This is the code I use for my planetary rings research. It was written a long time ago and needs some attention. I've started refactoring it so that indexing into various pools is more type safe. This is still very much a work in progress. There are also a lot of extra files in here from old student projects that aren't being maintained.
Basically, you probably don't want to use this code unless you are collaborating with me and I'm helping you get it set up.