MÉTRIS , Gilles

The MICROSCOPE mission tested the Weak Equivalence Principle (WEP) with an unprecedented precision of order 10-15 , two orders of magnitude better than the previous best lab experiments. While the WEP, the cornerstone of General Relativity (GR), does not sway, the decade-long problems faced by fundamental physics stay still: how can we unify GR...

MICROSCOPE is a space mission launched in 2016 that aims to test the validity of the Equivalence Principle (EP), the main postulate of General Relativity (GR), with a precision never reached before (Touboul et al. (2001)). EP states that two bodies of different compositions and masses fall with the same acceleration in the same gravitational...

The aim of the MICROSCOPE space mission is to test the weak equivalence principle (WEP) with a precision of 10−15, 100 times better than on-ground experiments. The WEP violation signal that we look for in flight has a particular frequency signature and must be extracted from the measurement of accelerations dominated by a colored noise...

The existence of a light or massive scalar field with a coupling to matter weaker than gravitational strength is a possible source of violation of the weak equivalence principle. We use the first results on the Eötvös parameter by the MICROSCOPE experiment to set new constraints on such scalar fields. For a massive scalar field of mass smaller...

This paper introduces the current special issue focussed on the MICROSCOPE mission. This mission is the first experimental test in space of the weak equivalence principle (WEP) using man-made test-masses—as opposed to astronomical tests—with the goal to reach a precision two orders of magnitude better than ground-based experiments. Selected in...

This article is dedicated to the use the MICROSCOPE mission's data to test chameleon theory of gravity. We take advantage of the technical sessions aimed to characterize the electrostatic stiffness of MICROSCOPE's instrument intrinsic to its capacitive measurement system. Any discrepancy between the expected and measured stiffness may result...

MICROSCOPE's space test of the weak equivalence principle (WEP) is based on the minute measurement of the difference of accelerations experienced by two test masses as they orbit the Earth. A detection of a violation of the WEP would appear at a well-known frequency f$_{EP}$ depending on the satellite's orbital and spinning frequencies....

Testing the weak equivalence principle to a precision of 10$^{−15}$ requires a quantity of data that give enough confidence on the final result: ideally, the longer the measurement the better the rejection of the statistical noise. The science sessions had a duration of 120 orbits maximum and were regularly repeated and spaced out to...

After performing highly sensitive acceleration measurements during two years of drag-free flight around the Earth, MICROSCOPE provided the best constraint on the weak equivalence principle (WEP) to date. Beside being a technological challenge, this experiment required a specialised data analysis pipeline to look for a potential small signal...

Since the MICROSCOPE instrument aims to measure accelerations as low as a few 10$^{−15}$ m s$^{−2}$ and cannot operate on ground, it was necessary to have a large time dedicated to its characterization in flight. After its release and first operation, the characterization experiments covered all the aspects of the instrument design in order to...

Odyssey 2 will be proposed in December 2010 for the next call of M3 missions for Cosmic Vision 2015-2025. This mission, under a Phase 0 study performed by CNES, will aim at Neptune and Triton. Two sets of objectives will be pursued. The first one is to perform a set of gravitation experiments at the Solar System scale. Experimental tests of...

This paper focuses on the description of the design and performance of the MICROSCOPE satellite and its drag-free and attitude control system. The satellite is derived from CNES' Myriade platform family, albeit with significant upgrades dictated by the unprecedented MICROSCOPE's mission requirements. The 300 kg drag-free microsatellite has...