Not just that. These are (presumably) telescopes designed for visible-light surface surveillance i.e. 100-200km. What kind of modifications will they need to be useful for long-range astronomical use, where distances are going to be measured in tens of lightyears and imaging in other spectrums?
The Hubble is based on these spy telescopes, so the modifications have already been done (The Hubble is longer which gives it a narrower field of view. ). Currently the plan is to use one of the scopes for wide field infrared studies without much modification.
As a bit of trivia the Hubble could have been replaced with a new telescope using an expendable rocket for less money for every time it was updated/maintained by a Shuttle mission.
“What kind of modifications will they need to be useful for long-range astronomical use, where distances are going to be measured in tens of lightyears and imaging in other spectrums?”
I can’t find any documentation, but my guess is that there will be very little, if any, focal change between 100km and “infinity”.
Secondly, basic earth sciences cameras used in orbit image in many different spectra. Probably not x-ray or far ultraviolet, but lots of frequencies below that.