By apsmith, Section Reviews Posted on Tue Jan 17, 2006 at 06:50:18 AM PST
Thanks to my stint reviewing books for The Huntsville (AL) Times (initiated by relationships formed here on sciscoop!), I received a review copy of Harrison Schmitt's latest book, Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space. I'd actually already purchased a copy for myself as well, since it's priced at just $25 for the hardcover. It's an interesting argument for a lunar return, based on the prospects for helium-3 as a fusion fuel.
Anyway, thanks to Katrina, the Huntsville Times isn't using my book reviews any more - but I did get this one on slashdot! Read on for an edited version of the review.
No matter what the subject, one has to admire a book written by an astronaut and former US senator, illustrated with photos of the author at work on the Moon. When the subject is one as potentially important to the future of our civilization as the energy resources geologist Harrison ("Jack") Schmitt sees buried in the lunar surface, along with our future in space, it becomes all the more daunting to take issue with it. Unfortunately Schmitt's potentially inspiring commercial justification in Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space rests on a shaky foundation.
Schmitt's book acknowledges that context but sets out in a unique
direction, arguing that the Moon will provide a critical contribution
to our civilization's energy needs, and the lunar return discussed
is primarily one of industry and commerce, rather than grand
national programs.
The argument for industrial use of our celestial neighbor hinges
on the utility of helium-3 fusion. However, that technology and the science
behind it is dealt with in a perfunctory 4 pages in this book;
Schmitt leaves the main argument to scientific papers from the
University of Wisconsin
Fusion technology Institute that has been promoting it.
Helium-3 fusion, while having the advantage of lower radiation levels,
is considerably harder than deuterium-tritium (D-T) fusion:
the extra proton in helium means the ideal fusion temperature for
He3-D mixtures is over four times as large. An alternative
hydrogen-boron reaction would require almost 10 times the D-T
temperature. That makes the traditional approaches to fusion reactors,
creating very hot and dense plasmas, essentially impractical for
He3 fusion. Non-traditional inertial electrostatic confinement (for example,
"Farnsworth fusor") technology gets around the high temperature problem by
essentially shooting the nuclei directly at one another in a
steady-state fashion. In principle any kind of fusion is possible
with such a design. However, in practice
the maximum power output obtained so far is 1 Watt - you would
need a hundred of them just to power a light bulb!
So that leaves a huge and unknown technology gap in scaling things
a factor of 1 billion or so to power plant size.
Schmitt lightly skips over this problem with the note that
"much engineering research lies ahead" and then bases an economic
analysis on the assumption that such a plant would have to compete
with fossil-fuel plants; we know roughly the numbers there. This
does provide real constraints on the costs of retrieval of He3
from the Moon, so it's a useful analysis. But there's still the fundamental
question of whether He3 fusion could ever be economically
practical.
Schmitt doesn't let those questions slow him down; cost estimates
for the "much engineering research" piece are folded into capital
cost estimates for building up to 15 fusion plants, building and launching
(and staffing) 15 lunar mining settlements, and operational costs
for the whole system to reach the conclusion that it could, after
the 15th set of facilities was completed, be close to competitive
with electric energy from coal. That's not a bad accomplishment, but
it rests on a lot of assumptions of unstated but likely very high
uncertainty.
Ironically, the best reason for replacing coal, the threat of
global warming from atmospheric CO2 release, is given short shrift
as an "international political issue" in Schmitt's introductory chapter
on our energy future. In this and in a bias toward non-governmental
solutions, Schmitt's text unfortunately betrays the caution
of an incompletely recovered politician.
Organizational approaches are covered in detail in chapter 8, where
Schmitt compares models ranging from all-government
to various public/private partnerships, to an all-private
approach, analyzing each model according to over two
dozen financial, managerial, and external criteria. After giving
each a 1 to 10 rating, he multiplies by another subjective
weighting factor and adds them all up. Somehow, the all-private model
wins every time. The text surrounding these numbers suggests
that, despite what the numbers say, several of the public-private
partnership approaches make a great deal of sense. This ranges
from the Intelsat multilateral model to simply encouraging government
funding of the necessary research, development, and testing, and passing
technology on to private industry to earn a profit.
Schmitt's discussion of lessons from Apollo is almost reverential,
including a proposal for a "Saturn VI" heavy-lift rocket,
to lower launch costs. It seems unlikely that the Apollo conditions can
be duplicated, but he does have an interesting argument in favor of
in-house engineering talent and having a large pool of
young engineers. This and the letters of chapter 10 are perhaps
too bluntly put to have an impact
on NASA directly, but could certainly help inspire organizational virtues
in a private venture, so NASA's more recent mistakes aren't repeated.
There is much that is good here. The book covers some ideas in
detail, including the lunar geology issues for helium-3 recovery.
Designs for mining equipment, the idea of finding
markets first in space, and only later on Earth, and the proposal
to make the miners permanent settlers, rather than just temporary
visitors are all interesting concepts developed here.
The author has included copious citations for more in-depth reading.
Much of the infrastructure Schmitt calls for could be applied
to any other commercial utilization of the Moon, for example to help
develop solar power satellites or lunar solar power facilities, to
provide lunar oxygen (or hydrogen) for in-space use, for lunar tourism,
and so forth. Schmitt believes the He3 approach provides easier
access to capital markets due to lower start-up costs, so less
government involvement may be needed than for those other commercial
justifications for a lunar return. However, the status
of He3 fusion itself
seems sufficiently uncertain that relying on private equity to make it
happen could still be a very slow process, at least once
development reaches the point of billion-dollar space missions.
This vision for a new day in lunar exploration is very different from
what we have been hearing from NASA, even in recent years when a human
lunar return has been on the table. There is considerable evidence
we have an urgent need for new energy sources. The possibility of
exploitation of the Moon for human benefit has hardly crossed public
consciousness yet, but it's something that we will increasingly be turning
to as humanity reaches limits here on Earth. We should all be grateful
Dr. Schmitt has helped here to get that ball rolling.
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