New Measurements of Gravitation in the Field of the Earth and the LARASE Experiment

We present some of the recent results of the LARASE experiment in terms of the improvements reached in the orbit determination of the LAGEOS and LARES satellites, in the development of new models for the gravitational and non-gravitational forces that produce a deviation of their orbit from that of the ideal keplerian two-body problem of Celestial Mechanics, and, finally, for relativistic measurements and tests of Einstein's theory of General Relativity. In particular, for the non-gravitational perturbations, we focus on the results of a thermal model we have developed to handle the solar Yarkovsky-Schach effect on the orbit of the older LAGEOS satellite. In this case, we also describe the model for the evolution of the spin of the satellite. The results for the model predictions of the orbit evolution are compared with the residuals in the orbit obtained by an independent analysis. Concerning the relativistic measurements, we discuss a new measurement of the precession of the orbit caused by the Lense-Thirring effect. The role of the errors related to the knowledge of the gravitational field of the Earth in this measurement is also discussed.