Relativity Experiments in the Solar System

Recent theoretical works on alternative metric theories of gravity give greater significance to solar-system tests of General Relativity. In particular, it is suggested that the post-Newtonian parameter $\gamma$ ought to be determined with great precision in order to discover possible preferred frame effects or effects related to a tensor-scalar theory of gravitation. In this work we focus on a future experiment, based on Doppler tracking of an interplanetary spacecraft near superior conjunction.