Station Keeping

Station keeping is the set of orbital adjustments needed to counteract perturbations that would otherwise cause a satellite to drift from its intended orbit or ground track. In GEO, station keeping maintains a satellite within its assigned longitudinal slot against gravitational perturbations from the Moon and Sun, and the Earth's non-spherical gravity field. East-west station keeping corrects longitude drift; north-south station keeping corrects inclination drift. In LEO, station keeping maintains altitude against atmospheric drag and corrects ground-track drift for repeat-pass interferometry or constellation phasing. Station keeping consumes propellant, and its frequency and precision directly affect satellite lifetime. Some operators have transitioned to electric propulsion for station keeping, which is more efficient but requires longer burn times. Autonomous station keeping, where satellites self-trigger maneuvers based on GPS or orbit determination, is increasingly common.