>>10839222The genius of Buran-Energia is that they were in no way locked into the design like Shuttle was.
They could have completely changed the orbiter in any way and it would have flown fine so long as it could remain bolted to the side of Energia and didn't weigh too much. Energia could have launched a vehicle meant to go from Earth orbit to the Moon, land, and return, similarly to Saturn V or N1. It could have launched large space station modules or even complete stations a la Skylab.
As others have pointed out, they could have also changed the Energia rocket itself to allow for reusability options. There were already plans for designing a flyback booster, which Energia would use 4 of. A different configuration turned the entire core stage into a giant orbiter which carried payloads in its nose, taller than the original Energia and with stubby wings but otherwise the same. Fully reusable Energia was possible, though it would have cut pretty hard into payload mass, but even if it cut it all the way down to just 40 tons per launch that's still enough to allow for a Moon landing mission in just two launches, so if their reusability technology turned out cheap to maintain they could have had access to a remarkably low cost-to-orbit super heavy lift system.
Reusable Energia wouldn't have beat Starship Super Heavy by any means of course, but it'd have shit on everything else at the time, Shuttle especially, and would have probably led to an international Moon base rather than the eventual development of the ISS we have today.
