If you want to do a Traveller-esque magazine, but can't (or would rather not) get into a licensing agreement with Marc and FFE, you might consider the option of doing a d20 future/sci-fi generica type thing. Considering the OGC already available in things like T20, Dragonstar and other sci-fi genre d20 products, and your stated interest in d20, it shouldn't be that hard to do.
Going the generica route also vastly increases your target audience, since you'd add players of Dragonstar, Star Wars d20 and the other offerings in the genre to your audience of T20 players. That's not even considering the d20 Future expansion to d20 Modern that Wizards is doing late this year or early next.
Now, this does mean of course that you would have to be considerate of the IP of all the Traveller licensees and owners (FFE, SJG and QLI especially) and wouldn't be able to do articles specifically for OOP Traveller rules sets right off the bat, but it depends on what your goals are. Once you are an established zine, it's also possible that you would have an easier time getting permissions to do the occasional Traveller specifc article. I'm not a publisher or a lawyer, so I don't know the specifics, but remember that magazines like Dragon and Different Worlds once published Traveller articles, so the possibly certainly exists.