  We obtain existence and conormal Sobolev regularity of strong solutions to
the 3D compressible isentropic Navier-Stokes system on the half-space with a
Navier boundary condition, over a time that is uniform with respect to the
viscosity parameters when these are small. These solutions then converge
globally and strongly in $L^2$ towards the solution of the compressible
isentropic Euler system when the viscosity parameters go to zero.
