Basically, all space capsules have their of gravity placed in such a way that they will automatically orient themselves heat shield forward once they encounter the atmosphere. So once the service module is gone, it should flip into the correct orientation just by physics alone.
(BTW, this is the same reason why the Crew Dragon spacecraft keeps it's aft section "ring" attached during a launch escape, where it's super draco thrusters drag it to a safe distance from a failing launcher.
The aft ring prevents the capsule from trying to flip over during the abort. Then once in safe distance from the vapor & debris cloud that used to be the launcher, the aft section is jettisoned and the capsule again automatically re-orients itself heat shield forward.)
