You get your own starship and as you level up you get better ones. You have both space battle missions and ground missions where you take 4 other bridge officers as an away team down to planets and asteroids to kill Klings and Orion's as well as other baddies.
It's superbly done and I can't get enough of it. ;)
I played that one for a couple of months. I am playing Star Wars: The Old Republic right now, and it puts everything else to shame. Incredible storyline and good game play.