Station Keeping

Station keeping is the process of using onboard propulsion to maintain a satellite within its assigned orbital position and orientation limits throughout its operational life. In satellite communications systems, station keeping is primarily concerned with counteracting natural perturbations due to the gravitational effects of the Sun and Moon, the non-uniformity of the Earth’s gravitational field, and solar radiation pressure.

For geostationary satellites, station keeping is typically divided into north–south station keeping, which controls inclination, and east–west station keeping, which controls longitude drift. North–south station keeping generally consumes the majority of onboard propellant. Reducing or ceasing north–south station keeping can extend satellite lifetime at the cost of allowing the satellite to drift into an inclined orbit, increasing tracking requirements at Earth stations.

Station keeping is distinct from attitude control, which maintains the satellite’s orientation rather than its orbital position.