  In this paper we study the subleading contributions to eikonal scattering in
(super)gravity theories with particular emphasis on the role of both elastic
and inelastic scattering processes. For concreteness we focus on the scattering
of various massless particles off a stack of D$p$-branes in type II
supergravity in the limit of large impact parameter $b$. We analyse the
relevant field theory Feynman diagrams which naturally give rise to both
elastic and inelastic processes. We show that in the case analysed the leading
and subleading eikonal only depend on elastic processes, while inelastic
processes are captured by a pre-factor multiplying the exponentiated leading
and subleading eikonal phase. In addition to the traditional Feynman diagram
computations mentioned above, we also present a novel method for computing the
amplitudes contributing to the leading and subleading eikonal phases, which, in
the large $b$ limit, only involves knowledge of the onshell three and
four-point vertices. The two methods are shown to give the same results.
Furthermore we derive these results in yet another way, by computing various
one-point amplitudes which allow us to extract the classical solution of the
gravitational back reaction of the target D$p$-branes. Finally we show how our
expressions for the leading and subleading eikonal agree with the calculation
of the metric and corresponding deflection angle for massless states moving
along geodesics in the relevant curved geometry.
