  We consider the gravity assist maneuver, that is, a correction of spacecraft
motion at its passing near a planet, as a tool for evaluating the Eddington
post-Newtonian parameters $\beta$ and $\gamma$, characterizing vacuum
spherically symmetric gravitation fields in metric theories of gravity. We
estimate the effect of variation in $\beta$ and $\gamma$ on a particular
trajectory of a probe launched from the Earth's orbit and passing closely near
Venus, where relativistic corrections slightly change the impact parameter of
probe scattering in Venus's gravitational field. It is shown, in particular,
that a change of $10^{-4}$ in $\beta$ or $\gamma$ leads to a shift of about 50
km in the probe's aphelion position.
