Junk orbit
A graveyard orbit, also called a junk orbit or disposal orbit, is an orbit that lies away from common operational orbits, typically a supersynchronous orbit well above synchronous orbit. Satellites are moved into such orbits at the end of their operational life to reduce the probability of colliding with operational spacecraft or generating space debris.
A graveyard orbit is used when the change in velocity required to perform a de-orbit maneuver is too large. De-orbiting a geostationary satellite requires a delta-v of about 1,500 metres per second (4,900 ft/s), whereas re-orbiting it to a graveyard orbit only requires about 11 metres per second (36 ft/s).
For satellites in geostationary orbit and geosynchronous orbits, the graveyard orbit is a few hundred kilometers above the operational orbit. The transfer to a graveyard orbit above geostationary orbit requires the same amount of fuel as a satellite needs for about three months of stationkeeping. It also requires a reliable attitude control during the transfer maneuver. While most satellite operators try to perform such a maneuver at the end of their satellites' operational lives, through 2005 only about one-third succeeded. However, as of 2011, most recently decommissioned geosynchronous spacecraft were said to have been moved to a graveyard orbit.
According to the Inter-Agency Space Debris Coordination Committee (IADC) the minimum perigee altitude above the geostationary orbit is:
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