المحافظة على مدار: الفرق بين النسختين

 

The deviation of Earth's gravity field from that of a [[Shell theorem|homogeneous sphere]] and gravitational forces from Sun/Moon will in general perturb the orbital plane. For [[sun-synchronous orbit]] the precession of the orbital plane caused by the oblateness of the Earth is a desirable feature that is part of the mission design but the inclination change caused by the gravitational forces of Sun/Moon is undesirable. For [[geostationary orbit|geostationary spacecraft]] the inclination change caused by the gravitational forces of Sun/Moon must be counteracted by a rather large expense of fuel, as the inclination should be kept sufficiently small for the spacecraft to be tracked by a non-steerable antenna.

[[en:orbital station-keeping ]]