^^Nobody would be able to submit a manuscript for something like Titan. The spec outline and sample chapters you submit are really more a test of your writing ability, as well as your ability to follow the instructions laid out in the guidelines. If you pass that test, then the editor may offer you a shot at a different project, or invite you to pitch a new proposal. It would be rather unusual for a spec outline to end up as a published book. And of course you shouldn't write a whole manuscript in advance, just the outline and sample chapters.
Basically identical to the Open Submission Policy they had for the TV series TNG, DS9 and VOY. That's how I got in to pitch my first time.
Almost twenty years later ...

--Ted