Satellite Telecommunications
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Satellite Telecommunications
Network and Telecommunications Concepts 360
September 11, 2005
Table of Contents
Introduction
Satellite Communications History
Sputnik Changed Everything
Americas Response
Future Trends in Satellite Communications
GEO vs. LEO
Bent-Pipe Satellite Relay vs. the Switch in the Sky
Companies Involved in Satellite Communications
Regulatory Issues in Satellite Communications
Global implications for the area
Conclusion
Figure 1-1 – Satellite System Diagram
References
Introduction
Telecommunications was forever changed when the then Soviet Union launched Sputnik, the first satellite to orbit the Earth. Since that first launch back in 1957 the telecommunication industry has exploded. So what it is a satellite and what can it do for us? What is the technology involved in making Satellites? What trends will we see in the telecommunications industry because of satellites? Who uses satellites? Are there regulatory issues concerning the use of satellites, and what are the global implications of using satellites? These are some of the issues that are common when people discuss the use of satellites, so throughout this paper we will try to thoroughly answer those questions and hopefully provide a better understanding of satellites and what they can do for us.
Before we venture in the world of satellite communication, lets get a clear understanding of what a satellite is. A satellite is an object that orbits another object. It could either be a natural object like the moon or it can be a technological device that is man made. For the purpose of this paper we will be discussing the man made satellites. Satellites are used for things like sending and receiving television signals. The television signal is sent from Earth to a satellite, and then it is rebroadcast to multiple locations back on Earth. Satellites are also used for sending and receiving telephone, fax, and computer communications. Because of these satellites we are capable of communicating with anyone in the world. Satellites are also used for observing activity on Earth. The Military uses satellites for things like locating the enemy or guiding missiles. The National Weather Service uses satellites to track storms. A perfect example was their ability to track Hurricane Katrina, just think of how much worse the storm could have been if satellite images were not available to give warnings of such horrible storms. Satellites are also used for taking pictures of the Earth. Scientists use these images to determine changes happening with the planet and its ecosystem. These are just some of the things that having the ability to orbit man made satellites offers us here back on Earth.
Satellite Communications History
Sputnik Changed Everything
July 1957 – December 1958 was to be the high-point in the eleven year cycle of sunspot activity. To take advantage of the once-in-a-decade-plus opportunity, Lloyd Berkner, of the International Council of Scientific Unions (ICSU) proposed in 1952 a series of global geophysical activities.
In March of 1953, the NAS appointed a US National Committee to oversee US participation in the IGY. The US program included investigations of aurora and airglow, cosmic rays, geomagnetism, glaciology, gravity, the ionosphere, determinations of longitude and latitude, meteorology, oceanography, seismology, solar activity, and the upper atmosphere. In connection with upper atmosphere research, the US undertook to develop an orbiting satellite program. It was from the IGY rocket and satellite research that the US developed its space program — with the advice of the NAS Space Science Board. (NASA, 2005)
In October 1954, the ICSU called for the launching of artificial satellites to assist in mapping of the Earths surface. In July 1955, the White House made its plans for the Vanguard satellite known to the public.
However, before the US could get off of the ground, the USSR launched Sputnik. Sputnik I was launched on October 4, 1957. Sputnik I weighed a mere 183 pounds, and took about 98 minutes to orbit the Earth in its elliptical orbit.
It was highly polished aluminum to keep the temperature controlled and it had two radio transmitters on 20.005 and 40.002 Megahertz (MHz) respectively. There was a group of silver-zinc batteries to provide one watt of power for up to three weeks. On the outside of the craft sprung to the open sweptback position were four rods about 9.5 feet long, the satellites antennae. (Graham, 1995)
Americas Response
As Sputnik circled the Earth, North Americans were able to tune in as it passed overhead. This struck fear into the Americans, having the Soviets high overhead, doing who knows what. If they were able to put a satellite up, they could easily land a nuclear weapon on our soil.
The US responded with first Vanguard, and then Explorer I. Vanguard was a total failure, the rocket carrying it rising to a total of 4 feet before falling back to the ground.
As the firemen were fighting the flames, they noticed a small object spinning in the grass. It was the Vanguard satellite, with antennas deployed, transmitting as though it were in orbit. The satellite worked flawlessly, but the launch platform failed completely.
Explorer 1 was a cylinder 80 inches long and 6 inches in diameter; it had eleven pounds of scientific instruments, batteries, and radios and was the fourth stage of the rocket. The orbit stretched out to an apogee of 984 miles putting it much higher than the Russian spacecraft. One set of instruments on board Explorer 1 was a series of Geiger Counters for measuring radiation. Strangely, the instruments would quit working at a