"Airplanes deal in massive mission models while the space models are trivial by comparison. It is easy to make a tentative engineering assessment of this but very difficult to get anyone to pay attention.

Space deals in hundreds of flights per year worldwide. Airplanes deal in millions. If one looks at transport airplane cost analyses, the general massiveness and high vehicle utilization result in the RDT&E and vehicle production cost being a very small portion of the ticket cost.

In space cost analyses, RDT&E reigns supreme. Airplanes operate at 2 to 3 times their fuel cost. If space did the same, the cost would fall by 2 to 3 orders of magnitude! We dream of a vast future in space. But we don't try to encompass it. To do so would involve using vast mission models which are not credible to your boss. Yet they would almost certainly yield different design optimums than the "reasonable" models.

If you dream of massive uses long before they are credible and then optimize the vehicle design for those dreams, you are engineering the dreams - not the current missions. The burgeoning interest in space tourism is the first glimmer of hope for airplane-like massive missions. It is really quite easy to create such vehicle designs - but extremely difficult to generate any credibility for the results in polite engineering society and impossible in science and academia. But it is among those dreams that the space analogy of the Douglas DC-3* resides. If one knew it, the programs could be vectored in that direction. This is what should be done. We've had enough of trivial mission models." ~Maxwell Hunter
"The Engineering of Dreams: The Future of Commercial Space"
published in the National Space Society's magazine " Ad Astra" (September/October issue)