Same Problem here. Deconstructed my hub, went to rebuild it.. no hub parts.. Looked in every inventory, can't find it.
And no, reloading won't help. All manual saves and autosaves have disappeared, except for one generated when I logged out to check what saves were available to load.
On the plus side.. I'll have a better idea what I'm doing next pass.
EDIT: OMG I FOUND IT!! It was in a despawn box that I covered with a foundation.. On a whim, I started deconstructing foundations near where I tore down the Hub.. and poof.. crate just sitting there, judging me for burying it..