Geostationary ring
Encyclopedia
The geostationary ring is a volume segment around the geostationary orbit
defined by variations in altitude and declination that can occur for uncontrolled objects left in the geostationary orbit
.
The geostationary orbit
is subject to orbit perturbations caused by anomalies in the gravitational field
of the Earth
, by the gravitational effects of Sun
and Moon
, and by solar radiation pressure.
A precessional motion of the orbit plane is caused by the oblatedness of the Earth
(
), and the gravitational effects of Sun
and Moon
. This motion has a period of about 53 years. The two parameters describing the direction of the orbit plane in space, the right ascension
of the ascending node, and the inclination
are affected by this precession
. The maximum inclination
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 the geostationary orbit
that ranges from 75 km below GEO to 75 km above GEO and from -15 degrees to 15 degrees declination.
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
defined by variations in altitude and declination that can occur for uncontrolled objects left in the geostationary orbit
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
.
The geostationary orbit
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
is subject to orbit perturbations caused by anomalies in the gravitational field
Gravitational field
The gravitational field is a model used in physics to explain the existence of gravity. In its original concept, gravity was a force between point masses...
of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, by the gravitational effects of Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, and by solar radiation pressure.
A precessional motion of the orbit plane is caused by the oblatedness of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
(
), and the gravitational effects of SunSun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
. This motion has a period of about 53 years. The two parameters describing the direction of the orbit plane in space, the right ascension
Right ascension
Right ascension is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. The other coordinate is the declination.-Explanation:...
of the ascending node, and the inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
are affected by this precession
Precession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
. The maximum inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
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 the geostationary orbit
Geostationary orbit
A geostationary orbit is a geosynchronous orbit directly above the Earth's equator , with a period equal to the Earth's rotational period and an orbital eccentricity of approximately zero. An object in a geostationary orbit appears motionless, at a fixed position in the sky, to ground observers...
that ranges from 75 km below GEO to 75 km above GEO and from -15 degrees to 15 degrees declination.