Just a little FYI, the programmer of Starshatter, a decent and fun space Sim (if a little over ambitious and mildly flawed because it was a single developer) has released the source code to the game now that the publisher has stopped selling it. The Mod site hosting the code has also posted the full game as well.
While not cutting edge by today's standards, it's incredibly and easily moddable (there are already full mods of Star Wars, BSG and others) and offers dynamic campaigns, planetary battles and and other cool little things. I am in not affiliated with the program or the website offering the downloads, but I bought the game back when it came out, and have a soft spot for it (quirks and all), especially since space sims have gone out of favor in recent years.
Info about the game can be found here:
http://www.matrixgames.com/products/334/details/Starshatter.-.The.Gathering.Storm
The game, source code and game mods/utilities can be gotten here:
http://www.starshattermods.com/news.php