Combine two saved rockets in KSP Mac

Solution 1:

As of version 0.22, this is possible with the newly-implemented subassemblies.

In Kerbal Space Program, each saved assembly (rocket, plane or subassembly for either) is stored as a .craft file in a subdirectory of the save folder ({KSP root}/saves/{name of save}/):

• Ships/SPH for Space Plane Hangar constructions
• Ships/VAB for Vehicle Assembly Building constructions
• subassemblies/SPH and subassemblies/VAB for the subassemblies respectivley.

Subassemblies and normal vessels have almost no differences. There is, usually, no need to change anything about the save files - merely move them from one directory to the other.

However, a subassembly requires a free attachment node at the root part. You need to make sure (either through save editing or through in-game editing and saving) that the root part (that is, the part that you first placed and then connected everything else to) has *at least one free attachment node.