Jon Goff has a must-read post on what we know and don’t know about reusable launchers, based on some insightful commentary by Jorge Frank.

The real mistake of the space shuttle was not that of attempting a reusable vehicle, nor a winged vehicle, nor a parallel-staged vehicle. The real mistake is that we attempted to build an “operational” vehicle before we had any real idea of what “operability” means in a space vehicle. The alternative – the real “road not taken” – would have been to build small experimental vehicles, starting from suborbital and working our way up, that explore all the different “corners” of the design trade space resulting from this multi-variable problem, and learning, one painful step at a time, what works and what doesn’t. Since these experimental vehicles would neither have carried payloads nor flown operational missions, there would be no attachment to them; they would have flown for a few years each and then retired and replaced with the next X-vehicle, just as happened with all the previous X-vehicles up to and including the X-15.

That approach may or may not have resulted in a truly economical launch vehicle by 2007, but it would surely by now have given us a better picture of what works and what doesn’t than the road we chose. By attempting an “operational” reusable vehicle that by definition would have to replace all the existing “operational” expendable vehicles, we locked ourselves into a path that was difficult to reverse and was expensive enough that we could not afford to replace it in parallel with flying it, necessitating another long and painful gap in our experience base.

And because that one vehicle represents the whole of our operational experience for the last generation, its failure has led many to overgeneralize. The space shuttle is a (partially) reusable, winged vehicle with parallel staging using a cryogenic propellant tank. And it failed to meet its cost, schedule, and reliability goals. Therefore, the reasoning goes, all reusable vehicles are bad, all winged vehicles are bad, all parallel-staged vehicles are bad, all cryogenically fueled vehicles are bad. This is nonsense. Were the emotionally charged names to be replaced with faceless variable names, any competent mathematics professor would reject this logic as faulty, and rightly so.

The latter is a point that I make often in response to the clueless and logic-challenged who think that Shuttle (or X-33) teach us that reusable vehicles aren’t possible.

Jorge’s comments are also a useful insight into what a kludgy compromise the Shuttle design was, and how many of the design choices were driven by other design choices, which were in turn driven by unrealistic requirements, both in terms of performance, and development budget.

As Clark Lindsey points out, we are going to be learning a lot of lessons from the suborbital business and rocket racing that will be directly applicable to orbital vehicles down the road. It’s a tragedy that it’s taken us so long to start this long process. But as long as the process might seem, at least we’re now going in the right direction (that is, to try a lot of different directions, and finally find out what works, and what doesn’t).