Geostationary Earth Orbit


Geostationary Earth Orbit 


The great scientist and science fiction writer Arthur C. Clarke was the first, I believe, to point out the existence of a very special orbit of the earth in which an object placed in that orbit would remain in a fixed position relative to the geography of the earth, and that such a site would be great for communication satellites so that transceivers could be aimed at a particular part of the sky and would remain pointed at the communication satellite without further adjustment. And in fact, the "satellite dishes" one sees scattered around are indeed pointing at such a satellite in Geostationary Earth Orbit, usually abbreviated "GEO". Geo is located some 22,300 miles above the earth's equator, and the direction of satellites placed there is the same direction as the Earth rotates; the satellites have the identical angular rotation rate as Earth does.

One of the early names for this special orbit was "The Clarke Belt", in fact, although one rarely hears that name now.

Some interesting info about GEO:

  • Is in earth's equatorial plane
  • Distance above the earth surface on average is 4.23E7 meters
  • 3.078E3 m / S = orbital velocity in GEO
  • Gravitational acceleration in GEO= 0.224 m / Sec2
  • Energy given to mass by moving it up from the Earth surface at the equator, into GEO: 7.15 KWh per pound mass At 10 cents per KWh, that is only $0.72 per pound moved from the ground up into GEO.