  We present measurements of the expansion of Kepler's Supernova Remnant (SNR)
over three epochs of Chandra X-ray observations from 2000, 2006, and 2014. As
the remnant of a historical supernova (observed in 1604 CE), Kepler's SNR
presents the rare opportunity to study the dynamical evolution of such an
object in real time. Measurements of the asymmetry in forward shock velocity
can also provide insight into the nature of the explosion and density of the
circumstellar material. Combining data from 2014 with previous epochs in 2000
and 2006, we can observe the proper motion of filaments along the outer rim of
the SNR. Prior studies of Kepler's SNR have shown proper motion differences up
to a factor of 3 between northern and southern regions around the remnant. With
the longer time baseline we use here, we find results that are consistent with
previous studies, but with smaller uncertainties. Additionally, by adding a
third epoch of observations, we search for any systemic change in the velocity
in the form of a deceleration of the blast wave, as was recently reported in
Tycho's SNR. We find little to no conclusive evidence of such deceleration, and
conclude that Kepler's SNR is encountering circumstellar material that is
roughly constant in density, though substantially varied around the periphery.
