Graveyard orbit

As a graveyard orbit (English graveyard orbit ), graveyard orbit or shortly graveyard orbit is referred to an earth orbit ( "Orbit " ) for your old apogee satellites. While spacecraft are disposed of in low orbit (LEO ) by lowering the trajectory in the atmosphere, the bullet to a higher orbit is the only option for geosynchronous satellites ( GEO).

The disposal of these objects is necessary because the interest for satellite orbits are sought after and because ( in lower orbits also by deceleration in the residual atmosphere ) could also be for the Earth by drifting a danger to other satellites, space shuttles and ( by Crash ) see space debris.

The limited lifetime of a satellite is mainly the fact that in addition to various possible defects, especially the on-board fuel that is needed to stabilize the orbit position is used or is only for a few maneuvers in a different orbit.

The graveyard orbit is usually on the regular orbit of the satellite, in the case of geostationary satellites about 300 km (super -synchronous orbit ). If a geostationary satellite occupying a graveyard orbit below the geosynchronous orbit (GEO), there is always the risk that it collides with a new satellite at the leading to the GTO GEO orbit. The Inter-Agency Space Debris Coordination Committee ( IADC ) defines the area to be kept free of geosynchronous orbits to ± 200 km and ± 15 ° of the geostationary orbit fixed. The minimum height of the train graveyard orbit above the geostationary orbit should be increased because of possible gravitational perturbations induced by a further 35 km and because solar radiation pressure-induced perturbations to a further dependent on the characteristics of Satellite amount:

Here is the Reflektivitätskoeffizient of the satellite, its maximum shadow area and its mass. The Reflektivitätskoeffizient is 1 case of complete absorption, 2 with total reflection, ie at ideal black or mirrored satellites. In practice, it is usually between 1.2 and 1.5.

Some unusual geostationary satellites could no longer be postponed and pose a risk to other geostationary satellites dar. Other failed, as they were brought to their position in GEO after a fault back. Thus, for example, is the cemetery of the orbit communications satellites DFS Copernicus 3 about 100 km below the geosynchronous orbit. There he was stabilized after drifting through a defect during the decision on how to proceed, as well as the railway was thus no longer geostationary and the satellite drifted as planned along the Equator to its previous position. However, he no longer had enough fuel to return to the GEO, so he remained in this unfavorable graveyard orbit.

For the track change specifically of scheduled fuel used. Have the satellite reaches the graveyard orbit, any remaining fuel is drained and discharge the batteries to prevent decomposition of the satellite due to uncontrolled release of energy.