Specific mechanical energy  Specific mechanical energy is the mechanical energy of an object per unit of mass. Similar to mechanical energy, the specific mechanical energy of an object in an isolated system subject only to conservative forces will remain constant. It is defined as:  formula_1  where    In the gravitational two-body problem, the specific mechanical energy formula_4 is given as:  formula_5  where   When calculating the specific mechanical energy of a satellite in orbit around a celestial body, the mass of the satellite is assumed to be negligible:  formula_12  where formula_13 is the mass of the celestial body.