Semi-synchronous orbit

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A semi-synchronous orbit is an orbit with a period equal to half the average rotational period of the body being orbited, and in the same direction as that body's rotation.

For Earth, a semi-synchronous orbit is considered a medium Earth orbit, with a period of just under 12 hours. For circular orbits, the altitude is approximately 20,200 km.(12,550mi)[1][2]

Semi-synchronous orbits are typical for GPS satellites.

See also[edit]


  1. ^ "NASA Technical Standard 8719.14 (draft)" (PDF). NASA Orbital Debris Program Office. 8 Aug 2006. 
  2. ^ "Catalog of Earth Satellite Orbits". 6 Sep 2012.