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 Earth orbits, the altitude is approximately 20,200 kilometres (12,600 mi).[1][2]

Semi-synchronous orbits are typical for GPS satellites.

See also


  1. ^ NASA Technical Standard 8719.14 (draft) (Report). NASA Orbital Debris Program Office. 8 Aug 2006. Archived from the original (PDF) on 2006-08-23.
  2. ^ "Catalog of Earth Satellite Orbits". 6 Sep 2012.