This is a saturn INT-21. A heavy lifter that can put up to 80 tons into a 400x400Km LEO orbit
It was done using some of the Project Apollo NASSP 6.4.0 meshes
and the scenario to launch the skylab requires you previously to download the Skylab1973 by Usonian at: http://www.orbithangar.com/searchid.php?ID=2976
*****UPDATE 1******
From now on general purpose
fairings are available.
Check the Doc
************************
Santy86