There are ways to do what you may want, but you would need to provide more detail. You can pilot Celestia now, using the movement keys. You can fly at any speed, in any direction, etc. Consult the Celestia Users Guide for great details on how to do that. The link to it is:
http://www.celestiamotherlode.net/creators/fsgregs/CelestiaUsersGuide1-5-1.docIf you want to do it in a script, then the trip will be scripted. You will be telling the user (yourself or someone else) where to go, when to go there, what speed to fly at, etc. If that is what you want, then a script can be written to do that, with ... or without response from the keyboard. The preferred script type is called a "celx" script. It is a kind of computer language with specific commands. It takes considerable time to learn properly (days), so you must know what you're doing. Although there are some tutorials on script writing in celx, they assume some familiarity with writing code and are not that easy to grasp the first time through.
FYI
Frank
