Orbital station-keeping

Orbital station-keeping is the use of controlled spacecraft maneuvers to preserve a desired orbit or relative position despite gravitational and other perturbations.

Orbital perturbation: A deviation from an idealized orbit caused by forces or effects beyond the simplified two-body gravitational model. Perturbations create the drift that station-keeping maneuvers must counter.
Geostationary orbit: A circular equatorial orbit in which a satellite appears fixed above one point on Earth. Satellites in this orbit correct longitude and inclination drift to remain near their assigned positions.
Two-body problem: The idealized calculation of two masses moving under their mutual gravitational attraction alone. It supplies the baseline orbit from which real perturbations are measured.
Orbit raising: The deliberate increase of a spacecraft's orbital altitude or energy. Raising an orbit changes its intended state, while station-keeping preserves one.
Geostationary orbit graveyard: A disposal region above geostationary orbit used to move retired satellites away from operational slots. End-of-life relocation follows station-keeping service and reduces interference with working satellites.
Orbital maneuver: A deliberate change to a spacecraft's trajectory, usually produced by thrust or another applied force. Station-keeping is a recurring, narrowly targeted form of orbital maneuvering.
Geostationary satellite: A satellite placed in geostationary orbit, commonly used for communications and weather observation. Its service depends on maintaining a stable viewing position over Earth.
Gravitational perturbation: An orbital deviation caused by gravity from bodies or mass distributions beyond an ideal central point mass. Earth's uneven gravity and third-body attraction alter spacecraft orbits over time.
Orbital transfer: A maneuver or sequence of maneuvers that moves a spacecraft from one orbit to another. Transfer targets a new orbit; station-keeping limits departures from the current target.
Orbital debris: Human-made objects in orbit that no longer serve a useful function, including fragments and retired spacecraft. Poorly managed disposal after active control ends can add long-lived debris.

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