Gravitational Acceleration of Spinning Bodies from Lunar Laser Ranging Measurements

The Sun's 1/c² order gravitational gradient accelerations of Earth and Moon, dependent on the motions of the latter bodies, act upon the system's internal angular momentum. Not only does this gravitational spin-orbit force (which plays an important part in calculating gravity wave signal templates from astrophysical sources) slightly accelerate the Earth-Moon system as a whole, it more robustly perturbs the internal Earth-Moon dynamics with a 5 cm amplitude, synodically oscillating range contribution which is presently measured to 4 cm precision by more than three decades of accumulated lunar laser ranging data.