Hi Tom

you said...
I highly suspect that by the time NASA's new systems are flying, they're going to be almost redundant.

...How much further do you think SpaceX can take their clustered engine approach? The Russians have done well with Proton-class launchers - which is in Falcon 9's range - but the big clusters didn't go so well with the Saturn-class launchers. The N-1s kept failing on the pad. When the Russians did get it right they made wholly new Zenits and Energia. Musk must surely be aiming at those sort of designs for HLLV missions.

By the time he's ready we'll have bucky-tubes strong enough for the Space Elevator - and the first segments will need HLLV...

Adam