This is a revision of RotoScan's Space Shuttle model, with most of the major components fixed to be properly manifold and normals corrected (according to both Blender and Slic3r) where needed. I also took the time to un-triangulate much of the models' faces for the sake of easier editing later, if necessary.
I kept everything as close to RotoScan's dimensions and shapes as possible (which is to say, no more than a few hundredths of a millimeter difference). It's not a re-draw, rather it consisted mostly of deleting faces and dissolving-out edges and vertexes and re-creating them a little at a time (so that I always have multiple original vertexes to model against).
The "mid" section of the Orbiter is unchanged from RotoScan's original.
Also, I've included the Blender work files I created during the revision, and a plated .amf.xml of the Orbiter and its Boosters since they're all printed in the same color anyway.
I used Micro Center's "Inland" PLA in white, orange, silver-grey, and black. Didn't print the base with settings as strong as recommended by the original post, but that's okay - if it breaks, that's what superglue is for. :-)