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Authors: Lorenzo Iorio

Date: 24 Nov 2008

Abstract: We investigate qualitatively and quantitatively the impact of the general relativistic gravito-electromagnetic forces on hyperbolic orbits around a massive spinning body. The gravito-magnetic field, which is the cause of the well known Lense-Thirring precessions of elliptic orbits, is induced by the spin $\bds S$ of the central body. It deflects and displaces the trajectories differently according to the mutual orientation of S and the orbital angular momentum L of the test particle. The gravito-electric force, which induces the Einstein precession of the perihelion of the orbit of Mercury, always deflects inward the trajectories irrespectively to the L-S orientation. We numerically compute their effect on the range r, radial and transverse components v_r and v_\tau of the velocity and speed v of the NEAR spacecraft at its closest approach with the Earth in January 1998 when it experienced an anomalous increase of its asymptotic outgoing velocity v_\infty o of 13.46 +/- 0.01 mm secˆ-1. The range-rate and the speed are affected by general relativistic gravito-electromagnetism at 10ˆ-2-10ˆ-5 mm secˆ-1 level. The changes in the range are of the order of 10ˆ-2-10ˆ1 mm.

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