Fundamental physics in the field of the Earth with the laser ranged satellites experiment (LARASE)

Abstract

LARASE represents a new experiment whose main goal is to provide accurate measurements for the gravitational interaction in the weak field and slow motion limit by means of the laser tracking of satellites orbiting around the Earth. Among the various ingredients needed, two of them play a very significant role: i) the quality of the tracking observations of the satellites orbit, and ii) the quality of the dynamical models implemented in a software code whose goal is to minimize, opportunely, an observable function and solve for the unknowns in which we are interested. Indeed, these models have to account for both gravitational and non-gravitational forces in such a way to reduce as better as possible the difference between the observed range and the computed (from the models) one. Of course, the better the minimization process through the orbit data reduction from one side and the better the estimate of the systematic error sources from the other, more precise and accurate will be the a posteriori reconstruction of the satellite orbit. Therefore, LARASE aims to improve the dynamical models of the current best laser-ranged satellites, as well as to improve the error budget estimates of the several perturbations that influence their trajectory around the Earth. This will allow to test in a reliable way Einstein's theory of general relativity with respect to other metric and non-metric theories for the gravitational interaction and to go beyond with respect to the present measurements as well as to the kind of tests carried out so far.