Fyron is right, but there is a bit more detail I think you might be interested in..
First, the stellar backgrounds are created in PSP using the Flamingpear Glitteretto, Solarcell and Lunarcell plugins. These are done at a 1024x768 rez.
Second, in bryce I have made a template where there is a 2D object in the background that I map the stellar background to. (with a bit of lighting to make it easier to see.
Third, I import the .3ds Versions of the
Actual ship models that are being used in SE5. I then play around with different compositions and churn out renders.
Fourth, When I make planets in Lunarcell I often like them so much that I save them as planet_map pics that aaron will be able to plug into SE5. So there is a good possibility that you will see many of the planets in my renders in the final game.
This info has been brought to you by "The curious minds fodder of artsville."
Cheers!
