Venus Equilateral

It's often the case that science fiction precedes science non-fiction.  Science fiction author Arthur C. Clarke envisioned satellite communications long before it was a reality.  In this case Clarke wrote a serious proposal called "Extra-Terrestrial Relays" for geostationary communications satellites in 1945. You can read that here. But he had been inspired by the Venus Equilateral series of short science fiction stories by George O. Smith. The first of these were published in 1942.  The Smith stories concern the Venus Equilateral Relay Station, an interplanetary communications hub. Smith had the idea 3 years before Clarke and 20 years before the Telstar 1 satellite was launched on July 10, 1962.

Prior to the use of communication satellites, we had only two systems to defeat the curve of the earth. We had terrestrial wired systems, and we had microwave relay systems with towers on hilltops about 30 miles apart. But these systems were not great. Spanning just the North American continent took 107 hops by microwave relay. Prior to 1954 transatlantic cables were mostly fiscal and/or technological failures. Until the 1950s transatlantic telephone service was primarily radio-based. Technology had to catch up to the idea, but in the years after Clarke's proposal, the world began considering another approach. (Which we ironically reversed over the last decade)

Sputnik I was launched by the USSR in October of 1957, and the USA launched Explorer I in 1958. These were satellites, but not communication satellites.  In December of 1958 we launched Score under the Defense Department's ARPA program (Advanced Research Projects Agency). It was a shiny metallic mylar balloon 100 feet in diameter. It was in the spirit of, if not the design of some passive reflector design proposals written by J.R. Pierce around 1954. The actual unit was designed by Kenneth Masterman-Smith.  It contained two tape recorders (for redundancy) and four antennas two for transmission and two for reception. The frequencies used were 150 MHz for the uplink and 132 MHz for the downlink. Its batteries lasted 12 days and it then burned up on re-entry in January of 1959. It broadcast the first human voice communication from space on December 19th. President Eisenhowers words were as follows:

"This is the President of the United States speaking. Through the marvels of scientific advance, my voice is coming to you via a satellite circling in outer space. My message is a simple one: Through this unique means I convey to you and all mankind, America's wish for peace on Earth and goodwill toward men everywhere."

That's what he said, but what he meant was the U.S. now had the ability to deliver a nuclear weapon from space. The Russians took this poorly. More here. AARPA moved on with a project called Advent and Echo to mixed success. Echo was another 100ft passive reflector mylar balloon this one launched in August of 1960. It remained in orbit until May of 1968. Echo II was a bit more interesting. It was bigger at 135 feet in diameter, and was launched January 25, 1964. It came down in 1969. Following Echo, passive communications satellites were abandoned. Telstar 1, the first production active communication satellite was launched on July 10, 1962.

The Clarke Orbit

Geosynchronous Orbit n. 
An orbital position with an orbital period that matches the rotation rate of the Earth measured relatively to  fixed stars. 

That orbital period isn't a 24 hour day actually. it's what they call a mean sidereal day, which is 23 hours 56 minutes and 4.091 seconds in length. It's not an exactly fixed interval because the Earth wobbles on it's axis, which is measured as two variables called Precession and nutation.  Btu that's getting picky. This is just the time it takes for the Earth to rotate once around its polar axis relative to a distant fixed point. Our sun is not a distant fixed point, so they use the vernal equinox. So far.. not about radio. Don't worry I'm getting there.

The first man-made anything in space was a V4 rocket in 1942. the first satellite was Sputnik in 1957. But the first geosynchronous orbit wasn't achieved until 1964 with the launch of Syncom 3. It was an American communications satellite.

The very idea of a geosynchronous communications satellite is quite old, almost as old as broadcasting. It was first considered and published by Herman Potocnikin 1928. Being an ethnic Slovak in an area now called Croatia... his national identity is up for some debate. But he sometimes used the name Hermann Noordung. He was a real-deal rocket scientist. He attended the University of Technology in Vienna and became a mechanical engineer. He was inspired by the research of Hermann Oberth and went into rocketry.  But Arthur C. Clarke stole his thunder. In a 1945 paper published in Wireless World magazine, titled "Extra-Terrestrial Relays — Can Rocket Stations Give Worldwide Radio Coverage?" More here. He even predicted the frequency band we'd be using. He was only off a few hundred GHz on the future location of the C and Ku bands. Not bad for a guy who writes fiction. the first US TV network to move all it's affiliate feeds to the Ku band was NBC in 1983. Read on:

"It may be argued that we have as yet no direct evidence of radio waves passing between the surface of the earth and outer space; all we can say with certainty is that the shorter wavelengths are not reflected back to the earth... Medium high frequencies go through the E layer twice to be reflected from the F layer and echoes have been received from meteors in or above the F layer. It seems fairly certain that frequencies from, say, 50 MHz to 100,000 MHz could be used without undue absorption in the atmosphere or the ionosphere."

In the piece Clarke first described a geosynchronous orbit as useful for broadcast and relay communications. Because of this much more widely read publication a geosynchronous orbit  is sometimes called a Clarke Orbit. Likewise the region of Earth orbit where near-geostationary orbits are possible is called the Clarke Belt. it is about 22,000 miles above sea level along the equator. To his credit, there are presently over 700 radio communications satellites in a Clarke Orbit. More here.