The position and velocity of the object, expressed in mixed spherical elements, as a function of time. The position is expressed using LLA elements, with respect to the vehicle's central body fixed coordinate system -- the requested coordinate system is immaterial. The velocity of the object is computed as observed from the requested coordinate system. The ephemeris can be requested in a variety of coordinate systems. The available coordinate systems depend on the object's central body. Nominally, the systems Fixed, Inertial, J2000, TrueOfDate, and MeanOfDate are supported, although some central bodies (notably the Earth and Sun) have more. The following lists the systems available for Earth.