
No, the thing is designed to be retrievable, in a pinch.  Indeed, this
dictated a rather odd design for the solar arrays, since they had to be
retractable as well as extendable, and may thus have indirectly contributed
to the array-flapping problems.

The retrieval problems are exactly as stated:  it would be costly, would
involve extensive downtime (and the worry of someone finding a reason not
to re-launch it), and would unnecessarily expose the telescope to a lot
of mechanical stresses and possibilities for contamination.