Geostationary or Geosynchronous earth orbit (GEO) GEO satellites are synchronous with respect to earth and should be placed approximately 36,000 Kms above the surface of the earth, travel in the rotational speed of earth and in the direction of motion of earth. These satellites appear to be stationary if we look at it from any fixed point on Earth with life expectancy of about 15 years. Three such synchronous stations located 120 degrees apart above the equator could provide worldwide communications coverage.

These satellites are placed 500-1500 Kms above the surface of the earth, providing high quality communication link but they are visible from any specific region on the earth for around ten minutes only.

MEOs can be positioned somewhere between LEOs and GEOs in orbits around 10,000 km and requires about a dozen satellites to cover the whole of Earth which is more than a GEO system, but much less than a LEO system. These satellites move more slowly relative to the earth’s rotation with satellite periods of about six hours, covering large areas and with few handovers.