This is a remix of the Shuttle and Booster Tank from the Autodesk 123D Gallery. They are interesting (albeit somewhat fanciful) models, but there was no way to connect the two together!
I modeled a set of sliding connectors (female and male) and integrated them with the shuttle and tank using Tinkercad.
Since I was doing it, I put a connector on both sides of the booster, that way you can launch two shuttles at once.
I've uploaded the plate files that contain the tank and shuttle split into segments, so they should print easily. Use support material to be sure, though I don't think the shuttle needs it.
The whole thing would probably benefit from being scaled up before printing 150% or 200%. Many details are too fragile at the current size.
I will probably edit the booster tank model to make the nozzles far more robust, they are currently too fragile to make a good toy.