Hello,
I would like to thank everyone that helped tech2000. Because all of you helped me as well.
I am running Kubuntu 7.04 on a AMD64 cpu with 2 gig of ram, and a Nvidia 7600 card.
And I was like a wave pounding on the rocks. That was what I felt like trying to get Celestia running with spacecraft, and other features, visible.
And then I found this thread, and in two hours I have Celestia up and running.
I haven't seen any weird behavior or obvious bugs yet.
Thank you everyone.