Einstein Gravity Explorer-a medium-class fundamental physics mission

Stephan Schiller (1) , Guglielmo M. Tino (2) , Patrick Gill (3) , Christophe Salomon (4) , Uwe Sterr (5) , E. Peik (5) , A. Nevsky (1) , A. Görlitz (1) , D. Svehla (6) , G. Ferrari (2) , Nicola Poli (2) , L. Lusanna (7) , H. Klein (3) , H. S. Margolis (3) , Pierre Lemonde (8, 9, 10) , Philippe Laurent (8, 9, 10) , Giorgio Santarelli (8, 9, 10) , André Clairon (8, 9, 10) , Wolfgang Ertmer (11) , Ernst Maria Rasel (11) , J. Müller (12) , Lorenzo Iorio (13) , Claus Lämmerzahl (14) , Hansjörg Dittus (14) , E. Gill (15) , M. Rothacher (16) , F. Flechner (16) , Ulrich Schreiber (17) , Victor Flambaum (18) , Wei-Tou Ni (19) , Liang Liu (20) , Xuzong Chen (21) , Jingbiao Chen (21) , Kelin Gao (22) , Luigi Cacciapuoti (23) , Ronald Holzwarth (24) , M. P. Heß (25) , Wolfgang Schäfer (26)

1 Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf]
2 UniFI - Università degli Studi di Firenze = University of Florence = Université de Florence
3 NPL - National Physical Laboratory
4 LKB (Lhomond) - Laboratoire Kastler Brossel
5 PTB - Physikalisch-Technische Bundesanstalt
6 Institute of Astronomical and Physical Geodesy, Technische Universität München
7 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Firenze
8 SYRTE - Systèmes de Référence Temps Espace
9 Métrologie des fréquences optiques
10 Références micro-ondes et échelles de temps
11 Institut für Quantenoptik, Leibniz Universität Hannover
12 Institut für Erdmessung, Leibniz Universität Hannover
13 INFN - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
14 ZARM - Zentrum für Angewandte Raumfahrttechnologie und Mikrogravitation
15 Department of Earth Observation and Space Systems, Delft University of Technology
16 GFZ - GeoForschungsZentrum
17 Fundamentalstation Wettzell
18 University of New South Wales
19 Purple Mountain Observatory
20 Shanghai Institute of Optics and Fine Mechanics
21 Peking University [Beijing]
22 Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences
23 RSSD - Research and Scientific Support Department, ESA-ESTEC
24 MPQ - Max-Planck-Institut für Quantenoptik
25 ASTRIUM Space Transportation
26 TimeTech

The Einstein Gravity Explorer mission (EGE) is devoted to a precise measurement of the properties of space-time using atomic clocks. It tests one of the most fundamental predictions of Einstein's Theory of General Relativity, the gravitational redshift, and thereby searches for hints of quantum effects in gravity, exploring one of the most important and challenging frontiers in fundamental physics. The primary mission goal is the measurement of the gravitational redshift with an accuracy up to a factor 10⁴ higher than the best current result. The mission is based on a satellite carrying cold atom-based clocks. The payload includes a cesium microwave clock (PHARAO), an optical clock, a femtosecond frequency comb, as well as precise microwave time transfer systems between space and ground. The tick rates of the clocks are continuously compared with each other, and nearly continuously with clocks on earth, during the course of the 3-year mission. The highly elliptic orbit of the satellite is optimized for the scientific goals, providing a large variation in the gravitational potential between perigee and apogee. Besides the fundamental physics results, as secondary goals EGE will establish a global reference frame for the Earth's gravitational potential and will allow a new approach to mapping Earth's gravity field with very high spatial resolution. The mission was proposed as a class-M mission to ESA's Cosmic Vision Program 2015-2025.

Domaines: Astrophysique [astro-ph]

Stephan Schiller, Guglielmo M. Tino, Patrick Gill, Christophe Salomon, Uwe Sterr, et al.. Einstein Gravity Explorer-a medium-class fundamental physics mission. Experimental Astronomy, 2009, 23, pp.573-610. ⟨10.1007/s10686-008-9126-5⟩. ⟨hal-03786609⟩