As you all know, I'm pretty big on the Energia/Buran design. It's fairly close to a SSTO vehicle, well maybe a 1 1/2 stage vehicle. The four zenit boosters are single stage and could be made reuseable. The Energia core is also a single stage rocket and goes into orbit along with the Buran shuttle. Here's an idea I've been toying with on how to get the most bang from this design.

Imagine a large dual keel space station in orbit. This station is built by and supplied with large components for deep space infrastructure by a Buran type orbiter. The engines on the Energia are an offshoot of the Integrated Powerhead Demonstrator engines being developed now. These engines are very robust and can be reused many times, so throwing them away on a launcher like Energia would not be very wise. However, as I said earlier, the Energia goes into orbit along with the orbiter.

What if the booster is made in such a way that removing the engines can be done fairly simply by astronauts at the space station? These engines could be removed and stored, then returned to Earth by the next shuttle supply mission to be reused on a later launcher. The rest of the Energia could be broken down and carried to a lunar base by the CEVs, where the materials could be used for any number of things.

What do you all think?