To Get a Broad View of Earth Initially, the only way humans could get a broad view of the Earth was to climb a tree or hike a mountain.

Later we used hot air balloons (1792), cameras( mid-1800’s), and kites to gain a birds-eye view.

San Francisco Bay 1906 Human ingenuity in 1906 resulted in the construction of an array of 17 kites moored to a boat in the San Francisco Bay to take pictures of the aftermath of the historic earthquake and resulting fires. Panorama of San Francisco in ruins, taken via kite photography approx. 2,000 feet (609 m) above San Francisco Bay overlooking water front.

Satellites The dawn of the space age in the 1950s enabled scientists to launch satellites into space equipped with remote sensing instruments that continuously monitor Earth. A satellite is an object that orbits a larger object, such as a planet. The earth’s moon is an example of a natural satellite; weather satellites are the result of human ingenuity.

What is a Satellite? Originated from Latin word ‘Satellit’ an attendant, one who is constantly hovering around & attending as a master a or big man. A satellite is an object that orbits a larger object, such as a planet. The word satellite originated from the Latin word Satellit, meaning an attendant, one who is constantly hovering around & attending as a master a or big man. A satellite is an object that orbits a larger object, such as a planet. A satellite is simply any body that moves around another (usually much larger) one in a mathematically predictable path called an orbit.

Earth’s Moon The earth’s moon is an example of a natural satellite;

Theory of Satellites Shoot something out into space at the right speed and on the correct trajectory and it will stay up there, orbiting Earth, for years. If the orbit is the right distance in space the satellite will keep pace with the rotation of the Earth. The theory of satellites was simple enough - shoot something out into space at the right speed and on the correct trajectory and it will stay up there, orbiting Earth, for years - if not forever.

Sputnik Early in October 1957 communications stations started picking up a regular beeping noise coming from space. The signals were coming from Russia's Sputnik 1, the world's first man-made satellite. The launch of the Russian satellite Sputnik in 1957 initiated our exciting exploration of space.

Explorer 1 It was January 1958, before a Jupiter rocket successfully launched Explorer 1, the first American satellite. 

History of Satellites con’d NASA's Syncom programme (1963) GEOs July 1963 - Hughes Aircraft Corporation launched the experimental Syncom 2 for NASA, the world's first geosynchronous communications satellite 1st live two-way satellite call between heads of state when President John F. Kennedy in Washington, D.C., telephoned Nigerian Prime Minister Abubaker Balewa in Africa. 3rd Syncom satellite transmitted live television coverage of the 1964 Olympic Games from Tokyo.   NASA's Syncom programme (1963) GEOs In July 1963 the Hughes Aircraft Corporation launched the experimental Syncom 2 for NASA, the world's first geosynchronous communications satellite. Its earlier sister, Syncom 1, had been blown up on launch earlier that year, but the second version was a huge success. It carried the first live two-way satellite call between heads of state when President John F. Kennedy in Washington, D.C., telephoned Nigerian Prime Minister Abubaker Balewa in Africa. The third Syncom satellite transmitted live television coverage of the 1964 Olympic Games from Tokyo.

History of Satellites con’d Early Bird (1965) World's 1st commercial communications satellite built for the Communications Satellite Corporation (COMSAT) by Hughes. April 6, 1965 placed in commercial service after moving into geosynchronous orbit 22,300 miles above the equator. always on station to provide line of sight communications between Europe and North America. didn't have a battery - worked only when its solar panels were exposed to the sun. The world's first commercial communications satellite was Early Bird, built for the Communications Satellite Corporation (COMSAT) by Hughes. The satellite was launched on April 6, 1965, and placed in commercial service after moving into geosynchronous orbit 22,300 miles above the equator. That meant it was always on station to provide line of sight communications between Europe and North America. Early Bird didn't have a battery - and worked only when its solar panels were exposed to the sun.

History of Satellites Later communications satellites Intelsat 3 satellites in 1969 created a global TV and speech communications network that spanned the Atlantic, Pacific and Indian Oceans. Multiple-beam antennas in 1980s brought new improvements in efficiency, as a satellite's power could now be concentrated on small regions of the Earth, making possible smaller-aperture (coverage area), lower-cost ground stations. Capacity (# simultaneous television and speech channels carried) grew as well. The launch of the Intelsat 3 satellites in 1969 created a global TV and speech communications network that spanned the Atlantic, Pacific and Indian Oceans. The introduction of multiple-beam antennas in the 1980s brought new improvements in efficiency, as a satellite's power could now be concentrated on small regions of the Earth, making possible smaller-aperture (coverage area), lower-cost ground stations. The Capacity (the number of simultaneous television and speech channels carried) grew as well.

Basics: How do Satellites Work Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means. The two stations can use a satellite as a relay station for their communication

How Satellites Work A Earth Station sends message in GHz range. (Uplink) Satellite Receive and retransmit signals back. (Downlink) Other Earth Stations receive message in useful strength area. (Footprint)

Basics: Advantages of Satellites The advantages of satellite communication over terrestrial communication are: The coverage area of a satellite greatly exceeds that of a terrestrial system. Transmission cost of a satellite is independent of the distance from the center of the coverage area. Satellite to Satellite communication is very precise. Higher Bandwidths are available for use.

Basics: Disadvantages of Satellites The disadvantages of satellite communication: Launching satellites into orbit is costly. Satellite bandwidth is gradually becoming used up. There is a larger propagation delay in satellite communication than in terrestrial communication.

Satellite Frequency Bands and Antennas (Dishes) The size of Satellite Dishes (antennas) are related to the transmission frequency. There is a inverse relationship between frequency and wavelength. As wavelength increases (and frequency decreases), larger antennas (satellite dishes) are necessary to gather the signal.

Next Time Types of Satellite Systems

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