I think it's been said by others here, but I'll reiterate as thay are my feelings also.
I would rather Mongoose didn't use someone else's setting (i.e., intellectual property). I can see how that is an easier option for the output of products, despite the outlay for rights. However, the more ambitious, and therefore I feel credible, approach would be to commision a few writers to come up with something original, like what was done with the Imperium of Classic Traveller. (Yes, yes we all know that was inspired by other people's IP such as Asimov's Foundation). There's a lot of sci-fi out there, so it will be hard (impossible?) to be truly orriginal, plus it will take time, but it can still be done (haven't Avenger done just this with their Far Avalon setting?) But pleeeeaase don't base it off of anything that has to do with comics.....