Currently running Mongoose Traveller, just recently wrappedc up a SW SAGA game, and I too have Starblazer and considering giving it a try. My problem is how similar FATE mechanics are to Traveller, so thinking of just adapting it to Traveller.
I'm currently running a Sufficiently Advanced campaign. Very hard SF, set in a post humanist setting, several thousand years in the future.
Best of all, it's 100% free.
Fantastic system and a very cool setting too.
You can download it (legally and aboveboard) here
I'm totally loving it.
Cool! Our "Thursday Irregulars Group" has been running various systems for about 6 week periods for a couple of years now, glad to see other people doing the same, on Maptools as well!
Would you count Rifts or Shadowrun as a generic sci fi?.
I think Sci Fi's big problem is it doesn't have a "standard" race mix like fantasy does, or a staple set of creatures that's generic enough. At this point and time, every science fiction universe is pretty unique; a common world hasn't yet been created that has unified sci fi, much like Tolkien's works did..
Very hard SF, set in a post humanist setting, several thousand years in the future.