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 .

Subject headings : celestial mechanics , stellar dynamics – gravitation – Earth – planets and satellites : Mars – dark matter