Star Fleet Battles lovers chagrin at the mention, but there's a somewhat simplified version known as Federation Commander, with a free quick play download at Fed Commander website.
Full Thrust is my favorite starship game, but it's played without hexes, which Starmada does, for the most part. Still, if you go to GZG's site, you can free download the game, but I suggest you go with all four books (FT, MT, FB1, and FB2). Use FT as the beginner's version, FB1 as the advanced, new, and improved, with everything else being candy.
Have had Starmada demo'd to me several times, found it as enjoyable as root canal, which I don't mind as much as some. Obviously, HUGE YMMV.
And the original SFB WAS a small pamphlet; it only grew to New York City directory size after years and years of people arguing the meaning of 'is' and the like. ;->=
Doug