The Solar Test of the Equivalence Principle

TL;DR

This paper explores how Earth-Mars ranging can test the strong equivalence principle (SEP) and estimate Jupiter's mass with high precision, offering an alternative to lunar laser ranging.

Contribution

It demonstrates that Earth-Mars ranging can effectively estimate the SEP parameter and Jupiter's mass, providing new methods and accuracy estimates for these measurements.

Findings

Earth-Mars ranging can estimate the SEP parameter η with high precision.

Future Mars missions could achieve an accuracy of (1-12)×10⁻⁴σ for η after ten years.

Ranging measurements will also yield the most accurate Jupiter mass determination.

Abstract

The Earth, Mars, Sun, Jupiter system allows for a sensitive test of the strong equivalence principle (SEP) which is qualitatively different from that provided by Lunar Laser Ranging. Using analytic and numerical methods we demonstrate that Earth-Mars ranging can provide a useful estimate of the SEP parameter $\eta$. Two estimates of the predicted accuracy are derived and quoted, one based on conventional covariance analysis, and another (called ``modified worst case'' analysis) which assumes that systematic errors dominate the experiment. If future Mars missions provide ranging measurements with an accuracy of $\sigma$ meters, after ten years of ranging the expected accuracy for the SEP parameter $\eta$ will be of order $(1-12)\times 10^{-4}\sigma$. These ranging measurements will also provide the most accurate determination of the mass of Jupiter, independent of the SEP effect test.