Instead of them being "grounded" and "rusting " away as the Saturn V's on display almost did, strip out the life support systems...lighten them up inwardly as much as possible...and equip them to the max with deployable solar panels, cameras, radar, telescopes...whatever NASA or some other space agency might could come up with and launch them unmanned into a high enough orbit, just like the Hubble, to remain. There should be enough spare equipment left from compatible stock that could make use of a potentially serviceable (at a later time) platform that an unmanned Shuttle could provide. NOT
launching them at the high inclination of the ISS, but on a lower one would provide extra momentum to attain a higher, more permanent orbit. Unmanned, the safety protocols for foam and debris dangers to the tiles would not be required. They could be serviced by whatever hopefully replaces them, private or government operated.
Anyway, it would seem a more respectable way for the shuttles to finish up their service...retired to space.
Just thinking out loud.