Speaker
Description
The Galileo for Science Project (G4S_2.0) is an Italian Project funded by the Italian Space Agency (ASI) that aims to provide Fundamental Physics measurements with the Galileo-FOC constellation. These concern both the analysis of atomic-clocks data and that of satellite orbits. A new accurate analysis of the satellites onboard atomic-clocks can lead to two significant results: i) measuring the gravitational redshift and, consequently, making a local position invariance (LPI) test, and ii) searching for possible Dark Matter Domain-Wall of Galactic origin. Conversely, precise orbit determination (POD) of satellites allows the relativistic precessions of satellite orbits to be measured at a much higher altitude than previous measurements with passive geodetic satellites.
In particular, the two satellites GSAT-0201 and GSAT-0202 on elliptical orbits will be exploited for the measurement of the gravitational redshift, as the on-board atomic clocks frequency is periodic-modulated with respect to on-ground clocks. Whereas for the Dark Matter constraints, the entire Galileo constellation will be considered: the goal is to search for interactions with possible Dark Matter candidates, such as Domain Wall, that would cross the entire constellation. If this happens, on-board clocks would have to change their frequency relative to a reference clock on Earth.
Finally, measuring the relativistic precessions will allow to study possible deviations from General Relativity and to compare its prediction with those of other theories of gravitation.
To pursue the goals of G4S_2.0, a fundamental key point in our analysis is obtaining the satellite’s position, as a product of the POD. As a consequence, modeling, as better as possible, the complex effects of the Non-Gravitational Perturbations (NGPs) is essential, such as the direct solar radiation pressure. Many of our efforts go in this direction. The state of the art will be presented, both as regards the measurements of Fundamental Physics and the development of new models for NGPs.
