Science, Technology and Mission Design for the Laser Astrometric Test Of Relativity

TL;DR

LATOR aims to significantly improve tests of relativistic gravity in the solar system by measuring the Eddington parameter mma with unprecedented precision using laser interferometry and space-based observations.

Contribution

This paper proposes a novel space mission, LATOR, combining advanced laser interferometry and optical design to achieve highly precise measurements of relativistic gravity effects.

Findings

Measurement of mma with one part in a billion accuracy

Detection of scalar-tensor modifications of gravity in the solar system

Design of a space-based laser interferometry experiment for fundamental physics

Abstract

The Laser Astrometric Test Of Relativity (LATOR) is a Michelson-Morley-type experiment designed to achieve a major improvement in the accuracy of the tests of relativistic gravity in the solar system. By using a combination of independent time-series of gravitational deflection of light in the immediate proximity to the Sun, along with measurements of the relativistic time delay on interplanetary scales (to a precision respectively better than 0.1 picoradians and 1 cm), LATOR will measure the key post-Newtonian Eddington parameter \gamma with accuracy of one part in a billion - a factor of 30,000 improvement compared to the present best result, Cassini's 2003 test. LATOR's primary measurement pushes to unprecedented accuracy the search for cosmologically relevant scalar-tensor modifications of gravity by looking for a remnant scalar field in today's solar system. We present a comprehensive discussion of the science objectives, proposed technology, mission and optical designs, as well as the expected performance of this fundamental physics experiment in space.