Prospects on measuring intrinsic gravitomagnetism with Lunar Laser Ranging

In this note we explore the possibility of measuring the action of the intrinsic gravitomagnetic field of the rotating Earth on the orbital motion of the Moon with the Lunar Laser Ranging (LLR) technique. Indeed, expected improvements in it should push the precision in measuring the Earth-Moon range to the mm level; the present-day Root-Mean-Square (RMS) accuracy in reconstructing the radial component of the lunar orbit is about 2 cm. The Lense-Thirring secular precessions of the node and the perigee of the Moon induced by the Earth’s spin angular momentum amount to 10 milliarcseconds per year yielding transverse and normal shifts of 10− 10 cm yr. The current uncertainty in measuring the lunar precession rates is about 10 milliarcseconds per year. Major limitations come also from some systematic errors induced by orbital perturbations of classical origin like, e.g., the secular precessions induced by the Sun and the oblateness of the Moon whose mismodelled parts are several times larger than the Lense-Thirring signal. Subject headings: Experimental studies of gravity, Moon