Fred J. McCall writes:

Can't be done. You have to worry about CG and moment arms for
reboost.


Yeah I was wondering about that too. You need to keep (which one, Zarya?) at
least the core module that provides propulsion at the CG to keep it on orbit.

Unless you design something that can mate to it on-axis to provide reboost
if it becomes inoperable. Would that be preferred/less-costly than fixing
it?

?

Dave