We don't _really_ need Hubble.

We can do better, and are. Both in orbit,
and on the ground. Astronomy will not be
seriously impared by Hubble's demise.

But an updated Hubble using that leftover
mirror and updated instruments/systems could
probably be kept rather busy. Launch it on
whatever unmanned rocket and keep options
open for future servicing.

Hubble is dying after having served us so well;
time to put our efforts into a replacement.

--Damon