Lockheed’s Star Clipper was a proposed Earth-to-orbit spaceplane based on a large lifting body spacecraft and a wrap-around drop tank. Originally proposed during a USAF program in 1966, the basic Star Clipper concept lived on during the early years of the NASA Space Shuttle program, and as that project evolved, in a variety of new versions like the LS-200.
The LS-200 was very similar to the earlier version, it was smaller overall, The M-1 engines were replaced with the Space Shuttle Main Engines.