It is very valid, except a few things have changed since then. The SCI was renamed to the Sherida-Atsu Industrial Group.
The Solaris-class is a fleet-in-being, the Horizon-class is a starbase-in-being. Except mobile.
A particle accelerator... interesting idea. I'd imagine it'd have a pretty hefty salvaging department, not sure about materials reprocessing. Sounds like it might be a job for a logistics ship. But then again, 4.2 km is a lot of space to fit equipment into.
And beeteedubs, a new challenger is approaching in the preview section!