Ephemeris

An ephemeris (plural: ephemerides) is a table listing the predicted position and velocity of a space object at regular time intervals. While TLEs provide a compact analytical representation propagated through SGP4, high-precision ephemerides use numerical integration of all relevant force models (gravitational, atmospheric, solar radiation pressure, third-body effects). NASA provides ephemerides for planetary bodies through JPL Horizons. For satellites, high-precision ephemerides in the OEM (Orbit Ephemeris Message) format are used for conjunction assessment and mission operations.