- Geostationary ring
The

**geostationary ring**is a volume segment around thegeostationary orbit defined by variations in altitude and declination that can occur for uncontrolled objects left in thegeostationary orbit .The

geostationary orbit is subject toorbit perturbations caused by anomalies in thegravitational field of theEarth , by the gravitational effects ofSun andMoon , and bysolar radiation pressure.A precessional motion of the

orbit plane is caused by the oblatedness of theEarth ($J\_2$), and the gravitational effects ofSun andMoon . This motion has a period of about 53 years. The two parameters describing the direction of theorbit plane in space, theright ascension of the ascending node, and theinclination are affected by thisprecession . The maximuminclination reached during the 53-year cycle is about 15 degrees. Therefore, the definition of the geostationary ring foresees a declination range from -15 degrees to +15 degrees.On the other hand,

solar radiation pressure induces an eccentricity that leads to a variation of the orbit radius by ± 75 kilometers in some cases.This leads to the definition of the

geostationary ring as being a segment of space around thegeostationary orbit that ranges from 75 km below GEO to 75 km above GEO and from -15 degrees to 15 degrees declination.

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