  This paper studies two perfectly conducting parallel plates in the weak
gravitational field on the surface of the Earth. Since the appropriate line
element, to first order in the constant gravity acceleration g, is precisely of
the Rindler type, we can exploit the formalism for studying Feynman Green
functions in Rindler spacetime. Our analysis does not reduce the
electromagnetic potential to the transverse part before quantization. It is
instead fully covariant and well suited for obtaining all components of the
regularized and renormalized energy-momentum tensor to arbitrary order in the
gravity acceleration g. The general structure of the calculation is therefore
elucidated, and the components of the Maxwell energy-momentum tensor are
evaluated up to second order in g, improving a previous analysis by the authors
and correcting their old first-order formula for the Casimir energy.
