I'm surprised that they had to design custom inertial stabilization, considering how many times it's been done successfully before. Was it NIH mentality? Or did it have some requirement for more precise stabilization than other space telescopes?
At a guess, I'd say that most satellites have different requirements due to the way their weight is distributed and where the inertial stabilization is done.
As far as I understand it, Satellite design is all about cramming the most amount of features in as small and light a package as possible. That would mean a lot of tight coupling and a hard time standardizing anything across different types of satellites.
While that's true for science payloads, when it comes to commercial satellites, there are a handful of 'busses' that form the core of the vast majority of satellites.
Commercial payloads are a lot of the time. Science payload have a harder time doing that because the instruments they're designed to carry come in weird shapes and can't really be chopped up and rearranged to fit into the standard satellite bus.
