  We study the kinematics of galaxies within massive clusters, as a probe of
the physics of star-formation quenching within clusters. Using N-body
simulations, we argue that satellite kinematics provide information about
galaxy infall that is complementary to the (instantaneous) spatial distribution
of satellites. Comparing the simulation results with measurements of real
cluster galaxies, we find evidence that the kinematics of red (quiescent)
satellite galaxies are consistent with earlier infall times than that of blue
(star-forming) satellites.
