Testing fundamental physics with satellite laser ranging: perspectives and goals of the larase experiment

The aim of LARASE (LAser RAnged Satellites Experiment) is to go a step further in the tests of the gravitational interaction in the field of the Earth (i.e. in the weak-field and-slow motion (WFSM) limit of general relativity) by the joint analysis of the orbits of the two LAGEOS satellites and that of the most recent LARES satellite. To reach such a goal, key ingredients are high-quality updated models for the perturbing non-gravitational (i.e., non-conservative) forces acting on such satellites. A large amount of Satellite Laser Ranging (SLR) data of LAGEOS and LAGEOS II has been analyzed using a set of dedicated models for satellite dynamics, and the related post-fit residuals have been analyzed. A parallel work is ongoing in the case of LARES that, due to its much lower altitude, is subject to larger gravitational and non-gravitational effects; the latter are in part mitigated by its much lower area-to-mass ratio. Recent work on the orbital analysis of such satellites is presented, together with the development of new, refined models to account for the impact of the subtle and complex non-gravitational perturbations. The general relativistic effects leave peculiar imprint on the satellite orbit, namely in the secular behavior of its three Euler angles. Recent results are provided, together with updated constraints on non-Newtonian gravitational dynamics.