President's Commission on Moon, Mars and Beyond

> Andrew,
> I really see no point to answeryour comments one at the time because
> they shows clearly that 1) you haven't even took a look at the
> proposed system and therefore speak only about prejudices and wrong
> assumptions, and 2) I think I've already answered most of the issue
> you raise already anyway.

I've read the study (albeit a long time ago). It presumes a level of
commitment to space colonization that has never existed and more than
likely never will exist. It also puts a massive technological effort
in the early phases of returning to the moon. Incremental development
works. There is no need to build infrastructure in advance of humans.
Insisting on doing so makes it more likely the project will fail before
anyone even gets to the moon.

> The bottom line is that shipping a seed plant and let it grow is
> cheaper and safer than a manned mission of comparable size that
> involve human operators.

The fundamental problem is that you want to build massive
infrastructure before even establishing where the useful resources are,
and what the markets might be. Incremental development works. Massive
centrally planned projects tend to do poorly.

> The unmanned operation can use all the space and weight required for
> personnel to carry more equipment, you can turn things around as much
> as you like but this simple basic fact won't change.

Nor will the fact that an individual human and associated life support
systems is more flexible and capable than the equivalent mass of
machinery. For exploration and early phases of development flexibility
is an absolute necessity.

> As for the large infrastructure the whole point is that you get them
> effectively for "free" using a seed plant, as it grows and creates
> them for you. The alternative you seem to prefer is to bring up people
> and equipment to make them, and that's surely is not more efficient
> from any point of view.

Why is it harder to build a "self replicating" factory with people
right on site to service it than to do so with the nearest service
personnel 250,000 miles away?

> As for the technology not being there, once again this is simply not
> true, all the technology required is basic industrial technology
> already used everyday in any modern factory.

Not in low gravity, hard vacuum, and exposed to incredibly abrasive
lunar regolith. All of those are going to be major issues for any
plans to develop the moon. That's just one reason why incremental
development is important.

> Try to think of it this way: what would you need to buildthe smallest
> ofmanned permanent bases on the moon?
> List all materials, equipment etc. now consider this: is it going to
> be more than hundred tonnes? That's very roughly the payload of four
> Apollo missions. I seriously doubt you could put up anything with less
> than a dozen times that payload.
> Now with those 100 tons alone you could have a basic system that will
> exponentially grow with a tiny amount of further supply, no more than
> a few tons per year, mostly rare raw elements and a electronics,
> anothing compared to the supply any manned mission would need. With
> this absolutely minimal support(in relative terms anyway) that seed
> would double every year, that's an exponential growth which roughly
> means in ten years time you'll have 102400 tons of working equipment
> in place, plus hundred of miles of paved surface, power lines, storage
> facilities etc, left over and ready to be used for human settlement,
> all at nearly zero cost after the initial investment.
> What would you have left after ten years of continuous spending on a
> manned mission? If everything goes well a square mile of pressurized
> bunker with half a dozen people in it. I don't think the two scenario
> even compare.

The two scenarios don't compare because one of them presumes
near-magical technology. A hundred tons for a seed in-situ resource
utilization plant is incredibly optimistic. All that needs to happen
is a few surprises early on in the program and you have exactly nothing
to show for your effort. If ISRU plants are so straightforward, send
up those hundred tons and a second hundred ton ship with a couple of
crew members to keep an eye on the plant. A basic hab with living
conditions no worse than those on a nuclear submarine ought to mass
less than a hundred tons. Even so, you're putting the cart before the
horse. Explore, then develop.

> As for feasibility, I don't see much point in keep arguing about it,
> to me the conclusion that a government committee drawn after spending
> a dozen millions in feasibility studies are good enough. They thought
> it was possible with 1980 technology, it certainly it isn't any harder
> today. If you doubt this I'd suggest you to read that study first,
> after allit was made by NASA, not by a mad scientist from a badly
> written SF novel... :)

NASA studies in the 1960s clearly showed that the way to make space
travel cheap and routine was to build the space shuttle. In the 1990s
they showed how X-33 would bring massive reductions in launch costs.
NASA studies need to be looked at very closely before one takes them
seriously. In some areas (notably when they aren't looking at billion
dollar programs) they can be quite useful. In others they border on
fantasy.

These sorts of studies are churned out by people who are very smart but
who for some reason ignore the lessons of history. This is close to
home for me, since the fusion community (in which I am a researcher)
has a fondness for this type of study, too. They'll extrapolate trends
way past what's justified, assume perfect government bureaucrats with
no personal agendas, assume ideal funding environment, and show how
amazing technical advances are quite reasonable, assuming no surprises.
Such studies serve a purpose, but they are not reliable guides to what
is realistically possible.

......Andrew