Here’s an excellent adaptation of Savage Worlds to the FireFly universe. I’m a fan of the all-too-short-lived Josh Whedon science fiction series.
EGBZine is an online archive of more than 10,000 pages of Edgar Rice Burroughs goodness — stories, articles, art and more. If you’re contemplating (as I am) a John Carter of Mars game, this is a good place to start.
The Iron Hand site has a tutorial on building a very nice building-sized laser defense battery for 25mm – 28mm science fiction games, such as Warhammer 40K. These would be great as the focal point of a scenario.
Although it was essentially a rip-off of Aliens, as a game, Space Hulk was one of GW’s best game efforts. Here’s a tutorial on building your own 3-D Modular Hulks.
Space Rat is an RPG written by Nathan Russell in just 24 hours. It’s inspired by the cheesy science fiction movies of the 70s. It looks like a lot of fun.