I have to admit that some of the information on that page has gotten out of date (though a lot of it is still relevant). Right now the DynamicScene layer is kind of a jumble of objects that store time-dynamic data for visualization and objects that parse CZML into them. In the future, I would like to better separate these two concepts to make it easy for people to store time-dynamic data client side regardless of the original source.
Technically, you can do that now by creating JSON objects that represent parsed CZML, but it’s not as easy as having an “addPositions” property on a DynamicPositionProperty for example. If you care about generating “static” orbits, then just use a Polyline and be done with it. If you need lead/trail times where the length of the orbits grow and shrink as the satellite moves, then that gets a little trickier, but ultimately just means efficiently regenerating the Polyline each time.
The good news is that my plate has freed up a bit and I’m going to have more time to work directly on Cesium again. Improving the DynamicScene layer so that it’s more easily usable when not working with server-generated CZML is one of the main things I’ll be looking at.
I hope this sheds some light on where we are at. Maybe I’ll look into writing up a SandCastle example showing how to do client-side generated CZML; this way we have a good example to point to whenever anyone asks about it.