  One of the challenges in connecting higher dimensional theories to cosmology
is stabilization of the moduli fields. We investigate the role of a Lorentz
violating vector field in the context of stabilization. Specifically, we
compute the one loop Casimir energy in Randall-Sundrum 5-dimensional
(non-supersymmetric) S^1/ Z_2 orbifolds resulting from the interaction of a
real scalar field with periodic boundary conditions with a Lorentz violating
vector field. We find that the result is an enhanced attractive Casimir force.
Hence, for stability, positive contributions to the Casimir force from branes
and additional fields would be required to counter the destabilizing,
attractive effect of Lorentz violating fields.
