entities for the management of frequency segments (bands) of the electromagnetic spectrum. Among the first private companies to apply were Hughes, Loral, Motorola, EchoStar, and Teledesic (Pelton, Oslund, & Marshall, 2004). A handful of private broadcasters were early pioneers in bringing satellite communications to the television viewing masses: Home Box Office, Turner Broadcasting, and the Christian Broadcasting Network being chief among them. Today, over 14 million homes in America have a satellite receiver for broadcast and broadband use, and the variety of private purposes served by satellites continues to grow.

Characteristics of Satellites

Operating satellites vary in their orbital type, which is chosen based on their expected life, functional characteristics, and intended purpose. Most existing and planned satellites hold a Low Earth Orbit (LEO), ranging from 200 km to 1200 km. These orbits are relatively inexpensive to achieve. The communications path used with LEO satellites is short, which provides a higher quality of service, and exposure to bothersome radiation is greatly diminished. LEO orbits cannot remain stationary over a single area; therefore, a constellation of LEO satellites is essential for most communications tasks. Satellites with an elevation lower than 300 km (180 miles) will experience atmospheric drag and a loss of energy that will result in a return to Earth that must be planned (Martin, 1991). …

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