Yes, there needs to be an ssc file, but Celestia uses all the .ssc files that it finds in the "extras" directory. You don't have to edit solarsys.ssc to add objects.
For a spacecraft that uses an xyz trajectory definition, its ssc file can be quite simple. For example, you can create voyager.ssc which just contains
Code: Select all
"Voyager" "Sol"
{
Class "spacecraft"
Mesh "voyager.3ds"
Radius 0.00085
Albedo 0.7
SampledOrbit "voyager.xyz"
}
Of course, this assumes you also have a voyager 3ds model.
I usually use "galileo.3ds" since I know the Galileo model is shipped with Celestia and I'm usually more interested in watching the things that it flies by.