“A “single-stage to orbit spaceplane”. That was the original goal of the Space Shuttle ... “
Never designed as single stage.
No, because it was later thought unpractical. But I remember the original NASA broadcasts in the 70’s, just after the final Apollo mission. It was supposed to be a true “space plane” that would take off and land like an airplane. But the difficulties in doing that resulted in the ugly space truck that we got.