Example image of eyePlorer eyePlorer map for 'Earth-centered inertial': ECEF Inertial space Equations of motion Orbit Astronomical object Ecliptic Equinox Fundamental plane Celestial equator Declination Right ascension Coordinates (mathematics) Geographic coordinate system Cartesian coordinate system Nutation Precession Epoch (astronomy) International Earth Rotation and Reference Systems Service Terrestrial Time North Pole International Celestial Reference Frame North American Aerospace Defense Command Two-line element set SGP4 ECI