Combat. Can no one come up with anything else? Is fighting the only thing to do in space?
You're in luck:
http://www.medphys.ucl.ac.uk/~martins/orbit/orbit.htmlI fear there's a chance that you won't find that a fun game, though. Which brings me to a famous quote: "Space is big. Really, really, big."
A very large proportion of computer games
in general are about fighting, and the games that also feature more complex activities tend to have complex environments to make use of. But how do you make a huge empty void into a fun game? Is it any wonder given the number of combat games set on solid ground that the usual solution to the big empty void problem is the same?
Sure you could have a game set on a ship or Space Station (go play the System Shocks or Startopia!), but then the "being in space" bit is almost incidental for the core gameplay. There are also games like MOO2 and "Strange Adventures in Infinite Space" which don't only involve combat, but aren't in 3D. You could have a sci-fi adventure where you need to travel through space to different locations, but if there's no danger in the travelling then it's probably more engaging to set the game on terra firma and have the player travel through something a little less void-like.
Feel free to brain-storm an awesome new space-based game dessign, though. I'm sure there are some good ones out there waiting to be made, I'm just not even remotely surprised that virtually all of the 3D space games out there are combat games.