Tests of Gravity with Future Space-Based Experiments
  Future space-based tests of relativistic gravitation-laser ranging to Phobos,
accelerometers in orbit, and optical networks surrounding Earth-will constrain
the theory of gravity with unprecedented precision by testing the
inverse-square law, the strong and weak equivalence principles, and the
deflection and time-delay of light by massive bodies. In this paper, we
estimate the bounds that could be obtained on alternative gravity theories that
use screening mechanisms to suppress deviations from general relativity in the
solar system: chameleon, symmetron, and galileon models. We find that
space-based tests of the parameterized post-Newtonian parameter $\gamma$ will
constrain chameleon and symmetron theories to new levels in the solar system,
and that tests of the inverse-square law using laser ranging to Phobos will
provide the most stringent constraints on galileon theories to date. We end by
discussing the potential for constraining these theories using upcoming tests
of the weak equivalence principle, and conclude that further theoretical
modeling is required in order to fully utilize the data.
