A new test of gravitational redshift using Galileo satellites: The GREAT experiment

Pacôme Delva (1) , Neus Puchades (2) , Erik Schönemann (3) , Florian Dilssner (3) , Clément Courde (4) , Stefano Bertone (5) , Francisco Gonzalez (6) , Aurelien Hees (1) , Christophe Le Poncin-Lafitte (1) , Frédéric Meynadier (1) , Roberto Prieto-Cerdeira (6) , Benoît Sohet (1) , Javier Ventura-Traveset (7) , Peter Wolf (1)

1 SYRTE - Systèmes de Référence Temps Espace
2 Departamento de Astronomía y Astrofísica
3 ESOC - European Space Operations Center
4 GEOAZUR 7329 - Géoazur
5 UNIBE - Universität Bern / University of Bern
6 ESTEC - European Space Research and Technology Centre
7 European Space and Astronomy Center

We present the result of the analysis of the GREAT (Galileo gravitational Redshift test with Eccentric sATellites) experiment. An elliptic orbit induces a periodic modulation of the fractional frequency difference between a ground clock and the satellite clock, partly due to the gravitational redshift, while the good stability of Galileo clocks allows one to test this periodic modulation to a high level of accuracy. GSAT0201 and GSAT0202, with their large eccentricity and on-board H-maser clocks, are perfect candidates to perform this test. Satellite laser ranging data allows us to partly decorrelate the orbit perturbations from the clock errors. By analyzing several years of Galileo tracking data, we have been able to improve the Gravity probe A test (1976) of the gravitational redshift by a factor of 5.6, providing, to our knowledge, the first reported improvement since more than 40 years.

Domaines: Sciences de la Terre

Pacôme Delva, Neus Puchades, Erik Schönemann, Florian Dilssner, Clément Courde, et al.. A new test of gravitational redshift using Galileo satellites: The GREAT experiment. Comptes Rendus. Physique, 2019, 20 (3), pp.176-182. ⟨10.1016/j.crhy.2019.04.002⟩. ⟨hal-02187651⟩