I’ve got an update to yesterday’s post, in which I discuss the flawed oil rig analogy. I should add that the submarine analogy is equivalently flawed. If we needed a giant and expensive machine to get an assembled submarine underwater, we might very well be tempted to do underwater assembly. But we don’t.

I’ve discussed this many times before, but Al Fansome has a useful comment over at Space Politics (scroll way down–it’s in the forties):

Other than Bob Zubrin (e.g., the Mars Society), I don’t know of any space advocacy organizations who have made super-heavy-lift a priority. The only reason that super-heavy-lift is a priority now is because Mike Griffin came in and made a command decision. He already knew the answer — ESAS was a facade to justify the decision he had already made.

Let me try to give you a serious response to your question.

Have you thought about how all the truly GREAT engineering projects on this planet have been built?

Let me list a few obvious ones.

– The Pyramids
– The Great Wall
– The Empire State Building
– The Hoover Dam (or pick your favorite dam)
– The Eiffel Tower
– The Kremlin
– The U.S. Capitol Building
– The Statue of Liberty
– The Golden Gate Bridge

They all have at least ONE thing in common. The pieces of each & every one of these great engineering projects were transported to the final site in pieces, and then assembled on site.

Great engineering in enabled by low-cost transportation and the ability to assemble the technology on site.

We are KILLING ourselves by not taking the same approach to space.

Next — think about standard home construction.

1) There are estimated to be more than 100 million homes in America.

http://www.census.gov/prod/1/pop/p25-1129.pdf+Number+of+houses+in+United+States&hl=en&ct=clnk&cd=2&gl=us

Of that number, the estimated number of mobile homes is ~9 million
http://www.census.gov/Press-Release/www/releases/archives/census_2000/001543.html

In other words, well over 90%, or over 90 million, of American “homes” (whether in single family dwelling, apartments, condos, etc.) are assembled by the same method that is used to assemble the great engineering projects. This choice is obviously driven by economics (nobody mandated this result.)

SUMMARY: The large majority of Western and Eastern civilization has been built using the approach of cheaply transporting the pieces of the construction project to the site, and then final assembly at that site.

So, why are we ignoring the dominant traditional approach that is used over the entire planet?

Why are we not assuming that the right way to build our space economy, and to develop the space frontier, is to develop & use reusable launch vehicles to transport things to space at very low costs, and then assemble the pieces on-site.

Mike Griffin gave a speech a couple years ago talking about constructing the great cathedrals in Europe. Well, those cathedrals were transported to the final site in millions of pieces, and then assembled.

We continue to treat space differently than earthly endeavors for contingent reasons of history, not rationality or technology. Thus we get the cargo-cult approach of ESAS, in which NASA attempts to replicate Apollo, except without either the associated urgency, or the budget.

[Update on Sunday afternoon]

Since some people seem to imagine that the oil rig is a useful analogy, let me expand on it. It actually is one, but not in a way advantageous to the heavy-lift fetishists.

Yes, it is assembled in port and then towed to its operational location. But this is in no way analogous to assembling on the ground and launching to orbit. This is because of the huge energy barrier between the two. It’s no big deal to tow something from one place in the ocean to another–that’s a very old technology, and an extensive transportation infrastructure exists with which to do so. Thus, it makes sense to assemble it essentially in the ocean, but near land, to take advantage of the local work force.

But note that what we don’t do with oil rigs is assemble them in Colorado, and then build a humungous custom truck (and associated reinforced roads, with clearances) to move it to the shore and put it in the water. But that’s essentially what people are proposing in saying that things should be fully assembled on earth, and then launched into space, on a giant rocket that flies just once in a while, at a very high cost (particularly after amortizing the development cost).

In space the oil rig scenario would be analogous to having an existing assembly facility in LEO (that had presumably been bootstrapped up), with a robust low-cost transportation infrastructure to get things to and from earth, and from point to point in space. The “oil rig” (or large telescope facility, or prop depot for use at L1) would be assembled there, and then a space tug would move it to its final destination.

This was in fact part of the original vision for the SSF in the eighties. The “dual truss” configuration was intended to act as an orbital assembly hangar. Unfortunately, we didn’t have the transportation infrastructure to support it. But the fact remains that what we need is not heavy lift, but affordable, reliable and frequent lift. Once we get the latter, it will become clear how to best utilize it to accomplish our goals.

A woman Down Under has a novel approach to asteroid management: wrapping it in foil.