KSP physics is not like RL physics, and not allow us to develop parts specific made for specific designs like the things involving a shuttle, unless you use mods. So... You have to adapt and change the lifter concept... http://forum.kerbalspaceprogram.com/threads/122320-Shuttle-M3 The only "exploit" in this one are the use of prograde assist right after launch to not flip... and it's basically stock, since the only mod it uses is Adjustable Landing Gear...