There's a technical description of how the one gyro control system here https://ntrs.nasa.gov/api/citations/20080023344/downloads/20...
Essentially using other sensors (star tracker and magnetometer) and kalman filtering for sensor fusion.
Essentially using other sensors (star tracker and magnetometer) and kalman filtering for sensor fusion.
I doubt it'll be from spacewalks on Dragon, given they probably can't support something as big as an MMU (unless they pull a really cool hat trick), but maybe with Starship.
I get that at some point it's more worthwhile to launch a new telescope (maybe one of those donated KENNENs from NRO), but Hubble is a big symbol of space exploration, and SpaceX is all about big symbols...