MG15 - Talk detail

Back to previous page

 Participant

Institution

Session

Accepted

Order

Time

Talk

Title

Abstract

The Theory of General Relativity first introduced the concept that space-time is curved by the presence of masses. As a consequence, any signal between two sources passing by a massive body is deflected and therefore experiences a transmission time delay with respect to the straight-line propagation. In the Parametrized Post-Newtonian Formalism - which makes use of a set of Post-Newtonian parameters to describe all metric theories of gravitation that assume Einstein Equivalence Principle - the curvature of space-time is accounted for by parameter $\gamma$. In General Relativity $\gamma=1$. The measure of $\gamma$ is one of the most popular General Relativity tests that have been undertaken since 1919. The current state-of-the-art measure of gamma is $\gamma=1+(2.1\pm 2.3)\times 10^{-5}$, obtained by radio tracking of the NASA/ESA/ASI Cassini-Huygens satellite near solar superior conjunction (Superior Conjunction Experiment - SCE). The ESA/JAXA BepiColombo mission to Mercury will undertake a SCE during its cruise-phase. Thanks to a more advanced telecommunication system, made up of a X/X, Ka/Ka, X/Ka multi-frequency link, BepiColombo will allow range measurements as accurate as 15 cm at 300 s integration time and range-rate measurements at the level of a few microns per second at 1000s integration time. In this work we present the results of numerical simulations of the BepiColombo Superior Conjunction Experiment. With the ORBIT14 orbit determination and parameter estimation software, developed at the University of Pisa, we are able to simulate measurements of range and range-rate of the BepiColombo probe during solar superior conjunction and obtain an estimate of $\gamma$ based on a non-linear least squares fit. Through a thorough and complete analysis, which includes the study of the effect of the presence of systematic errors in the range observables, we show that BepiColombo can improve the result yielded by Cassini up to a factor 10.

Pdf file

Back to previous page